Nutrient Availability and Community Structure
Species assembly and abundance in communities is dynamic and influenced by a variety of density dependent and independent factors. I am interested in how the availability of essential nutrients like sodium, nitrogen, and phosphorous influence leaf litter and soil invertebrate community structure. Our recent short- and long-term experiments examining sodium inputs over a variety of spatial scales have demonstrated that invertebrates low in trophic position, such as microbi-detritivores like collembola and termites recruit to sodium supplements when sodium is environmentally rare. This is the case for most inland forests. Increases in prey densities attract their predators such as ants and can affect ecosystem level functions like decomposition rate.
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Leaf Litter and Wood Decomposition
Understanding carbon cycling in terrestrial ecosystems is increasingly important as global climate change and anthropogenic influences alter ecosystems. In forest ecosystems, leaf litter and dead wood constitute a significant C pool, yet decomposition rates are understudied relative to their importance, particularly for dead wood. Even less understood are biotic regulators of decomposition. Through field experiments and laboratory mesocosm experiments, we are starting to better understand how interactions among heterotrophic fungi and invertebrate detritivores and their environment mediate decomposition rates.
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Riparian-Stream Connections
Riparian forests serve as integral areas of exchange and interaction of biota, matter, and nutrients between terrestrial and aquatic systems. Processes occurring in riparian zones thus impact inputs into streams and rivers. However, these two systems are often studied separately. Through field experiments and laboratory mesocosm experiments, we are investigating how changes in nutrient inputs impact processes in both riparian and aquatic ecosystems and the quantity and quality of resource exchange between these systems.
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Pollinator Diversity
Insect pollinators are diverse and include bees, flies, wasps, beetles, moths and butterflies. They both directly and indirectly support important ecosystem functions largely driven by increasing flowering plant success. As with many insects, land use and cover changes have resulted in their decline in many ecosystems. In the southeastern US conversion of land to pine plantations has resulted in the loss of the herbaceous ground cover formally native and pervasive in this region. Our lab is investigating how restoration to the native shortleaf pine-hardwood forest with its characteristic open canopy and savanna-like ground cover impacts pollinator diversity.
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Geography of Omnivory
Omnivory, consuming both plant and animal tissue, is widespread and ecologically important. Yet we understand relatively little about what drives the degree of omnivory (e.g., how carnivorous or herbivorous the organism is) across the range of a given species. By sampling conspecifics and closely related omnivore species across a large geographic range we can test hypotheses about factors, such as essential nutrient availability, that may regulate the degree of omnivory for a given species. This, paired with laboratory experiments testing significant geographic correlates can inform our understanding of how omnivory is regulated across broad spatial and temporal scales.
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Nutritional Ecology
A central goal of ecology is to determine the mechanisms driving food web structure across abiotic and biotic gradients. Resource availability influences food web structure on both a microscale (e.g., nutritional mismatches between diet and consumer) and macroscale (e.g., across landscape gradients of nutrient availability). Resource availability is the foundation of nutritional ecology, which uses principles of physiology to predict how an organism will respond to changes in the abundance of essential nutrients. My research combines nutritional ecology and stoichiometry to investigate how nutrients other than traditionally examined macronutrients (e.g., protein & carbohydrates) like sodium are regulated and impact insect behavior, physiology and ultimately community structure and function.
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