DISTRIBUTION AND STATUS OF CRAYFISHES OF THE GENERA CAMBARUS AND FALLICAMBARUS (DECAPODA, CAMBARIDAE) IN ONTARIO, CANADA

This comprehensive update of the distribution of crayfishes of the gen era Cambarus and Fallicambarus in Ontario includes substantial materia l collected since 1965 and a reexamination of previous records. Revise d provincial range limits are presented for two wide-ranging, open-wat er species, C. bartonii bartonii and C. robustus, as well as for 2 obl igate burrowers of more restricted distribution, C. diogenes and F. fo diens. Previously unreported locality records represent range extensio ns, fill in geographic gaps in known ranges, or confirm the persistenc e of populations for periods of several decades. Limits to the ranges of the 4 species appear to be established by patterns of postglacial m igration and habitat preferences. A diagnosis of the current status of each of these species suggests the potential impact of anthropogenic perturbations, such as lake acidification and wetland destruction, for the future of these crayfishes in Ontario.