As a molecular ecologist I use genetic markers to help answer ecological questions. Specifically, I am interested in using genetic approaches to facilitate the conservation and management of wildlife populations.
Developing eDNA assays for secretive or invasive species
Environmental DNA (eDNA), or shed genetic material, can serve as a reliable, noninvasive way to monitor aquatic systems for the presence of a secretive or invasive species. Assays based on the collection of eDNA are becoming increasingly popular, and, when optimized, can aid in effectively and efficiently tracking invasion fronts. My lab has been working to develop, test, or apply eDNA assays to the invasive rusty crayfish (Faxionus rusticus), eastern hellbender (Cryptobranchus alleganiensis), nutria (Myocastor coypus), and insect pollinators.
Hybridization and Introgression in the King-Clapper Rail Complex
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.
Landscape Genetics of Pond Breeding Amphibians
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.
Spatial Genetic Structure of Black Bears
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.
Population Estimation of Black Bears Using Genetic Tagging
Abundance estimates for black bears (Ursus americanus) are important for effective management as reliable population estimates are required to manage bear numbers to ensure a peaceful co-existence with humans, and to gauge the impact of hunting. Recently, DNAtechnology has resulted inwidespread use of non-invasive genetic capture-mark-recapture (CMR) approaches to estimate populations. Few studies have compared the genetic CMR to other estimation methods. I used genetic CMR to estimate the bear population at 2 study sites in northern New Hampshire (Pittsburg and Milan) in 2 consecutive years. I compared the estimates to those derived from traditional methods used by the New Hampshire Fish and Game Department using hunter harvest and mortality data. I found that genetic CMR methods were able to identify demographic variation at a local scale, including a strongly skewed sex ratio in the Milan population.
Habitat Preferences of Elephant-Shrews (sengis)
Africa’s tropical forests are home to large diversity of species, many of which are endemic to the African continent. With increases in both human population and deforestation, more and more animals are becoming threatened including the elephant-shrews or sengis. There are few records of the black-and-rufous sengi (Rhychocyon petersi) and the objective of this study was to estimate the density of sengis based on nest counts and analyze habitat preferences in a forest reserve where R. petersi had been sighted. The results from this study indicated the population density of R. petersi is lower in the Chome Forest Reserve than in most population in the Eastern Arc Mountains.