research
My current research investigates the diverse microbial communities on the skin of amphibians. I have ongoing research projects in both temperate and tropical systems.
LINKING ENVIRONMENTAL STRESSORS TO CHANGES IN THE MICROBIOME AND SUSCEPTIBILITY TO DISEASE
Can microbial symbionts mediate responses to environmental stressors? We think of amphibians as inhabitants of freshwaters, but, in actuality, some species of amphibians have adapted to live in saltier waters. Furthermore, human activities and climate change are increasing the salinity of freshwaters through rising sea levels, coastal storm surges and over wash events, salt application for road de-icing, drought, and dumping of industrial wastewater. This research, done in collaboration with Drs. Erica Crespi and Jesse Brunner at Washington State University, aims to expand our understanding of how environmental stressors influence early formation of the vertebrate microbiome, and how that, in turn, can alter interactions with disease-causing pathogens. Through this collaboration, we have been able to take a novel, integrative approach to understanding interactions between the microbiome, environmental conditions, host physiology, and responses to pathogen infection.
EXAMINING DRIVERS OF COMMUNITY ASSEMBLY IN HOST-ASSOCIATED BACTERIAL COMMUNITIES
How does a microbiome form on an individual host? The processes that govern the establishment and dynamics of host-associated microbial communities remain elusive. Metacommunity theory has driven recent advances in understanding the assembly of ecological communities, including host-associated microbial communities. Four processes drawn from metacommunity theory—dispersal, environmental selection, ecological drift, and diversification—are thought to interact to shape the diversity of these communities. While all of these processes play a role in community assembly, their relative roles may vary substantially depending on host characteristics or ecological context, and variation in the strength of these four processes likely contributes to the diversity in community structure that we frequently observe in nature.The aim of this research is to use both empirical and modeling approaches to deepen our understanding of the relative roles of these processes in structuring the bacterial symbiont communities on hosts.
EXAMINING THE TAXONOMIC, GENETIC, AND FUNCTIONAL DIVERSITY OF THE AMPHIBIAN SKIN MICROBIOTA
What is the relationship between diversity and function in symbiotic microbial communities? From forests to seagrass beds, there is compelling evidence that biodiversity contributes positively to the functioning of these ecosystems. However, the importance of diversity to function is less clear for microbial symbiont communities, in which there is often a high degree of functional redundancy.
My post-doctoral research investigated links between the diversity and function of bacterial symbionts on amphibian skin. These bacteria are known to play a role in protecting their hosts from a deadly fungal pathogen, Batrachochytrium dendrobatidis (i.e., chytrid fungus), that is having devastating effects on many amphibian populations around the globe. This research, which is ongoing, aims to better understand what the critical diversity components are within the bacterial community as well as how the presence of chytrid impacts these diversity components. In addition to addressing a central question in ecology—that of the importance of diversity to function—this research may lead to novel insight into methods to successfully enhance the disease resistance function of symbiotic microbes.
Searching for amphibians on a brisk spring morning in the Northeastern US.
My dissertation research focused on a different community of amphibian symbionts: the diverse organisms found in association with the arboreal egg masses of red-eyed treefrogs (Agalychnis callidryas)
INTEGRATING SPECIES INTERACTIONS AND SPATIAL PROCESSES TO EXPLAIN INSECT DISTRIBUTION ON A PATCHY RESOURCE
What are the relative roles of different ecological processes in structuring the abundance and distribution of organisms? The vast majority of organisms occupy spatially structured habitats, subsisting in collections of individual localities interconnected by dispersal. Because habitat spatial structure can greatly affect population connectivity as well as interactions between species, it is important to understand how and why individual localities (i.e., fragments or patches) vary in species composition within a given region. Explaining this variation requires considering processes occurring at multiple, hierarchical spatial scales, including both regional and local scales. Studies of regional processes determine how species distributions are shaped by differential colonization of patches based on dispersal limitation and habitat selection. Studies of local processes focus on differential survival occurring after colonization―that is, how species’ abundances within patches are altered by abiotic conditions and biotic interactions.
My dissertation research investigated several regional and local processes to explain observed variation in abundance and distribution of several organisms associated with the egg masses of red-eyed treefrogs. Specifically, I asked 1) how do the spatial arrangement and quality of habitat patches in the environment influence patterns of colonization by different species, 2) how do interspecific interactions facilitate dispersal and colonization, and 3) how do patterns of abundance continue to change following colonization depending on biotic interactions and habitat condition?