Infectious agents are usually viewed in one of two ways: either as integral members of ecological communities or as drivers of epidemics that decimate host populations. I seek a balance between these alternative views, and my research explores how global change might shift this balance. Thus, my research program in aquatic disease ecology investigates how anthropogenic influences alter interactions between parasites and their hosts. My research projects have a strong theoretical basis, integrate concepts and tools from the fields of ecology and parasitology, and combine empirical and modeling approaches. From the fragile salt marshes of California to snow-covered lakes in the Cascade range of Oregon, my research cuts across geographic regions and study systems. It also spans taxonomic boundaries, from the fascinatingly complex life cycles of trematode parasites to amphibian chytridiomycosis, an emerging infectious disease that has impacted amphibian populations globally.
The primary mechanism by which human activities alter disease dynamics is through changes in host density. Epidemiological theory predicts that contact rate between hosts and parasites should increase with host density, increasing parasite transmission. At the same time, for a given number of infective stages in the environment, high host density can decrease per-capita infection risk ("safety in numbers") because infective stages are divided (diluted) among all hosts in an area. As an NSF postdoctoral fellow at UC Santa Barbara, I am currently testing these predictions using field experiments and observational studies on the California horn snail and its trematode parasites in California salt marshes. Additionally, in collaboration with Dr. Kevin Lafferty, I am constructing a mathematical model that examines how per-capita infection/predation risk responds to host/prey density, while explicitly accounting for scale. This model will contribute to efforts to unite predator-prey and parasite-host theory under a common consumer-resource framework.
The recent emergence of many infectious diseases in wildlife has brought attention to the role of disease in population declines and species extinctions. Environmental factors can mitigate or exacerbate effects of pathogens on their hosts through direct or indirect mechanisms. One particularly sensitive group, amphibians, is at the leading edge of the sixth mass extinction, and the emerging infectious disease chytridiomycosis is implicated in their population declines and extinctions. My graduate research explored the influence of pesticides, eutrophication, and other members of the aquatic community on host-pathogen dynamics of the amphibian chytrid fungus, Batrachochytrium dendrobatids (Bd). This research was conducted at Oregon State University under the direction of Dr. Andrew Blaustein and in collaboration with Dr. Rick Relyea and Dr. Jason Rohr.
My research has been funded through a variety of sources:
- NSF Ocean Sciences Postdoctoral Research Fellowship (OCE PRF) 2015 - present
- NSF Doctoral Dissertation Improvement Grant (DDIG) 2012 - 2013
- OSU Zoology Research Fund (ZoRF) 2010 - 2012
- Society of Wetland Scientists (SWS) 2009
- NSF Graduate Research Fellowship (GRFP) 2008 - 2011
- NSF Research Experiences for Undergraduates (REU) 2006
- Howard Hughes Medical Institute (HHMI) 2005
Because effective communication of results to the public and the scientific community is an integral part of scientific research, I believe that my research benefits immeasurably from my teaching. Read more here about my teaching experience.