In Illinois, the Eastern Massasauga Rattlesnake (Sistrurus catenatus) has suffered a drastic decline and currently only has 1-4 known populations remaining. We have established a long-term monitoring program for the population at Carlyle Lake in Clinton County, and have a continuous time series going back to 1999 (approximately 15 years). One of the remaining gaps is to improve our understanding of the genetic population structure and molecular ecology. We used microsatellite DNA markers to genotype 94 Eastern Massasauga Rattlesnake collected across three time periods (2002, 2007, and 2012) from South Shore State Park (SSSP). We report on 1) within-population diversity (e.g., allele frequencies, observed heterozygosity), 2) estimates of effective population size (Ne), 3) evidence for bottlenecks, and 4) levels of migration for each temporal population. Levels of heterozygosity were moderate and remained stable over time but a number of rare alleles previously detected in 2002 and 2007 were undetected in 2012. Levels of migration were high from one temporal population to another but estimates of Ne were low and evidence for a recent population bottleneck (e.g., heterozygosity excess) was detected within time periods. Further, the gradual loss of rare alleles prior to a decrease in heterozygosity is consistent with predictions of genetic drift in small populations. This ongoing study will provide a firmer understanding of the genetic status of the Carlyle Lake population to further refine conservation strategies within the region, state, and range of the Eastern Massasauga Rattlesnake.
|Original language||English (US)|
|Title of host publication||2014 Joint Meeting of Ichthyologists and Herpetologists, 31 July - 3 August 2014 Chattanooga, Tennessee|
|State||Published - 2014|