Spatial Ecology and Habitat Selection of the Pygmy Rattlesnake (Sistrurus miliarius) in Southwestern

Maag, Dylan W.

Maher, Sean P.

Greene, Brian D

Department of Biology

Missouri State University

Springfield, MO USA

Current Affiliation (DWM): Biology Department

San Diego State University

San Diego, CA USA

Despite a wide distribution throughout the Southeastern United States, research on pygmy rattlesnakes (Sistrurus miliarius) has been largely restricted to Florida populations. We studied S. miliarius in a managed forested landscape on an 809-ha state conservation area in Southwest Missouri, near their northern range limit, during 2016 and 2017. We captured 54 individuals of S. miliarius, primarily during evening road driving surveys, and retained 19 (6 males and 13 females: 9 gravid, 4 nongravid) for a radio-telemetry study. Telemetered snakes were relatively sedentary, making short, infrequent movements that resulted in small minimum convex polygon home range estimates (range: 0.01–2.6 ha). Reproductive status of females strongly affected activity with mean movement distances and home range sizes of gravid females increasing five-fold following parturition. Parturition dates ranged from August 11–25 and maternal attendance of litters for 1–3 days was observed in five post-partum females. We encountered S. miliarius in all available habitat types, suggesting that habitat selection was mainly occurring at the microhabitat scale. Snakes were very secretive but typically concealed themselves within vegetation (89% of observations) or beneath surface cover (8.5% observations) rather than underground. Snakes selected microhabitats with more vegetative cover and woody debris, and less leaf litter, than random sites. Our S. miliarius used a variety of habitat types suggests that it is well adapted to the Ozarks landscape. We provide novel information on spatial patterns and habitat selection for the ecology of S. miliarius ecology that hopefully will stimulate comparative studies in other geographic regions.

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