HABITAT PARTITIONING AMONG 3 SYMPATRIC SPECIES OF MAP TURTLES, GENUS GRAPTEMYS

Three species of map turtles, genus Graptemys, were trapped in rivers, streams, and lakes of southeastern and south-central Kansas, and 32 e nvironmental variables were measured at each trap site to compare over lap in habitat use among species. Graptemys ouachitensis and G. pseudo geographica were collected in rivers with abundant basking sites. Howe ver, G. geographica was found exclusively in shady streams over rock a nd gravel substrata. The three species had high habitat overlap index values, but discriminant analysis based on environmental variables sep arated them into distinct groups. Variables most useful in distinguish ing among groups were, in order of decreasing discriminating power, pe rcentage rock substratum, percentage bare shoreline, dissolved carbon dioxide, percentage mud substratum, percentage shade, dissolved oxygen , pH, and stream width. Graptemys pseudogeographica was commonly found together with G. ouachitensis, but sites of co-occurrence were distin guishable from sites where only one of these species occurred.