Conservation of the Timber Rattlesnake in Massachusetts

Stengle, Anne

Sievert, Paul

University of Massachusetts

Amherst MA USA

Tyning, Thomas

Berkshire Community College

Pittsfield, MA USA

Timber Rattlesnake (Crotulas horridus) populations have become increasingly fragmented and isolated during the past 300 years, and probably most pronounced near the northeastern edge of their distribution in Massachusetts. Currently, five populations exist in the state, with only one site large enough to be considered a metapopulation. We evaluated connectivity between Massachusetts den sites of timber rattlesnakes through a combination of genetic analyses and radio telemetry. Genetic structure was assessed using 15 microsatellite loci, and analyzed with 300 samples taken from all New England populations. Individual movements of snakes were measured in the metapopulation over the course of 5 years. Preliminary results indicate that geographic distance is a poor predictor of genetic distance between dens, both between and within sites. Radio-telemetry results provide an initial mechanistic explanation for genetic structure at one site, but our understanding of between site variations in structure is hampered by poor knowledge of historical events leading to population isolation. Observations of facial lesions have also been noticed in these populations, and studied further with USFW grant. Some of these individuals have been tracked over multiple years, with some individuals appearing to be unaffected by the disease, but more drastic conditions have been reported in other Massachusetts populations. These findings should be useful to managers interested in maintaining genetically diverse and viable populations of timber rattlesnakes in an increasingly fragmented landscape. Currently Massachusetts is proposing customized conservation action items for each site, in addition to the possibility of introducing the species to a new site.