Nicole Blalock - Characterization of freezing tolerance in fifty-two Arabidopsis thaliana ecotypes: a study based on geographic distribution (Mentor: Mark Ungerer).
Limitations in the distribution of many plant species due to freezing temperature intolerance restrict agricultural productivity worldwide. While plant species from tropical regions of the world have essentially no capabilities that allow the tolerance of freezing temperatures, it has been demonstrated that herbaceous species from temperate regions can persist after similar exposure if there is first a period of cold non-freezing temperatures. During periods of cold acclimation, cold non-freezing temperatures stimulate the overexpression of the CBF (c-repeat binding factor) gene family, which allows the plant to resist damage due to below freezing temperatures. Fifty-two ecotypes of Arabidopsis, collected from a broad geographic range were used in this study to examine the effects of evolutionary pressures on freezing temperature tolerance. Nine phenotype characteristics (bolting time, flowering time, number of leaves at flowering, number of secondary branches, number of secondary basal shoots, fruit abundance on basal shoots, fruit abundance on secondary branches, total fruits observed, and biomass) were observed throughout each individual’s life cycle. CBF and cold responsive (COR) gene expression was assayed in four ecotypes. Three week survivorship rates indicate ecotypes from northern latitudes have a greater ability to tolerate freezing temperatures than those ecotypes from more southern regions. As more phenotype data is recorded, plant fitness can be assessed more thoroughly and comparisons between ecotypes made.

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 glabra showed 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). Mycorrhizal fungi are ubiquitous and abundant in tallgrass prairie. Arbuscular mycorrhizal (AM) symbiosis significantly increase plant uptake of phosphorus. Arbuscular mycorrhizal fungi have been shown to deliver up to 80% of a plant’s P requirements, and for some grass species, AM fungi may be entirely responsible for the uptake of inorganic phosphorus. AM fungi obtain their reduced carbon from the plant host. The amount of C allocated from the plant to the fungi can be substantial, with 10 to 50% of a plant’s total C budget translocated to mycorrhizal roots. The flow of carbon to the soil mediated by mycorrhizae play a major role in carbon translocation and sequestration into the soil. By establishing big bluestem microcosms, we compared the effects of phosphorus fertilization and AM fungi on plant growth and soil CO2 flux. We hypothesized that AM symbiosis would increase plant growth at low to moderate levels of soil P and that soil carbon would be greater in microcosms with active AM fungi. Forty-two microcosms were filled with steamed prairie soil, half of which were inoculated with AM fungi, and half left as nonmycorrhizal controls. Twenty big bluestem seedlings were established in each microcosm. Soil was amended with 0, 20, 60, 140, or 300 mg P per g soil. There were four replicate microcosms for each treatment. Plant height and tiller number (plant growth) was recorded each week, as was soil CO2 flux using a Li-Cor. Mycorrhizal fungal colonization of the roots was determined at 8 weeks. Plant growth was greater in the AM inoculated microcosms, regardless of P treatment. An additive effect was observed when plants were inoculated with AM fungi and received additional P. However, percent mycorrhizal root colonization was significantly lower at each increasing soil P level. We did not see any clear trends in CO2 flux, regardless of mycorrhizal inoculation.

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. deltoids) 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.

Last updated: December 2005