Competitive Exclusion Along a Habitat Gradient Between Two Species of Salamanders (Desmognathus) in Western Florida

The geographic distributions of two congeneric salamanders interdigitate in western Florida. A Coastal Plain endemic species (Desmognathus auriculatus) occurs throughout coastal swamps in ana between major drainages; it disperses upstream into drainages from population centres near drainage mouths. Desmognathus fuscus is a northern species (at its southern distributional limits in Florida) that disperses downstream in drainages from headwater population centres. Florida habitats occupied by either species can be ordered along a gradient ranging from lotic waters of first order streams (including the unique 'steepheads') to lentic conditions of swamps, sloughs, and lake margins. When allopatric, D. auriculatus occurs over the entire range of habitats and especially in steepheads; but where sympatric with D. fuscus, D. auriculatus occurs only in stream habitats greater than order 2. In several adjacent