Spatial Ecology of the Eastern Massasauga (Sistrurus c. catenatus) in a New York Peatland

Abstract

The eastern massasauga (Sistrurus catenatus catenatus) is listed as endangered in New York and is currently known from only two locations in the state. Characteristics of this species' spatial ecology and habitat preferences were investigated between 1989 and 1992 in Cicero Swamp, a large wetland complex near Syracuse, New York, which contains a 37 ha peatland of critical importance to massasaugas. Radiotelemetered male (N = 11) and nongravid females (N = 2) left the peatland for nearby swamp forest soon after spring emergence while gravid females (N = 2) remained in the peatland until parturition. All telemetered snakes overwintered in the peatland. Of individuals tracked for the entire active season, gravid females moved significantly shorter distances per day (i = 7.1 m) and per season (i = 751.9 m) than either males (mean distance/day = 20.5 m; mean distance/season = 2940.2 m) or nongravid females (mean distance/ day = 22.9 m; mean distance/season = 3712.2 m). Similarly, 100% minimum convex polygon activity range estimates were smaller for gravid females (x = 2.0 ha) than for either males (x = 27.8 ha) or nongravid females (x = 41.4 ha). These findings suggest that conservation efforts for eastern massasaugas in Cicero swamp should focus on peatland habitat used by gravid females. The spatial arrangement and movements of a mobile animal species clearly will reflect aspects of its behavior and ecology. Detailed knowledge of this information is critical to managers of wildlife resources, especially if the species in question is considered endangered, is regionally rare, or occurs on the periphery of its range in marginal habitat. Differences in activity patterns may exist between subgroups of a population, defined by size, age, sex, or reproductive condition, that will potentially impact conservation plans (Gibbons and Semlitsch, 1987). Additionally, there may exist seasonal or yearly differences in movement patterns, related to important life-history events, that need be determined (Gregory et al., 1987). Advances in radio telemetry have made the study of the spatial ecology of generally secretive or inconspicuous organisms like snakes possible and evidence of intrapopulation differences is becoming apparent in many species (Gregory et al., 1987; Reinert, 1993). The eastern massasauga (Sistrurus c. catenatus), a wetland associate across its range (Wright, 1941; Reinert and Kodrich, 1982; Seigel, 1986; Weatherhead and Prior, 1992), is at the easternmost point of its distribution in central New York. Here, as well as across its entire range, it is threatened with extinction and exists as relatively small and isolated relict populations (Beltz, 1993; Johnson and Breisch, 1993). The specific objectives of this study were to determine the activity range and movement patterns of eastern massasaugas by sex and reproductive condition in Cicero Swamp, near Syracuse, New York to (1) aid in the development of a management strategy for this species in the state and (2) compare results with telemetric studies of this species in other habitat types and geographic locations (i.e., wet prairie in western Pennsylvania, Reinert and Kodrich, 1982; coniferous forest/wetlands in Ontario, Weatherhead