Thursday, August 7, 2008

PS 54-31: Habitat selection and genetic diversity in a range-limited population of Blanding's turtles (Emydoidea blandingii)

Crystal Chybowski1, Susan E. Lewis1, Gary S. Casper2, Rachel Dees1, Cynthia J. Horst1, Jason Freund1, and Paul Vastag1. (1) Carroll College, (2) Great Lakes Ecological Services LLC

Background/Question/Methods

One of the largest risks faced by endangered and threatened species is habitat loss and fragmentation.  In addition to limiting the possible options for activities such as foraging and nesting, habitat loss may impose limitations on dispersal that can lead to further risks such as inbreeding depression and genetic drift.  Blanding's turtles (Emydoidea blandingi) are designated as a threatened species in Wisconsin.  They depend on a variety of wetland as well as upland habitats.  These habitats are at particular risk for development in urbanizing areas.  Over the last 5 years, we have tracked male and female Blanding's turtles from a small, relatively isolated population in the suburban/rural community of Genesee, Wisconsin, using radio telemetry.  In addition, we collected shell scrapings of several turtles from this population for DNA analysis.  DNA from each shell was purified, and the resulting DNA was amplified to obtain DNA fingerprints. A preliminary analysis of the genetic diversity within these turtles will be presented.

Results/Conclusions We have analyzed home range sizes and habitat preferences of these turtles using GIS.  The annual home range size for turtles in this study is dramatically smaller than that reported in the literature for turtles with access to larger blocks of contiguous habitat.  Turtles showed a significant preference for certain categories of wetlands [open water (W0Hx), deciduous forest wetlands (T3K) or forest/shrub wetlands (T3/S3K)] over all available habitats and all available wetland types.  In 2007, coincident with the arrival of beavers to the marsh, the turtles shifted their range markedly to take advantage of a new impoundment of shallow standing water created by the beavers.  This response to the beavers emphasizes the important of recognizing diverse community interactions when managing endangered or threatened species.