A Preliminary Assessment of Habitat Partitioning in a Freshwater Turtle Community at an Isolated Preserve

摘要

Understanding species-habitat relationships is important for achieving effective habitat management goals, but few studies have evaluated habitat use in co-occurring turtle species. We examined habitat partitioning among five species of freshwater turtles at an isolated preserve in northeastern Illinois. From May-September 2006, we conducted a radiotelemetry study to determine differences in macro- and microhabitat use, niche breadth, and niche overlap of 50 turtles representing rare (Emydoidea blandingii, Clemmys guttata) and common species (Chrysemys picta, Chelydra serpentina, Sternotherus odoratus). Both levels of habitat analysis showed strong partitioning between C. guttata and the common species as well as marked overlap in habitat use between E. blandingii and C. serpentina. Use of mesic dolomite prairie was greater in C. guttata compared to S. odoratus. Further, use of pond was greater in all common species compared to C. guttata and E. blandingii. Species strongly partitioned microhabitat along an axis comprised of vegetation height, understory canopy cover, water depth, and percent open water at surface, as well as in use of wetlands with organic substrates. Patterns of macro- and microhabitat use and measures of niche breadth and niche overlap suggest that E. blandingii and C. serpentina are habitat generalists whereas C. guttata is a habitat specialist. We found no evidence of agonistic interactions among species, thus habitat partitioning observed in our study is likely a result of species-specific traits and requirements. Our findings suggest that C. guttata is most vulnerable to habitat degradation and that variation in wetland habitat characteristics is necessary to support a diverse freshwater turtle community.