Spatial Biology of Blanding's Turtle (Emydoidea blandingii) at Weaver Dunes, Minnesota, USA

We compared the spatial biology of Blanding's turtle (Emydoidea blandingii) in typical and highly disturbed habitats in the Weaver Dunes area of Wabasha County, Minnesota. The typical habitat (Old Zumbro River Wetlands) is a large area of riparian forest with open shallow wetlands containing emergent vegetation, whereas the highly disturbed area (Weaver Bottoms) is a large shallow wetland that was previously vegetated but at the time of this study was mostly open water. Between 15 April 1999 and 1 April 2000, we used radiotelemetry to determine the distance and rate of movements of 35 adult turtles (23 females, 12 males). We used ArcView GIS to examine movements, activity areas, and home ranges of 16 females and 8 males with the most complete records. During the activity season, males made more and shorter-distance movements and had more activity areas (mean = 3.13, standard error = 0.40) than did females (mean = 1.75, standard error = 0.19), although females made longer overland movements typically associated with nesting. Mean home range estimates, calculated using the minimum convex polygon, bivariate normal density kernel, and poly-buff methods, averaged 91.59 ha (standard error = 29.95) for males and 46.0 ha (standard error = 7.40) for females. Poly-buff home ranges of adults in Old Zumbro River Wetlands were significantly smaller than in Weaver Bottoms. Average home ranges of adults at Old Zumbro River Wetlands were typical of Blanding's turtles and home ranges reported at other locations across their range, whereas the average home ranges of adults at Weaver Bottoms were approximately 7 times larger than that found in Old Zumbro River Wetlands and larger than reported for any other population of Blanding's turtles. The large home ranges at Weaver Bottoms were associated with expanses of open water and fragmented vegetated areas, which suggests that the maintenance of or even an increase in emergent vegetation in the Weaver Bottoms is important for the long-term stability of the Blanding's turtle population at the Weaver Dunes area.