Population Sizes and Foraging Ecology in a Tropical Freshwater Stream Turtle Community

The population sizes, densities, and food habitats of four freshwater turtle species inhabiting a sluggish stream at Chan Chen Junction, Corozal District, Belize, were investigated from January through April, 1984. Population estimates in January indicated that Trachemys scripta was most abundant and reached the highest density, followed by Kinosternon scorpioides, K. leucostomum, and Staurotypus triporcatus. Population estimates in April indicated little change in population size or density of T. scripta or S. triporcatus, but significant increases in numbers and densities of K. scorpioides and K. leucostomum. The increases probably reflect movement into the stream from nearby ephemeral habitats that dried during the prolonged spring dry season. Adult T. scripta of both sexes foraged throughout the stream and were primarily herbivorous, whereas juveniles were restricted to dense mats of vegetation along stream margins and were insectivorous. Adult K. scorpioides and K. leucostomum were ubiquitous and primarily insec- tivorous but their dietary similarity decreased as population sizes increased. Staurotypus foraged through- out the stream on large gastropods and turtles, the latter increasing in importance as the kinosternid population increased. The ecology of Neotropical freshwater turtles is poorly understood and infrequently inves- tigated. Even basic data are lacking for most species or derived from few specimens and hab- itats. Studies of Neotropical turtle ecology by Legler (1966), E.