Discovery Magazine

Photo Credit: U.S. Fish and Wildlife Service

Southeastern Beach Mouse Genetics Study

The southeastern beach mouse (SEBM) is threatened by habitat loss mainly attributed to coastal construction and erosion. Expanding residential areas near/on the beach has eliminated coastal habitat and increased recreational beach activity. This loss of habitat led the U.S. Fish and Wildlife Service to list the SEBM as threatened in 1989. We aim to answer several important questions for the management and conservation of SEBM using conservation genetic techniques. These questions include: Is there microspatial structure among subpopulations of beach mice? Previous studies have found a substantial genetic break among northern and southern populations and showed some evidence of small-scale population structure. We will assess whether or not there are boundaries to movement that would decrease the connectivity of subpopulation of SEBM. We will also use conservation genetic methods to test for gene flow among subpopulations to infer recent movement of individuals.

In addition, researchers have found that in species with large variances in reproductive output, survival and population size (such as the SEBM), census size (N) alone is a poor predictor of whether or not a population will exhibit loss of genetic diversity. The effective population size (Ne) is a more useful measure as it, in effect, tracks the number of individuals that send offspring into the next generation. We will use new conservation genetic-based methods to provide the first estimates of Ne for SEBM populations. Estimating Ne is important for population viability analysis and in determining which populations are the most at risk for inbreeding and extinction.

We will examine the conservation genetics of SEBM using 10 microsatellite loci developed for this species and shown to be polymorphic in other studies. The knowledge we gain from this research will enable managers to make important assessments about translocation, connectivity and extinction risk.