Cameron A. Cooley- Grassland Arbuscular Mycorrhizal (AM) Fungal Communities: Does Environmental Change Effect Structure? (Mentor: Ari Jumpponen).
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 Melilotus is 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.

Last updated: November 2002