Past REU Projects and Abstracts
2017 REU Projects and Abstracts (top)
Zainab Ali - University of California at Berkeley - Title needed (Mentors: Phillip Freda and Theodore Morgan).
Audrey Arner - Pennsylvania State University - Molecular Evolution and Physiological Adaptations in Response to Oxidative Stress in Poecilia mexicana (Mentors: Nick Barts, Ryan Greenway, and Michael Tobler).
Emily DeFelippis - The New School - Emily DeFelippis in the Greenhouse with the Flower Pots of Helianthus maximiliani Sunflowers Exhibiting Genome Size Variation (Mentor: Mark Ungerer).
Henry Escobar - University of Kansas - The Effect of Cold Acclimation on Survival and Reproduction in Drosophila melanogaster (Mentors: Elizabeth Everman and Theodore Morgan).
Edwin Harris - Beloit College -Parental Allocation in High Risk Habitats: Grasshopper Sparrows Tradeoff Clutch and Egg Size Within Season, but Do Not Respond to Parasitism or Predation Risk (Mentor: W. Alice Boyle).
Noah Mustafa - Oklahoma State University - The Effects of Tallgrass Prairie Management Practices on Ascelpias spp., an Important Danaus plexippus Host Plant (Mentor: Gail Wilson).
Anna Nagel - University of Minnesota - Mechanisms of Local Adaptation in Ecotypes of the Dominant Prairie Grass Andropogon gerardii Across a Precipitation Gradient (Mentor: Loretta Johnson).
Matthew Nieland - Morningside College - Soil N availability can promote copiotrophic over oligotrophic growth in tallgrass prairie: Results from a culture-for-diversity study (Mentor: Lydia Zeglin).
Spencer Parish - Yale University - Fit Freeloaders: Cheaters Arise in Populations of Agrobacterium tumefaciens Evolved in Environments with Plant Cues and Opines. (Mentor: Tom Platt).
Braiam Rosado - Turabo University - Influence of Brown-Headed Cowbird (Molothrus ater) Parasitism on the Nest Success of Three Focal Species of Grassland Songbirds (Mentor: W. Alice Boyle).
Darrien Savage - Kansas State University - Protecting Bird Biodiversity in Altered Landscapes: Nest Site Selection and Vegetation Structure in Grassland Songbirds (Mentor: W. Alice Boyle).
Liz Telleria - California State Polytechnic University Pomona - How Useful Is Fire After the Regime Shift?: An Assessment of Fire Impacts on Woody Species Following Decades of Fire Suppression (Mentor: Jesse Nippert).
Jordan Trant - Lyon College - Penium margaritaceum, an Emerging Model System to Study Land Plant Evolution (Mentor: Katherine Schrick).
Project Abstracts - 2017
Zainab Ali (University of California at Berkeley), Phillip Freda, and Theodore Morgan. Title needed. As organisms age, the environmental conditions they are exposed to constantly fluctuate, which results in differential selection across ontogeny. Specifically, each life stage is exposed to an often drastically different thermal environment. This effect becomes amplified in organisms that undergo complete metamorphosis and have complex life cycles. A complex life cycle is one in which life stages exhibit unique morphologies, physiologies, and behaviors. With such life cycles being so distinct from one another, it is possible that thermal responses evolve independently within each one. To explore whether it is possible for life-stage specific evolution of a fitness-related trait, thermal hardiness, we measured heat hardiness in both larvae and adults from isogenic lines of the Drosophila Genetic Reference Panel (DGRP), using survival at stressful high temperatures as the phenotypic metric. We discovered no significant correlation for heat hardiness between life stages in individuals reared at 18°C and 25°C, which suggests independent evolution of thermal hardiness in larvae and adults. In addition, we found that organisms reared at higher temperatures (25°C) fared much better in the stressful high temperatures than those reared at cooler temperatures (18°C). Further data analysis yielded the result that larvae are more heat hardy than adults. Comparison to a previously done study showed us that cold and heat hardiness are not correlated in adults, but are correlated in larvae reared at 18°C. The lack of phenotypic correlation regarding heat hardiness between life stages is an important consideration in evolutionary models of response to climate change. The specifics of genetic decoupling of environmental sensitivity across ontogeny in other organisms remains largely unexplored, and will require further quantitative or population genetic analysis in additional species.
Audrey Arner (Pennsylvania State University), Nick Barts, Ryan Greenway and Michael Tobler. Molecular Evolution and Physiological Adaptations in Response to Oxidative Stress in Poecilia mexicana. Physiological adaptation to various abiotic environmental conditions is ubiquitous, but the mechanisms through which such adaptations occur are often elusive. Natural systems in which different populations of the same species have evolved to inhabit contrasting environmental conditions are conducive to testing hypotheses about mechanisms of adaptation by comparing population specific responses to environmental stressors. To investigate mechanisms of adaptation to extreme environments, we studied Poecilia mexicana, a small livebearing fish. Some populations of P. mexicana have colonized environments rich in toxic hydrogen sulfide (H2S), differing from ancestral populations living in benign freshwater streams and rivers. H2S is lethal in micromolar concentrations to many organisms due to its inhibition of cytochrome C oxidase (COX), Complex IV of the mitochondrial electron transport chain. One of the major functions of COX is the trapping of reactive oxygen species (ROS) produced during metabolism. Therefore, ROS formation should increase when the complex is blocked by H2S. Since H2S toxicity is partly derived from ROS, we predicted differences in ROS production between populations of sulfidic and nonsulfidic fish, potentially giving rise to the elevated H2S tolerance in the sulfidic fish. Additionally, we expected genes associated with oxidative stress to bear evidence for positive selection. To test these hypotheses, ROS production was directly quantified in multiple tissues of individuals from each population after exposure to varying levels of H2S. We tested for positive selection on our focal genes by comparing the rates of nonsynonymous to synonymous mutations. H2S exposure experiments did not reveal significant differences in ROS production between the sulfidic and non-sulfidic populations. However, 64 genes showed evidence for positive selection, of which three had identical nonsynonymous point mutations shared across the three evolutionary independent sulfidic populations. In addition, twelve nonsynonymous point mutations were found to be deleterious, suggesting a change in protein structure with functional consequences. Together, our results demonstrate that adaptation to extreme environments is complex, involving multiple genes and pathways, and that different lineages of closely related populations can adapt to identical conditions through differing mechanisms.
Emily DeFelippis (The New School) and Mark Ungerer. Emily DeFelippis in the Greenhouse with the Flower Pots of Helianthus maximiliani Sunflowers Exhibiting Genome Size Variation. While nuclear genome size is known to vary considerably among different plant species, the extent to which genome size can be variable among populations of the same species is not well understood. The Large Genome Constraint (LGC) hypothesis predicts that populations experiencing natural selection for more rapid growth and reproduction should evolve a smaller genome size due to a negative correlation between genome size and cell division rate. We assess this hypothesis by studying genome size variation and growth rate variability in the widely distributed perennial sunflower Helianthus maximiliani. Prior flow cytometric work revealed that genome size decreases with increasing latitudes among four populations originating from Texas, Kansas, North Dakota, and Manitoba, in a common garden greenhouse study with 16 to 20 plants per population. To determine whether these populations also differ with regard to growth rate and biomass allocation consistent with the LGC hypothesis, we have monitored plant height over time and biomass allocation measures of Leaf Mass Ratio (LMR) and Root Mass Ratio (RMR). We found trends indicating that sunflowers from more northern populations exhibit more rapid growth as predicted by the LGC hypothesis. The biomass allocation for the North Dakota and Manitoba populations actually reveal that variation of the Leaf Mass Ratio (LMR) and Root Mass Ratio (RMR) are both negatively correlated with latitude for these two populations. Cell Production Rate (CPR) data gathered from measurements of fluoresced cell lengths as determined by the laser scanning microscope appear to show a trend that seed embryos from the more northern populations, such as North Dakota, grow faster than those from the more southern populations of Kansas and Texas that have been assessed so far. Our results provide general support for the Large Genome Constraint hypothesis and suggest environmental conditions and corresponding selection-induced growth patterns through which genome size may evolve at the population level within species.
Henry Escobar (University of Kansas), Elizabeth Everman, and Theodore Morgan. The effect of cold acclimation on survival and reproduction in Drosophila melanogaster. Survival and reproduction as aspects of fitness are important to test when attempting to identify the mechanisms that increase phenotypic responses. We used a diverse population of Drosophila melanogaster to conduct cold tolerance and mating behavior experiments on. We tested cold tolerance by acclimating flies and introducing them to mild and harsh cold stresses. We found that developmental acclimation and short term acclimation improved cold tolerance. Overall, short-term acclimation had greater relative benefit for flies reared under warmer conditions. We tested mating behavior by exposing groups of flies to one of four cold exposure treatments then conducting a mating assay by mating all the combinations of short-term acclimated and non-acclimated flies. We also found that cold exposure negatively influenced the occurrence of courtship in cases where flies reared under warm conditions were exposed to a cool experimental temperature. Overall, there doesn’t appear to be a reproductive cost to increased cold tolerance through developmental acclimation.
Edwin Harris (Beloit College) and W. Alice Boyle. Parental Allocation in High Risk Habitats: Grasshopper Sparrows Tradeoff Clutch and Egg Size Within Season, but Do Not Respond to Parasitism or Predation Risk. Ecological factors drive much variation in avian reproductive strategy, including inter- and intraspecific variation in clutch size and egg mass. In many Passerine species, female birds invest less in reproduction under high predation risk . However, there are many causes of nest failure, and under high risk from other factors, we expect similar reduction in parental allocation to occur. One source of nest failure that has not been explored in this context is brood parasitism by species such as brown-headed cowbirds (Molothrus ater). Cowbird chicks’ aggressive begging displays may attract predators, increase competition for food among nestlings, and increase energetic costs on parents, all of which could elevate risk of nest failure. Cowbirds parasitize nests of a wide variety of birds, and have a long coevolutionary relationship with many grassland species. Therefore, we predicted that in grassland environments, females would invest less in clutch size and egg mass to nests that were parasitized by cowbirds, or located in high risk habitats. We studied Grasshopper sparrows (Ammodramus savannarum) at the Konza Prairie Biological Station in northeastern Kansas. We located 126 nests between 2014 and 2017, and quantified clutch size and parasitism, and measured eggs at each of them. We monitored nests until they fledged or failed by checking them every 2-3 days, and conducting video observation. 46% of nests were parasitized, and 25% fledged successfully. Neither parasitism nor eventual nest fate was associated with variation in clutch size or egg mass. However, clutch size increased and egg mass decreased over the breeding season, indicating that birds may trade-off forms of investment, allocating more resources to fewer offspring as the season progresses. The surprising lack of association between allocation and risk could be due to insufficient spatial variation in risk, or to the unpredictability of parasitism and predation that prevents females from responding adaptively.
Noah Mustafa (Oklahoma State University), Eric Duell, and Gail Wilson (OSU). The Effects of Tallgrass Prairie Management Practices on Ascelpias spp., an Important Danaus plexippus Host Plant. Due to large-scale land-use changes in the tallgrass prairie, such as conversion to row crop agriculture, monarch butterfly (Danaus plexippus) populations have drastically declined over the last two decades. The monarch’s host plants, common milkweed (Ascelpias syriaca) and butterfly milkweed (Asclepias tuberosa), have declined in parallel with the monarch. While it is known that milkweed is an essential plant for the monarch’s larval and adult stages of their lives, not many studies have been conducted in regards to assessing long-term management practices on health and quality of milkweed species. My study was conducted on Konza Prairie Biological Station near Manhattan, Kansas to assess various management practices on plant performance of Ascelpias syriaca and A. tuberosa. I measured various plant metrics such as plant vegetative and reproductive biomass, plant defense characteristics such as latex production and foliar trichome density, and plant floristic qualities such as nectar production and quality. Ascelpias syriaca populations were selected in areas receiving annual or infrequent burning (4 year), or annual burning and fertilization (nitrogen). Populations of Asclepias tuberosa were selected in annual or infrequently burned watersheds or infrequently burned (3 year) and cattle-grazed. Annual burning increased vegetative and reproductive biomass production, and number of flowers and fruits per ramet, compared to infrequent burning, of A. syriaca. However, annual burning decreased trichome density (mm2). Fertilization increased latex production and nectar quality, but not nectar quantity, compared to areas not fertilized. Vegetative biomass production of A. tuberosa was not affected by burning or grazing. However, annual burning or grazing increased number of flowers per stem. Similar to A. syriaca, annual burning decreased trichome density, compared to grazed or infrequent burning. Understanding milkweed responses to grassland management is essential for monarch survival and growth, and could benefit milkweed conservation efforts, and ultimately provide cascading aid towards monarch butterflies.
Anna Nagel (University of Minnesota) and Loretta Johnson. Mechanisms of Local Adaptation in Ecotypes of the Dominant Prairie Grass Andropogon gerardii Across a Precipitation Gradient. It has long been recognized that interspecific variation in plant communities affects ecosystem productivity, stability, and resilience. Recent work has shown that intraspecific variation can have an even greater effect than interspecific variation on plant communities. Intraspecific variation is often the result of local selective pressures, leading to local adaptation. However, most studies of intraspecific variation in the field have a limited ability to uncover mechanisms of local adaptation. Andropogon gerardii, the dominant grass species in tallgrass prairie ecosystem, exhibits local adaptation to a precipitation gradient and occurs as wet and dry ecotypes its home sites of southern Illinois (SIL) and central Kansas (CKS), respectively. Here, we characterize the effects of intraspecific competition between ecotypes of A. gerardii in watered and drought treatments in a greenhouse experiment. We hypothesize that when the wet and dry ecotypes are grown together, the CKS ecotype and SIL ecotype will perform better when droughted and well-watered, respectively, as compared to when grown with their own ecotype. CKS and SIL ecotypes were grown in pots (4 plants/pot, 4 replicates, total 80 pots) in mixed ecotype and single ecotype combinations for five weeks, the last three of which were under drought conditions (watered approximately every six days compared to semi-daily for controls). Metrics of plant productivity and stress included height, SPAD (chlorophyll absorbance), Fv/Fm (dark adapted chlorophyll florescence), and photosynthetic rate. Prior to transplanting into multi-plant pots, SPAD and photosynthetic rate were significantly higher for the CKS ecotype compared to the SIL ecotype. There is no support for an effect of ecotype combination on response variables after five weeks of growth in multi-plant pots. SIL ecotypes were taller than CKS, and heights were reduced with drought for both ecotypes. SIL ecotypes showed lower Fv/Fm. For both ecotypes, Fv/Fm increased under drought. SIL had lower photosynthetic rates compared to CKS but only when droughted. SIL had lower SPAD, and both ecotypes increased SPAD under drought, especially for SIL. Combined, these results suggest that ecotypes of Andropogon gerardii have functionally different growth strategy tradeoffs. The dwarfed CKS ecotype has enhanced physiological performance under drought compared to SIL, while the tall SIL ecotype is less tolerant of drought. There was no evidence of differential competitive effects due to intraspecific variation, though longer timescales may be needed to elucidate these responses. This work provides additional evidence that local selection pressures have resulted in local adaptation and the development of ecotypic differences.
Matthew Nieland (Morningside College) and Lydia Zeglin. Soil N availability can promote copiotrophic over oligotrophic growth in tallgrass prairie: Results from a culture-for-diversity study. Anthropogenic alterations to tallgrass prairie ecosystems, such as fire suppression and nitrogen (N) enrichment, alters N availability for soil-dwelling bacteria that have a vital role in supporting plant and other microbial growth by degrading recalcitrant and complex organic materials in the soil. Community composition and microbial biomass change as a result, suggesting shifts in copiotrophic (r-selection) and oligotrophic (k-selection) growth patterns. Because a release from N limitation can increase maximum cellular growth rates, allowing copiotrophic populations to become competitively dominant and deplete available carbon (C), this can potentially disturb the soil C cycle. To determine whether prolonged land management practices have changed soil bacterial growth rates and efficiencies, growth curves and CO2 respiration were measured from bacterial isolates cultured from soil sampled from a 30-year field experiment of historical burning and N addition, as well as a recent N fertilizer application, from Konza Prairie Biological Station, Kansas, USA. We expected that average bacterial growth rates would be higher, and growth efficiencies lower, in strains isolated from soils with higher N availability (unburned, fertilized soils). 145 pure cultures representing 13 families within 6 bacterial (sub)phyla were isolated using eight different media types. Growth rates in more concentrated nutrient broth were higher in strains isolated from recently fertilized soils, and growth rates in dilute nutrient broth were higher in strains isolated from soils with the lowest N availability, as predicted. Variability in growth rates also increased in amended N plots. There was a positive relationship between cell density and respiration, with some isolates showing enhanced growth efficiency, but we did not observe the predicted negative relationship between growth rate and efficiency. Overall, the results show that with direct N fertilization, faster growing soil bacteria, corresponding to copiotrophic growth, are favored. Results also support the hypothesis that burning and fertilizer absence maintains ambient N levels, suppressing copiotrophs and allowing greater prevalence of oligotrophic growth patterns. N enrichment can induce the risk of more-readily available C being depleted via faster microbial growth, affecting aboveground net primary productivity, and further altering the prairie ecosystem.
Spencer Parish (Yale University), Courtney Sharp, and Tom Platt. Fit Freeloaders: Cheaters Arise in Populations of Agrobacterium tumefaciens Evolved in Environments with Plant Cues and Opines. Cooperative systems are often vulnerable to invasion by cheaters, genotypes that avoid cooperative costs but can access cooperative benefits. Agrobacterium tumefaciens is a plant pathogen that exhibits cooperative behavior during pathogenesis. We run an evolution experiment on populations of A. tumefaciens evolving in four separate environments varying with respect to the presence of cooperative public good resources and plant cues stimulating expression of the cooperative behavior (with or without opines and with or without plant phenolics) over 120 generations. Our research examines in what conditions under which cheaters evolve and the phenotypic differences between these evolved strains and wildtype A. tumefaciens. To investigate the phenotypic differences between these evolved populations, we assayed their retention of opine catabolism by growing strains in media with opine as the sole nutrient source and we assayed their retention of virulence by exposing potato discs to the populations to examine their ability to induce tumors. A. tumefaciens evolved in environments with plant cues but no opines often lost both their virulence and opine catabolic phenotype, while those that had evolved in environments with both opines and plant cues retained the opine catabolic phenotype while similarly losing the virulence phenotype. Furthermore, preliminary data indicate that the avirulent mutants displayed a significant fitness advantage when competed against wildtype A. tumefaciens. Despite this, approximately 10% of evolved strains in environments with phenolics retained the ability to express the genes associated with a key component of cooperative pathogenesis. This suggests frequency dependent selection that favors maintaining the virulent phenotype, the mechanism for which is unknown and a topic for future investigation.
Braiam Rosado (Turabo University) and W. Alice Boyle. Influence of Brown-headed Cowbird (Molothrus ater) parasitism on the nest success of three focal species of grassland songbirds. Populations of North American grassland songbirds have decreased drastically compared to other bird species and these decreases mean the survival of many birds species is at risk. Grassland birds are among the most threatened guilds of North American birds, and one potential driver of their declines is low nest success. Nests fail due to storms, predation, and the direct effects of parasitism by brood-parasitic Brown-headed Cowbirds. Cowbirds do not build their own nests, but lay eggs in the nests of other host species, often removing host eggs or young which can result in abandonment. Little is known, however, about how parasitism might affect predation risk. Cowbird chicks beg loudly and their fast growth rates require frequent delivery of food by parents. Therefore, increased noise and activity might lead to more or different types of predation at parasitized nest. We studied nests of three grassland songbirds: Grasshopper Sparrows (Ammodramus savannarum), Dickcissels (Spiza americana), and Eastern Meadowlarks (Sturnella magna). We predicted that the parasitism would negatively affect nest success, and specifically, increase risk of nest predation. We also explored whether the presence of cowbirds influenced the identity of predators. We searched for nests at the Konza Prairie Biological Station and monitored them every 2-3 day until nests fledged or failed. At a subset of nests, we placed a small, concealed video camera recorded the activity at the nest allow us to measure parental visits and the identity of predators. We found and monitored 54 sparrow, 58 Dickcissel, and 30 meadowlark nests between early May and mid- July 2017. Similar proportions of parasitized and unparasitized nests ultimately failed (~67%). Success of all nests was not affected by cowbird parasitism, and using only nests that failed after chicks hatched, those that contained cowbirds were ~20% less likely to fail due to predation, counter to our prediction. We used data from 13 nests monitored by video to determine predator identity. Of those nests that were depredated (7), 100% of those were attacked by snakes, regardless of whether nests contained cowbirds or not. We found no evidence that the parasitism affects nest success. We also found that the presence of parasitic chicks in the nest of our three focal species did not increase chances of predation. In fact, trends in the data were the reverse; 53% of unparasitized nests were destroyed by predators, whereas only 34% of parasitized nests failed due to predation. The fact that snakes were to sole predators of nests in this study could explain why parasitized nest failed at similar rates as unparasitized nest; the increased begging and parental visits resulting from parasitism may not be the cues that snakes use to locate they prey.
Darrien Savage (Kansas State University) and W. Alice Boyle. Protecting Bird Biodiversity in Altered Landscapes: Nest Site Selection and Vegetation Structure in Grassland Songbirds. Land management is critical to the persistence of declining grassland songbirds due to the strong effect on vegetation structure and composition. Some evidence from one grassland species suggests that during the crucial post-fledging period, survival is higher in areas with less dense vegetation, despite nest success typically being higher in such areas. However, the densities of different grassland-nests species vary considerably between areas having different vegetation structure. We have an incomplete understanding of the effects of vegetation structure on nest selection and nest success across taxa. We found and monitored the success of nests of the three dominant grassland-nesting species at Konza Prairie from May-July, 2017: Grasshopper Sparrows (Ammodramus savannarum), Dickcissels (Spiza americana), and Eastern Meadowlarks (Sturnella magna). We measured the micro-habitats surrounding successful and unsuccessful nests within a week of nest completion, quantifying the percentage of plant functional types and vegetation density at multiple locations with our vegetation plots. We also measured the same vegetation metrics three times during the season at randomly-located points within focal watersheds. We analyzed data collected at 40 successful and 93 unsuccessful nests, and 54 random points, in multivariate analyses, using PCA to identify vegetation characteristics associated with points of different types. We found that despite considerable overlap in vegetation characteristics, random points, and nests of the 3 focal species differed in habitat associations. However, successful and unsuccessful nests did not differ in ordination space. Unsurprisingly, in analyses including random points, we detected changes in vegetation over the season. However, in analyses of sites used by birds, we found no evidence of directional changes over time, implying that as the landscape changes around them, birds nest site preferences remain unchanged. Our results, derived from nest data across diverse land management types, are consistent with (a) Dickcissels selecting habitat that may be suboptimal for fledgling survival, and (b) other species selecting habitats in which Dickcissel fledglings thrive. Determining whether other grassland species’ nest selection might be shaped by post-fledgling needs will require additional tracking and monitoring of fledgling survival across species.
Liz Telleria (California State Polytechnic University Pomona) and Jesse Nippert. How Useful Is Fire After the Regime Shift?: An Assessment of Fire Impacts on Woody Species Following Decades of Fire Suppression. In the central Great Plains in North America, frequent fire is a key regulator of tallgrass prairie. Long periods of infrequent fire facilitate the conversion of herbaceous-dominated grassland to woody-dominated shrubland or woodland. At the Konza Prairie Biological Station in north-east KS, USA, one infrequently-burned portion of the landscape has undergone transformation from grassland to woodland following nearly 40 years without fire. In the Spring, 2017, a controlled burn was implemented to assess fire effectiveness following a vegetative state change. Much of the woody encroached watershed was not affected by the burn, which led to patchy mortality of multiple woody species. Geographic coordinates including topography, aspect, and elevation, and plant traits including damage from fire, height, and diameter were measured for multiple species. Height among species was classified into juvenile, adult, and super adult. Species height class and topographic location influenced the percent mortality following the fire. Species in a low height class experienced a greater amount of damage than those in higher height class. Species mortality varied by topographic position on the landscape; some species were more susceptible to fire in uplands than lowlands, while others showed no pattern with topography. These results can help inform grassland management focused on reversing woody encroachment, and provide insight relevant for broader ecological understanding of woody encroachment on grasslands throughout the world.
Jordan Trant (Lyon College) and Katherine Schrick. Penium margaritaceum, an Emerging Model System to Study Land Plant Evolution. Charophycean Green Algae (CGA) are uniquely situated as the closest ancestors of the land plants, with many structural similarities such as the presence of a plant cell wall. In comparison to the model system Arabidopsis thaliana, the CGA Penium margaritaceum is a simple unicellular organism of the Zygnematales that contains many important plant-specific genes, albeit with less genomic redundancy. Its similarity to land plants and overall simplicity make it an ideal model to study the emergence of drought-tolerant properties of the epidermis that were necessary for the transition from water to land. We focused on a transcription factor gene, called a Class IV Homeodomain Leuine-Zipepr (C4 DH-Zip), that is critical for epidermal cell differentiation in land plants, although its function in the CGA is not known. While there are 16 family members in Arabidopsis, only one is present in Penium, making it an ideal system to elucidate the original function of this gene family. To examine the resultant phenotypes from overexpression of the C4 HD-Zip gene in Penium, we performed an already existing Agrobacterium-mediated transformation protocol. In addition, work is in progress to test a protocol for Penium protoplasts, followed by transformation and regeneration of the cell wall. Using transcriptome data and the predicted sequences from a related Zygnemetale, Spirogyra pratensis, primers were designed for the Penium C4 HD-Zip gene and amplified from genomic DNA and cDNA. We successfully adapted a simple DNA extraction protocol used for Arabidopsis to Penium, as well as another plant protocol for RNA extraction from both normal and nitrogen-starved Penium, followed by cDNA synthesis. Sequencing of cDNA fragments from Penium is currently in progress. The goal of this work is to gain an understanding of molecular mechanisms that are critical for survival in changing environments. Penium and other close relatives will continue to serve as ideal model systems to study the initial adaptations for life on land, and how early plants dealt with extreme drought. Faced with global climate change, these adaptations for survival need to be understood to be able to accurately predict future responses plants might have to modifications in their environments.
2016 REU Projects and Abstracts (top)
Michael Blazanin - University of Minnesota - Twin Cities - Host cues establish selective conditions favoring the experimental evolution of avirulent agrobacterial cheaters (Mentor: Thomas Platt).
Jennifer Delzeit - Kansas State University - The effect of cold stress on reproductive behavior in Drosophila melanogaster (Mentors: Elizabeth Everman and Theodore Morgan).
Mira Ensley-Field - Macalester College - Diel Variation of Leaf Temperature and Stable Carbon Isotope Ratios in Simulated Browsed Dogwood Shrub Islands (Mentor: Jesse Nippert).
Evan Keep - Milwaukee School of Engineering University - Transcriptomic Analysis of Diapause Expression Across Species (Mentor: Greg Ragland).
Paige Krupa - University of Nebraska-Lincoln - Influence of nearby conspecifics upon display behavior in Acris blanchardi (Mentor: Eva Horne).
Jamie Ladner - Kansas State University - Polyploidy and diversity in Phlox: unusual patterns of genome size in P. nana Nutt. (Polemoniaceae) (Mentors: Mark H. Mayfield and Carolyn J. Ferguson).
Emmi Mueller - University of Michigan-Ann Arbor - Soil Microbial Diversity and Ecology in Response to Nitrogen Additions (Mentor: Lydia Zeglin).
Sarah Mueller - University of Puget Sound - Rangewide Multilocus phylogeography Pygmy Shrews (Sorex hoyi) (Mentor: Andrew Hope).
Alexander Okamoto - University of Chicago - Variation in male genital morphology within and between populations of Poecilia mexicana during ecological speciation (Mentor: Michi Tobler).
Laura Reyes - University of California-Santa Cruz - Characterizing Expression of Cytochrome P450 Genes in Frankliniella occidentalis (Mentors: Dorith Rotenberg, Derek Schneweis, and Anna Whitfield).
Elizabeth Renner - Augustana University - The effects of small impoundments on headwater prairie stream macroinvertebrate and fish community structure (Mentor: Keith Gido).
Lauren Spahr - Liberty University - The interactive effects of annual climatic variability and rangeland management on the reproductive success of Dickcissels (Mentor: Brett Sandercock).
Project Abstracts - 2016
Host cues establish selective conditions favoring the experimental evolution of avirulent agrobacterial cheaters. Michael Blazanin (University of Minnesota - Twin Cities), Spencer Parish, and Thomas Platt.
Cooperation often involves the production of a public good, wherein individuals contribute to the costly production of a resource that is widely available. The cooperative pathogenesis of the generalist plant pathogen Agrobacterium tumefaciens is conferred by genes encoded on the Ti virulence plasmid. Infection by A. tumefaciens involves genetic transformation of plant host cells and causes the plant to release nutritious opines. Catabolism of these opines requires another set of genes carried on the Ti plasmid. However, public goods provide an opportunity for cheaters who do not pay the cost yet receive the benefits of cooperative action. To better understand the genetic mechanisms and environmental conditions allowing for the origin of cheating in this system, we experimentally evolved populations of A. tumefaciens with or without vir-gene induction by a plant cue, and with or without opine nutrients. Pathogenesis gene expression consistently and rapidly declined over time among all populations evolving in environments in which vir-genes were induced, yet opine catabolic function was only rarely lost. These results suggest that de novo mutation can readily introduce cheating phenotypes that successfully invade initially-cooperative populations in environments where plant cues are present and that selection efficiently eliminated costly gene expression while maintaining beneficial functions.
The effect of cold stress on reproductive behavior in Drosophila melanogaster. Jennifer Delzeit (Kansas State University), Elizabeth Everman, and Theodore Morgan.
Drosophila melanogaster is a model organism employed for genetics, physiology, evolution, and behavioral biology. We have previously characterized the survival response to varying thermal stressors using a panel of naturally derived inbred lines of D. melanogaster. Although this stress response has been demonstrated to be genetically variable and important for survival, there have been very few studies that have actually evaluated how stressful environments affect D. melanogaster’s behavior. Previous research suggests that seasonal changes in temperature negatively effects behavior, but the effect of short-term stress is unknown. In this study, we exposed male flies to a short-term cold stress and evaluated this effect on their efficiency at mating, courtship behavior, and their ability to produce song when put in a vial with a female. In our experiment we only exposed male flies to the short-term stress because previous experiments showed that cold stressing females does not significantly affect the female’s ability to choose her mate, while cold stressing males affected the male’s ability to successfully mate with a female. Our hypotheses were that stressed males are less efficient at courtship and thereby less efficient at producing song. Female D. melanogaster are known to prefer song with pulses that are close together, and stressed males were expected to produce unattractive song with lengthened pulses. In this experiment we found that cold stress does affect the male’s ability to mate as compared to the control males, but does not affect their interest in courting a female when all elements of courtship are considered. Further, stressed males and control males sing approximately the same amount during courtship. However, the control flies do produce more attractive song early on in courtship, allowing them to spend less time courting the female than the stressed males do. The stressed males produce more attractive song only at the end of the courtship meaning they spend a longer time actually courting the female. The initial quality of the pulse song in stressed and control males has a large impact on the overall mating success of our experimental flies, and suggests that, in natural settings, males that experience even short-term fluctuations in temperature may experience decreased mating success.
Diel Variation of Leaf Temperature and Stable Carbon Isotope Ratios in Simulated Browsed Dogwood Shrub Islands. Mira Ensley-Field (Macalester College) and Jesse Nippert.
Cover and abundance of woody plants are increasing in many grasslands of North America and worldwide, often to the detriment of species richness and ecosystem functions. Research into the causes, impacts, and management strategies of woody encroachment is therefore of the utmost interest and importance to grassland ecologists worldwide. One management practice currently being studied at Konza Prairie Biological Station (KPBS) is simulated browsing pressure on roughleaf dogwood (Cornus drummondi) shrubs. Our study compares diel variation in leaf temperature as well as δ13C of dogwood shrubs that have been browsed against those that have not been browsed. We hypothesized that leaf temperatures in browsed shrubs would be higher due to increased solar radiation and acute plant stress, and that browsed shrubs would exhibit a higher δ13C indicating lower stomatal conductance. Once a week, leaf temperatures were measured at 6 AM, noon, 6 PM, and midnight using an IR radiometer. Stable carbon isotope ratios were assessed on new leaves every two weeks. Leaf temperatures of browsed shrubs in an unburned watershed were cooler than unbrowsed shrubs at 6 AM, but warmer at 6 PM than unbrowsed shrubs. During the noon and midnight hours leaf temperatures did not differ between browsing treatments. Leaf stable carbon isotope ratios in browsed shrubs were lower than in unbrowsed shrubs indicating more open stomata. Evaluating and quantifying the effects of simulated browsing on woody plants is crucial to gain a physiological understanding of the mechanisms associated with why woody encroachment is occurring and to identify potential management strategies.
Transcriptomic Analysis of Diapause Expression Across Species. Evan Keep (Milwaukee School of Engineering University) and Greg Ragland.
Diapause is a hormonally controlled seasonal response to environmental cues that results in developmental arrest, enabling arthropods to avoid unfavorable environmental conditions. Diapause can occur in all life-stages, although any given species typically has only one diapausing stage. Many insects utilize diapause for various purposes at different stages in their life cycles. Recently, a significant amount of transcript-level expression data regarding diapause has become available with the rise of efficient technologies such as RNA-seq. Here I used this data to test the hypothesis that there is a conserved, core set of transcripts that are universally up/downregulated during insect diapause. By using systematic statistical analysis of orthologous transcripts across species, the evolution of diapause-related gene expression was examined. In addition, I explored the relationship between groups of genes and their physiological processes, adding to an overall scientific knowledge of the mechanisms of dormancy control. A combination of RNA-seq and microarray transcript-level expression data in both diapause and non-diapause conditions was gathered from independent researchers for 11 different species of insects from 3 different orders. Orthology was determined using a BLAST-based pipeline. First, gene models were developed, and sequence files pre-processed before utilizing a combination of “Reciprocal Best Hit” and “Reciprocal Smallest Distance” BLAST methods against the model organism D. melanogaster. To examine gene expression changes between non-diapause and diapause-inducing environmental conditions a combination of the statistical programming language R and Bioconductor packages were used to transform and analyze expression data. Most orthologous genes displayed higher expression in non-diapause than in diapause conditions. Two genes were found to be universally downregulated in non-diapause conditions, FlyBase genes Ctr1A and Pdp1. These genes are known to regulate circadian rhythm and heart rate in D. melanogaster. Furthermore, genes were identified in which a statistically significant number of species showed the same direction and/or degree of regulation. The data set was divided into evolutionarily closely related groups of which K-means clusters were developed and functionally enriched with DAVID. When testing all 11 species, 4 clusters were identified. Of these, three were more likely to show downregulation during non-diapause conditions, and one was more likely to show the inverse. The processes used provide a useful set of methodologies for the generic identification of orthologs from low-quality fragmented transcript data. Various groups of genes have been identified as useful candidates for further analysis, with the potential to increase understanding of patterns of diapause control across species.
Influence of nearby conspecifics upon display behavior in Acris blanchardi. Paige Krupa (University of Nebraska-Lincoln) and Eva Horne.
Visual displays have been recorded in twelve families of anurans and are usually found in diurnal species living in environments where high noise levels interfere with vocalizations. Displays are performed in both agonistic and courtship encounters. Arm-waving and leg extensions are most common during agonistic bouts between males. Displays are also performed by males to advertise their location to females. In some species, females reciprocate displays to find males and visually signal in agonistic encounters with other females. Blanchard’s cricket frogs, Acris blanchardi, exhibit both visual and acoustic displays during breeding season. Although past research has focused on acoustic displays, little is known about visual signaling in the species. I tested the hypothesis that the sex of nearby conspecifics influences display behavior. I set up four experimental treatments: 1) one male, 2) one male with one or more females, 3) multiple males, and 4) multiple males with one or more females. Each replicate was filmed for 45 minutes. Display behaviors and basic activity were enumerated for each individual. Because in previous studies visual displays were concurrent with choruses, I also collected data to characterize some conditions under which choruses occur. The average number and length of choruses decreased over the sixteen days of the study, while increasing from afternoon to sunset each day. The number and length of choruses also decreased with increasing substrate temperature. Display behavior did not significantly differ between the four treatments. However, visual displays occurred most frequently in the multiple male with female(s) treatment; one display also occurred in the multiple male treatment. This result indicates that male-male bout interaction seems to be the most common form of visual display. However, a male in the one male treatment and a female in the one male with female(s) treatment exhibited brief visual displays. These instances suggest that perhaps visual displays are not limited to male-male interactions.
Polyploidy and diversity in Phlox: unusual patterns of genome size in P. nana Nutt. (Polemoniaceae). Jamie Ladner (Kansas State University), Mark H. Mayfield, Alan Prather, and Carolyn J. Ferguson.
Cytotypic variation is prominent in the genus Phlox. The species P. nana is of particular interest because diploid, tetraploid and hexaploid populations occur across parts of the species’ distribution in the desert southwest, and factors favoring the polyploids are poorly understood. A recent study highlighted two areas wherein inference of cytotypic patterns has been challenging: the Davis Mountains region of West Texas, and a site on the Pecos Plains of New Mexico (“Caprock”). Plants in these areas have presented unusual genome size measurements that did not enable clear inference of ploidy levels. One reason for the unusual patterns could be that multiple ploidy levels are present at these sites. Such mixed cytotype populations have not been documented in P. nana, but they do occur in closely related species. Another cause could be the presence of B chromosomes. These small non-coding chromosomes would increase the genome size of the organism. This study intensively sampled these areas from 2015-2016, with increased sampling of sites within the Davis Mountains and individuals at the Caprock site. Flow cytometry was used to estimate the genome sizes of samples. Three instruments were utilized, and several different plant taxa were used as internal standards. Chromosome counts were conducted to confirm ploidy levels. Evidence to date supports the presence of diploid and tetraploid individuals at one site (a mixed cytotype population). Chromosome counts on a sample from another site confirms the presence of B chromosomes. This study promises not only to clarify patterns of cytotypic diversity in these particular areas, but will focus ongoing study to improve our understanding of the ecological and genetic factors that promote polyploid establishment.
Soil Microbial Diversity and Ecology in Response to Nitrogen Additions. Emmi Mueller (University of Michigan-Ann Arbor) and Lydia Zeglin.
Changes in land management influence nutrient availability in soils. Nitrogen (N) availability limits the growth of biota in many ecosystems, including the tallgrass prairie, and while negative effects of N availability on soil microbial diversity have been observed, the mechanisms are not well understood. It is known that bacteria can be broken down into two life history categories: copiotrophic organisms, which have high growth rates, grow quickly in high nutrient conditions, but are maladapted to metabolize complex carbon, and oligotrophic organisms, which grow slowly because they use energy to synthesize expensive enzymes for digesting less labile carbon in low nutrient environments. I predicted that increased growth of copiotrophic bacterial populations in response to short-term N addition would cause a decrease in bacterial diversity, and that the effects would scale with the N added and the background N available in the soil due to historical land management treatments. Field soil samples were collected from the 30-year Belowground Plot Experiment (BGPE) at Konza Prairie Biological Station, where field plots are subject to different burning regimes and fertilization. Soil samples from the BGPE were divided into five subsamples and subjected to addition of different N concentrations (as NH4NO3) in the laboratory. During the 12-day incubation, microbial respiration (CO2 loss from soil) was measured daily as a proxy for the use of available soil carbon sources. After the incubation period, DNA and RNA were extracted from all soils. DNA yield was quantified as a proxy for total soil microbial biomass. The copy numbers of bacterial 16S rRNA gene per g soil were quantified as a proxy for bacterial population growth, and numbers of bacterial ribosomes (16S subunit) were quantified as a proxy for the bacterial protein production. Also, sequencing of the bacterial microbiome (MiSeq libraries of 16S rRNA genes and ribosomes) was used to measure changes in community composition and diversity. As predicted, I observed evidence of larger ambient bacterial populations in field treatments with more background N availability and greater bacterial growth with laboratory N addition. However, these changes were not proportional to the amount of N added and were not consistent across the field treatments. The prevalence of copiotrophic organisms within soil bacterial communities appears to vary qualitatively with N availability, but quantitative population growth responses may be related to carbon availability or other unmeasured factors. Further analysis of microbial community composition may provide more insight into these factors.
Rangewide Multilocus phylogeography Pygmy Shrews (Sorex hoyi). Sarah Mueller (University of Puget Sound) and Andrew Hope.
Cycles of glaciation during the Quaternary period drove diversification of many species through repeated episodes of allopatry and sympatry. Many boreal mammals distributed across North America show a common pattern of distinct Western and Eastern clades, reflecting a primary phylogeographic break in the Mid-west. One such species is the pygmy shrew (Sorex hoyi). A recent preliminary molecular assessment suggested that this shrew was actually two species: western (S. hoyi) and eastern (S. thompsoni). However, this was based only on a single mtDNA locus, and there remain additional disjunct populations that have yet to be sampled. In particular, the specific status of an isolated population centered in the Rocky Mountains of Colorado remains unresolved. The Southwest has been shown to harbor distinct regional diversity across many taxa, in some instances at the level of independent species. Our goal was to determine the status of this Southwest population of shrews in relation to western and eastern species. We obtained rangewide samples including the Colorado population and sequenced three independent loci from the mitochrondrial and nuclear genomes. Phylogenetic genealogies and species tree provide further support for recognition of Eastern and Western clades as separate species, with genetic divergence of 3.3% falling within the range of other sister species of shrews. The Southwestern population is a modestly divergent clade within the Western species, S. hoyi, but not a distinct species. Of two individuals from North Dakota, within the contact zone of the Eastern and Western clades, one belonged to the Eastern and one to the Western clade, suggesting that hybridization has the potential to occur where recently diverged species meet. The Mid-west may therefore be a critical area for understanding speciation processes.
Variation in male genital morphology within and between populations of Poecilia mexicana during ecological speciation. Alexander Okamoto (University of Chicago) and Michi Tobler.
Male genital morphology is one of the most rapidly evolving traits in internally fertilizing species. Male live-bearing fishes of the family Poeciliidae are characterized by the gonopodium, a modified anal fin, used to transfer sperm to the females. Poecilid gonopodia are morphologically complex, exhibiting variation in the number and position of ornaments and weapons across species. Fishes in the Poecilia mexicana species complex have independently colonized toxic hydrogen sulfide-rich springs in multiple tributaries of the Río Grijalva in southern Mexico. Sulfide spring fishes are reproductively isolated from ancestral populations in adjacent non-sulfidic habitats. Several barriers to gene flow have been documented in this system, yet they are not sufficient to explain observed levels of reproductive isolation. Variation in male gonopodia morphology between populations could be serving as an additional reproductive barrier. In this study, we quantified variation in gonopodia between sulfidic and non-sulfidic populations of P. mexicana in order to test for lock-and-key mechanisms. We also investigated variation within populations associated with different male mating strategies. These analyses were replicated across four pairs of sulfidic and non-sulfidic populations to determine whether gonopodia morphology has evolved in convergence. We assessed male body size and shape, as well as the size and shape of isolated gonopodia for each of our focal populations. We found a negative allometric relationship between gonopodium length and body length related to male mating strategy. Our results provide no clear evidence for lock-and-key mechanisms between sulfidic and non-sulfidic populations. However, there is a consistent pattern of within population variation in gonopodia, with larger males exhibiting more ornamentation. Several mechanisms of sexual selection could be driving convergent evolution of male gonopodia morphology in P. mexicana. Future studies on the functional consequences of different gonopodia morphologies and the reproductive success of different male mating strategies are necessary to elucidate the processes generating evolutionary convergence in gonopodia structure.
The effects of small impoundments on headwater prairie stream macroinvertebrate and fish community structure. Elizabeth Renner (Augustana University) and Keith Gido.
Low-order headwater prairie streams provide critical habitat for lotic fishes and aquatic macroinvertebrates. Unfortunately, these streams are experiencing hydrologic disturbance as aquifers are drained and small impoundments are constructed for watering livestock, irrigation, flood control, and recreation. The influence of these small impoundments on macroinvertebrate and fish communities is not yet well understood. The purpose of this study was to analyze the influence of small impoundments on the macroinvertebrate and fish communities in headwater streams within the Tallgrass Prairie National Preserve near Strong City, KS. We hypothesized that seston levels would be significantly higher downstream of ponds, which would translate into increased biomass of filter-feeding macroinvertebrates. We also hypothesized that macroinvertebrate and fish richness would decrease downstream of ponds and that there would be a greater percentage of centrarchids in pond-influenced reaches. To test these hypotheses, we sampled 12 100-meter stream reaches, divided into 6 sites influenced by ponds upstream and 6 control sites. Macroinvertebrate samples were taken at each site on two separate sampling events in June and July 2016 from pools using a stovepipe benthic corer and from riffles using a Surber sampler. The fish community was sampled in June 2016 via backpack electroshocker and seining. Seston and benthic organic matter samples were collected and the stream habitat was characterized for each site. There was no significant difference in seston levels (p = 0.626) or filter-feeder biomass (p = 0.346) between control and pond-influenced reaches. Ponds had no detectable effects on downstream macroinvertebrate communities. There was no significant difference in species richness between control and influenced reaches for either the core (p = 0.672) or surber (p = 0.168) samples. Moreover, we found no significant difference in fish species richness between control and influenced reaches (p = 0.0503). Our results suggest that the macroinvertebrates that inhabit headwater prairie streams are resilient in the face of disturbance, which could explain why impoundments had little effect on them. The decline in species richness at influenced sites suggests that the habitat fragmentation generated by impoundments is detrimental to stream fishes. It is important to recognize that detecting shifts in community structure generally requires multiyear sampling efforts. Future studies should examine how communities respond to multiple impoundments over the course of a stream continuum to determine whether there is a compounding pond effect and analyze whether the distance downstream of an impoundment influences macroinvertebrate and fish community structure.
Characterizing Expression of Cytochrome P450 Genes in Frankliniella occidentalis. Laura Reyes (University of California-Santa Cruz), Dorith Rotenberg, Jonathan Oliver, Derek Schneweis, and Anna Whitfield.
Frankliniella occidentalis, the Western flower thrips is an herbivorous insect that has a broad geographic and plant host range. F. occidentalis is the first species in the orderThysanoptera to have its genome sequenced. Recent research efforts have focused on annotating the F. occidentalis genome to enable studies aimed to elucidate the function of thrips genes in biological, ecological and evolutionary contexts. In addition, the genome provides much-needed sequence information for gene target selection for RNA-interference-based pest control strategies. Cytochrome P450 genes are conserved across insect and other animal species with roles in development and detoxification and these genes were annotated as part of the thrips genome project. The goal of this work is to characterize changes in expression of these genes in F. occidentalis across life stages and after insect feeding on different food sources. Our first objective was to examine gene expression of six cytochrome genes at different F. occidentalis developmental stages. We hypothesized that gene expression will follow the same trend seen in the RNA-seq work by Schneweis and Rotenberg. Thrips were first collected at larval (L1), pupal (P1), and adult (A1) stages. RNA was then extracted from whole bodies and midgut tissue, and gene expression analysis was performed using qRT-PCR. For our second objective, after feeding, we characterized the gene expression of cytochrome P450 genes within an expansion within the CYP6 family. We hypothesized differential expression of these genes as F. occidentalis fed on tomato leaves, green beans, sucrose, and Nicotiana benthamiana leaves. Adult (A1) thrips fed on the different food sources for 48 hours and were collected every 12 hours; RNA was extracted and qRT-PCR performed for gene expression analysis. This gene expression characterization will broaden our understanding of the functionality of cytochrome genes in F. occidentalis and allude to which gene targets to use for possible RNAi-based control as a thrips control strategy.
The interactive effects of annual climatic variability and rangeland management on the reproductive success of Dickcissels. Lauren Spahr (Liberty University), Bram Verheijen, and Brett Sandercock.
Many species of grassland songbirds have experienced long-term population declines due to intensive rangeland management, habitat fragmentation, and conversion of prairie to crop land, all of which reduce reproductive success. Factors contributing to reproductive success include availability of appropriate cover in which to build nests, abundance of insects to feed young, and effects of brood-parasitism by Brown-headed Cowbirds. Patch-burn grazing has been proposed as a rotational burning scheme that increases vegetative heterogeneity in pastures managed for cattle production by burning land in patches, rather than all at once. Although this alternative management scheme has increased reproductive success in some bird species, existing studies fail to take into account annual variation in climatic conditions in tallgrass prairie systems. During a six year study in the summers of 2011-2016, we measured the reproductive success of Dickcissels on five pastures within the Konza Prairie Biological Station: three pastures are managed with patch-burn grazing (PBG), one is annually burned & grazed (ABG), and one is annually burned but ungrazed (ABN). We located nests by observational methods and opportunistic flushing of incubating females. Once located, we monitored nests to completion and recorded the number of eggs and young for Dickcissels and cowbirds. We estimated daily survival rates with nest survival models available in the RMark package in R, and linked estimates of daily survival to rangeland management type and mean temperature and annual precipitation from the long-term databases of NOAA and Konza LTER. We found that daily survival rate of Dickcissel nests tended to be lower for the ABG treatment than for the PBG and ABN treatments. Daily nest survival was best predicted by the model including mean temperature, winter season precipitation, and their interaction, which had 7.5 times more support than the constant model. Even in dry years, PBG units had higher daily survival rates than the ABG unit did in wet years, although these differences were not significant. Mean annual temperature was negatively correlated with daily survival rates. Thus precipitation and temperature play important roles in reproductive success, and accounting for changing climatic conditions is an important step in developing management schemes for the tallgrass prairie ecosystem.
2015 REU Projects and Abstracts (top)
Project Abstracts - 2015
Laura Reyes - University of California-Santa Cruz, CA - Exploring the Thrips’ Gut Response to Tospovirus Infection. (Mentors: Anna Whitfield, Dorith Rotenberg, and Derek Schneweis)
Katherine Culbertson - Harvard University, MA - Got Carbon? Investigating Organic Nutrient Sources Among Biofilm and Sediment Microbial Communities throughout a Prairie Stream Network. (Mentors: Allison Veach and Lydia Zeglin)
Nicholus Ledbetter - University of Central Arkansas, AR - The persistence of the effects of cold acclimation on nineteen inbred lines of Drosophila melanogaster. (Mentors: Elizabeth Everman and Ted Morgan)
Yisel Marquez - Weber State University, UT - Effects of severe storms on grassland birds. (Mentor: Alice Boyle)
Anna O’Hare - Oklahoma State University, OK - Grassland restoration following removal of non-native invasive grasses. (Mentor: Gail Wilson)
Sarah Winnicki - Denison University, OH - Aggregation of Grasshopper Sparrow (Ammodramus savannarum) territories: a test of the extra pair mating and cooperative care hypotheses. (Mentor: Alice Boyle)
Roberto Carrera-Martínez - University of Puerto Rico, Mayagüez, PR - Invasive plants and earthworms: Conspiracy for ecosystem domination? with new reports of earthworms at Konza and for the Western Hemisphere. (Mentors: Mitchell J. Greer, Bruce A. Snyder)
Mitchell Czerwinski - Illinois State University, IL - Does dominant grass removal alter species recruitment in restored tallgrass prairie? (Mentor: John Blair)
Robert Harris III - Carleton College, MN - The Effect of Management Regime on Sex Ratios among Regal Fritillary (Speyeria idalia) Populations in the Central Great Plains. (Mentors: Gene Albanese and David Haukos)
Miwa Wenzel - Haverford College, PA - Seed Coat Mucilage: Natural Variation and Biochemical Composition in Arabidopsis. (Mentor: Kathrin Schrick)
Zeke Gonzalez - University of Maryland, MD - Thermal Tolerances of Central Stoneroller (Campostama anomalum) & Southern Red-Bellied Dace (Chrosomus erythrogaster). (Mentors: Bryan Frenette, Michael Tobler, and Keith Gido)
2014 REU Projects and Abstracts (top)
Project Abstracts - 2014
Andy Muench - University of Wisconsin, WI - Comparative ecohydrology between a common forb and shrub - implications for woody encroachment. (Mentors: Kim O’Keefe and Jesse Nippert)
Sarah Winnicki - Denison University, OH - Aggregation of Grasshopper Sparrow (Ammodramus savannarum) territories: a test of the extra pair mating and cooperative care hypotheses. (Mentor: Alice Boyle)
Breanna Canning - Rhode Island College, RI - The genetic basis of Chlamydomonas aggregation behavior in the presence of predators. (Mentor: Bradley J.S.C. Olson)
Joshua Yeomans - Pittsburg State University, KS - Aspects of Sterol Function in the Model Organism Arabidopsis thaliana. (Mentors: Janet Paper and Kathrin Schrick)
Hannah L. Clipp - West Virginia University, WV - Impacts of grassland management strategies on Dickcissel territoriality. (Mentors: Bram H.F. Verheijen and Brett K. Sandercock)
Marcelina Parra - Whitman College, WA - Dickcissel responses to different types of territorial incursions. (Mentor: Tim Parker)
Jessica Jimenez - California State University, Monterey Bay, CA - Differences in Growth and Condition of Prairie Stream Fishes Along an Elevational Gradient. (Mentor: Keith Gido)
Matthew Harder - Hope College, MI - Gene expression patterns in the embryonic notochord of Ciona intestinalis. (Mentors: Wendy Reeves and Michael Veeman)
Melissa White - Tufts University, MA - Expression and methylation dynamics of LTR-retrotransposon sublineages in the genus Helianthus. (Mentors: Hannah Tetreault and Mark Ungerer)
Frances ‘Kate’ Hunter - Iowa State University - The Effects of Cold Acclimation on Mating Ability of Drosophila melanogaster. (Mentors: Elizabeth Everman and Ted Morgan)
2013 REU Projects and Abstracts (top)
Steffanie Munguía - University of South Florida - Why do territorial male Grasshopper Sparrows aggregate? (Mentor: Alice Boyle)
Emily Pavlovic - Earlham College - The development of microRNA genes as a barcode to characterize nematode community composition. (Mentor: Michael Herman)
Nicole Richardson - University of Iowa- The Evolution of Multicellularity: Driven by Predation? (Mentor: Bradley J.S.C. Olson)
Elizabeth S. Mays - Colorado College - The role of sterols in cellulose synthesis: genetic and evolutionary approaches (Mentor: Janet M. Paper and Kathrin
Bonnie Bernard - Centenary College of Louisiana - Cytotypic and cryptic morphological variation in and among Phlox hoodii populations of the Black Hills. (Mentors: Carolyn Ferguson and Mark Mayfield)
Casie Lee - University of California, Berkeley -The Thrill of Victory, the Agony of Defeat: Developing and Testing a Standard Protocol for Field Estimates of Short Term Growth in Fish Predators. (Mentor: Martha Mather)
Benjamin Ketter - Kansas State University - Natural abundance of stable isotopes as an indicator of hydraulic lift under field conditions. (Mentor: Kim O'Keefe and Jesse Nippert)
Liliana N. Calderon - University of Illinois - Effects of Fire Treatments and Slope Position on Macroinvertebrates in North American Tallgrass Prairie. (Mentor: Ellen Welti and Bruce A. Snyder)
Armand Cann - Xavier University - Small mammal responses in relation to vegetation recovery in patch-burn grazing pastures. (Mentors: Drew Ricketts and Brett Sandercock)
Alessandro Bartolo - Hampshire College - Effects of Patch-Burn Grazing on Dickcissel Territory Size. (Mentors: Bram Verheijen and Brett Sandercock)
Jenny Lohmiller - Bethany Lutheran College - Vegetation architecture effects on the diversity and abundance of web-building spiders (Mentors: Jesús Gómez and Anthony Joern)
Project Abstracts - 2013
Steffanie Munguía - Why do territorial male Grasshopper Sparrows aggregate? (Mentor: Alice Boyle)
Emily Pavlovic - The development of microRNA genes as a barcode to characterize nematode community composition (Mentor: Michael Herman).
Nicole Richardson - The Evolution of Multicellularity: Driven by Predation? (Mentor: Bradley J.S.C. Olson)
Elizabeth S. Mays - The role of sterols in cellulose synthesis: genetic and evolutionary approaches (Mentors: Janet M. Paper and Kathrin Schrick).
Bonnie Bernard - Cytotypic and cryptic morphological variation in and among Phlox hoodii populations of the Black Hills (Mentors: Carolyn Ferguson and Mark Mayfield).
Casie Lee - The Thrill of Victory, the Agony of Defeat: Developing and Testing a Standard Protocol for Field Estimates of Short Term Growth in Fish Predators (Mentor: Martha Mather).
Liliana N. Calderon - Effects of Fire Treatments and Slope Position on Macroinvertebrates in North American Tallgrass Prairie (Mentors: Ellen Welti and Bruce A. Snyder).
Armand Cann - Small mammal responses in relation to vegetation recovery in patch-burn grazing pastures (Mentors: Drew Ricketts and Brett Sandercock).
Alessandro Bartolo - Effects of Patch-Burn Grazing on Dickcissel Territory Size (Mentors: Bram Verheijen and Brett Sandercock).
Jenny Lohmiller - Vegetation architecture effects on the diversity and abundance of web-building spiders (Mentors: Jesús Gómez and Anthony Joern).
2012 REU Projects and Abstracts (top)
Amber Jensen - Nebraska Wesleyan University, NE - Big bluestem ecotypic differences in leaf nitrogen content as a possible mechanism for increased performance of western Kansas ecotypes in reciprocal gardens planted across the Great Plains (Mentor: Loretta Johnson).
Nalley Barron - Kansas State University, KS - Muticellular Evolution: Driven by Predation (Mentor Brad J.S.C. Olson)
Christopher M. Berger - Kansas State University, KS - Genotype by environment interactions affecting thermal plasticity in Drosophila melanogaster (Mentor: Ted Morgan)
Nervalís Medina-Echevarria - University of Puerto Rico in Humacao, PR - Adult Regal Fritillary (Speyeria idalia) density among fire and grazing regimes at Konza Prairie with notes on the occurrence patterns of its host plant, Prairie Violet (Viola pedatifida) (Mentors: Gene Albanese and David Haukos).
Evan Pugh - Denison University, OH - Landscape Scale Nitrogen Availability in a Nutrient-Limited Tallgrass Prairie Ecosystem (Mentor: Kendra McLauchlan).
Rachel Thayer - Brigham Young University, UT - Differential gene expression along the anterior-posterior axis of the Ciona notochord (Mentors: Wendy Reeves and Michael Veeman).
Shan Kothari - Michigan State University, MI - Characterizing variability of coding sequences and gene expression in Arabidopsis (Mentor:Chris Toomajian).
Jennifer Sojka - Lake Forest College, IL - Effects of Patch-Burn Grazing on the Demographic Performance of Grassland Songbirds (William E. Jensen and Brett K. Sandercock).
Rachel Pain - Saint Olaf College, MN - Ecological Variation and Species Boundaries in Phlox of the High Plains Prairies (Mentor: Carolyn Ferguson).
Project Abstracts - 2012
2011 REU Projects and Abstracts (top)
Annie Klodd - Grinnell College, IA - Consistent Relationship between total Foliar N and Canopy Density in Grazed (bison and cattle) and Ungrazed Tallgrass Prairie (Mentor: Jesse Nippert)
Lynsey Daniels - Saint Joseph's University, PA - The Effect of Fire on Tree Recruitment Along the Forest-Grassland Ecotone (Mentor: David Hartnett)
Charlotte Levy - Skidmore College, NY - How local selection pressures and individual gene expression influence variable cold tolerance in Helianthus maximilliani (Mentor: Mark Ungerer)
Nelson G. Castillo Rivera - Univeristy of Puerto Rico, Mayaguez, PR - Identification and comparison of viruses in a native grass (big bluestem, Andropogon gerardii) and a crop plant (wheat, Triticum aestivum) across Kansas (Mentors: Anna Whitfield and Dorith Rotenberg)
Mary Glover - University of Tennessee, TN - An exploratory study of the effects of a chemosterilant on adult survival, sperm motility, mating behavior and patterns of egg laying in a cricket (Mentor: Jeremy L. Marshall)
Rebecca Sullivan - University of Dallas, TX - Variation in Lifetime Fitness among Thermal Genotypes: Effects of Selection and Thermal Environment (Mentor: Ted Morgan)
Lauren Bansbach - Missouri State University, MO - Comparing Fecal Bacteria Levels in Prairie Streams (Mentor: Walter Dodds)
Patricia Zarate - Swarthmore College, PA - Effects of anthropogenic conditions on spore loads and foliar fungal lesion area (Mentor: Ari Jumpponen)
Benjamin Blanchard - University of Michigan – Ann Arbor, MI - The Effects of Habitat Heterogeneity on the Distribution and Composition of Ant Communities in a Tallgrass Prairie (Mentor: Tony Joern)
Project Abstracts - 2011
Annie Klodd - Consistent Relationship between total Foliar N and Canopy Density in Grazed (bison and cattle) and Ungrazed Tallgrass Prairie (Mentor: Jesse Nippert).
Lynsey Daniels - The Effect of Fire on Tree Recruitment Along the Forest-Grassland Ecotone (Mentor: David Hartnett).
Charlotte Levy - How local selection pressures and individual gene expression influence variable cold tolerance in Helianthus maximilliani (Mentor: Mark Ungerer).
Nelson G. Castillo Rivera - Identification and comparison of viruses in a native grass (big bluestem, Andropogon gerardii) and a crop plant (wheat, Triticum aestivum) across Kansas (Mentors: Anna Whitfield and Dorith Rotenberg).
Mary Glover - An exploratory study of the effects of a chemosterilant on adult survival, sperm motility, mating behavior and patterns of egg laying in a cricket (Mentor: Jeremy L. Marshall)
Rebecca Sullivan - Variation in Lifetime Fitness among Thermal Genotypes: Effects of Selection and Thermal Environment (Mentor: Ted Morgan)
Lauren Bansbach - Comparing Fecal Bacteria Levels in Prairie Streams (Mentors: Danelle Russell and Walter Dodds).
Patricia Zarate - Effects of anthropogenic conditions on spore loads and foliar fungal lesion area (Mentor: Ari Jumpponen).
Benjamin Blanchard - The Effects of Habitat Heterogeneity on the Distribution and Composition of Ant Communities in a Tallgrass Prairie (Mentor: Tony Joern).
2010 REU Projects and Abstracts (top)
Project Abstracts - 2010
Vocal dialects of migratory songbirds are a useful model for the study of behavioral variation and evolution of culture. The vocal convergence hypothesis proposes that long-term dialects develop through biased transmission of local call types and purifying selection against foreign call types. However, these pressures are relaxed in areas with higher rates of abandonment and introduction of new individuals. In this study, we examined the effect of low individual site fidelity on the development of local dialect by measuring the song similarity of male Dickcissels (Spiza americana) at sites in northeastern Kansas with varying levels of individual apparent survival. We hypothesized that sites with higher within-season apparent survival would have higher within-year song sharing and higher across-year song sharing, creating a stronger dialect. The hypothesis was tested by comparing song similarity on agricultural sites, where frequent crop changes cause low rates of individual return, to undisturbed prairie sites with higher site fidelity. The songs of banded individuals and individual apparent survival at both agricultural sites and prairie sites were recorded four times at even intervals during June and July of multiple years. The similarity in songs of individuals was quantified by cross-correlation of spectrograms of comparable song elements. Preliminary results show a positive relationship between higher site fidelity and greater song similarity, although the lower density of individuals supported at agricultural sites may inflate this effect.
Amanda Bennett - The effects of climate extremes on forbs in the tallgrass prairie (Mentor: Melinda Smith).
The Climate Extremes Experiment examines the effects of extreme heat and drought conditions on the tallgrass prairie, focusing specifically on co-dominant C4 grasses and Solidago canadensis, a dominant C3 forb. Rainfall was reduced by 75% in half of the 40 plots studied, with the other half receiving ambient rainfall throughout the course of the experiment to establish wet and dry conditions. In addition to these precipitation manipulation treatments, each plot received one of four heat treatments consisting of +0, +3, +6, and +9 degrees Celsius above ambient temperature over a two-week period to simulate a heat wave. Throughout the growing season, growth measurements were taken periodically on marked individuals within each plot. Additional measurements of productivity conducted included water potential, specific leaf area, biomass, and life cycle analysis. From this experiment, a better understanding of how heat waves affect the growth, physiology, and life cycles of dominant forbs in dry and wet conditions will be gained. Futhermore, experimental results will provide a good comparison between a C3 forb and the co-dominant C4 grasses being studied within the same environmental conditions.
Anika Bratt - Variability in ecosystem metabolism rates in a prairie headwater stream (Mentor: Walter Dodds).
Stream ecosystem metabolism measurements provide data on fundamental ecosystem processes, such as gross primary productivity (GPP) and community respiration (R). These data are a reflection of in-stream nutrient cycling and organic matter processing, and thus are critical to characterizing streams and defining their role in nutrient cycling dynamics downstream and across landscapes. Little is known about how these processes vary along the stream continuum and among watersheds. There is a paucity of information because most measurements are conducted over short durations of time during optimal conditions. In this study, we used measured O2, discharge and light to model stream metabolism dynamics of N2B, which is part of the Kings Creek watershed. This headwater prairie stream is located on Konza Prairie Biological Station (KPBS), near Manhattan, KS. We measured daily rates for one day per week, during times when the stream was flowing, for one year (April 2009-2010). We examined seasonal and weekly variability. R rates were consistently higher than GPP, suggesting that this is a net heterotrophic stream. Rates increased temporally from April to May. GPP and R rates were greater in May 2009 than May 2010. The lower rates in 2010 seemed to be primarily driven by precipitation regimes (flooding and drying), as discharge was considerably lower in spring 2010. We also compared GPP to metabolism data collected in experimental streams located on KPBS prairie in July 2010. Average GPP of artificial streams (n = 33) was comparable to late May 2010 GPP in N2B, indicating that artificial streams closely mimic natural ecosystem metabolism. Changes in precipitation regimes can have substantial effects on stream ecosystem metabolism, ultimately influencing nutrient cycling downstream and across surrounding landscapes.
Elizabeth Delfing - Determination of 18S ribosomal RNA gene copy number in five nematode species (Mentors: Brian Darby and Michael Herman).
Nematodes are important components of the soil ecosystem, and enumerating species in field samples can aid in understanding their roles in the food web and interactions with other soil microorganisms. Traditional methods of enumeration involve identifying individuals by their morphology, but this approach is time-consuming and limited to a course level of taxonomic resolution due to their morphological similarity. As an alternative, high-throughput sequencing can be used to identify and enumerate nematodes in field samples to a finer taxonomic resolution. The 18S rRNA (small subunit) gene is a commonly used barcode for species identification by amplicon sequencing, but the exact number of repeat copies in tandem arrays within the genome is unknown for most species. This parameter can be used to relate sequencing read counts to individual counts. I sought to develop a method to empirically determine the rRNA copy number in five species of free-living nematodes of the family Rhabditidae: Caenorhabditis elegans, Oscheius tipulae, Oscheius sp. 2, Mesorhabditis sp., and Rhabditis sp. Portions of the 18S rRNA gene and the single-copyama-1 RNA polymerase II gene for each species were cloned separately into the pGEM-T Easy Vector and the molecular weight of each plasmid was estimated according to known base composition of both fragment and vector. SYBR Green-based quantitative PCR on a dilution series of plasmid DNA was used to create a calibration curve for each gene and then quantify absolute and relative gene copy numbers in genomic DNA for each species. Our results show that the copy number for C. elegans may be twice as much as previously estimated. These methods yielded varied results for the other nematode species. The procedure appears promising, but currently requires a high quantity and quality of genomic DNA preparation, and the ability to clone a single-copy gene. Further research should determine whether 18S copy number relates to genome size or developmental rates.
Cecily Foo - Dialect change in Dickcissels (Spiza americana): due to song changes in individuals (Mentor: Tim Parker).
Song learning via song sharing in oscine passerines is a well-known phenomenon occurring between conspecific birds with both neighboring and non-neighboring territories. Students collected song recordings of individual banded male Dickcissels (Spiza americana) at Konza Prairie Biological Station (KPBS) in north-eastern Kansas every summer between the years of 2006-2010. Dickcissels are territorial, abundant on KPBS and each individual typically only has one song in its repertoire. The purpose of my study is to determine if dialects change over time in part due to changes in songs within individuals, often because younger birds are tutored by older neighbors. Song assessment of individuals using cross-correlation software will be used to determine whether individual’s songs recorded on different dates within a season correlated more strongly than individual’s songs recorded in different years.
Teddy Gelderman - Landscape level variation in the temperature sensitivity of soil carbon respiration (Mentor: Joe Craine)
Terrestrial organic carbon constitutes a significant percentage of all global carbon. Microbial decomposition of soil organic matter (SOM) into CO2 plays an important role in the flux of atmospheric CO2 levels. It is expected that as global temperatures rise, SOM conversion in CO2 will increase. However, the extent of how soil moisture will affect microbial decomposition of SOM remains largely unknown. A common measure of a soil’s sensitivity to temperature and moisture is a Q10 measurement, or the rate by which CO2 respiration increases for an increase in soil temperature of 10ºC. Energy of activation (Ea), a synonymous measurement to Q10, was used for this study to measure temperature and moisture sensitivity. In general, a higher Ea implies a greater sensitivity to temperature and moisture. The Arrhenius equation, k = Ae-Ea/RT describes the relationship between temperature and Ea, where k is the rate of reaction, T is temperature (K), R is the gas constant and A is a reaction-specific constant. We used this equation to further understand the relationship between soil moisture and Ea of SOM decomposition. Eight 0-20 cm soil samples from both upland and lowland areas of the Konza Prairie were collected for this investigation. Soil sample replicates were incubated at varying temperatures (10, 15, 20, 25 and 30ºC) while held at a range of moistures (30, 45, 60 and 75% of water holding capacity). Samples were incubated for 48h and CO2 respiration rates were recorded with an infrared gas analyzer. We hypothesized that as soil moisture and temperature increased, so too would CO2 respiration and therefore, energy of activation. Our data currently show promising trends and further inquiry is needed to help refine our models of SOM decomposition rates in an increasingly warmer climate and to better predict future CO2 atmospheric levels.
Chelsea Heatherington - Population genetic study of the Konza Prairie bison herd (Mentor: Mark Ungerer).
The Konza Prairie Bison Herd was established from 48 individuals in 1987 to study the long-term effects of ungulate grazing in tallgrass prairie ecosystems. Today, the Konza herd is maintained with an average of 300 individuals and is culled annually with the goal of maintaining genetic variation, increasing herd productivity, and reflecting natural predation. To inform management practices and conservation efforts for the herd, we analyzed allelic variation at 25 microsatellite markers in the bison genome for individuals in the herd from 2007 to 2009. Likelihood-based parentage analysis revealed that the majority of offspring are consistently sired by older males, with 87% of calves sired by males of ages 6-8. Observational data of cow/calf pairings differed from genetic results twice in the three years considered, suggesting that adoption occurs at a low frequency in the herd. Further results of our analyses indicate low levels of inbreeding depression and high levels of heterozygosity. While primarily valued for their contribution to ecological research, the Konza herd may also serve as a potential source of animals for recovering populations of Plains Bison. A comparison of management practices across herds and the resulting levels of genetic diversity can further contribute to the success and recovery of the Plains Bison.
Hanna Kahl - Vocal culture of Spiza americana: social tutor system and the effects of geographic barriers (Mentor: Tim Parker).
Young male Dickcissels Spiza americanamay learn local mating song dialects from older, neighbouring birds. If our hypothesis is true, we expect that the young males’ songs would be most similar to the songs of the older males holding adjacent territories. We estimated age of individual males by examining tailfeather morphology, marked these individuals with unique leg band combinations, and then recorded their songs. Within each of our six sites, we compared yearling Dickcissel songs to songs from older males on adjacent and non-adjacent territories using cross-correlation. We also analyzed the effects of geographic barriers on the evolution of vocal culture.
Jon Lambert - Postmating prezygotic phenotypes as initiators of speciation in Allonemobius socius (Mentor: Jeremy Marshall).
Speciation research over the past two decades has shown that postmating, prezygotic phenotypes, such as conspecific sperm precedence and the ability of a male to induce a female to lay eggs, are important factors in reproductively isolating closely related species. However, little is known about the genetics behind these phenotypes. The Allonemobius sociuscomplex of crickets presents a unique opportunity to investigate the genetics underlying such phenotypes, and ultimately speciation, because the only barriers to gene flow between species in this complex are postmating, prezygotic phenotypes. Using proteomic techniques, our lab has identified two candidate genes, APBP and Arginine Kinase, that may be involved in postmating, prezygotic isolation. My goals this summer were to (1) test whether or not these genes could be successfully knocked-down using RNAi, and (2) to test for what phenotypes associated with these genes might be responsible for reproductively isolating the species within this complex. I found that APBP could be significantly knocked down using RNAi, but no phenotypes were identified within a single mating context. Data is still being collected for Arginine Kinase, but preliminary results suggest that sperm motility may have been affected by RNAi knock-down. These results provide a starting point for further investigations into how these genes are phenotypically involved in reproductively isolating species in the Allonemobius socius complex.
Spencer K. Lickteig - Urbanization as a driver of contemporary evolution in fungi (Mentor: Ari Jumpponen).
As the human population continues to increase at a steady rate, the amount of natural land being converted into thriving urban environments is at an all-time high. With this continual ecosystem transformation, many questions have been raised about the effect that the urbanization is having on the organisms in affected areas. We focused on the higher concentrations of heavy metals that were present in an urban environment and if this radical change is a possible driver of evolution for those organisms: primarily fungi. Starting with a library of 116 different fungal isolates that were harvested from two urban and two nonurban trees, the fungi were organized into morphological groups, the largest group that spanned both urban and nonurban sources being Discula quercina, a common leaf spot fungus. Six of the Discula, three urban and three nonurban, were then grown in media with varying concentrations of heavy metals (Cadmium, Zinc, Copper). The fungi were measured over the course of twelve days and the EC50’s, the highest concentration that did not hinder growth dramatically, of the urban were compared to that of the nonurban. The data showed that there was no noticeable difference between the urban and nonurban fungi for any of the heavy metals tested. The enrichment of heavy metals in the air and soil is only one element of urbanization, our future studies plan on looking into the other effects.
Aaron Novick - Individual recognition in collared lizards (Mentor: Eva Horne).
I attempted to test the hypothesis that male collared lizards, Crotaphytus collaris, recognize individuals that live nearby. Past research shows they recognize neighbors with whom they share a territory boundary, but did not test their recognition of neighbors with whom no shared boundary exists. Male collared lizards defend territories that provide access to food and females. Males on territories at Konza Prairie or Milford Dam were exposed to tethered intruders from either the same location or a different location. Subjects defended their territories with displays and fights, which were quantified and compared between the two conditions. Reduced aggression towards neighbors would indicate recognition of neighbors. Not enough data were collected to achieve statistically significant results, nor did the data show any trend indicating less aggression toward neighbors. However, they did show a trend (though not significant) of greater aggression from Milford lizards than from Konza lizards, potentially indicating that territoriality changes by location. More research is needed to see whether this disparity actually exists, and, if it does, what causes it. Milford is much more densely populated with collared lizards than Konza is, suggesting that population density may affect territoriality.
Arjun Potter - The effects of nutrient additions on patterns of above-ground herbivory (Mentor: Melinda Smith).
Nitrogen, phosphorus, and potassium increase plant growth by facilitating the manufacture of primary and secondary metabolites. As herbivory is largely driven by forage palatability, nutrient additions to vegetation should impact palatability and thus spatial patterns of herbivory in nutrient-limited communities such as the grasslands in Konza Prairie. We collected plant samples from 6-8 focal species between areas with and without the yearly addition of 10g/m2 of N, P, (and K) in areas with a short-term (2 years) and long term (7 years) fertilization regimes. We assessed type and extent of leaf damages visually and collected data on a number of plant traits, such as plant height, number of green, senesced, and emergent leaves, leaf area, dry weight, and toughness. The six main focal species were the (forb) Solidago missouriensis(forb), Ambrosia psilostachya(forb), Dichanthelium oligosanthes(C3 grass), Schizachyrium scoparium(C4 grass), Andropogon gerardii(C4 grass), and Sorghastrum nutans(C4 grass)—two additional forbs,Conyza canadensisand Oxalis stricta, were also included in the long-term fertilization area where they were especially abundant. These focal species were chosen to represent major species and functional groups (cool-season & warm-season grasses, forbs) and a diversity of growth patterns. Nutrient additions showed no affect on rates of folivory, though binary measurements (presence or absence of damage) for Andropogonand Sorghastrumindividuals indicated that significantly fewer Sorghastrumtillers showed damage in plots fertilized long-term with N and P. There were significant differences in herbivory levels between species, with the forbs, especially Ambrosiaand Solidago, the most damaged and the grasses, particularly Schizachyriumand Sorghastrum, eaten the least. Herbivory levels were negatively correlated with plant toughness and the ratio of green to senesced leaves, indicating that plants with leaf damage were more likely to be delicate-leaved and have a higher proportion of dying leaves.
Eric Ross - Investigating the effects of low levels of song sharing on the rate of localized dialect change in the Dickcissel (Mentor: Tim Parker).
The phenomenon of a passerine birdsong dialect is described as a uniform similarity in the predominant song type that differs from one population to another. Dialects have been studied in the past to investigate avian speciation, song learning, and the mechanisms of social communication. The Dickcissel (Spiza americana) is a useful model species to investigate avian dialects and vocal culture while it summers in the American Midwest because of its high local abundance and consistent song type. Dialects evolve and change due to several mechanisms and we hypothesize that this change over time is accelerated by lower levels of song sharing within a population. To test this hypothesis, Dickcissel songs were collected from multiple sites in northern Kansas from 2006-2010 (data not collected in 2007) and were then compared using a cross-correlation analysis. During data processing, the filtering of background noise was investigated for its effect on our results under the hypothesis that filtering out background noise will have a positive effect on our calculated correlation values.
Caitlin Singer - Isopod ecology in tallgrass prairies (Mentor: Bruce A. Snyder).
Isopods are terrestrial crustaceans whose role in the tallgrass prairie ecosystem remains little explored. To better understand this, we devised two related experiments. Our first experiment was a survey of different experimental plots at Konza Prairie LTER to investigate the diversity and abundance of isopod species present. We selected two sites from each prescribed fire frequency and grazing treatment at Konza. Isopods were hand collected for 30 person-minutes at three randomly chosen 3m x 3m plots in each watershed. When found, isopods were identified by sight and released. To account for weather, sampling was restricted to within 5 days of rain. Due to this restriction, along with the summer heat, the survey remains incomplete. Of the four known species found in Kansas thus far, all non-native, Armadillidium vulgare was the most abundantly found, though an additional species was found when searching the headquarters area of Konza. Preliminary results of the Konza survey suggest a negative relationship between fire frequency and isopod density, but more work is needed to support this association. The second experiment was a food preference study which considered whether or not isopods showed a significant preference when given the option between native plant seed and their known diet of leaf litter. Granivory (seed consumption) in isopods has only recently been reported by Saska (2008), and it is unknown if non-native isopods may be seed predators on native plants. Isopods were placed in a petri dish with the food options of seed and leaf litter for the duration of a 6-12 day trial. The contents of the petri dish were weighed before and after three trials. This study showed that isopods had a significant preference against two of the ten total native plant seeds offered, and no preference for the remaining eight. However, isopods did eat seeds even when leaf litter was present. These studies suggest that terrestrial isopods pose little threat to tallgrass prairie ecosystems due to their low density under most fire regimes and lack of preference for native plant seeds. More extensive studies, involving a preference study with more seeds and a survey in a cooler, moister part of the year, are needed to further define the role of isopods in tallgrass prairie.
Runqi Song - Climate change and invasibility of a tallgrass prairie ecosystem (Mentors: David Hoover and Melinda Smith).
The rate of invasion by an exotic species depends on resource allocations. Current predictions of climate change include increased variability in rainfall, which may disturb the present resource balance and thus the invasibility of an ecosystem. We tracked the progress of invasive species Bromis inermisin a tallgrass prairie via seedling establishment and survivorship. Bromis inermiswas introduced to Rainfall Manipulation Plots (RaMPs), infrastructures that simulate climate change. The plots received either the ambient treatment, where rainfall is redistributed immediately after natural precipitation, or the altered treatment, where the plots undergo longer dry spells intercepted by bigger rainfall events. Some plots received additional heat treatments. In summary, invasion was monitored in four different environments: ambient with no heat, ambient with heat, altered with no heat, and altered with heat. Our results thus far show that there is more seedling establishment in altered treatments and less in heated ones.
Rachel Wieme - Grazing alters distributions of root classes by depth in tallgrass prairie (Mentors: Jesse Nippert and Joseph Craine).
The tallgrass prairie is a productive ecosystem with nearly two-thirds of the biomass produced belowground. Due to the difficulty of measuring belowground biomass compared to aboveground biomass, few studies have investigated changes in root lengths and the types of roots produced under various prairie management regimes (i.e., grazing and fire). The purpose of this project is to compare the effects of grazing and topographic position on root systems in the tallgrass prairie: the amount of biomass and root length located throughout the soil profile, as well as what types of roots are present at certain depths. We collected soil cores (to 2.5 m where possible) from upland and lowland positions within adjacent grazed and ungrazed watersheds on Konza Prairie. Soil cores were divided into sections; roots were washed from cores using a 2 mm sieve. Total root length and diameter were measured using WinRhizo image analysis program on scanned images of the extracted roots. Grazing significantly decreased the total amount of root length throughout the soil profile. For example, ungrazed prairie had 60% more root length and 33% more biomass than grazed prairie. For both grazed and ungrazed prairies, the amount of belowground biomass exponentially decreased with depth. In ungrazed areas 58% of total root length was located within the upper 20 cm, and 54% of total root length was found in the upper 20 cm in grazed areas. On average nearly 60% of the roots produced in the upper 10 cm were less than 0.15 mm in diameter, and this proportion decreased with depth. Additionally, roots in ungrazed prairie tend to have a higher proportion of the finest (£0.15 mm) roots. Topographic location did not have a significant effect on the distribution of root classes, root length at each depth, or biomass. These results suggest grazing impacts root class distribution compared to ungrazed prairie and illustrate differences in resource availability and carbon allocation in tallgrass prairie.
2009 REU Projects and Abstracts (top)
Project Abstracts - 2009
Kelsey Hixson-Bowles - Generality of nematode bacterial defense pathways (Mentor: Michael Herman).
Brian V. Kearns - Change in vocal culture of Spiza americana based on density, distance, and habitat (Mentor: Tim Parker).
Rose Keith - Development of simple sequence repeat loci in Helianthus maximilianii (Mentor: Mark Ungerer).
Matt Nielsen - The genetics and evolution of cold tolerance within the Drosophila genus (Mentor: Ted Morgan).
Nathan Pavlovic - Nitrogen and phosphorus addition affect microbial polar lipid metabolism in a grassland ecosystem (Mentors: Richard Jeannotte and Ruth Welti).
Dumi Presuma – Variables affecting nitrogen uptake in prairie streams (Mentors: Alex Reisinger and Walter Dodds).
Zak Ratajczak - Positive micro-climate feedbacks lead to expansion of the shrub Cornus drummondii in tallgrass prairie: source water partitioning (d18O and dD), litter dynamics and leaf area index (Mentor: Jesse Nippert).
Rebecca Spurr - Landscape-level variation in temperature sensitivity of soil carbon respiration (Mentor: Joseph Craine).
Gabriella Sterne - Dickcissel site fidelity and local vocal culture (Mentor: Tim Parker).
Maya Wilson - Ecology of the Texas horned lizard (Phrynosoma cornutum) in the Flint Hills of Kansas (Mentor: Eva Horne).
2008 REU Projects and Abstracts (top)
Project Abstracts - 2008
Adaptive evolutionary processes can be tested in contemporary settings if we focus on systems that show sufficient variation at the population scale, particularly when the variation shows a regular pattern. We investigated regional variation in mtDNA and phenotypic color traits in midwestern populations of the common garter snake, Thamnophis sirtalis, in order to assess whether an observed microcline in Manitoba is the result of secondary contact between phenotypically distinct forms that share a north-south contact zone stretching from Canada to Texas. We combined phenotypic data from Kansas populations with novel genetic data and genetic data from the literature to characterize the variation. We found that a microcline also exists in Kansas in the same phenotypic and geographic direction as that in Manitoba, and that the cline in each region occurs within in separate clades that themselves are contained within one large western clade. Because the clines do not reflect mitochondrial patterns of diversification among our target populations, we conclude that some unknown large-scale adaptive process is driving the clinal variation in midwestern T. sirtalis.
Carina Castro – Temporal changes in the song dialects of Dickcissels (Spiza americana) (Mentors: Tim Parker and Brett Sandercock).
In many songbird species, individuals learn songs from each other, and as a result such species often show geographic patterns of song-type sharing, sometimes known as dialects. When young males first learn to sing, they learn from surrounding male "tutors". Despite this local learning, local dialects can still be subject to change. For instance, high population turnover due to an increase in adult immigrants could lead to introduction of foreign songs that are then learned by new recruits. High turnover could also lead to an increase in recruitment of yearlings who must learn their song. Since learning is imperfect, errors in learning, known as cultural mutations, can also alter dialects. Such temporal changes in dialects are poorly studied to the extent that even the rate of change among years is unknown in most species. We studied temporal dynamics in song dialects in the Dickcissel (Spiza americana), a species in which individuals learn songs and populations have easily recognized dialects. In previous studies, neighboring Dickcissels shared similar songs, but as distance increased between neighbors, song sharing decreased. Also, songs of individual Dickcissels remained constant throughout the breeding season. However, it is not known how Dickcissel song changes between seasons. We compared songs recorded among neighbors in 2006 to songs we recorded in 2008 at two different locations at Konza Prairie Biological Station, Kansas. Two of 9 birds banded in 2006 returned to the same areas in 2008. Despite within-season consistency in 2006, the songs of the two returning birds' changed substantially in structure between seasons. Given that result, it is less surprising that the dialect also changed on territories that had changed ownership since 2006. Song similarity between the 2006 and 2008 populations was low as measured by song type classification and assessed with the Jaccard Index of Similarity. It appears that Dickcissel dialects are dynamic over short time frames and that individual males are able to continue to learn song throughout their lifetime.
Nicholas DiRienzo – Nuptial feeding in the southern ground cricket Allonemobius socius: Conflict or investment? (Mentor: Jeremy Marshall).
In the southern ground cricket Allonemobius socius, the males provide females with a nuptial gift in the form of hemolymph. During copulation, the female chews open a specialized spur on the male’s tibia, allowing her to extract hemolymph. For females, this nuptial gift significantly increases reproductive life span and thus, lifetime fitness. For males, however, the cost of this gift can be rather significant, ranging from 0.5-8% of the male’s body mass and a significant decrease in reproductive life span. This raises an important question: Is this behavior maintained as a result of paternal investment, or rather is it a male cost for mating that is a target for sexual conflict? These opposing hypotheses set up opposite evolutionary predictions. If the behavior is a form of paternal investment, males will be selected to maintain long feeding times and there should be a positive relationship between feeding time and female measures of fitness (e.g., fecundity and offspring survival). However, if nuptial feeding is simply an upfront cost to mating for males, then males will be selected to minimize feeding time and there should not be a positive relationship between feeding time and female fitness. Here, we tested the hypothesis that feeding time is positively correlated with egg-laying in females. Specifically, virgin females were each mated with a single male. Approximately half of the females were prevented from receiving the nuptial gift. This was accomplished by covering the male’s tibial spur with liquid band-aid, which blocks the female’s access. The remaining females were not prevented from receiving the nuptial gift. Successfully mated females were allowed to lay eggs for seven days, after which the number of eggs laid was recorded. After analyzing the data we found that the females who were allowed to feed stayed in second mount (the time period in which females feed) for significantly more time than those who were not allowed to feed. Also, females who were allowed to feed laid a greater number of eggs compared to those who were not. Neither treatment showed a significant correlation between the duration of feeding and the number of eggs laid. Also, there was no difference in mating success rate or spermatophore attachment duration for either treatment. These data suggest that receiving any hemolymph during feeding, rather than the quantity received, increases the rate of egg-laying in females. This result can be explained by one of three, non-mutually exclusive, possibilities: (1) any hemolymph is a significant gift, (2) hemolymph provides additional cues to the female to lay more eggs, or (3) the hemolymph contains an egg-dumping protein by which males manipulate females to lay more eggs. Regardless of the explanation, it is clear that longer feeding times, while beneficial to females, do not enhance this component of male fitness. In all, nuptial feeding appears to be a target of sexual conflict.
Jennifer Fill – The influence of habitat variation on snake body temperature and behavior at Konza Prairie (Mentor: Page Klug and Kimberly With).
Snakes are important members of the threatened tallgrass prairie ecosystem, not only for their own intrinsic value but also as predators of grassland bird nests. An understanding of how snake behavior is influenced by tallgrass prairie management (burning and grazing) is critical in understanding how they will respond to the anthropogenic changes to the ecosystem and how this may affect their predatory relationship with grassland birds. In order to understand how snakes are impacted by various management regimes it is crucial to look at the basic relationships between snake body temperature and habitat. Since snakes are ectotherms, their body temperature is critically dependent on the thermal properties of their environment, and body temperature has a profound influence on their physiology, fitness, and behavior. My objective was to investigate the influence of burning and grazing on snake behavior. To do this I looked at the relationship between snake body temperature and habitat structure resulting from experimental grazing and burning treatments on Konza Prairie. I radio-tracked yellow-bellied racers (Coluber constrictor) and Great Plains ratsnakes (Pantherophis emoryi) on Konza Prairie from June to August, recording body temperature and both watershed (treatment type) and habitat at each location. ANOVA results showed that body temperature differed significantly between species and within each species it differed among snakes located in grassland, edge, forest, and shrubby draws. Contrary to the expectation that racers would be found most often in grassland and least in draws, and that ratsnakes would be found more often in edge than in grassland (areas in which body temperature most closely matched the preferred temperature of the species), I found racers using shrubby draws more often in less frequently burned areas while ratsnakes exhibited no outstanding trend. Based on the correlation between body and litter temperatures in the racer and between body and under-rock temperatures in the ratsnake, I conclude that behavioral use of habitat in the racer is more strongly affected by management due to alteration of substrate by burning. Average body temperature of the racer varied significantly among individual watersheds, and the lack of a difference in body temperature among macrohabitats within each watershed would suggest the influence of management treatment. Differences in use of macrohabitats may also be a result of foraging strategy, availability of macrohabitat, or predator avoidance. While the direct effects of this behavioral change on snake fitness due to management are uncertain, it represents a reaction to alteration of the landscape that may have important implications for biodiversity conservation.
Laura Kangas – Spatial and temporal physiological variation among tallgrass prairie plants (Mentor: Jesse Nippert).
Landscape-level relationships of plant productivity and composition in response to the dominant influences of fire, grazing, and drought in the tallgrass prairie have been well documented. However, less is known about the relationships at a smaller scale within the same area. The objective of this study was to characterize the physiological variability along a topographic gradient at community and individual levels and identify drivers of this variation. We measured leaf area index by plot and stomatal densities, leaf-level physiological characteristics, predawn and midday water potentials, and canopy height for each species in ten plots along a topographic gradient. Environmental data was logged by sensors near each plot. Leaf area index was similar across the topographic gradient in June, and differentiated as the summer progressed, becoming greatest in the lowland (LAI = 4.6) and least in the upland (3.4). Above-average rainfall during the growing season resulted in minimal water stress, even in the uplands. Stomatal density, determined for Andropogon gerardii and Sorghastrum nutans, was not significantly correlated with conductance rate, however, the stomatal densities of both species showed decreasing trends along the topographic gradient. For the C4 grasses, photosynthesis (A), conductance (gs), and transpiration (E) were highest in the beginning of the summer and declined over June and July, while gas exchange rates for C3 forbs and grasses varied considerably between sampling dates. Multivariate analyses of environmental factors indicated that A, gs, and E in C4 grasses were related to relative humidity and soil temperature. As a group, there was no significant relationship between abiotic factors and gas exchange rates for C3 species, with the exception of Dichanthelium oligosanthes and Ambrosia psilostachya. With these exceptions, these results are consistent with previous studies of the positive response of C4 plants in relation to abiotic conditions, while C3 forbs and grasses indicate no response; and rather are influenced by biotic interactions, related to that of grass productivity (Briggs and Knapp 2001). The above-average rainfall during the growing season provided interesting implications for this study, as both C4 and C3 species had high rates of leaf-level gas exchange. However, even when water did not limit growth, the community and individual-level variability measured along the topographic gradient indicated microsite complexity with varying environmental drivers between the C4 and C3 species present.
Jorge Mendoza – Investigating the home-ranges of Common Nighthawks (Chordeiles minor) (Mentors: Rebecca Lohnes and Brett Sandercock).
Limited studies have been conducted with Common Nighthawks (Chordeiles minor) and much of their natural history remains unknown. One questions is whether nighthawks maintain territories or home ranges. Previous studies based on observations of unmarked birds in urban areas have concluded that nighthawks are territorial. In order to study the home range of Common Nighthawks at Konza Prairie we used radio telemetry (a more precise and unbiased method). We captured six male Common Nighthawks by spotlighting at night at Konza Prairie. All birds were weighed, measured (wings, tarsus, total head), and blood was collected. To each bird, we attached a backpack radio transmitter with a necklace and thorax harness. Two of the six nighthawks with radio dispersed from Konza Prairie and one radio was dropped with a week of attachment. Movements recorded during the summer indicated that male nighthawks maintain large home ranges ranging from ~1 to ~3 km2 in area, and birds used different locations depending the time of day (morning, afternoon, evening and at night). Our movement data also showed some overlapping in the evening at the point where nighthawks showed the most flying activity. We did not observe any form of territoriality and it should be studied better in the future. Our results showed that radio telemetry can be successful with nighthawks and it could be useful to monitor their activity in order to investigate questions regarding their mating system and breeding behavior.
Amy Strauss – Effects of habitat on geographic patterns of song sharing in Dickcissels (Spiza americana) (Mentor: Tim Parker).
Dickcissels (Spiza americana) are oscine songbirds in which males use song in territorial defense and possibly to attract females. Males learn their song by imitating nearby territories, and this creates localized geographic patterns of song sharing, sometimes known as ‘dialects’. Various factors are hypothesized to influence the creation of these dialects, including the rate of learning errors ('cultural mutations'), immigration and emigration between populations (rate of territory turnover), proximity of each individual to neighboring territories, and the ability of sound to travel across a particular distance. These factors are presumably impacted by the conditions and quality of the habitat in which the birds live and breed. We investigated whether or not varied habitats showed differential patterns of song similarity between adjacent male Dickcissels by recording the songs of neighboring Dickcissels along continuous road transects, and noting the proportion of different habitats along those transects. Songs were then analyzed by comparing spectrograms, and classified into categories based on similarity. There was no significant correlation between general habitat cover and average Dickcissel density or between general habitat cover and average song similarity between adjacent birds (Jaccard Index of Similarity). We did find that average song similarity between adjacent birds increased as a function of declines in the average Dickcissel density per transect. This result could be explained by the fact that Dickcissel density on transects was unrelated to the density of recorded birds, which indicates that transects with higher Dickcissel density presumably had a higher number of unrecorded birds between adjacent recorded birds. More sophisticated analyses will be necessary to determine how song similarity changes over increasing distances between two birds, how variance in habitat and Dickcissel density may be related to patterns of song sharing, and how more specific designations of various habitats impact song sharing to ultimately understand the link between patterns of geographic song sharing and ecological factors.
Katie White – Evaluating fish habitat usage in the Kansas River at species and community levels (Mentors: Craig Paukert and Joe Gerken).
In large river systems, little is understood about the influence of different habitat types on species and community-level characteristics of fish. This study had two goals: 1) to assess differences in fish species and community attributes between three habitat types (mud bank, log jam, rip rap) at 439 randomly selected sites within the main channel along the entire Kansas River, and 2) to investigate fish utilization of two flooded secondary channels in a river reach located near Manhattan, Kansas. Daytime low pulse electrofishing during May-August 2006 and 2007 yielded 1468 total fish dominated by five taxa (flathead catfish Pylodictis olivaris, red shiner Cyprinella lutrensis, river carpsucker Carpiodes carpio, freshwater drum Aplodinotus grunniens, and blue sucker Cycleptus elongatus) from the three habitat types in the main channel along the entire river. Standardized seine hauls with a 4 meter seine net yielded 1288 fish from 6 samples taken within the main channel, dominated by four taxa (red shiner, white bass Morone chrysops, freshwater drum, and gizzard shad Dorosoma cepedianum), and 584 fish from five samples taken within the secondary channels, dominated by three taxa (red shiner, sand shiner Notropis stramineus, freshwater drum). Species richness and diversity were significantly highest in rip rap, and four species (shovelnose sturgeon Scaphirhynchus platorynchus, flathead catfish, blue sucker, smallmouth buffalo Ictiobus bubalus) had significantly higher abundances in one of the three habitat types. Discriminant function analysis and percent similarity indices indicated that fish assemblages did not differ among the three habitat types in the main channel or between secondary and main channels. The Kansas River fish community is dominated by habitat generalists and tolerant species that can exploit various habitats, potentially leading to a lack of community-level habitat associations. This pattern could also result from temporal effects (little habitat partitioning in the summer season), or unnoticed association patterns (habitat selection by specific fish life stages). Future research should focus on the mechanisms of how fish are utilizing different habitat types in the river and should ideally sample throughout the year and across age classes to assess any temporal or ontological trends in habitat associations.
2007 REU Projects and Abstracts (top)
Project Abstracts - 2007
The tallgrass prairie is one of North America’s most endangered ecosystems with approximately 4% of its historical extent remaining. This remaining fraction is endangered by various factors, one of the largest being C3 woody species expansion, converting the tallgrass prairie to forest. Fire, an integral part of the tallgrass prairie, has been excluded from most of this diminished ecosystem, which has allowed for increased establishment and recruitment of native, early successional C3 shrub species. Of particular concern at Konza Prairie Biological Station is Cornus drummondii (rough-leaf dogwood), a rapidly spreading species that multiplies vegetatively to form shrub islands. Such islands spread radially and can: 1) displace native prairie species at the periphery, 2) shade out any remaining species in the understory, and 3) facilitate conversion of prairie to forest by providing suitable habitat for late successional C3 arboreal species, which eventually transform shrub islands to forest tracts. Starting in 2000, two restoration techniques for the removal of C. drummondii were executed in specific watersheds at Konza Prairie: annual shrub island burnings, and mechanical/herbicidal removal. This study centers upon the post-restoration analysis of both techniques in order to determine the efficacy of each, quantified through Morisita’s index of community composition, species diversity, species richness, total woody cover, and proportion of forb cover. Based upon a hypothetical sere model detailing the transition from prairie to forest, a total of five communities were chosen for sampling: post-fire (FD), post-mechanical removal (MR), Grassland State (GS) as the desired end point of restoration and positive control group, undisturbed shrub islands (USI) as the negative control, and Shrubland Transition State (ST) as an intermediate control. While the MR and FD communities were 73% similar, in what they differed the MR communities were greater in similarity to the desired GS communities with 63% similarity, as opposed to the FD communities which were only 54% similar. Conversely, the FD and USI communities were more similar (36%) than the MR and USI communities (18%). The MR communities possessed a higher mean species diversity (2.31) and mean species richness (7.2) than the FD communities (1.60 and 4.5, respectively). The FD communities possessed the second highest total woody cover (20.0) after the USI communities (40.4). The MR, GS, and ST communities all possessed significantly comparable low woody cover (10.4, 9.4, 4.8, respectively). There was no significant difference in the proportion of forb cover among all five groups. After seven years, the data describe the MR communities as having a more similar composition to the desired GS state than the FD communities, and, consequently, mechanical/herbicidal removal of C. drummondii appears to be a more effective restoration technique than fire within the short-term.
Melissa A.R. Blundell – Are brood parasites unique in their begging? A comparative approach with the Red-winged Blackbird (Mentors: Jim Rivers and Brett Sandercock).
Obligate brood parasites lay their eggs in the nests of other individuals and rely on those hosts to raise their young. Kin selection theory predicts that parasitic young should beg more intensely than host young due to the lack of genetic interest in the survival of their nest mates or in the host reproductive success. To test if begging displays are unique in an obligate brood parasite, the Brown-headed Cowbird (Molothrus ater), I compared the begging displays of the cowbird young with that of a closely related non-parasitic relative, the Red-winged Blackbird (Agelaius phoeniceus). I predicted that the cowbird young would have more exaggerated begging displays than the blackbird, and would result in a higher rate of host food provisioning. Single cowbird young and a single blackbird young were video recorded in the nest of a common parasitic host, the Bell’s Vireo (Vireo bellii). Begging posture, call rate, frequency of begging, volume food provisioned to young and visit rate were measured. All variables measured were similar between the cowbird and blackbird. These results suggest that the cowbird young are not uniquely adapted in their begging behavior. This similarity coincides with Molothrus as the youngest clade of brood parasites. Possibly a more specialized parasitic behavior in the young has not yet evolved as opposed to older parasitic lineages of birds where parasitic young kill host nestlings.
Adam J. Carter – Subsidies of Kansas streams: the diet of an omnivorous fish (Mentors: David Hoeinghaus and Walter Dodds).
Ecosystems have porous boundaries, with organisms, nutrients and energy passing between adjacent systems. These subsidies may play an important role in structuring the recipient food web, with potentially cascading ecosystem-level effects. Stream ecosystems interact with the terrestrial landscape through the riparian zone. For example, insects emerging from the stream may subsidize terrestrial food webs, and insects falling into the stream may subsidize the stream food web. Even though riparian zones are increasingly being altered or reduced by humans, only limited research has investigated the role of riparian characteristics on the relative importance of terrestrial subsidies to stream food webs. In this study, we used an omnivorous fish, the Red Shiner (Cyprinella lutrensis) as a study organism to evaluate the effects of percent canopy cover on the relative importance of terrestrial-derived items in its diet. The red shiner is a model study organism because it is known to consume both terrestrial and aquatic food items, and is widespread and locally abundant in prairie streams. I hypothesized that as percent canopy cover decreased, red shiners would consume more aquatic food items and fewer terrestrial food items. Fourteen stream sites were sampled across northeast Kansas, and physical measurements of each stream (depth profiles, substrate composition, percent canopy cover) were taken at five transects spaced approximately 30 meters apart. Standard seining methods were used and all fish were identified in the lab to the species level. Gut contents of 30 random red shiners from each site were identified and quantified. Importance of dietary items was evaluated using the feeding index IA which incorporates the frequency of the diet item as well as the percent volume. Terrestrial organisms were dominant diet items in more than half of the sites, and all sites had some type of terrestrial food contribution, illustrating the importance of riparian-derived subsidies. Percent canopy cover was not significantly correlated with the overall dietary importance of combined aquatic food items or combined terrestrial food items across all sites. However, the dietary importance of some individual prey categories (e.g. algae, Hymenoptera, Coleoptera, Lepidoptera) were related to percent canopy cover. Further riparian measurements, such as tree density, may improve our understanding of factors affecting the relative importance of terrestrial subsidies to stream food webs.
Anthony C. Dalisio – The response of male Dickcissels to geographic song variation (Mentors: Tim Parker and Bill Jensen).
In some oscine songbird species, young males imitate the songs of the neighbors they encounter when they settle on their adult territories. This leads to geographic patterns of song sharing, sometimes known as dialects. Male Dickcissels (Spiza americana) exhibit dialects on a microgeographic scale as expected if this process of adult neighbor song learning is at work. Song sharing between male Dickcissel decreases as distance increases up to 10 km between birds. This led us to ask what selection pressures favor learning song from adult neighbors in the Dickcissel. We tested the “Deceptive Mimicry” hypothesis in which selection favors imitation of the songs of established males because by sounding similar to established birds, the mimic will elicit less aggression from established birds. Our experiment tested territorial males’ responses to three different song playback treatments: 1) songs from their own territory (local), 2) songs from nearby neighborhoods (intermediate) and 3) songs from populations far away singing radically different songs (foreign). In playback experiments, males tended to respond very aggressively to the local song playback. During the trials, they sang the most songs to local and foreign playbacks, and after the trials they sang the most songs to local and intermediate playbacks. Further, Dickcissel males made more flights towards the speaker during playback of local songs than during the other treatments, and after the trials, males flew most towards the speaker for the local and foreign songs. These results contradict the prediction of the Deceptive Mimicry hypothesis that local songs would elicit the least aggression. Thus, we expect another selection pressure favors learning song from neighbors.
Jesús E. Gómez-Carrasquillo – Hide-and-seek among wolf spider and grasshoppers: applying ecology of fear theory to invertebrates (Mentor: Tony Joern).
The past study was realized at Konza Prairie Biological Station at Kansas in which the ecology of fear theory used to describe the nonlethal interactions between major vertebrate carnivores and their prey. The theory was applied to spider (Lycosidae) and grasshoppers (Acrididae) community interactions. The goals of the past study were to determine if spider presence alters the spatial distribution of grasshoppers, to determine variability in grasshopper and spider density among sites, and their relationship to one another. We predicted that grasshoppers will feed more in areas with a lower predation risk, but that vegetation structure would affect the spider and grasshopper community interactions and abundance. The Ecology of Fear predicts that spider abundance should alter grasshopper feeding. Spider abundance was determined using pitfall traps at nine sites. Body sizes were measured to the nearest mm and each spider was identified to Family, Genus and Species level. Grasshopper densities were determined with ring count transects, and feeding distributions were measured using bioassays plot inside the spider pitfall trap plots. Vegetation biomass was determined for five 0.2 m2 clip plots (forbs & grass). Our results show that there is no relationship between vegetation biomass and spider or grasshopper density. The negative relationship between grasshopper and spider density suggests that biotic interactions are important. Spatial distribution of feeding by grasshoppers was influenced by spider density. The spatial feeding distribution of grasshoppers within the plot followed predictions of the Ecology of Fear.
Auctavia D. Grant – The effects of grazing on prairie butterflies (Mentor: Jodi Whittier).
Our study examined the grassland butterfly communities found in grazed and ungrazed areas on the Konza Prairie biological station. Bison (Bison bison) was the large ungulate in the grazed units. We suspected that we would find more adult butterflies using the grazed units because grazing tends to promote increased prevalence of forbs. We aimed to establish the species richness of the butterfly community was higher in the grazed area rather than in an ungrazed area. We established study sites in grazed and ungrazed sites that were all burned on a 4-year cycle. Each site had 4 transects in the uplands and 4 in the lowlands to examine the breadth of species using each treatment. Transects were sampled 3 times over a period of 5 weeks. Along each transects the percent cover of flowering plants was estimated. As expected the total number of butterflies was higher on the grazed sites compared to the ungrazed sites. We saw a similar result for the flowering fords with nearly three times the coverage on the grazed transects. Our results suggest that vertebrate grazing may increase, in cover of flowering plants, and increase species richness of butterflies, as well as a higher taxon diversity in the ecosystem.
Lauren M. Hallett – Effect of warming and altered precipitation of the growth rates of two dominant C4 grasses (Mentor: Melinda Smith).
Anticipated effects of climate change in the Midwest United States include increased temperatures and more extreme precipitation regimes. Previous research suggests that the two dominant C4 grasses in North American tall grass prairies, Andropogon gerardii and Sorghastrum nutans, differentially respond to changes in temperature and precipitation. To determine if differences exist at the level of individual growth, relative growth rates of both species were compared across a control and three treatment types: altered precipitation, increased temperatures, and altered precipitation and increased temperatures. The altered precipitation regime was achieved using the Rainfall Manipulation Plots (RaMPs), in which rainout shelters divert, collect, and reapply rainfall to increase the inter-rainfall period by 50% while keeping total amount of precipitation the same. Temperatures were increased by ~2o C using infrared lamps suspended above the plant canopy. Non-destructive growth measurements (height, number of leaves, leaf area) were taken of 10 representative individuals per species throughout the growing season. Prior to each set of measurements, allometric equations were generated to link non-destructive measurements to dried aboveground biomass by measuring and harvesting individuals in areas adjacent to the RaMPs. R-squared values for these equations were always > 0.9. Consistent with previous studies at the level of physiology and ANPP, Andropogon and Sorghastrum exhibited differential responses to alterations in temperature and precipitation at the level of individual growth. Andropogon exhibited a higher sensitivity to altered temperature, with consistently higher relative growth rates in the control and delayed-control plots than in those with increased temperature. In contrast, Sorghastrum was more responsive to altered precipitation, with lower relative growth rates consistently observed for the delayed-warmed treatment. Because Andropogon and Sorghastrum are dominant tall grass species, differences in their performance at the individual level may have large scale implications for tall grass prairie ecosystem response to climate change.
Sara L. Jackrel – Evaluation of habitat use by nesting grassland birds and their snake predators (Mentors: Page Klug and Kim With).
The tallgrass prairie is the most endangered ecosystem in the United States, therefore further degradation of this rare habitat impacts many species. Grassland birds are of particular concern, having declined more than any other group of birds in North America. Vital to the long term success and recovery of grassland birds is reproductive success. The primary factor influencing nest failure is predation, with snakes being responsible for many of these predation events. Despite high rates of nest predation, little is known on how management practices impact snake movement and snake habitat selection. One concern is that habitat alteration may simultaneously attract both birds and their predators, creating predation hotspots. I evaluated habitat use of the Eastern Racer and the Great Plains Rat Snake, two common snake species found on KPBS, and compared this with habitat used by nesting grassland birds, predominantly Dickcissels. Nest monitoring results showed snakes as important nest predators on KPBS, possibly accounting for up to 72% of all nest failures, with a greater rate on four year burns compared to annual burns. From the fifteen vegetation variables analyzed at nest sites, Program MARK identified high vegetation height matched with low percent live woody coverage as the best candidate model. Therefore, the higher the vegetation height with less live woody coverage, the higher the nest’s daily survival rate. A Discriminant Function Analysis, explaining the variance between habitat use of the two snake species as well as fledged nests and predated nests, was most heavily loaded on vegetation height and live wood. From the separation of the fledged nests from the predated nests shown by the DFA, it can be concluded that the lower the vegetation height and the higher percent live woody coverage surrounding a bird nest, the more likely that nest was predated. With habitat of Eastern Racers more similar to that of predated nests and habitat of Great Plains Rat Snakes more similar to that of fledged nests, the Eastern Racer may be the snake species more responsible for nest failure. Since habitat indirectly impacts nest survival by its direct impact on predator populations and behaviors, knowing the snake community found in regions of the tall grass prairie is important to understand the effects of habitat on these predators. Since my findings suggest that nest survival is non-random, my research emphasizes the need to provide grassland birds with a type of habitat that provides them with the highest chance of successfully fledging a nest. In this case, the rate of snake predation may be reduced with management techniques that maximize vegetation height while minimizing invasion of woody species, reducing quality habitat for snakes and other predators and promoting grassland bird population recovery.
Tyler J. Kohler – Effects of nutrient loading and grazing on periphyton communities in experimental streams (Mentor: Keith Gido).
Prairie Streams are one of the most endangered habitats on the planet, largely due to anthropogenic activities which can lead to excessive nutrient loading. Nutrient influx can have a significant effect on the biomass, community composition, and stoichiometry of periphyton in these habitats. Grazing fish can have an impact on the nutrient cycling of these systems due to the trophic level at which they feed, as well by the redistribution of nutrients and altering of nutrient ratios in the water body through excretion. Therefore, the interaction between these grazers and nutrients may aid in providing us with a better understanding of the dynamics of these systems, as well as have applications for conservation. This lead us to the development of two questions: 1) How is periphyton biomass, community composition and nutrient ratios affected by gradients of nutrient loading and fish density, and 2) Does the proximity of the periphyton to the rock have an effect on these variables? In our experiment, we used the experimental streams on Konza Prairie Biological Station to manipulate 6 different nutrient loading treatments, as well as 6 different grazing densities of Southern Redbelly Dace (Phoxinus erythrogaster) to test how these two variables interact to affect periphyton. Samples were taken from both the riffle and pool portions of the experimental streams, and were further stratified into over and under-story components by removing material at different proximities relative to the substrate. Samples were then analyzed for biomass, C:N ratios, and community composition. Our data suggested that increasing nutrient loading had a significant effect by increasing biomass, decreasing the ratio of green algae to diatoms, and decreasing C:N ratios. Grazers, while having a weak effect on biomass and community composition, were found to have a significant effect by lowering the C:N ratio of over-story periphyton as fish density increased. The weak effects of the grazers on biomass and community composition is consistent with previous studies performed on Konza Prairie. These results may be due to foraging stimulating or maintaining productivity rather than decreasing it, as well as the possibility that grazers are feeding without preference. The lowered C:N ratio produced as an effect of higher grazer densities may increase the nutritional value of the periphyton for other organisms, as well as have effects on community structure.
Clairisse E. Nash – Applying a new herbarium database: Geographical patterns of collection of introduced species and targeted plant collecting (Mentor: Carolyn Ferguson).
Katie Parsons – The response of the dominant C4 grasses to extreme temperatures (Mentor: Alan Knapp).
Andrea M. Severson – High water habitat: Fish populations in two Kansas River backwater areas (Mentor: Craig Paukert).
2006 REU Projects and Abstracts (top)
Project Abstracts - 2006
Big Bluestem (Andropogon gerardii) and Indian Grass (Sorghastrum nutans) are the dominant warm season grasses on the tallgrass prairie and affect both above ground plant communities and the belowground microbial community structure. This study follows the long-term changes in the above- and belowground communities and soil characteristics resulting from the removal of A. gerardii and S. nutans from plots in two watersheds of the Konza Prairie Biological Research Station. In the initial years after grass removal, treated plots showed large differences in plant species composition, mycorrhizal root colonization, and nematode community structure. Removal plots had significantly less mycorrhizal colonization, fewer herbivorous nematodes, and more plant species richness. An intensive study ten years after the removal investigated above- and belowground parameters including plant species composition, total soil C and N, soil microbial biomass C and N, phospholipid fatty acid (PLFA) content, neutral lipid fatty acid (NLFA) content, soil aggregation, the nematode community, and arbuscular mycorrhizal fungi root colonization. Average above ground cover of A. gerardii was still different between treatments, but average cover of S. nutans appeared to have recovered. After ten years, Tall Dropseed (Sporobolus asper) had increased in the removal plots. All belowground variables showed that the removal plots had recovered. The study did reveal distinct differences in the belowground communities of the two watersheds studied, despite identical burn regimes and similar elevation.
Aaron Berdanier - How pressing is increased nitrogen? Rethinking plant responses and the pulse paradigm (Mentor: John Blair).
Human activity in the last century has greatly increased the amount and mobility of biologically-available nitrogen (N) in the biosphere. In terrestrial ecosystems, increased N deposition can significantly alter ecosystem processes, such as productivity, C storage and nutrient cycling, and is a threat to plant diversity and long-term soil fertility. Much of our understanding of the effects of elevated N deposition comes from field fertilization experiments, which are consequently important for predicting future ecosystem responses to N enrichment. Most of these nutrient addition experiments are conducted with discrete, “pulsed” nutrient applications (i.e., once per year). However, actual increases in nutrient inputs (e.g., elevated atmospheric N deposition), occur in a more continuous, or “pressed”, manner. Fertilization experiments utilizing a pulse approach may not be appropriate for predicting the effects of more continuous inputs. This experiment was designed to compare the differential effects of equal amounts of N, added either in a single pulse or as a series of smaller amendments across the growing season, on soil N availability and plant responses in native tallgrass prairie. We applied inorganic N (NH4-NO3) in solution to 60 experimental plots in irrigated and non-irrigated upland tallgrass prairie; 20 pulsed with a one-time application of 10 g N m-2 early in the growing season, 20 pressed with 10 additions of 1 g N m-2 added at 10-day intervals throughout the growing season, and 20 non-fertilized control plots. Extractable soil N was measured four times during the growing season to assess patterns of soil N availability. At 10 day intervals, leaf samples of Andropogon gerardii were collected from each plot and analyzed for C and N concentrations. Ceptometer readings were taken above and below the canopy at mid-day on six dates during the growing season to assess canopy light interception as a non-destructive index of canopy growth. We found strong interactions between irrigation and N treatments across dates for both available soil N and canopy development. In general, there was significantly greater soil N availability in the pulsed treatment, relative to the pressed treatment or control. Canopy development was positively affected by both N treatments in the irrigated plots only, but the response to the pulse treatment was significantly greater than to the press. There was also significant separation in N treatments for leaf tissue quality as the growing season progressed. These results suggest that pulsed and pressed N inputs have different effects on soils and plants, and that this should be considered when designing experiments to assess the impact of chronic N enrichment.
Clayton Bowers - The growth cycle of the Common Nighthawk (Chordeiles minor): an unusual mode of development (Mentor: Brett Sandercock).
Unlike many of the bird species around the world, quantitative estimates of growth and development have not been published for nightjars (F. Caprimulgidae). Nightjars are difficult to study because they have cryptic plumage, crepuscular activity, and an overall secretive way of life. This field study is one of the first investigations of the development in the young of any nightjar. Growth rates of nighthawks are of interest for at least two reasons. First, nighthawks have semiprecocial young, a mode of development also found only in unrelated species of marine birds such as terns, gulls, murres, jaegers, and albatrosses. Second, nighthawks lay their eggs directly on the ground with no nest substrate. I hypothesized that the predation on exposed eggs and young should select for rapid growth. Nests were located on the Konza Prairie in Northeastern Kansas during the summer months of 2006 by observation of aerial adults, and by walking through areas that looked to be potential nesting areas. I located a sample of 31 nighthawk nests. When nests were located and chicks hatched, five growth characters (head, wing, tail, tarsus, mass) were recorded every two days. To compare growth data with the asymptotic body size of adults (A), I captured adult nighthawks at night on gravel roads using a spotlight and dip net (n = 2 females, 6 males). A logistic growth curve was fit to the data, and non-linear regression was used to model the intrinsic growth rate (K) and the inflection point (I). Head (K = 0.14, I = -0.28) and tarsus (K = 0.26, I = -0.62) were quick to reach A, but wing (K = 0.16, I = 16.1) and tail (K = 0.19, I = 20.8) were slower in growth. Degree of asynchrony and brood number were also tested in attempt to find some difference in growth. It was found that the degree of asynchrony was marginally significant for wing and mass in that the first hatched chick of a two chick brood grew somewhat faster (P = 0.07, P = 0.06, respectively). No significance was found for growth between one and two chick broods.
Eric Kightley - Potential effects of the introduced bullhead minnow (Pimephales vigilax) on the native bluntnose minnow (Pimephales notatus) (Mentors: Darren Thornbrugh and Keith Gido).
The bullhead minnow, Pimephales vigilax, was introduced into the Kansas River drainage in 1976 where it now occurs with the native bluntnose minnow, Pimephales notatus. Because they are congeners, we hypothesized P. vigilax would negatively interact with P. notatus. Four possible impacts of P. vigilax on P. notatus were tested: 1) spatial overlap, 2) spawning habitat competition between males, 3) diet overlap, and 4) hybridization. Three tributary creeks were sampled at five locations within 10 km from the Kansas River mainstem to identify spatial overlap. Mesocosms with spawning habitat structures were constructed to observe competition between males. Gut contents from fish caught during field surveys were analyzed to identify diet overlap. Morphometric measurements were taken to identify hybrids. Abundance of P. notatus increases away from the Kansas river, whereas P. vigilax abundance was moderate at all sites. Pimephales notatus was dominant over P. vigilax in seven of 10 competition trials for spawning habitat. No significant diet overlap was found, as P. notatus guts were composed mainly of detritus, and P. vigilax mainly invertebrates. Morphometric analysis suggested distinct species with no hybridization. Future research could help elucidate the consequences of increased energy expenditure due to spawning site competition in males, examine the fertility, reproductive, and survival rates of both species. Field studies that remove P. vigilax from spawning sites in a stream to see if P. notatus eventually replaces these fish would help verify the impact of P. vigilax on P. notatus.
Viviana Loaiza - Is phosphorus a limiting nutrient for nymphs of Melanoplus bivittatus (Orthroptera:Acrididae)? (Mentor: Tony Joern).
Food can be highly variable in both availability and nutritional quality, especially for herbivores. Moreover, nutritional needs change depending upon physiological and biochemical requirements resulting from stress or developmental needs. Major nutrients for grasshoppers include N-based proteins/ free amino acids, and C-based carbohydrates/ sugars, as a source of energy, and from which lipids can be derived. While the effects of dietary nitrogen and carbohydrates on grasshoppers are well studied, the importance of phosphorus (P), a third major elemental category, remains unaddressed. Grasshopper performance studies using controlled diets and field-based estimates of herbivory on plants fertilized with nitrogen and phosphorus fertilizer were undertaken In the feeding study, fifth instar nymphs were fed artificial diets consisting of three different ratios of protein and carbohydrate, each crossed with three levels of phosphorus until final molt to the adult stage. In the field, leaf damage on the grass Andropogon gerardii and the forb Solidago missouriensis were estimated; grasshopper densities were measured in P- and N-fertilization plots. The interaction of P with the protein:carbohydrate diet treatment significantly affected the amount of diet consumed but not the amount of frass produced, suggesting a difference in diet assimilation. Growth rate (mass-increase/day) over the developmental stage increased with greater P consumption, possibly due to elevated metabolic rates or ARN transcription. High levels of P in the diet significantly delayed development. In the field, the interaction between phosphorus and nitrogen fertilization was significant with respect to foliar damage from insect herbivores (mostly grasshoppers). A higher grasshopper density (individuals/m2) was observed in all plots fertilized with nitrogen, and no effect of P-fertilization was detected. At the individual level, phosphorus can be limiting as expected. But, when scaling to the population level, other variables (i.e. food palatability) may change the behavior observed so that P-limitation is not readily observed.
Kelsey Reider - A lizard on the rocks: collared lizards and Konza geography (Mentor: Eva Horne).
In the Flint Hills of Kansas, collared lizards (Crotaphytus collaris) appear to depend heavily on the presence of rock outcrops for habitat. At Konza Prairie Biological Station (KPBS), alternating mudstone and limestone layers form slopes and resistant benches, respectively. In various locations around KPBS the resistant benches allow 11 limestone layers to outcrop where the less resistant mudstones have been eroded. Each layer outcrops in characteristic ways, some of which may provide better habitat for collared lizards. I identified which limestone outcrops had lizards and characterized the outcrops to identify habitat differences between them. Of the 11 limestone layers, lizards or fecal pellets were found on four layers: Cottonwood, Eiss, Funston, and Florence. The presence of lizards was significantly correlated with rock height (P = 0.013), the availability of refuge spaces (P < 0.001), and percent rock cover (P = 0.002). The presence of refuge spaces appeared to be the most important factor in lizard habitat selection. The four limestone layers where lizards were found had higher mean refuge spaces than layers without lizards. I also evaluated toe painting as a mark-recapture method, and compared lizard size and parasite loads between two limestone layers. I estimated the population of collared lizards on a 350-meter transect of the Cottonwood limestone to be approximately 11 individuals. I compared lizard snout-vent length and total chigger load between animals captured on the Cottonwood limestone (n = 9) and those from the Funston limestone (n = 5). Neither parameter was significant, though Cottonwood lizards tended to have larger (2x) chigger loads than the Funston lizards. This study could provide direction for a population census of collared lizards on KPBS.
Loren Reinhardt - Spatial heterogeneity of ammonium uptake in prairie streams (Mentor: Walter Dodds).
Nitrogen uptake has always been thought of as a complex process, but generally researchers sample on a coarse scale in order to increase replication. What information are we sacrificing for replication? There could be smaller scale patterns important to stream nutrient dynamics that have not been seen. In this study, we focused on differences between pool and riffle nitrogen uptake. Today, channelization of streams is causing them and to loose their riffle, pool structure. Knowing how riffles and pools function independently of one another will be key to predicting future changes of stream nutrient retention. We tested these differences by injecting ammonium chloride and sodium bromide (nonconservative and conservative tracers, respectively) into three prairie streams on the Konza LTER during the summer of 2006. On each sampling date we injected at three concentrations, allowing for accurate quantification of spiraling metrics at background rates. We also sampled algae and coarse benthic organic matter (CBOM) standing stocks. We found that in each stream ammonium uptake was greater in riffles (U=0.979- 1.9 μg/m2/s) than in pools (0.0430-1.37 μg/m2/s) with runs tending to fall in the middle (0.428- 1.50 μg/m2/s). Chlorophyll per unit area was the best predictor of uptake (more chlorophyll increases U), whereas CBOM was not a good predictor. As expected, chlorophyll per unit area decreased with increased depth, higher stream velocity and CBOM increased with increased depth, lower stream velocity. It appears that channelizing streams would increase nitrogen retention, but there are other factors such as increased turbidity due to less debris damns that would change this result.
Derek Schook – Microgeographic song variation and the formation of dialects in the Dickcissel (Spiza americana) (Mentor: Tim Parker).
Many songbirds have been shown to demonstrate distinct song dialects in different areas within a population. Most studies, including a 2005 study on Dickcissels in the Flint Hills, have identified dialects by sampling separate sites within a population. In contrast, my study aimed to investigate Dickcissel dialects by viewing song sharing on a continuous scale to explore dialect sizes and the transitional zones that occur between dialects. After recording the songs of 32 banded Dickcissels throughout the breeding season, I conducted a repeatability analysis of six quantitative components in their songs. A high positive correlation (r = 0.70–0.96) revealed that songs do not change over the season. This result validated my comparison of songs recorded at different times throughout the summer. A qualitative analysis of the songs of 578 birds recorded on the Konza Prairie revealed that song syllables do show clustering, which sometimes can be viewed at multiple scales. The additional sampling of 107 birds along three road transects showed inconsistent trends in song component turnover. Sampling at both Konza and on the road transects revealed that Dickcissel song sharing and variation demonstrates complex patterns not clearly revealed by our current analytical methods. Additional analysis, including methods relating to quantitative song measurements and geostatistics, will be explored with these data in the near future.
Emilie Throop – The effects of nest, local and landscape scale habitat features on snake depredation of grassland birds (Mentors: Page Klug and Kimberly With).
In a grassland ecosystem, snakes may play an important role in the nesting success of songbirds. The objectives of this study were to determine if grassland birds and snakes share much of the same preferred habitat, and if nesting success can be modeled through relationships between nest sites and preferred snake habitat features. I radio-tracked Yellow-bellied Racers (Coluber constrictor) and recorded location information such as treatment type and immediate habitat cover. I also monitored nests of the Dickcissel (Spiza americana), Grasshopper Sparrow (Ammodramus savannarum), Lark Sparrow (Chondestes grammacus), Field Sparrow (Spizella pusilla), and Eastern Meadowlark (Sturnella magna). Nest successes and failures that may have been due to snake predation were recorded, and habitat variables at the nest site, local scale, and the landscape scale were measured. Principal components analysis was run for habitat features such as litter depth, Robel pole readings, distance to shrubs, forest, rock outcrops, treatment edges, and draws for Dickcissels alone and then all species combined. MARK analysis for Dickcissels revealed that shrubby habitat features positively influence nest success. This may be due to the occurrence of both Dickcissels and snakes in shrubby areas, as well as snake foraging strategy. As shrubby habitat increases, there is less chance an incidental predator, such as a snake, might find a nest. MARK analysis for all species combined revealed that an overall heterogeneous habitat positively influences nest success. Because several of the birds monitored have different nesting strategies, the increased nest success due to heterogeneous habitat may be more influenced by nest site preferences than snake predation. These habitat features describe a complex relationship between grassland songbirds and the snake predator community with regards to nest, local and landscape scale characteristics.
2005 REU Projects and Abstracts (top)
Project Abstracts - 2005
Jeff Eitzmann - Spatial and temporal patterns of Blue Suckers (Cycleptus elongatus) in the Kansas River, Kansas (Mentor: Craig Paukert).
We studied the population dynamics of blue suckers (Cycleptus elongatus), a species in need of conservation, to determine spatial and temporal patterns in abundance and growth of this species. Pulsed DC electrofishing was used at 101 fixed sites to determine seasonal (e.g., spring, summer) distribution, and 302 random sites were sampled in summer to determine distribution and abundance throughout the river. A total of 71 fish were collected, with most of the fish between 600-700 mm total length. No fish less than 425 mm were collected with very few fish outside of this length. Higher abundance of fish was observed in the upper river reaches, and below a low-head dam in the lower river reaches. Although abundance was higher in the upper reaches, no difference in growth throughout the reaches was noticed. No seasonal trends in abundance were observed in the fixed sites for spring and summer. Blue suckers in the Kansas River had slower growth than other populations in the Great Plains, including the Neosho River, Kansas. No fish under age 4 were collected, which was common in other studies. Future research on early life history is needed to better understand the population dynamics of this rare fish.
Krysta Hougen - The effect of fire regime on woody shrub abundance in the tallgrass prairie (Mentors: Gail Wilson and Dave Hartnett).
The tallgrass prairie is a fire-dependent ecosystem, which includes Konza Prairie in Northeast Kansas. Fire is needed to slow the encroachment of invasive species onto the prairie and maintain the open grassland. Woody shrubs, including those common on Konza (Ceanothus herbaceous, Rhus glabra, Symphoricarpos orbiculatus, Cornus drummondii and Juniperus virginiana), frequently invade the tallgrass prairie. The season and frequency of fire affects the abundance of these woody shrubs, as measured by their percent cover and frequency. We surveyed two watersheds for each summer, spring, winter, fall, 4-year and 20-year burn regime. As the frequency of fire decreased (annual, 4-year and 20-year) we noted a linear increase in the percent cover and frequency of the woody shrubs. Most woody shrubs showed increases in abundance with decreasing fire return interval, but Rhus glabrashowed greatest abundance with intermediate burn frequency. Comparing seasonal burns, there was a smaller percent cover and frequency of woody species during the dormant season burns (fall and winter) and greater abundance in spring and summer (although the summer-burned watersheds are burned biennially). Contrary to popular opinion, our data suggest that dormant season burns may be just as or more effective at controlling the invasion of woody shrubs than spring or summer burns.
Karan J. Odom - Upland Sandpiper nest site selection and daily nest survival in four burning and grazing treatments (Mentor: Brett Sandercock).
Numbers of Upland Sandpipers (Bartramia longicauda), a grassland indicator species for native prairie, have been decreasing over the past several decades. The decline has been linked, in part, to loss of habitat associated with modified land use by humans, particularly agriculture. I tested the effects of four combinations of burn and grazing treatments (burned/ungrazed, burned/grazed, unburned/grazed, and unburned/ungrazed) on nest site selection and daily survival rates (DSR) of nests. The analyses were performed using five years of data in which radio-marked Upland Sandpipers were tracked by radio telemetry to locate and monitor nests at the Konza Prairie LTER site. Chi-square tests revealed a significant preference for nest sites in unburned/ungrazed treatments in three out of four years tested (P = 0.001 in 2002, 0.0181 in 2003 and 0.0492 in 2005). Nesting success was modeled with the nest survival procedure of Program Mark. The best fit model indicated that DSR varied similarly throughout the breeding season all five years, with the highest success rate midseason. The next best model revealed greater influences of grazing than burning treatments on DSR with respect to incubation stage. DSR were lower for young nests in both unburned and burned treatments within ungrazed habitat compared to grazed habitat, but increased more dramatically with nest age. Modeling DSR versus the four treatments, nests in unburned/grazed units exhibited significantly higher survival rates (0.9609) than those found in burned/grazed treatments (0.9273), especially upon comparing apparent nest success throughout the entire incubation period (31.4% and 11.4%, respectively). Conservation implications include the need for management practices aimed at obtaining a variety of landscapes among tallgrass prairie, especially maintenance of unburned/grazed land to ensure population viability for this important grassland bird.
Crystal Sinn - A comparative study: soil fertility vs. mycorrhizal symbiosis on Big Bluestem growth and soil CO2 flux (Mentors: Tim Todd and Abby Kula).
Alyssa Standorff - Canopy effects on stream metabolism (Mentor: Walter Dodds).
Stream metabolism is important because gross primary production or respiration may reflect processes that form the base of the stream food web. Food webs in some streams may be dominated by the production by algae. Other streams may be dominated by microbial production fueled by the breakdown of allochthonous organic material. Dissolved oxygen (O2) in streams increases during the day due to photosynthesis and it decreases at night due to respiration. This study focused on how canopy cover affected stream metabolism. I hypothesized that reaches with little or no canopy cover would have a higher gross primary production (GPP) than areas with extensive canopy. Reaches in two different areas of Kings Creek were studied, upstream in the prairie and downstream in the gallery forest. A series of about 15 reaches in each area were assessed for changes in O2 across each reach during the night to estimate respiration (R) and during the day to measure net primary production (NPP). Physical characteristics (light, average depth and width, discharge, dilution and aeration) were measured in each reach. Discharge and dilution were found by doing a rhodamine release. Aeration was calculated from the rate of decline of acetylene released to each reach. The amount of dissolved oxygen was analyzed with the Azide-Winkler method. Dissolved oxygen increased downstream during the day and night in both areas. This could be due to groundwater influences or equilibration with the atmosphere. A measurable difference was found within some reaches, but a difference was not found in all reaches because some were not long enough. Statistical analysis found a reach of at least 14-19 meters would be needed to find significant differences in dissolved oxygen between upstream and downstream sites. During the day, NPP was < 1 because R often exceeded GPP. There was no relationship found between light and GPP. The physical characteristics that were measured could not be used to predict the aeration coefficient across the riffles and pools. NPP tended to be less than one which suggested that heterotrophic processes exceeded rates of autotrophic processes. GPP was apparently saturated by light levels in mid day, even under substantial canopy cover.
Samantha Tolve - Female mate choice in Collared Lizards: Use of chemical or visual signals in detection of chigger mite ectoparasites on males (Mentor: Eva Horne).
To avoid parasitism, female collared lizards (Crotaphytus collaris) may rely on chemical and/or visual information about available males when choosing a mate. My study attempted to determine whether female collared lizards could detect chigger mites (Eutrombicula cinnabaris) on male lizards by scent, and whether chemical or visual cues (red patches formed by congregations of mites) were more important to females in choosing a mate. Lizards were captured at Konza Prairie Biological Station and Tuttle Creek Reservoir near Manhattan, Kansas (N = 11 females, 22 males). Male lizards were paired by similarity of physical characteristics, and mites were removed from a randomly chosen male of each pair. Male scents were collected by housing each on filter paper for 24 hours. Filter paper containing each male’s scent was placed on either side of an observation tank and a randomly chosen female was introduced to the center of the chamber. The trial was ended when a female had clearly spent more than 50% of her time (minimum time was 30 minutes) on one male’s side and that male was considered to be preferred. Of 11 females tested, 9 preferred the “no chigger” scent (chi-square p = 0.03). Females also spent a higher percentage of their time on the side of the male who did not have chigger mites (p = 0.075). The preferred male in the scent test was then painted with a red spot to simulate the presence of chigger mites and the rejected male was painted with a more camouflaged green spot. The two males were tethered on either side of the observation tank, with each male on the side where his scent had been located in the first trial. The same female was then reintroduced to the chamber and observed until she spent more than 50% of her time on one male’s side of the tank. In the second, visual test, females did not choose one male over the other. Female collared lizards are able to detect the presence of chiggers on a male through chemical cues. However, visual cues that contradict chemical signals appear to either reinforce the choice made on scent alone or cause the female to change her mind. While the presence of ectoparasites on a potential mate may be important indicators for choice, females may base their final decision on a combination of other factors as well.
Ben VanderWeide - Fire resistance of common trees of the tallgrass prairie of northeast Kansas (Mentors: David Hartnett and Gail Wilson).
In the fire-dependent ecosystem of the tallgrass prairie, including Konza Prairie in northeast Kansas, common tree species (e.g. Celtis occidentalis, Populus deltoides, Gleditsia triacanthos, Quercus muehlenbergii, Q. macrocarpa, and Juniperus virginiana) of the gallery forests may have developed mechanisms to tolerate fire. Key properties of bark (thickness, density, and moisture content) dictate the susceptibility of trees to fire. The objective of our study was to test fire resistance of various tree species based on the heat transference of the bark to the vascular cambium. We applied fire to the bark of trees under conditions mimicking grass fires (400 oC for 2 min.). If the vascular cambium temperature remained below 60 oC, it was considered resistant to fire. Although trees with thicker, dry bark (e.g. Q. muehlenbergii, Q. macrocarpa, P. deltoides) retained heat longer, the thick bark also served as superior insulation from the brief fire. Trees with thinner, moister bark experienced a more rapid temperature increase in the vascular cambium but were able to dissipate the heat more quickly. This may reflect the greater thermal conductivity of water compared to air. Q. muehlenbergii and Q. macrocarpa are the dominant tree species in the gallery forests of the tallgrass prairie and only P. deltoides has historically grown on the open plains near sources of water. Their success may be due, at least in part, to the superior fire resistance provided by their thick bark.
Alyssa Whu - Comparison of two passive collecting techniques for Hymenoptera in a tallgrass prairie (Mentor: Greg Zolnerowich).
Two methods of sampling hymenoptera in a tallgrass prairie were studied. Comparisons were made between Malaise trapping and pan trapping in terms of fauna collected. In addition the effects of pan color (red, blue, yellow, white) and burn frequency (two and twenty years) of the prairie was also studied. For bees, blue pans were the most effective method overall. Aculeates, exclusive of bees and ants, were found in both sampling methods. Bees and aculeates were not found in red pans. Chalcidoids and Braconidae were sampled in the highest numbers in Malaise traps. Scelionidae were collected in all pan colors and in the Malaise trap with no apparent preference for either. The highest abundance diversity was found in the twenty year burn.
Perry J. Williams - Local song dialects in the Dickcissel (Mentors: Tim Parker and Bill Jenson).
Many bird species have been proven to exhibit distinct song dialects among neighboring populations. I sampled the songs of Dickcissels (Spiza americana) from 37 field sites within the Flint Hills of Kansas and Oklahoma in order to describe their song-dialects, if any, and to determine at what geographical scale these dialects exist. Distinct differentiation in dialects were classified according to song morphology, song metric features, and syllable combinations. Dickcissels sang similar songs within fields, but different songs occurred among bird populations at the local fields scale. Birds within a sub-regional field site (northern, central, and southern Flint Hills) scale showed no more of a tendency to sing similar songs than did birds among sub-regions. Similarities in Song dialects of the Dickcissel thus appear to be restricted to the local level field scale. For such striking local dialects to be maintained, first year males returning from their South American wintering grounds must either return to the dialect area in which they learned their song during their first summer, or they must learn songs when they settle on their first breeding territory. Based on knowledge of other songbirds, the former scenario may be most likely, but further work will be needed to distinguish these possibilities.
Jackie Wilson - Altering C:N:P ratios to assess mycorrhizal function (Mentors: Gail Wilson and Nancy Johnson).
Arbuscular mycorrhizae are ubiquitous symbioses between plant roots and specialized fungi. Previous research indicates that resource availability (specifically soil P, soil N, and light) are important controllers of the mutualistic function of arbuscular mycorrhizal (AM) symbioses. Global changes such as increases in atmospheric CO2 and anthropogenic N deposition, pollution, land use change, introduction of exotic species are known to alter the relative abundances of C:N:P; however the ramifications of these impacts on AM symbiosis are unknown. If carbon or N:P ratios shift, will the beneficial relationship between mycorrhizal fungi and plants shift to a more parasitic (less beneficial) relationship? In this study, the native tallgrass prairie grass, big bluestem, was grown under varying C:N:P ratios, with and without mycorrhizal symbiosis. Carbon was altered by growing the plants under ambient light, or 30% and 60% shading. Soil N and P ratios were altered by using soils from three different sites that naturally varied in N:P ratios. Plant growth and photosynthetic rate were recorded weekly. Fungal abundance in the soil, determined at 8 weeks using fatty acid analyses, indicated that the nonmycorrhizal soil contained low levels of fungi and significantly less AM fungi than the AM-inoculated soil. Seedlings planted in low P soil failed to grown without the symbiosis, regardless of C or N. Moderate levels of soil P allowed for growth of nonmycorrhizal seedlings, but these were smaller than their mycorrhizal counterparts. Photosynthetic rates of mycorrhizal plants were higher than nonmycorrhizal counterparts, however, shading reduced both photosynthetic rate and growth of mycorrhizal plants at all N:P ratios. In this study, mycorrhizal symbiosis was beneficial to big bluestem seedlings regardless of C:N:P ratios, and no evidence of parasitism was observed.
2004 REU Projects and Abstracts (top)
Project Abstracts - 2004
Brian Holloway - Factors affecting the establishment of a native tallgrass species in areas dominated by the invasive grass Bothriolchola bladhii (Mentor: John Blair).
Rebecca Lohnes - Nest defense behavior of female Common Nighthawks (Chordeiles minor) (Mentor: Brett K. Sandercock).
Kristen Pitts - Effects of flooding on the fish distribution on Kings Creek, Kansas (Mentor: Craig Paukert).
Laura Sellens - Insect visitation of introduced versus native plant species at Konza Prairie (Mentor: Carolyn Ferguson).
The purpose of this project was to begin collecting baseline data of the pollination habits of several forb species on Konza Prairie, and to compare insect visitation of introduced and native plants. Eleven plant species were studied: the natives Verbena stricta, Ratibida columnifera, Erigeron strigosus, Teucrium canadense, Linum sulcatum, Dalea candida, Dalea purpurea, and Lythrum alatum, and the introduced species Coronilla varia, Hypericum perforatum, and Dianthus armeria. For each species insect visitation observations were carried out during five different time intervals on each of four days: early morning (6-8 am), late morning (9-11 am), early afternoon (1-3 pm), late afternoon (4-6 pm) and evening (8-10 pm). Visitation rates were calculated for each species. When all species were compared, the visitation rate of Hypericum perforatumwas significantly higher than all the others, and those of Teucrium canadense, Lythrum alatum, Coronilla varia, and Dianthus armeria were significantly lower than the rest. Comparisons of native versus introduced plants' visitation rates were not significant due to high variability between species. This study was the first of its kind on Konza Prairie, and rare in general due to its breadth and its inclusion of time intervals throughout the day. It provides some superficial information on the pollination habits of these species and a wealth of baseline data that should aid future research in pollination biology on Konza Prairie and elsewhere.
Jeremy Thornbrugh - Carnivore community distribution in tallgrass prairie (Mentor: Samantha Wisely).
Carnivore communities are affected by a variety of ecosystem processes, from primary productivity, to insect abundance, to small mammal populations. Because of this, they can be used as an indication of ecosystem health. This project looked at the effects on the carnivore community by different grazing schemes and burn regiments. I conducted a spotlight survey within Konza Biological Station. My route included bison grazed, cattle grazed, and ungrazed watersheds. I searched for Canis latrans, Mephitis mephitis, Didelphis virginiana, Taxidea taxus, Lynx rufus, and Procyon lotor. I also included identified scat in my data. I found a overall diversity (Shannon Diversity Index) of 1.04 in the cattle grazed watersheds, 1.17 in the bison grazed watersheds, and 1.36 in the ungrazed watersheds. Also, many of the species were found in higher concentrations within one grazing scheme, compared to the other two. Effects of burning regiment were not able to be analyzed due to most of the sightings occurring on a road. While the data suggests that some species might be affected by grazing, more research is needed to be conclusive.
Andrew Tilker - Interaction of small-stream fish with natural and artificial barriers (Mentor: Keith Gido).
Both natural and artificial barriers inhibit the movement of small-stream fish. To adequately construct a the movement patterns of these fish we must understand how they deal with these barriers. In an attempt to reconstruct fish movements we marked two species, Campostoma anomalum and Phoxinus erythrogaster, with acrylic paint above and below selected stream barriers. Approximately two weeks later we sampled the entire reach of King's Creek to re-capture marked fish. By then noting their location we could see how these fish moved in response to barriers in the stream. Of nine re-captured fish, none traversed a barrier of any kind. We also build an experimental stream setup to test whether or not these fish were physically able to overcome a typical artificial barrier. By placing individuals of both species "downstream" and then running a current through a culvert barrier, we found that both species were able to traverse the barrier. Both of these experiments have shed light on the physical abilities and behavioral attributes of small-stream fish.
Melinda Williamson - Dominance and territoriality in the Great Plains Skink, Eumeces obsoletus (Mentor: Eva Horne).
The Great Plains Skink, Eumeces obsoletus, is a lizard found primarily in south-central North America about which little is known in regards to behavioral interactions. This study looked at aggressive behavior in male-male and female-female interactions. The objectives of the study included determining if: 1) the skinks are territorial, 2) if they exhibit dominance and 3) if so, whether or not size plays a role. Animals were collected on Konza Prairie Biological Station and surrounding areas between the months of April and July 2004. Measurements (snout-vent length, total length, mass) were taken and the animals were housed in separate containers. Nineteen animals were captured and we set up an experiment as follows: one animal was placed in a 200 liter tub for 48 hours to establish “residency.” Water, shelter, and a rock were provided in the new home. Artificial light in the observation room simulated natural day and nighttime conditions (14L:10D). After 48 hours an intruder was introduced and the behaviors of both animals were recorded for 30 minutes in 30 second intervals. The individual behaviors were categorized into 5 general behavioral groups: aggressive, submissive, assertive, exploratory, and escape. Aggressive behavior was focused on and when the data were analyzed we found no significant difference in aggressive behaviors between residents and nonresidents. However, nonresidents did exhibit significantly more exploratory behavior than did residents. We also found no significant differences in dominance or aggression between large and small animals. We conclude that the Great Plains Skink, like other Eumeces species studied, are not territorial, but, unlike others, they do display aggressive behaviors outside of the breeding season.
2003 REU Projects and Abstracts (top)
Project Abstracts - 2003
Ecologists have not given adequate emphasis to the role of plant diseases in natural systems. Pathogenic fungi are no exception and while plant pathogens in the genus Fusariumhave been studied extensively in agricultural contexts, they have received almost no attention in prairie systems. This study examined the rate of infection by Fusariumspp. in the roots of three prairie forbs (Solidago canadensis, Lespedeza capitata, and Asclepias verticillata). The effects of topography and burning frequency were also considered. Root samples were collected at the Konza Prairie Biological Station, from upland and lowland sites in ungrazed prairie watersheds which had either been burned annually for approximately 20 years, or that had been unburned for an equal period. Surface sterilized, milled root samples were combined with a modified Nash-Snyder semi-selective media and the number of colony forming units per gram of dry root material was determined after 7-10 days of growth. Rates of infection seemed to vary more by environment (combinations of topography and burning frequency) than by host plant. When the data was grouped according to host plant species, significant differences were not detected. However, for Asclepias verticillata and Lespedeza capitata, the rate of infection was significantly higher in annually burned uplands than in either unburned uplands or unburned lowlands (p < 0.05). A clear trend (p = 0.056) of higher infection rates in annually burned sites was observed. This seems counterintuitive, as fire might be expected to destroy disease inoculum, but may be explained by the limited nature of the direct effects of fire below the soil surface. Changes in soil moisture and plant community composition due to frequent fires are likely important. The growth of single spore isolates is still in progress, and should allow for interesting comparisons of the relative abundance of various Fusariumspecies.
Elizabeth Bockman - Above and belowground vegetation characteristics in native and restored tallgrass prairie. (Mentors: Gail Wilson and David Hartnett)
Within the contiguous US, tallgrass prairie once extended from Kansas to Ohio and Texas to Canada, but today < 4% of this once expansive grassland remains. Attempts to restore agricultural land back to tallgrass prairie have been met with varying degrees of success, and little research has been conducted to assess the recovery rates and trajectories of different components of the structure and function of these ecosystems. This study examined aboveground characteristics (plant productivity and species richness) and belowground parameters (mycorrhizal colonization, and rhizome and bud bank densities) to assess the recovery of five tallgrass prairie restoration sites varying in age from 1 to 25 years since initiation of restoration. Arbuscular mycorrhizal fungi are ubiquitous in tallgrass prairies and form a symbiosis with most prairie plants. These fungi aid in phosphorus acquisition, improve water relations and increase disease resistance. Additionally, their external hyphae increase soil macroaggregate formation, which can control erosion and increase root penetration. Belowground meristem populations (rhizome bud banks) are important in tallgrass prairie because aboveground plant populations and vegetation dynamics are strongly driven by vegetative rather than seed reproduction, as seedling establishment is rare due to high competition and low resource availability. Thus, soil bud banks strongly regulate aboveground population dynamics and primary productivity. Plant species richness and biomass were significantly lower in restored sites relative to native; this difference may be driven by differences in forb abundance as forbs were relatively rare in all restored sites. In this study, mycorrhizal colonization was significantly lower in restored relative to native sites. The lower colonization in the restored sites may be a response to shifting limiting resources, particularly P:N ratios. Grass bud bank densities were not different between restored and native sites. The ratio of belowground buds:stems, an index of meristem limitation, indicated higher demographic potential in native sites relative to restored. This meristem limitation in restored sites may also account for lower productivity in restored sites.
Isaac Deal - Life history and mark-recapture analysis of the Regal Fritillary (Speyeria idalia Drury) at Konza Prairie, Kansas. (Mentor: Brett Sandercock).
Regal Fritillaries are butterflies associated with native North-American prairies. Historically, these insects ranged from the Midwest to the East Coast. Their range has shrunken to about one quarter of that size and is now almost wholly confined to the Midwest. Regal Fritillary larvae rely on host plants that are sensitive to changes in the vegetative structure of the prairie. The sensitivity of the Regal Fritillary’s host plants makes the presence of the butterfly an indicator of pristine prairie. A population study was conducted on the Regal Fritillaries utilizing mark-recapture methods in order to identify trends in the population in response to variables such as time of year and burn treatment. The study was conducted at Konza Prairie Biological Station. Two watersheds were assessed, one was burned on a 4-year basis (N4C), the other was less frequently burned (N20A). Both watersheds were grazed by native bison (Bison bison). Within each watershed, three sampling sectors were established, each sector being a circle 200m in diameter. Butterflies were caught by a hand net and each was given an individual mark with a black Sharpie® marker prior to release. Time of capture, location (GPS), sex, behavior, and wing wear were recorded for captured butterflies. A total of 375 individuals were captured and marked in the study, with 47 recaptures. Mean linear distance traveled by recaptured butterflies between their first and last capture coordinate was 90.0 meters among males and 50.6 meters among females. Male Regal Fritillaries were found to have a flight season lasting approximately one and one-half months from early June to mid July. Females emerged by mid June and persisted through the end of the study period in mid July. Data collected in the study indicates that Regal Fritillaries are univoltine. Residency of Regal Fritillaries in the sample sites was estimated to be short. Analysis of the data by use of a duration decay curve resulted in a mean residency estimate of 7.7 days with a range of 4.8 to 19.1 days. Analysis of the data by the use of mark-recapture models resulted in a mean residency of 6.4 days with a range of 3.9 to 10.9 days.
James Eckberg - Effects of altered rainfall patterns on C3 tallgrass prairie communities. (Mentors: Jesse Nippert and Alan Knapp).
General circulation models predict that greater surface temperatures will increase rainfall variability. The Rainfall Manipulation Plots (RaMPs) were established in 1997 to assess the effects of increased rainfall variability on intact tallgrass prairie plant communities by increasing intervals between rainfall events. RaMPs results show that increased rainfall variability decreased productivity, primarily in C4 grasses, and increased C3 diversity. Changes in C3 diversity may be impacted by differential water stress and insect herbivory responses. In this study, we examined insect herbivory and water stress in the RaMPs. To illuminate water stress and herbivory effects in the RaMPs, the irrigation transects were sampled to provide baseline data for comparison. The isotopic signature of carbon (d13C) was determined using an EA-IRMS. This procedure allowed us to assess water use efficiency (water stress) in six C3 species representing three growth forms; shrub, forb and grass. Insect herbivory was visually assessed. d13C analysis in the irrigation transects showed no treatment effects between irrigated and control. This may be due to no difference in water availability between the irrigated and control prior to sampling. Younger leaves had water use efficiency (higher d13C) than older leaves. There were different water use efficiencies between species. Solidago canadensis herbivory was higher in the delay versus ambient (Kruskal Wallis p<0.05) and control versus irrigated during June and July. Higher herbivory in the drier treatments (delay and control) support that water stress increases herbivory response. All other species showed no herbivory trends within the irrigation transects or RaMPs. In turn, C3 community composition may be responding to differential water stress and herbivory. Percent cover of xeric late season species (Aster ericoides) was higher in delay relative to ambient treatments. Percent cover of the moderately water use efficient, early season Dicanthelium oliganthes was not affected by the delay treatment. Conversely, the low water use efficient, late season Solidago canadensis was affected negatively by the delay treatment. In conclusion, differential water stress and herbivory responses may be an important part of predicting C3 community changes under altered rainfall patterns.
Courtney Franssen - Effects of barriers on the distribution and movement of prairie stream fishes after a flood. (Mentor: Keith Gido).
Prairie streams undergo harsh environmental conditions, thus fish must either be tolerant of these conditions or able to move into refugia habitats. Moreover, ephemeral habitats in prairie streams may provide abundant resources, but fish must also move to access these areas. Thus, to understand the dynamics of prairie stream fish assemblages we must understand movement patterns. Because floods increase connectivity of intermittent habitats and barrier permeability, fishes would be expected to move during high water periods. We marked four species of prairie stream fishes (Semotilus atromaculatus, Campostoma anomalum, Phoxinus erythrogaster, Etheostoma spectabile) in Kings Creek on the Konza Prairie Biological Station, Kansas. Four hundred fish were batch marked with a subcutaneous injection of one of three site-specific colors of acrylic paint. Marked fish were returned to the stream on both the upstream and downstream side of three barriers four days prior to a flood that resulted in a 30-fold increase in discharge. In the week following the flood, a five km reach of the stream was sampled by backpack electrofishing to monitor movement. Most marked fish were found within 100 m downstream of their release point. Semotilus atromaculatuswere found as far as 0.5 km downstream of their release point. Although most movement was downstream, one C. anomalum moved nearly a kilometer upstream. Our ability to follow movements of fish after natural disturbances has increased our understanding of how floods interact with prairie fish dynamics.
Sarah Haller - Pollination ecology of Lespedeza(Fabaceae): a native and an invasive. (Mentor: Carolyn Ferguson).
Four species of Lespedezaoccur on Konza Prairie Biological Station (KPBS). While three of these species are natives, one is an introduced perennial native to Asia and Australia. Used extensively for forage crop, erosion control, and wildlife habitat, Lespedeza cuneata (Dumont) G. Don (“sericea lespedeza”) is now considered a noxious weed in many states including Kansas. Knowledge regarding pollination and breeding systems in this species as well as in other Lespedezaspecies is needed not only to better understand reproduction in L. cuneata, but also to assess the potential for hybridization between native and non-native Lespedeza species. A thorough pollination study was designed and implemented for the non-native Lespedeza cuneata and the native Lespedeza capitata Michx. focusing on 1) visitor observations 2) pollinator effectiveness and 3) breeding system. Three study sites were chosen, KPBS (L. capitata), Ashland Bottoms (L. cuneata) and Ft. Riley Military Reservation (where both species are abundant and co-occur). Netting of inflorescences was carried out to obtain virgin flowers for the pollinator effectiveness trials, and whole plants were caged as part of the breeding system study. Data collection and analysis are ongoing; final data will be collected following all seed set in September or October.
Dustin Jasken - Effects of fire and grazing on belowground architecture and vegetative reproduction in tallgrass prairie perennials. (Mentors: David Hartnett and Gail Wilson).
Plant population dynamics in tallgrass prairie are strongly driven by patterns of vegetative reproduction, as successful establishment from seed is rare and episodic. Belowground meristem populations (rhizome bud bank) may also play an important role in regulating aboveground primary production and vegetation structure. The objectives of this study were to: 1) examine variation in belowground architecture (rhizome length and diameter) and vegetative reproduction (rhizome bud demography) among six tallgrass prairie perennial plant species, and 2) to assess the effects of key ecological processes (fire and grazing) on belowground architecture and demography. Rhizome systems were excavated from approximately .05 m2 areas surrounding stems of Andropogon gerardii, Sorghastrum nutans, Andropogon scoparius, Koeleria pyrimidata, Solidago canadensis and Vernonia baldwinii between June 10 and June 25. Plants were sampled in the following treatments; grazed/annually burned, ungrazed/annually burned, and ungrazed/four-year burn. Rhizome architecture and demography was determined by measuring the previous years rhizome length and diameter, and counting new (current season) rhizomes and rhizome buds. There was a significant effect on belowground architecture due to fire frequency for only two species, S. nutans and S. candensis. Similar architectural responses to fire and grazing were observed for S. nutans and A. gerardii. Significant effects of fire and grazing on total meristem production occurred in all species except K. pyrimidata and V. baldwinii. This study suggests greater variability in belowground architecture exists between species than between treatments (fire frequency and grazing). Belowground demography was variable between both species and fire and grazing treatments. Furthermore, the relative abundances and composition of aboveground vegetation in tallgrass prairie does not necessarily reflect belowground patterns of rhizome and bud densities.
Elizabeth Murray - Territoriality in male Blanchard’s cricket frogs, Acris crepitans blanchardi. (Mentor: Eva Horne).
Many male animals expend energy to actively defend their territory from conspecific intruders. When there are limited resources, males compete with each other, and may escalate conflicts into physical encounters. Many anurans, including Acris crepitans blanchardi, use acoustic and visual signals in order to defend a territory and maintain spatial separation. I focused on a population of Blanchard’s cricket frogs located at a permanent pond at Konza Prairie Biological Station, Riley County, Kansas. Male cricket frogs were often site specific, rarely moving more than 0.5 m during a single night, and returning to the same general location on subsequent nights. Overall, males congregated on land within the first meter of the water’s edge, and calling males remained an average of 0.5 m apart. However, over time, they tended to move out into the pond as aquatic plants emerged and there was floating vegetation to sit on. In manipulations where I removed cricket frogs from a m2 plot, fewer frogs emigrated into the site the next night, and the ones that did had significantly smaller mass, implying that larger males have already established calling sites and have no need to invade a new area. However, in staged laboratory encounters, size (SVL and mass) had no effect on call rates. Cricket frogs appear to defend calling sites using both acoustic and visual signals, but the particular characteristics that determine dominance are unclear.
Judd Patterson - Analysis of soil properties six years after prairie restoration. (Mentor: John Blair).
The conversion of prairie soils to agricultural fields alters soil structure, and results in loss of stored carbon (C) and nitrogen (N). Although dominant plant species communities and aboveground processes can be restored quickly, the rate at which soil properties and nutrient pools recover after prairie restoration can be extremely slow. This project looked at various soil properties, including bulk density, total C, total N, and mineralizable C to assess trends in the recovery of ecosystem properties six years after restoration. In addition to testing soil from restoration plots, soil from adjacent agricultural fields and native prairie was also analyzed. We found that total soil C and N increased relative to levels in the agricultural field, but they were still 47% and 37% (respectively) below the levels found in native prairie. In contrast to total C, we observed that mineralizable soil C recovered much quicker, and was comparable to native prairie within six years in some of the restoration treatments. When looking at bulk soil density, the restored prairie soil was much denser than native prairie and was not significantly different from the agricultural field. These results illustrate the complexity and variability inherent in prairie restoration. While some soil properties seem to have nearly recovered to native prairie levels in the span of six years, others may need significantly more time.
Beth Ross - The effect of prairie vole (Microtus ochrogaster) runways on tallgrass prairie. (Mentors: Aaron Reed and Don Kaufman).
In tallgrass prairie, large herbivores such as bison (Bos bison) play a critical role in increasing plant heterogeneity through herbivory and nitrogen deposition. While much is known about herbivory by large ungulates in tallgrass prairie, less is known about the effects of small mammal herbivory. This study was carried out during the summer of 2003 to determine the effects of Microtus ochrogaster runways on tallgrass prairie. Vole densities were low relative to peak abundance in tallgrass prairie (mean= 72.8 voles/ha; range: 35.7-107.1). I took two five centimeter soil cores within vole runways, on the edge of the runway, twenty-five centimeters from the center of the runway, and over two meters away from any runway in order to determine the concentrations of nitrate and ammonia in the soil. Big bluestem (Andropogon gerardii) was harvested at the edge of runways, 25 cm from the center of runways, and over two meters away from runways and carbon to nitrogen ratios were found using a Carlo Erba. Plant biomass also was measured using these same distances surrounding runways. I found a significantly higher concentration of nitrate at the edge of the runway relative to samples taken two meters away from runways. Ammonia concentrations were found to be highest 25 cm from runways, with a significant difference between runway and edge of runway samples compared to 25 cm samples. There was no significant difference between C:N ratios in A. gerardii. Biomass was found to differ significantly between samples collected along the runway and samples taken two meters away from runways. The differences in ammonia concentrations found throughout micro-sites could be due to increased plant uptake of ammonia in relation to increased herbivory along runways. Increased herbivory along runways could also be the cause of decreased biomass along runways.
2001 REU Projects and Abstracts (top)
Project Abstracts - 2001
Arbuscular mycorrhizal (AM) fungi are ubiquitous mutualistic symbionts of plant roots aiding uptake of water and nutrients. The AM fungi are obligate heterotrophs and acquire carbon from host photosynthates. Despite the importance of the AM fungi to the functioning of the hosts and ecosystems as whole, very little is known how the fungal communities respond to environmental change. Studies focusing on effects of anthropogenic nitrogen have reported shifts in fungal community structure as measured by ectomycorrhizal fruiting body or AM spore abundance. This project focuses on effects of nitrogen amendment on root inhabiting fungi. Fine roots were collected from soil cores removed from grassland plots (2 m2) which received randomly assigned treatments of 0g N/m2 and 10g N/m2 in 1999 and 2000. Genomic DNA was extracted and a fragment of AM rDNA was polymerase chain reaction (PCR) amplified with eukaryotic primer NS1 and fungal specific primers AM1 and NS31. Mixed templates from environmental samples did not allow target amplicon yields great enough to perform successful cloning reactions. Optimizing PCR conditions will improve the amplification and subsequent cloning. Restriction fragment length polymorphism data will then be used to confirm distinct 18S rDNA groups. Sequencing and neighbor-joining analysis of group representatives will reveal the identities of the fungal symbionts.
Brian Darby - Soil Resource Partitioning in Grasses and Forbs: Implications for Tallgrass Prairie Productivity in a Variable Climate (Mentor: John Blair).
While the bulk of tallgrass prairie biomass is accounted for by the dominant warm-season grasses, most of the prairie’s diversity comes from composites, legumes, and other forbs. Grasses and forbs have different root morphologies, depth distributions, and responses to climatic variation. To better understand grass-forb interactions and grassland responses to climate change, a field study and computer simulation were conducted to 1) determine if grasses and forbs exhibit differences in vertical patterns of root uptake activity, and 2) model the relationship between precipitation inputs and aboveground primary productivity. For the first objective, forty-six root exclusion tubes containing Irwin silty clay loam soil were planted with either a monoculture of grass (Sorghastrum nutans), monoculture of forb (Vernonia fasciculata), or a polyculture of both the grass and forb. Tracer elements RuCl or LiCl were injected into the soil either at 15 cm or 30 cm. Leaf tissue was harvested and assessed for Ru and Li to quantify root uptake activity. For the second objective, the program ‘Watermod’ was used to simulate ANPP and soil moisture profiles in a Konza Prairie watershed from observed climatic data. Aboveground biomass accumulation could be accurately simulated using Watermod, however the program tended to underestimate soil water content, especially deeper in the profile. Both the tracer experiment and the computer simulation show promise for examining grass and forb responses to climatic variability.
Brian G. DeGasperis - Substrate-induced respiration for determining eukaryote:prokaryote ratios in soils (Mentor: Charles Rice).
The substrate-induced respiration (SIR) technique of Anderson and Domsch (1973) and West (1986) for determining eukaryote:prokaryote ratios was refined for use on tallgrass prairie soils. Glucose (1000 mg g-1 soil) was used to stimulate anabolic microbial metabolism. Antibiotics (streptomycin sulfate, chlortetracycline, chloramphenicol and cycloheximide) were tested at various concentrations to ascertain their effectiveness at inhibiting microbial respiration. Form of antibiotic addition (in solution vs. dry), optimal incubation period and method of solution preparation were also investigated. Of the antibiotics tested, chlortetracycline, added in solution, was the greatest suppresser of prokaryotic respiration. A concentration of 8600 mg g-1 soil was selected based on effectiveness and solubility. Of the concentrations tested, 13333 mg g-1 soil was selected for cycloheximide (eukaryotic protein inhibitor). Four hours was found to be the maximum incubation period which continuously yielded a constant rate of microbial respiration. Magnetically stirring for 2 hours at 24C proved to be the most effective and practical method of solution preparation. After preliminary testing of the SIR technique on a homogenous field sample, the study was extended to a limited sample of field-treated soils to explore its effectiveness at registering shifts in microbial populations prior to its use in a large-scale field study. The effects of burning and N addition on microbial community composition were investigated. There were no significant differences in bacterial:fungal ratios (BFRATIO) in the plots studied. There was a trend for a decrease in BFRATIO with burning and an increase in BFRATIO with N addition. Field-treated samples were also tested for initial inorganic N, microbial biomass (MBM) C and N, and total soil C and N. Burning increased MBM C and decreased MBM N. Nitrogen addition decreased MBM C and N.
Travis Engelbert - Pre-fledging growth rates of Common Nighthawks Chordeiles minor (Mentor: Brett Sandercock).
Growth and development of birds has been well studied overall and typically seen to be nonlinear, but these patterns have not been established for any nightjar. The purpose of this study is thus to measure the patterns in development and growth rates of juvenile Common Nighthawks (Chordeiles minor). Growth rates of this species are of special interest for three reasons. First, nighthawk young are semiprecocial, an uncommon mode of development shared with few other bird species such as gulls, terns, and other seabirds. Second, the female lays the clutch on the ground where predation pressure is high, which should select for rapid growth rates. Last, by measuring growth rates, growth curves may be established that aid in aging avian young in nests that are found after hatching. This will help workers to estimate timing of laying for breeding populations of nighthawks. Growth curves were established using a logistic growth curve commonly seen in the development of avian young. Nonlinear regression was used to estimate the intrinsic growth rate (K) and the inflection point (I) from repeated measures of chicks. Asymptotic body size (A) was taken from females captured on the nest. Using the growth rate for the mass of Common Nighthawks, it appears that they develop at a rate very similar to other semiprecocial birds as would be expected.
Theresa Kelly - Invasive ecology of Melilotus officinalis (yellow sweet clover) in undisturbed tallgrass prairie (Mentor: Alan Knapp).
Melilotus officinalis, originally from Eurasia, was introduced to North America for its nitrogen fixing ability and its use as a cover crop for birds. Although it has been found to be an aggressive invader of grasslands of the Northern Great Plains, the invasive ecology of Melilotusis not well understood. To better understand factors affecting establishment and growth of Melilotus, seeds were added to plots in upland and lowland tallgrass prairie sites in annually burned and unburned watersheds located on Konza Prairie. In addition, growth of Melilotus in plots with reduced grass cover and biomass was examined to determine how competition might influence success of this exotic legume once established. Seedling establishment was highest in the annually burned lowland site. Melilotus in the annually burned upland site received the most light but had higher mortality rates than the seedlings in the lowland area of the same watershed. This indicates that greater moisture availability in the lowlands allows for increased seedling establishment. Seedling establishment was lowest in the unburned sites, regardless of position in the landscape; however, the growth rate of Melilotus was significantly higher than in the annually burned site. Once Melilotus was established, biomass was highest in plots with the lowest grass cover and biomass. Therefore, it appears moisture and sunlight are key factors in Melilotus establishment and seedling growth, but once established competition appears to limit the success of Melilotus.
Amanda Kieke - Effects of root microflora on big bluestem seedlings and soil-borne fungi associated with prairie plant roots (Mentor: Karen Garrett).
Soilborne pathogenic fungi can have dramatic effects on plant productivity in agricultural systems, but very little is known about their role in ecosystems such as the tallgrass prairie. We conducted two studies to investigate (1) the effects of soil and root microbial communities on big bluestem (BB) seedlings and (2) the composition of fungal communities associated with the roots of five prairie plants at Konza Prairie Biological Station (KPBS). The seedling study (1) included three soil treatments (untreated KPBS soil, steamed KPBS soil, and vermiculite) and four root treatments (addition of washed BB root segments, surface-sterilized BB root segments, autoclaved BB root segments, or no addition of roots) in a factorial design. After one month, BB seedlings growing in these different treatments were harvested and root and shoot weights were measured. In an analysis of variance, there was evidence (p < 0.05) for an effect of the soil treatment on root biomass and an effect of the root treatment on both root and shoot biomass. In a mean separation test, the autoclaved root addition produced significantly lower root and shoot biomass than the surface-sterilized root addition. One explanation for this difference might be that the autoclaved BB roots contain a compound that inhibits growth of the BB seedlings. The community composition study (2) was based on fungi isolated from a collection of five plant species (Andropogon gerardii, Panicum virgatum, Sorghastrum nutans, Asclepias verticillata, and Solidago canadensis) from four sites at KPBS. Roots were surface sterilized, cut into segments, plated on potato dextrose agar amended with streptomycin and oxytetracycline, and fungi were isolated from the plates. In an analysis of variance, there was evidence (p < 0.05 in each case) for a plant species effect on abundance of each of the four primary fungal types recovered from the roots. Fusarium species were the most abundant overall. The different fungal communities associated with the different plant species may contribute to spatial partitioning of the plant community.
Heather Nippert - Movement and activity patterns of bison (Bos bison) at Konza Prairie Biological Station (Mentor: Brent Brock).
Bison preferentially graze burned watersheds. Semiweekly observations indicate that within burned watersheds, bison prefer watersheds with long fire return intervals. A study was conducted to determine if bison on Konza Prairie Biological Station (KPBS) exhibit diurnal movement and/or activity cycles; explore whether diurnal bison movements reflect grazing preferences; and determine if fine scale temporal observations agree with course scale (semiweekly) observations in quantifying bison spatial patterns. A series of 24 hour observations were conducted at weekly intervals to determine the spatio-temporal patterns of bison activity on KPBS. The locations and activity of subherds and two marked individuals were recorded at half hour intervals across 24-hour time periods. Daily area covered by marked individuals ranged from 72 ha to 544 ha. Bison were observed on burned watersheds proportionately more (92.3% of all observations) than the amount of burned area (54%) available. Within burned watersheds, the majority of observations (73.7%) occurred on infrequently burned watersheds (n>1). Peak activity periods occurred during early morning (6-8 am), and during late evening (8 pm to midnight). 24-hour observations were consistent with semiweekly observations during the same growing season regarding the percent time each watershed was used. Our results provide no evidence that bison on KPBS follow predictable diurnal movement cycles. However, periods of peak activity do appear to following diurnal cycles. Fine scale temporal observations aggregated over time agree favorably with semiweekly observations.
Audrey Owens - Home range organization and sexual dimorphism in the collared lizard, Crotaphytus collaris collaris (Mentor: Eva Horne).
In this study, I measured sexual dimorphism in collar width and mapped home ranges of collared lizards in the Flint Hills of eastern Kansas. Sexual dimorphism studies in collared lizards have linked larger body size in males and bright blue coloration with advantages in male-male competition and female choice interactions. Both male and female collared lizards have two collars around their necks. I examined collar thickness between the sexes, expecting male collars to be thicker than female collars. I found that sexual dimorphism exists in collar thickness; males have thicker collars than females. Because it is known that sexual selection exists in collared lizard populations and because exaggerated traits in males are often selected for through sexual selection, I propose that sexual selection is the mechanism causing the sexual difference in collar thickness. I also used GPS to map home ranges of collared lizards at a natural and an artificial habitat (Konza Prairie Biological Station and Tuttle Creek Dam) to compare shape and organization of home ranges between the two sites. At Tuttle Creek Dam there was great overlap in home ranges, including several adult males over one female home range, similar to what would be expected in polyandrous societies. Home ranges at Konza were linear with no overlap, restricted in shape by exposed limestone ridges. High population density of collared lizards at Tuttle Creek Dam may explain the overlap between adult males in what is normally considered a lizard with a polygynous social structure. This study suggests that home range shape and organization in a social lizard is dependent on habitat.
Amy Seery - Parent/offspring interactions in Bison (Bison bison) at Konza Prairie (Mentor: Christopher Smith).
R. L. Trivers' model of parent-offspring conflict observes that offspring are more closely related to themselves than to their own parents or siblings. Offspring should thus attempt to gain more investment than parents are selected to give despite losses to parents or siblings and resulting conflicts. The extent of this conflict was observed for Bison bison between June 6- July 24, 2001 at Konza Prairie Biological Station. Activities studied included initiation and breaking of contact between mothers and calves, responses to separation, and the milking routine. Newborn behavior was also studied until between the first and second week of life when overt maternal behavior began to decrease. Calves were then responsible the majority of the time for initiating contact and milking, and showed a tendency to exhibit higher levels of stress upon separation. Mothers were observed to vocalize more often than calves, though calves vocalize with greater intensity. No significant differences were observed between June and July for the majority of these activities though the rate of calves returning to their mothers, versus mothers returning to calves, increased dramatically in July. No significant differences were observed between older and younger mothers though older mothers and their calves appeared to exhibit lower levels of stress upon separation. Unexpectedly, it was observed that mothers would allow older offspring, up to 3 years olds, to continue milking despite the competition for resources for the calf. Calves competing with yearling siblings were smaller than calves without yearlings present. The effect on fitness of mothers, calves, and yearlings from this prolonged nursing would be a significant test of Trivers' hypothesis.
Matthew Trager - Effects of topographic position and burn regime on the vegetation of bison wallows (Mentor: Karen Hartnett).
This study examined the effects of topographic position and burn regime on the vegetation of active bison wallows in a Kansas tallgrass prairie. Study sites were located on mid-level terraces and upland areas in watersheds burned at 1- and 4-year intervals. I sampled vegetation from wallows and their respective habitat matrix in both June and July, 2001. Though most plant species were shared among wallows and undisturbed matrix vegetation, the relative abundance of many species differed between the habitat types and each hosted species not present in the other. Wallow vegetation was less diverse than matrix vegetation and generally comprised a mix of dominant prairie species and early successional ruderal species. There was significant floristic and structural variation in wallow vegetation associated with topographic position, burn regime, sampling period and the interaction of these factors. From June to July species composition of matrix sites converged as the rarer cool-season species decreased and the dominant warm-season prairie grasses increased, but species composition of wallows diverged due to differences in wallowing intensity and microhabitat availability. These findings suggest that active bison wallows provide potentially important habitat for many species and represent a heterogeneous and dynamic patch type in tallgrass prairie.
Kyle Whittinghill - Differences in microhabitat use between populations of Physella integra with and without native fish predators (Mentor: Walter Dodds).
Prey populations may develop distinct anti-predator strategies depending on the specific predator regime in their natural habitat. Although many studies have been done on anti-predator behavior in Physella, few have looked at how the response of different populations of snails to a single predator differs. I observed the microhabitat use of different P. integra size classes in three sites with fish and three sites without fish at Konza Prairie Biological Station. Snails at fish sites were significantly smaller than those in the no fish sites. Physella 2 to 5mm in length used covered habitat more than those in larger size classes and more P. integra used covered habitat in the fish sites than in the no fish sites. In a common garden experiment I observed the behavioral responses of two populations of P. integra, one from a site with fish and one from a site without fish to a common predator, creek chub (Semotilus atromaculatus). P. integra from a site with fish exhibited more anti-predator response than P. integra from a site without fish when fish chemical cues were present. P. integra from the site with fish exhibited a lower proportion of near surface and covered habitat use in the absence of fish cues. However, snails from a population without fish showed a greater proportion of both near surface and covered habitat use in the absence of fish cues than in the presence of fish cues. P. integra exhibit differences in microhabitat use depending on the predator regime at their original habitat both in the laboratory and in the field.
2000 REU Projects and Abstracts (top)
Project Abstracts - 2000
R. A. Fisher's sex ratio model predicts that for sexually reproducing, outbred species, natural selection will favor females who allocate equal resources to male and female offspring. Because pods arise from female reproductive organs in the flower, outbreeding plant species which produce large, multi-seeded pods appear to violate Fisher's theorem by overinvesting resources in female effort. Individuals of the insect-pollinated species Asclepiodora acerctes, Baptisia australis, Oenothera missouriansis, Oenothera speciosa, Penstemon cabaea, and Schrankia nuttalii were censused two to three times a week between 5 June -24 July 2000. The number of buds, flowers, and pods initiated and pods completed were recorded. Average dry weight measurements were obtained for stamens per flower, pistils per flower, petals and sepals per flower, and pods. The resulting male to female weight ratios indicated that Fisher's theorem was satisfied differently between the species studied. The expected 1:1 male to female ratio when comparing total stamen weight to total pistil weight was observed in A. acerates and O. speciosa. The closest approximation to Fisher's theorem also occurred within the flowers O. missouriansis and S. nuttallii, but at male to female ratios of 1:2 and 10:1, respectively. For B. austalis, the same 1:3 ratio was observed when female weight was defined as total pistils and male weight was defined as total stamens and when female weight was defined as total completed pods and male weight was defined as the total flowers not bearing completed pods. Fisher's theorem was satisfied in P. cobaea with a 1:1 ratio when female weight was defined as the total flowers which eventually produced mature pods and male weight was defined as the total flowers which did not bear completed pods. More observation of O. missouriansis, S. nuttallii, and B. australis would clarify which sexual factors satisfy Fisher's theorem for those species.
Barry Broeckelman - Effects of Rainfall Timing and Quantity on Goldenrod Leaf Rust (Mentor: Karen Garrett).
Many climate change models for the Great Plains predict that future precipitation patterns will change, reducing the amount of growing season rainfall and increasing the interval between rainfall events. An unnatural amount of rainfall or interval between rainfall events can therefore potentially influence the incidence and severity of leaf rusts in a plant community. In 1997, twelve Rainfall Manipulation Plots (RaMPs) were constructed in a tallgrass prairie ecosystem in the Flint Hills of northeastern Kansas. These rainout shelters were designed to apply and study the effects of a reduced quantity of rainfall, an increased interval between rainfall events, and a combination of these amount and timing variables on the tallgrass prairie plant community. The shelters manipulated precipitation patterns while keeping other atmospheric factors virtually constant. The RaMPs were used to study the effects of rainfall timing and quantity on the incidence and severity of Goldenrod (Solidago canadensis) leaf rust. A reduced quantity of rainfall or an increased interval between rainfall events lowered the incidence and severity of the leaf rust. Throughout the growing season, incidence and severity of the leaf rust in unsheltered control plots declined much more rapidly than sheltered plots treated with ambient precipitation patterns. So the results in this study cannot be applied directly to natural systems. However, because there was a difference detected between incidence and severity levels for the simulated treatments, there would probably be comparable differences in the natural environment. If climate change predictions for reduced precipitation in the future are realized, Goldenrod leaf rust will probably be less common.
Cameron A. Cooley - Observed Molecular Diversity of Arbuscular Mycorrhizal Fungi in Koeleria pyramidata (Mentor: Ari Jumpponen).
Arbuscular mycorrhizal (AM) fungi are virtually ubiquitous symbionts of plant roots aiding uptake of inorganic nutrients and are the beneficiaries of host photosynthates. Counting and identifying spores has been the conventional way to study these communities, but new molecular methods provide useful alternatives. We amplified the small subunit of the ribosomal RNA gene with primers (AM1 and NS31) specific to AM fungi. DNA was extracted from the roots of Koeleria pyramidata, a cool season (C3), perennial bunch grass native to the prairies of Kansas. Roots were collected at Konza Prairie Biological Station in mid-June. Sequencing and neighbor-joining analysis of cloned amplicons and previously identified AM fungi revealed identities of symbionts. All sequenced clones were in the genus Glomus. No representatives of Gigasporaceae or Acaulosporaceae appeared in the analysis. The species identified in this community were Glomus intraradices, Glomus sinuosum, and Glomus vesiculiferum. The highest number of clones formed a monophyletic group, remained unidentified, and was accordingly assigned as Glomus sp. The presence of only one genus, though not totally improbable, warrants further investigation. Future studies should be able to determine how this dominance responds to life stage transitions, changes in climatic conditions and other dynamic environmental parameters.
Anna Fiedler - Leaf Level Photosynthesis and Resource Availability in Restored Prairie (Mentor: John Blair).
Natalie Pheasant - Agonistic Behaviors of the Great Plains Skink Eumeces obsoletus (Mentor: Eva Horne).
Relatively little is known about the Great Plains skink (Eumeces obsoletus) and its behaviors. During an encounter between two skinks, the more aggressive skink is likely to have access to more resources, including food, shelter and mates. Thus the outcome of an encounter could be potentially important for a skink's survival as well as for its fecundity. In this study, we hypothesized that aggressiveness would be affected by tail regeneration, sex, snout-vent length, or mass. However, there were no significant differences between levels of aggression (measured by the aggression index) or the number of bites, in skinks with intact versus regenerated tails or between male and female skinks. However, male skinks did tend to bite more than female skinks. Neither snout-vent length nor mass were correlated with aggression. We were thus able to conclude that aggressiveness in the Great Plains skink (Eumeces obsoletus), measured with the index of aggression and number of bites, appeared not to be significantly affected by having an intact versus a regenerated tail, sex, snout-vent length, or mass.
Renae Schmitt - The Association between Brown-headed Cowbird Foraging and Ungulate Grazing on Native Tallgrass Prairie (Mentor: Jack Cully).
The Brown-headed Cowbird (Molothrus ater) is a brood parasite whose historic breeding range was located primarily in the Great Plains of North America. Cowbirds often forage for insects around large grazing ungulates, such as bison and cattle. Grazing ungulates help foraging cowbirds by flushing insects from vegetation. Recent research has focused on how ungulates and habitat structure affect cowbird foraging behavior and populations. However, much of the research takes place in areas with no native prairie and focuses on the cattle-cowbird association. Since cattle and bison behaviors differ, and cowbirds evolved with bison on tallgrass prairie, it is necessary to research how cowbirds forage on tallgrass prairie with both bison and cattle. I hypothesized that bison and cattle behaviors differed significantly and that cattle grazed more than bison. Because cattle behavior would be more predictable, foraging cowbird flocks would be larger around cattle than bison. I also hypothesized that foraging flocks would be larger on cattle-grazed than ungrazed tallgrass prairie because of shorter vegetation and that foraging flocks would be larger around cattle herds than in any other area on cattle-grazed prairie. I observed bison and cattle in separate enclosures and noted the time they spent performing eight behaviors and the numbers of cowbirds in each enclosure. I performed flush counts on cattle-grazed and ungrazed watersheds and noted any foraging cowbird. I also compared the number of cowbirds flushed around cattle herds to the number flushed in areas away from the cattle herds. I found that bison and cattle behaviors did not differ significantly nor did they affect cowbird flock size. More foraging cowbirds were on cattle-grazed than ungrazed watersheds, although there were still very few cowbirds on cattle-grazed watersheds. However, there were a large number of cowbirds foraging around cattle herds, suggesting that cowbirds select grazed tallgrass prairie because of the cattle and not the shorter vegetation. Much more work needs to be done on the ungulate-cowbird association in order to gain new insights on how cowbirds select and use habitats.
Zachary Simpson - Diel Horizontal Migration of Daphnia galeata mendotae and Simocephalus in Response to Multiple Predator Cues (Mentor: Christopher Guy).
Vertical and horizontal diurnal shifts of cladoceran species have been well documented in previous studies. Such shifts for daphnids are typified by a nighttime ascent in the water column and a pre-dusk or pre-dawn descent into the hypolimnion of stratified lakes. Shifts in horizontal habitat preference between littoral and limnetic habitats have also been observed. Diel horizontal and vertical migrational (DHM and DVM, respectively) patterns are thought to be mediated primarily by kairomones, or chemicals given off inadvertently by potential predators. Light and food abundance also influence DHM and DVM. However, the effect of multiple predator and environmental cues on DHM has yet to be examined for most daphnid species. In order to examine the behavioral effect of multiple predator and environmental cues on a daphnid species, an experimental design was established in which chemical cues from juvenile bluegill (Lepomis macrochirus), Chaoborus lichtenstein (a planktivorous midge larvae), and macrophytes (Chara pondweed and associated organisms) were either present or absent. Combinations of these cues yielded eight different treatments. Cue concentration was regulated to resemble threshold literature values which elicited significant daphnid response. Five Daphnia galeata mendotae or Simocephalus were placed in aquaria with one-half of the tank filled with plastic macrophytes; the other part of the tank was open. The number of Daphnia in the clear part of the tank was recorded five times during both daytime and nighttime light intensities. Mean daytime and nighttime position was not significantly different for either D. galeata or Simocephalus for each treatment. Simocephalus position was mediated somewhat antagonistically by the presence of bluegill and C. lichtenstein cues in mixture. A significant open water response was found for D. galeata mendotae in the treatment with all cues present. Bluegill, C. lichtenstein, and macrophyte cues had significant effects on D. galeata mendotae habitat preference. The effect of such cues is thought to be additive with respect to D. galeata mendotae habitat preference. This study shows that habitat specificity in cladoceran species may be mediated by not one, but many, predator and environmental chemical cues.
Sarah (Sadie) Solomon - Habitat Associations of Coleoptera in Tallgrass Prairie (Mentor: Ray Matlack).
Insects were collected using pitfall traps in native tallgrass prairie at Konza Prairie Biological Station, Kansas. Insects were sampled in two watersheds, one long-term unburned watershed (K20A) and one watershed that is burned every two years (K2A) including the year this study was conducted. Insects were sampled in lowland, slope, and upland prairie within the two watersheds. Insects were collected from each watershed for four consecutive days. Only hard-bodied insects (adults and immatures of hemimetabolous insects and adults of holometabolous insects) were collected, with the exception of ants, which were excluded from the study. A total of 383 insects were collected from K20A and 491 insects were collected from K2A. Coleoptera was the most abundant order collected during sampling. Within the order Coleoptera, comparisons between watersheds were made at the family level. The Carabidae were found to be more abundant in K2A than K20A, while all other common beetle families were more abundant in K20A than in K2A. Coleoptera were more abundant in the lowlands of K20A and in the uplands of K2A. Carabidae were especially abundant in K2A and appear to be driving the distribution pattern seen for beetles in this watershed. Removing Carabidae from the analysis resulted in a shift in habitat associations of Coleoptera within K2A from Coleoptera being most abundant in uplands to being most abundant on slopes. Removal of Carabidae from the data had no effect on the distribution pattern of Coleoptera in K20A. Factors driving these distribution patterns are unknown, but may include habitat selection based on the effects of fire disturbance, prey availability, or differences in patterns of vegetation growth. Species level comparisons may also reveal patterns that are not apparent at the levels examined in this study.
Arden Thomas - Population Ecology of the Tallgrass Invasive Species Andropogon bladhii: Implications for Management (Mentor: Gail Wilson).
While there has been much exotic species research, few studies have examined the processes that enable invasive species to become established and persist. Population level studies of established nonnative species can provide insights on the traits that enable certain exotic plants to be both successful colonizers and competitors in a new environment. Additionally, integrating general population ecology knowledge with information about how nonnative populations respond to various management treatments can indicate the best strategies for controlling exotic species. Our study focused on Andropogon bladhii, a C4, warm-season tallgrass prairie invasive grass. We performed two pair-wise comparisons on an established population of A. baldhii: herbicide treatment vs. unburned. In the herbicide treatment vs. control comparison, we randomly selected plots out of a grid of 5m by 5m plots to receive one treatment of Glyphosate, while the control plots received no herbicide. A. bladhii clones in both herbicide plots and control plots were identified and tagged. In the unburned area, 31 clones were randomly selected and tagged. Clones were censused in mid June and late July to assess growth, treatment effects, and resource allocation patterns. Our results indicated that most clonal tillering occurs early in the growing season, burn treatment skews population demography towards smaller clone sizes, and vegetative reproduction and mortality are size dependent. Resource allocation assessment shows that unburned clones allocate more resources to sexual reproduction than do burned clones. Herbicide treated clones allocate more resources to juvenile tiller growth than do untreated clones. These results imply that a spring burn treatment increases herbicide effectiveness. Additional resource allocation analysis, continued population monitoring, and comparisons of life history strategies to native tallgrass prairie grasses are still needed.
Laura Wiles - Temporal Variation in Aquatic Invertebrate Communities of Bison Wallows (Mentor: Jim Garvey).
Bison wallows are a type of ephemeral aquatic habitat created from the wallowing behaviors of bison. Ranging in size from about 0.30 to 3.93 m3, they hold water on the order of days to weeks. Although they can be full any time of the year, they are most likely to be full in May and June. This study hypothesized: (1) that there would be an increase in taxa richness over time within years from spring through summer and within wallow filling events and (2) that the wallow community would shift over time within years. Wallows were sampled at Konza Prairie Biological Station in spring and summer of 1997 and 1998. In June 1997, wallows were manually filled with well water due to a lack of precipitation. While the wallows held water, they were sampled every few days with a 0.7 mm mesh dip net. Sampling was done for three minutes. Organisms were identified as far as possible; for insects, this was generally to the genus level. Total taxa richness, adult insect richness, and larval insect richness were all examined with the general linear models procedure of SAS. Comparisons were made within years and wallow fillings, as well as between years and wallow fillings.In 1997, samples were collected in April and June. In 1998, wallow fillings in April and August were sampled. In all, the data represented four wallow fillings. No support was found for the hypotheses that taxa richness would increase within years or wallow fillings. However, there was a trend toward an increase to a peak and then a decrease within wallow fillings. This trend was seen in all the types of richness examined, though not always in every filling. A great deal of variation was seen in all types of richness. No other patterns were apparent. Between April 1997 and April 1998, we did not find significant differences in richness (p = 0.52). However, when June 1997 and August 1998 were added to the comparison, richness was significantly different (p = 0.0491), indicating that the differences were due to seasonal variation. Different organisms were present in the wallows during different months of the year. For example, Hemipteran adults were absent in August samples, while Baetid Ephemeropterans and clam shrimp (Order Conchostraca) were absent in April. We conclude that (1) richness did not increase over time within years or wallow fillings, (2) there was seasonal variation, though not annual variation in the richness of the invertebrate communities of bison wallows, (3) there was a trend toward a peak in richness in the middle of wallow filling, and (4) the wallow community changed over time within years.
Julia C. Wilcox - Effects of Plant Density on Growth of Tallgrass Prairie Forbs (Mentor: Alan Knapp).
The effects of community plant density on forb biomass, growth, and mortality were examined at Konza Prairie, an undisturbed tallgrass prairie. Individuals of Ambrosia psilostachya, Aster ericoides, and Asclepias verticillata were monitored during the summer of 2000. Stems of select C4 grasses and forbs were removed in 0.5 m2 plots so that a total of 72 plots would fall into one of three density levels: high, medium and low. Decreasing plot stem densities resulted in an increase in growth of Ambrosia, but this was not seen in Aster or Asclepias. Instead, decreasing plot stem densities increased mortality in Asclepias and possibly also Aster, but not in Ambrosia. This study indicates that forb species do not have a uniform response to changes in plot stem density, and care is needed when making generalizations about functional groups of plants.
1999 REU Projects and Abstracts (top)
Project Abstracts - 1999
In general, global climate change models predict opposing outcomes for the midwest under global warming in terms of the area either becoming increasing warmer or cooler. Predictions do agree, however, that a rise in atmospheric moisture is inevitable and will be responsible for increasing the intensity and variability of rainfall events. In order to understand how this increased intensity and variability would affect a tallgrass prairie ecosystem, the rainfall manipulation plots (the RaMPs) were built on the Konza Prairie in 1997. The RaMPs are designed to keep out natural rainfall and allow for rainfall collection in large water storage bins located in each plot. The collected rainfall is then used for re-application according to one of four designed treatments. The RaMP treatments have been designed to be factorial combinations of two specific treatments: the amount of rainfall applied and the timing of a rainfall event. The focus of this project was to determine the effects of altered precipitation on nutrient cycling, specifically nitrogen cycling. In order to examine the effects, a number of techniques were used. Resin bags, which consist simply of ion exchange beads, were placed in the plots for a period of one month to collect ammonium and nitrate ions from soil water. In addition, soil samples from all fifteen plots were collected and analyzed for extractable inorganic nitrogen and microbial biomass nitrogen using the techniques of KCl extraction and chloroform fumigation extraction respectively. For all of the data, statistics were run to test for a main effect of the drought treatment (change in the amount of rainfall) and for a main effect of the delay treatment (change in the timing of a rainfall event) and for any interaction between the two treatments. It was found that the delay treatment resulted in less plant available soil nitrogen and an increase in the amount of nitrogen sequestered in soil microbial biomass. The drought treatment had less of an effect on plant available nitrogen and microbial biomass. Overall, changes in the timing of rainfall events may have a greater effect on soil nitrogen cycling than changes in the average amount of rainfall, at least short-term.
José Checo Colón-Gaud - Growth rates for Chironomidae (Diptera) in two habitats in King’s Creek (Mentor: Matt Whiles).
Temperature-dependent growth rates of Chironomidae (Diptera) from communities characteristic of two distinct stream habitats were examined in Kings Creek at the Konza Prairie Research Natural Area. In situ growth chambers were stocked with various length-classes of chironomids to compare growth rates from the different habitats. Two replicates of the test were run during the months of June and July 1999, with the time intervals of approximately 11 to 14 days each. The average daily biomass growth rate for individuals across all replicates was highest for the Gallery2 community (0.1320 d-1) followed by the Gallery1 community (0.1301 d-1). Lower growth rates of 0.1271 d-1 and 0.0758d-1 were found in Prairie site tests 1 and 2, respectively. No significant difference in growth rates were found between the habitats (p values = 0.90 and 0.31 for tests 1 and 2, respectively). Further growth studies are still in progress. Growth rates of this numerically dominant aquatic organism will be used for a larger project to determine the secondary production of the aquatic insect community of Kings Creek.
Alexandra Latham - Brown-headed Cowbird Parasitism Rates on Ground-Nesting Birds of the Tallgrass Prairie in Bison-grazed and Ungrazed Habitats (Mentor: Jack Cully).
The Brown-headed Cowbird (Molothrus ater) is North America’s best known obligate brood parasite. It is believed to have coevolved with bison, which played an important role in the existence of the cowbird by disturbing insects from the ground cover, on which the birds could feed. The Dickcissel, the Grasshopper Sparrow, and the Eastern Meadowlark are common grassland hosts of the cowbird. We hypothesized that nests of the three species would exhibit higher rates of cowbird parasitism in bison-grazed than in ungrazed habitat. The study was conducted between 6 June and 19 July on Konza Prairie Research Natural Area, in the Flint Hills, northeastern Kansas, where bison graze approximately 1,000-ha of the research area. Sixty-six nests were located. Rates of cowbird parasitism were higher for all host species in the bison-grazed area than in the ungrazed area. Rates of parasitism for all species grouped together were significantly different between sites. Results indicate that parasitism may be enhanced by shorter and less dense grass, characteristic of bison-grazed habitat, which improves the probability of locating host nests. Further studies would be valuable to determine the importance of these two factors.
Molly Magill - Side-pool Dynamics of King’s Creek, Konza Prairie (Mentor: Walter Dodds).
King’s Creek on the Konza Prairie Research Natural Area consists of a main channel and several adjacent pools and channels that arise due to changes in water flow and level. These pools share hydrology with the main channel at times, but as the water level decreases, exchange between the two also decreases. Research completed during the summer of 1999 revealed some of the characteristics of these pools. Nitrate levels in the pools is significantly lower than in the main channel, indicating that the microbial activity in the pools has a great effect on their chemistries. Pools that have more organic and silt composition tend to have lower dissolved oxygen. Also, by releasing a known amount of sodium bromide and measuring the concentration over time, it was shown that the pools had reduced water exchange (turnover time) with reduced volumes, and the longer the turnover times, the less dissolved oxygen in the pools. Finally, by comparing the oxygen demand of the various substrata, it was concluded that turnover times and substrate composition both contribute to the oxygen levels in the pools, as organic silt substrata had higher oxygen demand within the substrate.
Jim McFadden - Environmental History and the Trajectory of Scientific Management Since 1971 on Konza Prairie Research Natural Area, Riley and Geary Counties, Kansas (Mentor: Jim Sherow).
Konza Prairie Research Natural Area is a managed landscape, and the plant and animal communities in its boundaries respond to and reflect human land use practices. The record of human manipulation of the Konza Prairie (KP) landscape is fairly continuous, long-lasting, and profoundly real. After 1850 Euroamerican settlement began and KP experienced tremendous landscape modification as a result of agricultural and ranching practices. In 1971, scientific experiments began to alter the landscape as well. Consequently, Konza is not natural in the sense that it is an undisturbed, unmanaged landscape, seemingly set apart from human civilization. Rather, its visual appearance, its built environment, and its biotic characteristics reflect the history and pattern of human use and ecological perception of the land. Individual backgrounds and ecological philosophy greatly affect how scientists envision the landscape. Plant and animal communities show dynamic responses to human land-use practices, so future KP geography and the visible, built, and biotic environments of the prairie depend on the human relationship with the land. The past is not over. It is merely a prologue, and it reappears again and again, as a walk to the old 12th Street intersection shows. Scientific management ensures the constant presence of human beings at KP into the future. As long as it continues, KP will continue to need human beings to guide and shepherd it ecosystem.
Hope Phillips - Evaluation of Population Estimation by Removal Sampling in Kings Creek (Mentor: Christopher Guy).
Population estimation is an integral part of fisheries science. Electro-fishing using the depletion removal method is one of the most common techniques used to obtain population. The objectives of this study were 1) to determine if fish density and catch-per-unit-effort (CPUE) from a single-pass electro-fishing event is correlated with the population density estimates obtained from the depletion removal method and 2) describe relationships among habitat variables and probability of capture from electro-fishing in Kings Creek. The study was conducted on Kings Creek, within Konza Prairie Research Natural Area in the Flint Hills region of eastern Kansas. Two species of fish, southern redbelly dace (Phoxinus erythrogaster) and central stoneroller (Campostoma anomalum) were analyzed. Significant correlations were found between CPUE and estimated density (fish/m2) and first pass catch density and estimated density (r2 = 0.42, p = 0.03; r2 = 0.85, p = 0.0001, respectively) for southern redbelly dace. estimated density r2 = 0.30, p= 0.1). There were no high correlations between any of the measured habitat parameters and probability of capture for either species. These results suggest that it would be effective and time efficient to use the first pass catch density estimates to estimate southern redbelly dace populations in Kings Creek. More research is needed for the other species in Kings Creek.
Catherine Stewart - Growth of Andropogon gerardii and Solidago canadensis Under Altered Precipitation Regimes (Mentor: Phil Fay).
Rising temperature has been predicted to reduce growing season rainfall and increase the intervals between rainfall events. The Rainfall Manipulation Plots (RaMP) were implemented in 1997 to study the effects of altered rainfall regimes on plant species composition, nutrient cycling, and above‑ and below‑ ground plant growth dynamics on Konza Prairie, in northeastern Kansas. Twelve semi‑permanent greenhouse structures were constructed and four treatments were established in a randomized complete block design. These combined two treatments a) altered growing season rainfall quantity and b) altered timing of rainfall events. To determine the effects of altered precipitation regimes on plant growth, Andropogon gerardii and Solidago canadensis were measured through June and July 1999. Growth rates and biomass predictions were then calculated. Decreased rainfall altered plant growth only when the interval between rainfall events was increased. A. gerardii showed elevated growth, while S. canadensis showed depressed growth in these plots. A. gerardii had a variable growth rate which was rapid at the beginning of the season and decreased toward the end. S. canadensis had a constant growth rate which declined over the season. In the increased interval plots, growth rate responded negatively to increased periods of drought and increased after applied rainfall. Biomass correlated positively with total leaf area in A. gerardii, and total leaf length in S. canadensis. Predicted biomass over the season revealed similar patterns of the growth pattern data. The differences between A. gerardii and S. canadensis are best explained by C3 and C4 physiology.
Amy Toth - Preliminary Studies on the Foraging Behavior of the Western Slender Glass Lizard (Mentor: Eva Horne).
Ophisaurus attenuatus, the Western Slender Glass Lizard, is a little-studied member of the family Anguidae. The Anguids are generally considered to be actively foraging lizards with high prey chemical discrimination (PCD) abilities. A preliminary study on the foraging behavior, PCD ability, and behavioral effects of tail autotomy was conducted using 6 lizards from Kansas. Foraging behavior observations indicate low overall activity levels and no differences between various aspects of lizard behavior in the presence or absence of food items (crickets). These observations point to a sit-and-wait strategy of foraging for this species. There was a striking trend showing greatly reduced activity of lizards which had lost part of the tail as compared to lizards with complete tails. PCD ability was studied by presenting cotton swabs bearing prey and control odors to lizards and noting responsiveness to the odor based on tongue-flicking and predatory attacks. Moving and stationary cotton swabs were also tested to determine if these lizards are responding to visual cues from prey. Results showed a lack of PCD ability by the lizards and a tendency to rely more on visual cues in attack “decisions”. These results are intriguing in that they are characteristic of sit-and-wait predators, contrary to what one would expect from an Anguid species. More work is needed to cement these findings, since sample sizes were too small to adequately support any of the observed trends.
1998 REU Projects and Abstracts (top)
Project Abstracts - 1998
Predation is the major cause of nest failure on the tallgrass prairie. Current land management practices such as cattle grazing and annual burning may increase predation rates, causing the population declines seen among species that breed on the tallgrass prairie. High predation may also be due to the low structural diversity of vegetation in prairie ecosystems, which limits nest site selection. Artificial nests were placed along transects in eleven watersheds on Konza Prairie Biological Station to measure the relative rates of predation between combinations of burned and grazed land treatments. Nests were placed either in the bush or under forbs on the ground to compare predation between the two types of nest locations that exist on the prairie. The results also suggest that burning decreases daily survival, whereas grazing increases the daily survival rates. These results are contrary to data obtained from real nests. However, heterogeneity of vegetation is higher in grazed sites and lower in burned sites. Hence, the predators may be more capable of developing a search image for nests in burned ungrazed sites because forbs are less diverse and at a lower density in these watersheds.
Nathan Heavers - The effects of cattle ranching on the Dewey Ranch Ecosystem (Mentor: Jim Sherow).
The Dewey Ranch, south of Manhattan, Kansas, was part of a rich cultural and ecological history of cattle grazing in the Flint Hills. Changes in cattle management practices on the Dewey Ranch between 1930 and 1977 had a critical impact on the ecosystem. The ranch ecosystem consisted of all the geographic features of the area including climate, soil quality, water availability, and fire, as well as biological components, such as vegetation, cattle, and man. Man’s interactions within the ecosystem are the focus of this historical analysis which considers both culture and developing technology as ecological factors. In reconstructing the history of the Dewey Ranch, it is apparent that man was a central figure in this ecosystem and the cattle management practices he employed resulted in ecological change.
Mary Jamieson - Pollen-Ovule Ratios and Breeding Systems of Prairie Forbs (Mentor: Christopher Smith).
Plant mating systems control patterns of gene flow and thus genetics variation of plant populations. Self-fertilization has evolved repeatedly in the plant kingdom despite the pressures of inbreeding depression. This phenomenon, in particular has created great interest in understanding the evolution of plant breeding systems. Many studies attempt to elucidate the mechanisms of pollination biology and to describe the dynamics and components of plant reproduction. One aspect of plant mating systems that has been widely studied is the pollen-ovule ratio of plants. Two non-mutually exclusive theories exist regarding the relationship of P/O and plant breeding systems (Cruden 1977 and Charnov 1982). Our study examines the correlation of P/O and the breeding systems of 20 selected species of forbs on the Konza prairie. P/O was quantified by counting pollen grains with a haemacytometer and ovules under a dissecting scope in a solution of aniline-blue in lactophenol. P/O was then compared to outcrossing indices determined in an earlier study (Townsend 1984). Using Spearman’s rank correlation it was shown that no significant correlation exists in species across phylogenetic groups (r=0.200; N=20;p<0.05). However, supporting both Cruden’s and Charnov’s hypotheses regarding closely related taxa, P/O was shown to be negatively correlated with outcrossing indices of species within tested families. Thus, P/O may be a useful tool to assess plant mating systems within monophyletic groups.
Amanda J. López - Nutrient Uptake in Prairie Streams (Mentor: Walter Dodds).
Understanding nutrient dynamics in streams is an important aspect of study of aquatic nutrient pollution. Nutrient uptake studies were conducted in a prairie reach and a gallery forest reach of King’s Creek on the Konza Prairie Biological Station. Nutrient uptake rates and uptake lengths were measured with several short-term additions of nitrate, ammonium or phosphate at constant release rates in the spring and summer of 1998. A conservative tracer of sodium bromide was used to account for biotic dilution. Linear regression was used to fit uptake rates. The results from different concentrations were used to determine whether the uptake was limited by the biotic capacity of microorganisms to accumulate nutrients, or by the stream’s physical characteristics (including limitation by hydrological transport into stream biofilms). Our results demonstrate that uptake rates can be saturated, indicating limitation by hydrological transport can be exceeded at high nutrient concentrations in the stream. However, the absolute concentration that uptake was saturated at varied among reaches and nutrients.
Jennifer Nelson - Indirect Interspecific Interactions: Average Interaction Strengths of Indirect Interaction Chains (Mentor: Walter Dodds).
Interactions among species shape and structure communities. When looking at a community, one can see that there are a large number of possible direct interactions among species. Moreover, some species can have profound impacts on other species with whom they do not interact directly. How important are these indirect interactions in general? For this study, I looked at the average interaction strength for direct, and indirect interaction chains of various lengths. Direct interaction strengths were determined from published community matrices. Interaction chains were made with "links" provided by direct interactions. Each link species appeared only once in each chain. In general, the average strength of the interaction chain decreased with increasing number of links in the chain. In communities dominated by negative interactions, (i.e. competition) a positive indirect interaction offset the negative direct interactions.
Tanya Smutka - Food Habits and Predation Rates of Creek Chubs (Mentor: Christopher Guy).
The purpose of this study was two-fold; (1) to determine the food habits of creek chubs, and (2) determine predation rates of creek chubs and largemouth bass on southern redbelly dace. Creek chubs were collected from Four Mile Creek on Fort Riley and from Kings Creek on Konza Prairie. Food habits of creek chubs collected from Four Mile Creek consisted of aquatic invertebrates (71%; mean percent composition), terrestrial invertebrates (15%) and unidentified invertebrates (15%). However, the diet of creek chubs from Kings Creek consisted of more terrestrial invertebrates (73%) than aquatic invertebrates (27%). In the laboratory predation study, largemouth bass had a significantly higher (P<0.0001; mean = 2.8) piscivory rate (number of southern redbelly dace per day) than creek chubs (mean = 0.5). The difference in food habits between these two populations may be due to differences in the fish assemblage between the creeks. Although no fish were found in the food habits data of creek chubs collected from Four Mile and Kings Creeks, creek chubs did exhibit piscivory in the laboratory experiment. However, the impacts of piscivory on stream fish communities by largemouth bass are likely greater than creek chubs.
Shawn Papon - Nutrient Contents of Invertebrates on Different Sites (Mentor: Robert Robel).
Invertebrate biomass commonly comprises over half of the dietary intake of breeding grassland birds. The nutrient content of this invertebrate forage base for birds differs by taxonomic category and site. One of the reasons proposed to explain the differences in nutrient contents of invertebrates from different sites was the food substrate quality of the invertebrates collected. To test this hypothesis we collected invertebrates from sites of different soil fertility (determined by total C and N content) and compared the nutrient contents of those collections. Pitfall traps were used to capture invertebrates from annually burned and 6-yr burned sites on the Konza Prairie Biological Station in eastern Kansas and from a sand sagebrush site in southwestern Kansas. Representatives of Carabidae, Gryllidae, and Acrididae were separated from the invertebrate collections and analyzed for nutrient content. Total C and N contents in soil samples from the southwestern Kansas site were significantly lower (p<0.05) than those from eastern Kansas sites; total C and N in soils of annually burned sites were not significantly different than those of 6-yr burned sites. Total C contents of invertebrates were significantly higher on Konza, and total N (crude protein) contents of the herbivorous invertebrates, i.e., Gryllidae and Acrididae, were significantly higher in more fertile sites. Data collected in this study indicate that the site-related differences reported earlier in nutrient and energy contents of invertebrates.
Sophie Parker - Dogs as Models in the Study of Predator Olfaction (Mentor: Phil Gipson).
Standardized odor attractant tablets are often used as tools in the study of predator ecology, particularly with scent stations to assess mammalian predator populations. Despite their frequent use, little has been done to determine how far predators can smell these tablets, or how the distance of first detection varies with changes in weather conditions. Two male Australian Shepherds and one female Samoyed, all obedience and agility trained, were used to study how far standard odor attractant tablets can be detected. The greatest downwind distance a test dog was able to detect odor from a tablet was 1029 meters. This occurred with 85% relative humidity, an air temperature of 74°F, and a slight breeze (<1 mph). The shortest downwind distance at which a test dog detected the odor was 470 meters. This occurred on a morning with 90% relative humidity, an air temperature of 66°F, and no wind. The average distance from the tablet at first detection over ten trial runs was 829 meters. Changes in the dogs’ first detection distances appear to be correlated with wind and other weather conditions. This information may aid researches in estimating the distances from which wild predators could be attracted to scent stations.
Natali E. West - The Effect of Bison Grazing on Soil Respiration on the Konza Prairie (Mentor: Loretta Johnson).
It has recently been thought that large mammals such as bison have substantial influence over ecosystem processes such as nutrient cycling and may serve as a keystone species on tallgrass prairies. The focus of this research was to explore the effects of bison grazing on soil respiration. Data indicates that grasses often preferentially allocate carbon resources for aboveground growth following defoliation (or grazing); it was therefore hypothesized that soil respiration would decline under grazed conditions. The N4D grazing lawn on the Konza Prairie served as the study site. Soil respiration measurements were made using a Licor 6200 Photosynthesis System. Measurements were made both in the grazing lawn itself and in ungrazed enclosures assembled on the study site. Soil temperature and moisture were measured simultaneously with respiration. Microbial respiration under moderately and heavily grazed conditions was also analyzed through controlled incubations. Results indicated that bison grazing did significantly decrease soil respiration and significantly increase soil temperature, but had no significant effects on soil moisture or microbial respiration.
Charmaine Woodard - Abundance and Diversity of Burying Beetles (Silphidae) on Konza Prairie (Mentor: David Rintoul).
The burying beetles of Konza Prairie Research Natural were surveyed for their seasonality and diversity, as well as any possible preference for watersheds varying in burn frequency from one to 20 years. Seven pitfall traps on three sites were employed. The possibility of finding the endangered species, Nicrophorus americanus, may also exist, so appropriate precautions were taken in case of this event.
1997 REU Projects and Abstracts (top)
Project Abstracts - 1997
The North Kings Creek gallery forest of Konza Prairie Research Natural Area is a relatively narrow strip of deciduous forest limited to the draws of several watersheds. Little is known about the factors controlling net primary production (NPP) of the gallery forests, but studies have shown that the surrounding prairie responds to precipitation (PPT) with a four fold variation in NPP. We have assumed the gallery forest will respond to PPT also. Litterfall and precipitation data from the Konza Long Term Ecological Research (LTER) data bank were used to test this assumption. Using ring-width data from trees as an estimate of wood production, a two-fold variation in NPP was found, but with no correlation to PPT. Litterfall also varied two-fold without a relationship to PPT. Seed production was found to vary ten-fold temporally, but the accuracy of the samples is questionable due to wildlife being seen foraging in the litterfall traps. Litterfall, seed, and PPT data from 1981-1995 were compared to tree ring measurements from the same years but no significant correlations were detected. We concluded from this study variation in NPP of the gallery forest appears to be driven by factors other than PPT.
Michael Cottam - An Analysis of Wallowing Behavior in American Bison (Bosbison) (Mentor: Don Kaufman).
Past hypotheses concerning the causes of wallowing behavior of bison (Bos bison) include social constructs and relief from irritation associated with shedding and external parasites; none of these hypotheses have been adequately studied. During June-July, 1997, I examined wallow use by bison on the Konza Prairie. Wallow use peaked in early July; wallow use was also greater during early afternoon than during other times. Males and adults used wallows significantly more (p < .0001) than females and yearlings, respectively. No environmental or physiological factors I examined (temperature, humidity, wind speed, shedding) were significantly correlated with wallow use. My results suggest that the factor(s) influencing wallow use vary temporally and among sex/age groups.
Melissa Hill - Activity of White-tailed Deer (Odocoilius virginianus) (Mentor: Glennis Kaufman).
Little work has been done on activity patterns and habitat use of White-tailed deer (Odocoileus virginianus) in native tallgrass prairie. I examined daytime spatial and temporal distribution of White-tailed deer on Konza Prairie. Routes were driven at specific times to observe activity. My results indicate that activity of White-tailed deer was non-random both spatially and temporally. Activity was greater in areas with relatively more woody vegetation. Activity also was greatest in lowlands, and least in upland areas. Deer were more active near dawn and dusk. These results are part of a year-long project that will compare interseasonal as well as intraseasonal activity.
Jamie S. Johnson - Habitat Preference of Mammalian Predators in the Flint Hills of Kansas (Mentor: Phil Gipson).
Several methods, including telemetry and trapping, have been utilized to study the habitat preferences of mammalian predators. We used another technique which incorporated scent stations, that are commonly used to census predators. Often, such stations are placed alongside roads and, thus, would seemingly only census those individuals traveling along roads. This project focused upon determining the habitats preferred by key mammalian predators, including coyotes, bobcats, raccoons, and opossums. We placed scent stations in the dominant habitats at Fort Riley Army Base, and along roads in those habitats. Scent stations were baited with a fatty acid scent tablet for 24 hours and checked for signs of visitation. We concluded that predators as a group did not display a choice between forest and prairie habitats, but coyotes preferred prairie and raccoons preferred forest habitat. No preference for or avoidance of roads was detected.
Laura Krueger - Diversity and Food Preference of Carrion Beetles (Coleoptera: Silphidae) on Konza Prairie (Mentor: David Rintoul).
Silphid diversity was studies on Konza Prairie using pitfall traps and blacklighting. Six species of silphids were captured. Burying beetles (Nicrophorus sp.) are known to be attracted to rotting meat in pitfall traps. We examined preference of beetles for the type of bait used, the age of the bait, and the location of the trap (upland or lowland). Mice and beef liver baits were used and beetles preferred traps baited with mice. Beetles were captured only in traps with bait aged two days or more. The beetles did not prefer upland or lowland habitats. Results showed that if carrion beetles are presented with a choice in baits they prefer a natural carrion source aged at least two days.
Daniel E. Neafsey - Interactions Between Three Trophic Levels: A Carrion Flower, Its Insect Pollinators, and Crab Spiders (Mentor: Christopher Smith).
Old Plainsman (Hymenopappus scabaeosis) produces a carrion-like odor by which it attracts flies and other insects to accomplish pollination. Crab spiders (Thomisidae) reside covertly on the inflorescences and capture visiting insects, preferring plants with larger inflorescences that attract more insect. Using size-selective insect exclosures I found that pollination was occurring primarily through visitation by insects of the size preyed upon by spiders. I determined that spiders were not significantly affecting pollination by means of a controlled spider removal treatment. The percentage of viable seeds obtained from a plant was used as an estimation of pollination success. Plants which had their carrion odor masked by perfume were less successful at attracting insects. Inflorescence size was found to be primarily limited by local resource availability.
Aaron T. Pearse - Effects of Food Supplementation on Incubation Behavior of Bewick's Wrens (Thryomanes bewickii) and House Wrens (Troglodytes aedon) (Mentor: John Cavitt and Jack Cully).
The extent of paternal investment during the incubation period varies between passerine species. For example, the provisioning of incubating females by males (incubation feeding) is a common behavior found in over 40% of passerines. I examined why Bewick's Wren males provide food to incubating females at a higher rate than House Wrens males. A ration of 15 g of mealworm larvae (Tenebrio molitor) was delivered to supplemented nests every 1-2 days. Mealworms were placed in small containers attached to the inside of nestboxes. Parental behavior was monitored by video taping nest activity. Females provided with additional food had longer incubation bouts and shorter incubation recesses but there were no significant effects on correlates of fitness examined.
Melissa Ann Pline - Characterization of Eastern Redcedar Forests in Northeastern Kansas (Mentor: John Briggs).
The increase of eastern redcedars (Juniperus virginiana L.) In northeastern Kansas is a recent, fire-protected phenomenon that threatens native tallgrass prairie ecosystems. The physical characteristics of density, species composition, and photosynthetic active radiation were studied in upland redcedar forests using a combination of aerial photographs and tree coring. The age of these forests ranged from 30 to 65 years. The stands were found to have dense overstories, greater than 90% bareground, low species richness and ground level PAR. This study found that in a period of 30 years redcedars can invade unburned prairies and mature to dense monoculture overstories that limit understory growth.
Tara Schubert - The Effects of Competition and Mycorrhizae on Selected Tallgrass Prairie Plants (Mentor: David Hartnett).
Arbuscular mycorrhizal fungi are abundant and ubiquitous in the tallgrass prairie. This experiment investigated the effects of both mycorrhizae and interspecific plant competition on plant growth and stem density of three tallgrass prairie plants. Two experimental manipulations--suppression of mycorrhizae and removal of two of the dominant competitors (Andropogon gerardii and Sorghastrum nutans)--were made. The growth of three tallgrass prairie plant species Dicanthelium oligosanthes, Ambrosia psilostachya, and Salvia azurea, and plant species composition were measured monthly. The C3 grass, D. oligosanthes, showed a greater response to the treatments than the two forbs (A. psilostachya and S. azurea). Suppression of mycorrhizae caused an increase in stem density of D. oligosanthes, and caused a significant increase in its vegetative growth when combined with removal of the 2 dominant plant competitors. In contrast, only removal of the dominant competitors had a significant effect on the two forbs: growth of individuals of A. psilostachya and S. azurea was significantly greater in removal plots. No mycorrhizal effect and no effect on stem density was observed for these forb species.
Rachel Smit - Stocking the Prairie: The Changing Historical Landscape of the Dewey Ranch, 1900-1930 (Mentor: Jim Sherow).
The Konza Prairie Research Natural Area was once a ranch. From 1900 to 1930, this ranch was owned and managed by C.P. Dewey and his son Chauncey Dewey. The individual personalities of these men, as well as the knowledge, culture, and economics of the times, all affected the way the prairie was perceived and managed. The importance of these factors was determined through newspaper articles, property tax records, and oral interviews. Management decisions shaped the Konza landscape because the unique grazing pattern and stocking rate of each livestock species has a distinct impact on prairie ecology. The Deweys' ranching also changed the landscape through physical materials such as fences, roads, and buildings. Their location was determined by old maps and aerial photographs. Remnants of these material objects are still visible on Konza today. The history of the Dewey Ranch contributes to the Konza's current spatial heterogeneity.
1996 REU Projects and Abstracts (top)
Project Abstracts - 1996
I used randomly amplified polymorphic DNA (RAPD) products using two methods of whole blood PCR in an attempt to assess parentage of House Wrens (Troglodytes aedon) and Bewick's Wrens (Thryomanes bewickii). Blood samples were obtained from four House Wren and four Bewick's Wren nests at Konza Prairie. The first method of whole blood PCR employed heat cycling of blood, in the PCR mixture, three times between 94o C and 55o C for three min at each temperature. Taq polymerase was then added and contents were subject to PCR cycling. A second method involved heating the blood in H2O for 15 min at 95o C. After heating, the remaining PCR reagents were added and contents were subject to PCR cycling. PCR with RAPD primers was also done on purified tree sparrow (Spizella arborea) DNA. PCR did not amplify any discrete RAPD markers in either House or Bewick's Wrens, however markers were obtained from purified DNA. Problems with whole blood PCR may be a result of PCR inhibiting factors found in blood. RAPD analysis with whole blood PCR was determined to be an unreliable means of assessing parentage in House Wrens and Bewick's Wrens.
Jon Beckmann - Habitat and Spatial Distribution of the Eastern Woodrat (Neotoma floridana) on Konza Prairie (Mentor: David Hartnett).
During 1 June-7 August 1996 ten watersheds covering more than 1600 acres were walked at Konza Prairie Research Natural Area in order to evaluate habitat and spatial distribution of the eastern woodrat (Neotoma floridana) in tall-grass prairie. The ten watersheds were chosen in order to get a representation of the various experimental burning treatment regimes at Konza Prairie. The watersheds included fall burns as well as annual, two-year, four-year, and twenty-year spring burns. Eastern woodrats construct large conical stick nests and these nests were used as signs of woodrat habitat selection and spatial distribution. Fire frequency, topography, and vegetation characteristics were found to interact in complex ways to influence woodrat spatial distribution. Limestone outcrops associated with woody vegetation, especially mast-producing tree species, were found to be ideal eastern woodrat habitats on Konza Prairie.
Nicole Ann Castro - The effect of predator type on the nest defense strategy of Brown Thrashers (Toxostoma rufum) (Mentor: John Cavitt).
My research focused on the effect of predator type on the nest defense strategy of Brown Thrashers (Toxostoma rufum). My field work consisted of searching throughout the prairie for nests almost everyday. At the nestling stage, I presented model crows and snakes near the nest. I then recorded the vocalizations given by the adults in a ten minute time period. Also, I recorded the behaviors displayed and the distance the adults were from the predator every twenty seconds. I tested four hypotheses in this project. First, I found there was not a difference in the number of vocalizations between the crow and snake even though the crow can hear sound through the air and the snake relies on ground vibrations. Also, I determined that the adults took the same amount of risk with both predators. More aggressive parents also did not have a significantly higher fledging success than less aggressive adults. Finally, I determined that Brown Thrashers increase aggression over the nesting cycle, thereby following the parental investment theory.
Jean Fantle - Delivery of social cues in the eastern woodrat, Neotoma floridana (Mentor: Eva Horne).
My research focused on delivery of social cues in the eastern woodrat, Neotoma floridana. Using a Y-maze, I conducted preference tests on about 22 woodrats to determine if they could find any cue as to the size, and thus dominance status or fitness of a conspecific. Male and female woodrats were run against large vs. small male mid-ventral gland exudate, large vs. small male urine, large vs. small estrus female urine and estrus vs. non-estrus female urine. Female woodrats were run against large vs. small male exudate, large vs. small male urine, and large vs. small estrus female urine. Neither males nor female showed any preference for either sized male based on exudate or urine. Males showed no size preference for other males based on male exudate or urine, or for either size of estrus female based on her urine. Males did, however, prefer estrus females to non-estrus females. Females preferred the urine of a larger female to that of a smaller one.
Audra Gallaspy - Farming and Ecological changes on Konza, 1855 to 1950: An Environmental Historical Interpretation (Mentor: Jim Sherow).
In the four decades after 1850, four Euro-American farms were established on present day Konza, bring with them new values and ideas of land management. Each one of these farms combined with environmental factors created microenvironments that transformed the land and left visible changes that can still be identified on present day Konza. Agricultural Rolls, Tax Rolls, Newspapers, Maps and Deed Records were used to determine what crops were grown, how long the farms were in use and the ethnicity of the farmers. From this information I learned how each farm was run and what impact it might have had on the ecology of Konza. Soil sample were taken to determine the change in Carbon and Nitrogen. Tree cores were taken to determine the ages of the trees. Species Composition was measured to determine new establishments.
Kerri Kobbeman - The effects of mycorrhizal fungi suppression on growth, demography, photosynthesis, and water potential of three tallgrass prairie forbs (Mentor: Gail Wilson).
I researched the effects of mycorrhizal fungi suppression on growth, demography, photosynthesis, and water potential of three tallgrass prairie forbs. I discovered that each forb responded quite differently to mycorrhizal suppression. Salvia azurea, had significantly higher biomass in the mycorrhizal plots. Artemesia ludoviciana demonstrated the opposite response. Its biomass increased in the fungicide treated plots. Aster sericeus was uneffected by the inhibition of mycorrhizae. I found that abundance of stems and clones were greater in the fungicide treated plots for all three forbs. There were also significantly more stems per clone in the mycorrihae suppressed plots. I also determined that Salvia and Artemesia were not influenced physiologically by the suppression. I concluded that factors that influence growth are not necessarily the same as those which control demography. Also, I found that Salvia responded positively to the mycorrizal fungi colonization while Aster was neutral and Artemesia reacted negatively. In the treated plots, Artemesia was possibly experiencing a competitive release from the dominate grasses, which need mycorrhizae in order to thrive, and becoming more successful.
Scott D. Kocher - Distribution of Carnivore Dens on Konza Prairie, Kansas (Mentor: Don Kaufman).
This study addressed the distribution of coyote and badger den burrows with respect to the major topographical regions on Konza Prairie (upland prairie, inclined slopes, lowland prairie, and riparian areas) and structural features on slopes (points, sides, and ravines). Angle and aspect of burrows on slopes were also evaluated in relation to available terrain. Burrows were found significantly more frequently on slopes than in riparian areas, and in riparian areas than in either upland or lowland prairie. Furthermore, slope points are preferable to either sides or ravines for den sites. Steeper slopes and south and west facing slopes were chosen significantly more frequently over shallow slopes and north and east facing slopes. Selective pressures are likely to include ease and efficiency in excavation of burrows.
John R. Matchett - The Effects of Bison Grazing On Soil Nitrogen Transformations in the Tallgrass Prairie (Mentor: Loretta Johnson).
In many grassland ecosystems, grazing by large herbivores has been found to enhance nitrogen cycling. Grazing results in more labile forms of nitrogen (i.e. dung and urine) being returned to the soil. Grazing may also lower the carbon to nitrogen ratio of root tissue and reduce root biomass-which further enhance nitrogen cycling. These hypotheses were tested with bison grazing in the tallgrass prairie. Plant available forms of N (nitrate and ammonium) and N mineralization rates where measured in soils of grazed and ungrazed areas. Grazed areas had significantly higher available nitrate, higher total N mineralization rates, and higher nitrification rates than did ungrazed areas. However, available ammonium and ammonification rates showed no difference. Root biomass was also found to be significantly lower on grazed areas.
Erin J. Questad - Physiological Responses of Andropogon gerardii to Grazing Pressures From Bison and Cattle (Mentor: Alan Knapp).
Since Andropogon gerardii has evolved with selective pressures from grazers, it should exhibit compensatory, physiological responses when grazed: decrease in water potential, increases in net photosynthesis (PN) and stomatal conductance, higher nitrogen content of leaf blades, and greater forage quality. A. gerardii should not differ in its response to grazing by cattle or bison. PN, g, and were measured throughout July 1996 in bison and cattle grazing patches and ungrazed plots. Leaves were collected twice for tissue analysis. A. gerardii grazed by bison showed significantly less water stress 3 out of 4 measurements with a significant difference in mean (p<0.05). PN was greater for 50% of measurements in cattle plots, and 100% in bison patches (P < 0.05; Fig. 1). A. gerardii grazed by bison showed a mean increase in PN of 53% and a maximum increase of 150%. PN and g measurements followed similar trends. Nutrient analysis of leaves supported the idea that nitrogen deposition (via dung and urine) was higher in bison grazing patches than cattle. Forage quality, measured by C:N, also significantly increased in bison patches, but not cattle. However, a longer-term study would be required to determine if cattle grazing would result in patterns similar to the bison later in the season. Based on these data, Andropogon gerardii showed greater compensatory responses to grazing by bison than cattle.
Elizabeth Zacharias - Herbivory tolerance of New Jersey Tea, Ceanothus herbaceous (Mentor: Phil Fay).
New Jersey Tea's (Ceanothus herbaceous, Rhamnaceae) tolerance of galling by the gall moth, Periploca ceanothiella (Lepidoptera: Cosmopterigidae), and of browsing by the white-tailed deer (Oedicolius virginianus) was studied under varying fire regimes in order to determine the role of fire and herbivore feeding styles in New Jersey Tea's herbivory tolerance. Herbivory tolerance was assessed on both naturally galled and manually browsed ramets in an annually burned and an adjacent unburned watershed. Herbivory tolerance was characterized by measurements of ramet growth and architecture, and stem water potential and leaf photosynthesis. Fire affected New Jersey Tea growth much more than browsing or galling. Frequent fire reduced New Jersey Tea shoot number 17-fold and total leaf area 2-fold compared to unburned ramets. In contrast, fire had only minor effects on photosynthesis and stem water potential, while galling and browsing increased photosynthesis compared to intact ramets. A 'tolerance index' calculated from the product of whole ramet leaf area and leaf photosynthetic rate suggested that ramets in the unburned watershed were most tolerant of herbivory, and that ramets were equally tolerant of browsing and galling. For New Jersey tea, fire is a major factor affecting herbivory tolerance, and herbivory tolerance appears not to be herbivore specific.
1995 REU Projects and Abstracts (top)
Project Abstracts - 1995
The effects of two algivorous grazers, Campostoma anomalum and Orconectes neglectes, were investigated in artificial stream channels at Konza Prairie. These two organisms were placed into stream channels according to their natural densities in Kings Creek. After two weeks, treatments with O. neglectes had less periphyton (P<0.08 ANOVA); those with C. anomalum were not significantly different from the controls. We observed less filamentous green algae when O. neglectes was present. The decrease in algal biomass may be the result of herbivory or physical disturbances. Further investigation involved the manipulation of C. anomalum density to determine if densities in the first experiment were simply too low to have an effect. Analyses of fecal material and algal species composition are in progress.
Christopher A. Desjardins. - Nutritional Analysis of Nymphs and Adults of Orthopterans (Arcididae and Tettigoniidae) of the Flint Hills Region of Kansas (Mentor: Robert Robel).
Nutritional analysies were conducted on nymphs and adults of five species of Acrididae and two species of Tettigoniidae to determine differences in the nutritional value of the different life stages. The nutritional attributes determined were protien, energy content, ash, calcium, phosphorous, potassium, fat, and crude fiber, with priority given in that order if not enough sample was available. The Orthopterans used in the study were collected on the Konza Prairie Research Natural Area over the months of June and July by sweepnetting. Results showed few differences between the various life stages, while there were greater differences between species, subfamilies, and families. Protein content did not change between different life stages, but energy content showed a general trend of increasing energy as the species progressed through the life stages. Calcium showed an increasing trend with age, while phosphorous showed a decreasing trend with age. Most of these differences are thought to be due to the growth of the Orthopterans.
Natalie Dubois. - Territorial Responses in Sympatric House Wren and Bewick's Wren Populations (Mentor: Dale Kennedy).
Both House Wrens and Bewick's Wrens are found in the gallery forests on Konza Prairie. Egg-tossing activities by unmatured male and pre-laying female House Wrens have been found to significantly decrease the reproductive success of Bewick's Wrens. Conspecific and interspecific territorial responses of both species were monitored by use of playback tapes at various nesting stages. Conspecific responses of House Wrens were significantly stronger than those of Bewick's Wrens. House Wrens reacted more aggressively to the song of conspecifics than to the song of Bewick's wrens. Conversely, Bewick's Wrens were more responsive to the song of the House Wrens than to their conspecific song. The aggressiveness of Bewick's Wrens to the songs of House Wrens may be a response to the nest vandalism by House Wrens.
Jason Hoeksema. - Response of Big Bluestem and Indian Grass to Interaction with an Introduced Grass, Caucasian Bluestem in Tallgrass Prairie (Mentor: David Hartnett).
Invasion of an introduced species, caucasian bluestem (Andropogon bladhii) provides an opportunity to investigate strategies of an invading species, the characteristics and responses of the native community being invaded, and the potential for the invading species to become established in the native community. We pursued these objectives with three experiments in an annually burned, ungrazed site in tallgrass prairie. For the first experiment, we measured the growth of A. bladhii clumps within an established, relatively monotypic stand of conspecifics, and also outside of these stands where A. bladhii is invading and is surrounded by native vegetation. The second experiment compared the growth of native grasses transplanted into a monospecific stand of A. bladhii compared with native grasses transplanted reciprocally into native vegetation. The third experiment measured the growth of native grasses at varying distances from A. bladhii clumps which had either been trimmed to ground level, killed with Roundup, or left untouched. Intraspecific competition was stronger than interspecific competition for A. bladhii. Transplanted native grasses grew better with A. bladhii neighbors than with native neighbors. Native grasses grew better nearby control clumps of A. bladhii clumps than nearby trim or Roundup clumps. So at the individual level over a short time period, native grasses seem to grow better in the presence of the introduced grass. However, grazing could cause the negative effect of A. bladhii on native grasses to be much stronger.
Micah Kaufmann. - Distribution of Bison Wallows on a Tallgrass Prairie (Mentor: John Briggs).
The size and distribution pattern of American bison (Bos bison) wallows on a tallgrass prairie were examined on watershed N04D in July, 1995. 100 different wallows were mapped into a GIS (ARC/INFO). The size of the wallows ranged from 1 to 46 squared meters with an average of 8 squared meters (SE = 0.71m). Overall, the wallows were clumped in several clusters on relatively flat areas within the watershed. The average distance between all of the wallows was 708 meters (SE =5.6m ). Since these wallows were placed in a GIS, the long-term importance of these disturbances in the tallgrass prairie ecosystem can now be examined.
Stacy J. Morris. - The Effects of Predator Exclosures on the Nesting Success of Dickcissels (Mentor: John Cavitt).
Predation is the greatest source of mortality for open nesting birds. Previous studies suggest that snakes are major predators of birds on grasslands. The dickcissel, a ground nesting species that is abundant in tallgrass prairie, loses almost half of its nests to predation. Wire mesh enclosures were placed around dickcissel nests to determine their effect on nesting success. The daily survival rate, the date of nest initiation, and the proportion of eggs that became fledglings in enclosed nests and unenclosed nests were not significantly different. The clutch size of enclosed nests was significantly greater than that of unenclosed nests. Either snakes are not effectively precluded by these exclosures, snakes are not the primary predators of dickcissels, or the small sample size of this study is not representative of the community.
Jennifer A. Rudgers. - Comparison of the Reproductive Strategies of Three Milkweed Species (Mentor: Christopher Smith).
Inflorescence size may influence plant reproductive success as inflorescences of different numbers of flowers are likely to be differentially successful as pollen donors or recievers because they attract more pollinating vectors. Past studies have suggested that inflorescence size in Asclepiashas evolved from selection acting on male reproductive success. To test this pollen donation hypothesis, A. viridis, A. tuberosa, and A. stenophylla were studied during their flowering and fruiting seasons on an annually burned watershed at Konza Prairie Research Natural Area, KS. Leaf morphology and photosynthetic capabilities were quantified as well, for the three species flower successively through the dramatically changing seasons of the tallgrass prairie. The number of pollinia removed was used to estimate male success and the number of pods produced to assess female success. The number of pollinia removed per flower was correlated with the number of flowers in A. viridis (p<0.008) and A. stenophylla (p<0.016). The number of pods per flower was negatively correlated with the size of inflorescence for A. viridis (Spearman r = 0.38, p<0.03). These results support the pollen donation hypothesis. Inflorescence size is also bound phenotypically to the availability of resources. Leaf area and number of leaves were significantly correlated with the number of flowers per plant for A. viridis and A. tuberosa. This correlation did not result for A. stenophylla largely because, unlike A. viridis and A. tuberosa, A. stenophylla did not vary in the number of stems per plant. Photosynthetic capacity differences were discovered between species. A. stenophylla, the last of the three to flower had a higher photosynthetic capacity at higher levels suggesting an adaptation to water stress in late summer.
Erik Sparling - Single Plant Species Effects on Carbon and Nitrogen Cycling and Microbial Populations in the Tallgrass Prairie (Mentor: Charles Rice).
Plant community structure is important in nutrient cycling. We examined the importance of single plant species on C and N cycling by looking at microbial biomass and activity in soil beneath five common tallgrass prairie plant species. Soil microbial biomass C and N varied significantly beneath some species. Of all measured microbial parameters, soil respiration rates were most frequently affected by dominant plant species differences. Mineralization rates were also different beneath some plant species. Additional measurements and correlation analysis suggested that the plant above ground biomass C and N content differences, as well as below ground biomass differences, may be some of the most important factors regulating microbial population size and activity.
Heather Throop. - Impacts of Fire and Herbivory on Ceanothus herbaceous Architecture and Reproduction (Mentor: Phil Fay).
Fire and herbivory can both be major causes of damage and mortality to woody plants in grassland environments. Ceanothus herbaceous (New Jersey Tea), a prevelant species in Flint Hills tallgrass prairies, experiences herbivory through deer (Odocoileus spp.) browsing and stem galling by the moth Periploca ceanothiella. The relative impacts and interactions between galling, deer browsing, and fire on C. herbaceous growth and architecture were investigated by comparing numbers of shoots, buds, and inflorescences; bud vitality; and herbivory rates between plants on an annually burned and an infrequently burned watershed. Fire had very strong effects on C. herbaceous growth patterns, reducing the number of shoots per ramet, increasing ramets per plant and shoot length, and preventing sexual reproduction. The effects of herbivory were much weaker than those of fire. Galling rate was higher on the infrequently burned watershed. Galled ramets had shorter shoots but increased numbers of shoots and inflorescences than ungalled ramets. The browsing rate did not differ significantly between the two watersheds. Browsed ramets produced more inflorescences on both watersheds, fewer shoots per ramet in the annually burned watershed but more shoots per ramet in the infrequently burned watershed. Fire appears to be the major regulator of C. herbaceous population dynamics, through direct effects on architecture and reproduction, and by indirectly affecting the rates and consequences of herbivory.