Vanessa Agosto -  Sex Ratio in Six Insect-pollinated Species (Mentor: Christopher Smith).  
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 ration 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.

Last updated: November 2002