Event Title

Eastern Massasauga Rattlesnakes in Southwest, Michigan: Population Monitoring using Genetic and Demographic Data

Location

Hager-Lubbers Exhibition Hall

Start Date

19-4-2016 3:30 PM

Description

The Eastern Massasauga rattlesnake (Sistrurus catenatus) is threatened or endangered in every state and province where it occurs, with the exception of Michigan where it is a state species of special concern. Due to their cryptic nature, Eastern Massasaugas are generally difficult to detect causing monitoring efforts to be costly and time consuming. Therefore, the viability of populations throughout the species’ range is not well understood. In this study, we used capture-recapture data to estimate demographic parameters and investigate the viability of Eastern Massasauga populations at two sites in southwest Michigan. We also used genetic data to estimate effective population size as a comparative measure of genetic diversity. At the first site, we estimated an adult abundance of 105 (95% CI=86–161) individuals and an effective population size of 56 (95% CI=36–103) individuals. At the second site we estimated an adult abundance of 137 (95% CI=110–198) individuals and an effective population size of 31 (95% CI=22–46) individuals. Additionally, at the first site, we estimated annual apparent survival to be 0.70 (95% CI=0.50–0.85) for adult males and 0.65 (95% CI=0.42–0.83) for adult females. These results indicate that both populations are relatively small and isolated, which could hinder their long-term viability. These estimates may be useful to resource managers in an adaptive management framework to examine the impacts of habitat manipulations and restoration activities on Eastern Massasaugas.

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Apr 19th, 3:30 PM

Eastern Massasauga Rattlesnakes in Southwest, Michigan: Population Monitoring using Genetic and Demographic Data

Hager-Lubbers Exhibition Hall

The Eastern Massasauga rattlesnake (Sistrurus catenatus) is threatened or endangered in every state and province where it occurs, with the exception of Michigan where it is a state species of special concern. Due to their cryptic nature, Eastern Massasaugas are generally difficult to detect causing monitoring efforts to be costly and time consuming. Therefore, the viability of populations throughout the species’ range is not well understood. In this study, we used capture-recapture data to estimate demographic parameters and investigate the viability of Eastern Massasauga populations at two sites in southwest Michigan. We also used genetic data to estimate effective population size as a comparative measure of genetic diversity. At the first site, we estimated an adult abundance of 105 (95% CI=86–161) individuals and an effective population size of 56 (95% CI=36–103) individuals. At the second site we estimated an adult abundance of 137 (95% CI=110–198) individuals and an effective population size of 31 (95% CI=22–46) individuals. Additionally, at the first site, we estimated annual apparent survival to be 0.70 (95% CI=0.50–0.85) for adult males and 0.65 (95% CI=0.42–0.83) for adult females. These results indicate that both populations are relatively small and isolated, which could hinder their long-term viability. These estimates may be useful to resource managers in an adaptive management framework to examine the impacts of habitat manipulations and restoration activities on Eastern Massasaugas.