Structure and composition of a southern Illinois freshwater turtle assemblage

We report on a six-year study (1994-1999) of a diverse turtle assemblage in Gallatin County, IL. Ten species of freshwater turtles representing four families were recorded. Species richness increased as a function of trap hours, with 3000 trap hours required to capture all species. The greatest density and biomass was for Trachemys scripta. Pseudemys concinna ranked second in density, but Chelydra serpentina ranked second highest in biomass. Females comprised the majority of the biomass in emydids, biomass ratios were even in Sternotherus odoratus, and males comprised the majority of the biomass in C. serpentina. Relative abundance did not significantly differ among the six years, although some uncommon species were not captured in all years.