Size-sex variation in survival rates and abundance of pig frogs, Rana grylio, in northern Florida wetlands

During 1991-1993, we conducted capture-recapture studies on pig frogs, Rana grylio, in seven study locations in northcentral Florida. Resulting data w ere used to test hypotheses about variation in survival probability over di fferent size-sex classes of pig frogs. We developed multistate capture-reca pture models for the resulting data and used them to estimate survival rate s and frog abundance. Tests provided strong evidence of survival difference s among size-sex classes, with adult females showing the highest survival p robabilities. Adult males and juvenile frogs had lower survival rates that were similar to each other. Adult females were more abundant than adult mal es in most locations at most sampling occasions. We recommend probabilistic capture-recapture models in general, and multistate models in particular, for robust estimation of demographic parameters in amphibian populations.