Amphibian Chytrid in West Africa

The chytrid fungus Batrachochytrium dendrobatidis (Bd) is implicated in global declines and extinctions of amphibian species. Although Bd is found on all continents where amphibians persist, disease dynamics and prevalence remain poorly quantified and understood in certain regions of the world, such as West Africa. The only study investigating Bd in this region suggested that the pathogen is absent in amphibian populations west of the Dahomey Gap despite environmental niche models that indicate suitable habitat for Bd in West Africa. I leveraged fluid-preserved amphibian specimens to determine the historical prevalence of Bd in West Africa and generated updated environmental niche models to provide a greater context for Bd disease dynamics and its predicted range in this region. This research was done with Dr. Rayna Bell of the California Academy of Sciences and Dr. Gui Becker of Penn State University as part of the Columbia Department of Ecology, Evolution, and Environmental Biology senior thesis requirement.

African Reed Frog Systematics

Reed frogs (Hyperolius spp.) are the most species-rich genus in the family Hyperoliidae, a group of frogs endemic to sub-Saharan Africa and the Gulf of Guinea islands. Three species are endemic to oceanic islands in the archipelago, but the diversity and distribution of reed frogs on Bioko—a land bridge island in the archipelago—remains unclear. Two species, H. tuberculatus and H. ocellatus ocellatus, were formally documented on Bioko in the colonial era; however, two additional reed frog species have been detected in recent surveys. In addition, observations of heterospecific amplexus suggest one of the unidentified species and H. o. ocellatus may be hybridizing on the island. I examined mitochondrial DNA (mtDNA), nuclear DNA (nuDNA), morphological, and acoustic data to confirm the tentative identifications of the reed frogs and determine if there is any evidence of hybridization. This research was done with Dr. Rayna Bell of the California Academy of Sciences and was funded by the SSI NSF-REU program.

Global Change and Tropical Ecology

Herbivory can significantly alter plant communities and ecosystem functions. Several traits are known to regulate leaf level herbivory such as leaf toughness and leaf nutrient concentration, but the drivers of ecosystem herbivory are not well understood, particularly in tropical forests where herbivory pressure is high. To evaluate the drivers of ecosystem herbivory, we used a longstanding fertilization experiment in Agua Salud, Panama, to examine the effects of soil fertility, forest succession, and plant species on herbivory damage. This work was done with the Batterman Lab at the Cary Institute of Ecosystem Studies and was funded by the Cary Translational Ecology NSF-REU program.