Range-Wide Analysis of Eastern Massasauga Survivorship

Decisions affecting wildlife management and conservation policy of imperiled species are often aided by population models. Reliable population models require accurate estimates of vital rates and an understanding of how vital rates vary geographically. The eastern massasauga (Sistrurus catenatus catenatus) is a rattlesnake species found in the Great Lakes region of North America. Populations of the eastern massasauga are fragmented and only a few areas harbor multiple, sizable populations. Eastern massasauga Received: 31 August 2011; Accepted: 19 April 2012 Published: 5 July 2012 E-mail: [email protected] Present address: Waterloo Wildlife Office, Department of Natural Resources, 13578 Seymour Road, Grass Lake, MI 49240, USA. Present address: J. Clark Salyer National Wildlife Refuge, Upham, ND 58789, USA. Present address: 2395 Conservation Road, Campbellville, ON, Canada L0P 1B0. Present address: Department of Biology, State University of New York at Potsdam, Potsdam, NY 13676, USA. Present address: Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA 50011, USA. Present address: Department of Fisheries, Wildlife, and Conservation Biology, University of Minnesota, St. Paul, MN 55108, USA. Present address: Navajo Nation Department of Fish and Wildlife, Window Rock, AZ 86515, USA, The Journal of Wildlife Management 76(8):1576–1586; 2012; DOI: 10.1002/jwmg.418 1576 The Journal of Wildlife Management 76(8) research has typically focused on single populations or local metapopulations but results suggest that demographic parameters vary geographically. We used 21 radiotelemetry datasets comprising 499 telemetered snakes from 16 distinct locations throughout the range of the eastern massasauga to characterize geographic patterns of adult survival using the known-fate model in ProgramMARK. Annual adult survival ranged from 0.35 to 0.95 (mean 1⁄4 0.67) and increased along a southwest to northeast geographic axis. Further analysis of 6 datasets indicated no consistent difference in survival between males and females. Our results provide a better understanding of the relationship between survivorship and geography for the eastern massasauga and suggest that such variation should be incorporated into population models as well as local and regional management plans. 2012 The Wildlife Society.