Research

Wetland wildlife are threatened by the decline and loss of habitat due to human activities such as climate and land use change. King rails (Rallus elegans) and clapper rails (Rallus crepitans) are two marsh bird species with similar distributions, morphology, and behavior. They are thought to be found a long a salinity gradient with the king rail in freshwater marshes and the clapper rail in estuarine marshes. This separation, however, is not absolute and there are reports of hybridization, In Virginia, clapper rails are more abundant than king rails, the latter of which are listed as a species of very high conservation need. In conjunction with visual and audio surveys, I am using genetic methods to acquire baseline data on occupancy and introgression to help develop an effective strategy for monitoring and management.

Connectivity across a landscape is an important component of healthy animal populations as it allows for the rescue of declining populations and promotes genetic diversity. With increasing human influence and associated land use changes, this connectivity is in jeopardy. Understanding the factors that facilitate or inhibit movement is therefore essential for conservation management. My doctoral research used approaches from the emerging field of landscape genetics to investigate how natural and anthropogenic influences contribute to the genetic connectivity of two amphibian species, the wood frog (Lithobates sylvaticus) and the spotted salamander (Ambystoma maculatum) in a forest managed for timber harvest. Through genetic sampling, I calculated the heritable contribution of successfully reproducing immigrants and measured connectivity by inferring rates of gene flow between populations. Further, I used estimates of gene flow to assess the permeability of different land cover classes and identify barriers to dispersal, which is essential for conservation management.

Anthropogenic influences such as hunting pressure and habitat fragmentation can alter the spatial patterns of wildlife populations. Understanding the consequences of these impacts is a challenge for natural resource managers, which can be overcome by investigations using spatial genetic techniques. I used spatial autocorrelation and landscape genetic analyses to compare the impacts of anthropogenic forces on the spatial genetic structure of two female black bear (Ursus americanus) populations in northern New Hampshire with similar bear densities but varying human densities, hunting pressure and sex ratios. I found evidence of an impact of hunting mortality on the spatial genetic structure of female black bears.