Spatial Ecology of the Western Massasauga (Sisturus Tergeminus) in a Large Interior Wetland

Abstract

Insight into the spatial ecology of a population of animals provides information valuable to the management and conservation of a species. Reptiles are facing global declines, with 1 in 5 species currently threatened with extinction. For cryptic taxa such as snakes, radio-telemetry allows for individuals to be reliably located on a consistent basis. I used radio-telemetry to investigate the spatial ecology of the Western Massasauga (Sistrurus tergeminus) at Cheyenne Bottoms in Barton County, Kansas. Eighteen individuals (12 male and 6 female) were implanted with very high frequency (VHF) radio transmitters during 2016-2017 and tracked twice weekly from July to November in 2016 and April to October in 2017. Home range estimates were calculated for 15 individuals with 30 or more unique locations using minimum convex polygons (MCP) and kernel density estimators (KDE). Average home range estimates for these individuals using 100% MCP were 12.90 ha (0.37-60.99 ha) and 1.41 ha (0.07-5.12 ha) for 95% KDE. Core use area estimates using 50% MCP averaged 2.80 ha (0.05-13.48 ha) and 0.06 (0.001-0.21 ha) for 50% KDE. Male estimates were larger than female estimates across all estimators. Estimates for S. tergeminus on the constrained landscape of the Cheyenne Bottoms Wildlife Area (CBWA) were smaller than estimates on the more natural and less manipulated Cheyenne Bottoms Preserve, although the sample size was much larger on the CBWA. This study provides important insight into the biology of S. tergeminus and is information that can be used to help conserve this species across its range.