We live in an era of unprecedented global change. Long-distance transport of organisms, both intentional and inadvertent, has resulted in numerous biotic invasions. A rapidly growing human population is altering vast areas of land to support itself, in the process reducing or altering habitat for other species. As human settlements encroach on previously undeveloped land, new hosts and parasites meet for the first time, with potential for novel pandemics. Meanwhile rapid biodiversity loss continues to forever alter the composition of biological communities around the world, with consequences that are not entirely understood but potentially alarming.
Biodiversity loss may alter disease dynamics as hosts go extinct or change in abundance. Responses are expected for the pathogens that use these hosts as resources. A challenge in contemporary disease ecology is to develop a predictive framework that can anticipate when and how biodiversity loss will alter disease dynamics. Currently I am working with collaborators to integrate and synthesize research on the evolution of host traits, pathogen transmission dynamics, and processes that drive extinction in biological communities with the goal of enhancing this predictive framework.
Amphibians face many threats worldwide, even in protected wilderness areas and national parks. My most recent amphibian conservation work has focused on tracking and explaining individual level patterns of chytrid (Batrachochytrium dendrobatidis) infection in wild frogs, with the goal of better understanding spatial and temporal determinants of disease status. Furthermore, this work provides insights into habitat use patterns, overwintering behavior, and metapopulation dynamics of local amphibians that can be used to inform management decisions.
Multiple species of parasites often inhabit the same resource or host, and interactions within hosts can be competitive, predatory, commensal, mutualistic, and even parasitic. Communities of parasites within hosts are rarely constant through time, with potential in many disease systems for seasonal patterns in transmission, host population size, host density, or host defenses. Similarly, communities of parasites within hosts might be expected to show spatial patterns in heterogeneous environments. Spatial and temporal variability in parasite community composition may affect parasite interactions within hosts, but the consequences of such variability for disease dynamics are not yet generally understood.
Gall-forming wasps have been used as a model system for community ecology in the past, and have shown to be useful for understanding the dynamics of parasite interactions as well. In the Central Valley of California, the wasp responsible for creating oak apple galls, Andricus quercuscalifornicus, displays differences in the composition of parasitoids and inquilines (which use gall tissue, at times to the detriment of the gall maker) over space and time. Investigating how variation in parasite community composition affects parasite interactions and host fitness may provide a useful starting point for developing a general understanding of how spatiotemporal variability in parasite communities affects disease dynamics.