Eric T. Hileman, Northern Illinois University
Richard B. King, Northern Illinois University
John M. Adamski, Seneca Park Zoo
Thomas G. Anton, Field Museum
Robyn L. Bailey, Cornell University
Sarah J. Baker, University of Illinois at Urbana-Champaign
Nickolas D. Bieser, Indiana University - Purdue University Fort Wayne
Thomas A. Bell Jr., New York State Department of Environmental Conservation
Kristin M. Bissell, Michigan Department of Natural Resources
Danielle R. Bradke, Grand Valley State University
Henry Campa III, Michigan State University
Gary S. Casper, University of Wisconsin - Milwaukee
Karen Cedar, Ojibway Nature Centre
Matthew D. Cross, Bowling Green State University
Brett A. DeGregorio, University of Illinois at Urbana-Champaign
Michael J. Dreslik, University of Illinois at Urbana-Champaign
Lisa J. Faust, Lincoln Park Zoo
Daniel S. Harvey, University of Illinois at Urbana-Champaign
Robert W. Hay, Turtles for Tomorrow
Benjamin C. Jellen, Urban Chestnut Brewing Company
Brent D. Johnson, State University of New York Syracuse
Glenn Johnson, State University of New York Potsdam
Brooke D. Kiel, Grand Valley State University
Bruce A. Kingsbury Ph.D., Indiana University - Purdue University Fort WayneFollow
Matthew J. Kowalski, Indiana University-Purdue University Fort Wayne
Yu Man Lee, Michigan State University
Andrew M. Lentini, Toronto Zoo
John C. Marshall, Indiana University-Purdue University Fort Wayne
David Mauger, Forest Preserve District of Lake County
Jennifer A. Moore, Grand Valley State University
Rori A. Paloski, Wisconsin Department of Natural Resources
Christopher A. Phillips, University of Illinois at Urbana-Champaign
Paul D. Pratt, Ojibway Nature Centre
Thomas Preney, Ojibway Nature Centre
Kent A. Prior, Parks Canada
Andrew Promaine, Parks Canada
Michael Redmer, United States Fish and Wildlife Service
Howard K. Reinert, College of New Jersey
Jeremy D. Rouse, Ontario Ministry of Natural Resources
Kevin T. Shoemaker, University of Nevada, Reno
Scott Sutton, Parks Canada
Terry J. VanDeWalle, Stantec Consulting Services Inc
Patrick J. Weatherhead, University of Illinois at Urbana-Champaign
Doug Wynn, Ohio State University - Main Campus
Anne Yagi, Ministry of Natural Resources

Document Type


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Public Library of Science



Peer Reviewed



Elucidating how life history traits vary geographically is important to understanding variation in population dynamics. Because many aspects of ectotherm life history are climate-dependent, geographic variation in climate is expected to have a large impact on population dynamics through effects on annual survival, body size, growth rate, age at first reproduction, size–fecundity relationship, and reproductive frequency. The Eastern Massasauga (Sistrurus catenatus) is a small, imperiled North American rattlesnake with a distribution centered on the Great Lakes region, where lake effects strongly influence local conditions. To address Eastern Massasauga life history data gaps, we compiled data from 47 study sites representing 38 counties across the range. We used multimodel inference and general linear models with geographic coordinates and annual climate normals as explanatory variables to clarify patterns of variation in life history traits. We found strong evidence for geographic variation in six of nine life history variables. Adult female snout-vent length and neonate mass increased with increasing mean annual precipitation. Litter size decreased with increasing mean temperature, and the size–fecundity relationship and growth prior to first hibernation both increased with increasing latitude. The proportion of gravid females also increased with increasing latitude, but this relationship may be the result of geographically varying detection bias. Our results provide insights into ectotherm life history variation and fill critical data gaps, which will inform Eastern Massasauga conservation efforts by improving biological realism for models of population viability and climate change.


Animals, Climate Change, Female, Genetic Variation, Great Lakes Region, Male Models, Biological, Viperidae



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