Spatial and temporal patterns of woody seed dispersal by birds may facilitate woody encroachment in tallgrass prairies

Eliza Soczka, Department of Integrative Biology, UW–Madison
Advisors: Ellen Damschen and Katherine Charton

Woody encroachment threatens the diversity, productivity, and persistence of tallgrass prairies. By researching the causes of woody encroachment, we can better understand how these species come to persist in tallgrass prairies. I propose to investigate the role of birds as woody seed dispersers and how they may create a positive feedback loop that enables further woody encroachment. My experimental study will test whether existing plants with or without fleshy fruits can weaken the positive feedback loop between birds and woody species. In conducting this research, I will both move forward our understanding of the mechanisms driving woody encroachment and provide recommendations for better land management practices to minimize this accelerating process that can potentially benefit Arboretum land practices in the future.

Common Scents

Luciann Heeg, Department of Botany, Emeritus, UW–Madison
Advisor: Ken Keefover-Ring

Chemotypes (chemical phenotypes) are determined by secondary compounds plants produce to defend against herbivores and/or to attract pollinators. Chemotypes may vary between individuals within a species. Monarda fistulosa and Thymus vulgaris, two Lamiaceae species, share five chemotypes despite life histories and geographic separation on two continents. I will investigate if these shared chemotypes are due to convergent evolution or common ancestry; I will analyze the enzymes responsible for synthesizing the main terpene in each chemotype. Leaf glandular trichomes – terpene production centers – will be isolated and processed for RNA extraction to make cDNA libraries that will be sequenced. T. vulgaris follows an epistatic cascade of chemotype dominance, and I will explore if this persists in M. fistulosa by controlled crosses between chemotypes by hand pollination in a common garden, and progeny analysis. Feeding trials with generalist and specialist herbivores will measure insect performance and survival to expose differential responses to chemotypes.

Nesting ecology of Bombus species

Genevieve Pugesek, Department of Biology, Tufts University
Advisor: Elizabeth Crone

Nesting habitat for the rusty-patched bumble bee (Bombus affinis) has been poorly characterized, leaving habitat managers to make policy decisions based on the resource requirements of other more commonly studied Bombus species. We propose a study to identify B. affinis nesting habitat by 1) evaluating the movement behavior of nest-searching queen B. affinis as an indirect metric of nesting habitat preference, and 2) conducting mark-recapture surveys for bumble bee nests to estimate nest densities for B. affinis (as well as other bumble bee species). To make comparisons between selected and available sites, we will also assess the conditions at each survey plot and transect (e.g., floral resource and nesting substrate, availability, vegetation height, etc.). The proposed study will be the first to survey nesting bumble bees in regions critical for management of B. affinis and will evaluate the feasibility of monitoring B. affinis and other at-risk Bombus species populations, using both direct and indirect methods.

Variation in plant defense

Joseph Cammarano, Entomology and Nematology Department, University of Florida
Advisor: Phil Hahn

Intraspecific variation in floral phenotypes is a well-documented phenomenon across and within plant populations, and geographic variation has even been associated with entirely different pollinator guilds within species. Notable limitations in many of the current studies of this phenomenon, include disentangling the roles of phenotypic plasticity and non-pollinator species such as herbivores in mediating these variations. Defense against herbivory is another trait that may vary within species, and which may compromise attraction to pollinators, leading to evolutionary tradeoffs. The resource availability hypothesis posits that tradeoffs between defense against herbivory and plant growth occur across resource gradients between species, with defense being favored in low-resource environments and growth in high-resource environments, but does not address possible tradeoffs between defense and attraction of pollinators and does not necessarily address trends within species. We are addressing these ideas with common beebalm (Monarda fistulosa), a chemically defended entomophilous plant with a wide geographic range in North America, including both arid and mesic habitats.

Preliminary comparison of snake species diversity and population characteristics across Madison-area prairies

Will Vuyk, Nelson Institute for Environmental Studies, UW–Madison
Advisor: Catherine Woodward

Despite being some of the most abundant reptiles in Wisconsin, little is known about snake populations in urban and suburban prairie sites around Madison. This study aims to provide baseline data on snake diversity and population characteristics at five prairie sites in the Madison area, including the Green Prairie at the UW–Madison Arboretum. Cover boards and time-constrained visual encounter surveys will be utilized at these sites to standardize data collection. This baseline data is needed to begin addressing questions about how snakes recolonize prairie restorations, what qualities make a prairie more suitable for certain snake species, and how snakes disperse in urban environments. The results of this study will allow the managers of prairie sites to compare their snake populations with the populations of nearby sites, potentially impacting management decisions, and will allow for more informed herpetological studies of Madison area natural spaces in the future.

Community dynamics of an 86-year-old tallgrass prairie restoration

Mary-Claire Glasenhardt, Nelson Institute for Environmental Studies, UW–Madison
Advisor: Paul Zedler

Monitoring is a necessity in a time of climate change. Curtis Prairie is ideal for monitoring as an early tallgrass prairie restoration site with a history of vegetation surveys. Long-term monitoring is critically important to understand how ecosystems are changing over time, identify factors driving these changes, and enable evidence-based management decisions. Resurveying Curtis Prairie will 1) create a quantitative picture of the current vegetation community, and 2) identify how diversity and distribution have changed over time at the site and species level. Additionally, I will look at the relationship between 3) vegetation and functional traits associated with ecosystem function, 4) species diversity on invasion resistance, 5) invasive species cover on species richness, and 6) effects of disturbance caused by management on diversity. Identified patterns in succession, invasion resistance, or management techniques that reduce invasive species or increase diversity, will benefit other tallgrass prairie restoration efforts.

Lost City Invasive Shrub Management

Tim Kuhman, Edgewood College
Brad Herrick and Christy Lowney, UW–Madison Arboretum

Invasive species are prevalent in southern Wisconsin. Landowners and managers allocate a lot of resources (time and money) into controlling invasive species. By studying management practices, including forestry mowing, forestry mowing followed by prescribed fire, hand clearing, and hand clearing followed by prescribed fire, we will be able to assess the efficacy of these management techniques for controlling woody invasive shrubs and allowing native herbaceous species to establish.