The first half of my dissertation asks how small mammal populations and communities respond to defaunation, mediated via changes in vegetation/food abundance. This research is part of the Ungulate Herbivory Under Rainfall Uncertainty (UHURU) experiment, which uses size-selective fencing to exclude large herbivores from 1-hectare plots on the savanna, replicated three times across a climate gradient. UHURU mimics the ongoing large herbivore population declines occurring across many savanna systems, enabling us to test the impacts of defaunation on the species that persist. I use mark-recapture surveys and fecal DNA metabarcoding to determine small mammal (rodent/shrew) diets. By comparing small mammal diets and demographics across treatments, I seek to understand how defaunation and climate interactively affect small mammal foraging behavior and trophic network structure.
This work is supported by student research grants from the American Philosophical Society, the Animal Behavior Society, and the Institute at Brown for Environment and Society.
The second half of my dissertation asks how small mammals avoid predation when foraging in risky environments. Within Kenya, I test for intraspecific differences in hindlimb traits across populations in “risky” and “safe” environments and use functional assays to determine whether these trait differences affect predator-escape performance.
I also ask whether and how these local processes generate macroevolutionary patterns. By taking micro-CT scans of museum specimens from species across the gerbil phylogeny, I can test for large-scale trait-habitat associations that are consistent with adaptations for predator escape in risky environments. By combining the field and museum components of this research, I seek to test one mechanism by which ecological interactions affect trait evolution across the tree of life.
This work is supported by student research grants from the American Society of Mammalogists, the Society of Integrative Biologists, the American Society of Naturalists, the Institute at Brown for Environment and Society, and Brown EEOB. The museum specimens are kindly loaned by the Field Museum of Natural History in Chicago and the American Museum of Natural History in NYC.
Communities are formed by the interactions of myriad individuals nested within species, all of whom face the fundamental trade-off between the need to eat and the need to avoid being eaten. Limited food resources drive competition both within and between species, leading to dietary niche partitioning, character displacement, and competitive exclusion. Species alter their foraging behavior in response to perceived predation risk, and over time they may evolve morphological adaptations to mitigate that risk. All of this occurs on a backdrop of changing resources and abiotic factors. My research asks how the bottom-up effects of resource availability and top-down effects of predation pressure interactively determine community structure via impacts on herbivore morphology and foraging behavior. I also ask how these local patterns are reflected in larger scale evolutionary processes.