The Habitat Ecology of Bog Turtles (clemmys Muhlenbergii) in Southwestern Virginia
Carter, Shawn L.
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I radiotracked 31 bog turtles (Clemmys muhlenbergii) from May 1995 to December 1996 at 4 study areas in southwestern Virginia. Radio location data were used to provide measures of annual activity, spatial distributions of animals, and habitat selection. The techniques I used in this study were as follows: distance measurements between consecutive locations, home range estimators (Minimum Convex Polygon [MCP] and cluster analysis), compositional analysis of habitat selection, and measurement of microhabitat variables. Results suggest a random pattern of movement by bog turtles within habitats. Average net movements recorded between consecutive locations (separated by < 7 days) during 1995 and 1996 measured 15 m and 20 m for females and 14 m and 23 m for males respectively. Eighty-six percent of all net movements (n = 824) were less than 30 m, whereas only 2% were greater than 100 m. In 1996, average home range sizes (95% MCP, 95% cluster) were 0.47 ha and 0.17 ha for females and were 0.57 ha and 0.13 ha for males. Bog turtles selected wet meadow areas and bulrush (Scirpus spp.) patches more than expected randomly and avoided dry meadow areas and streams. Turtles were located more frequently in mud (x = 24.3 cm) and water (x = 5.2 cm) than expected by random selection (P < 0.001). I found no differences between sexes in movement, home range, or habitat selection by bog turtles. Bog turtles select specialized habitat types and microhabitats within wetlands. Large-scale movements are infrequent and the risk of site isolation may be high if wetland habitat loss continues at historic rates. Future management should protect spatially-close sites which contain multiple habitat types, soft substrate, and pockets of water.
- Masters Theses