Ecological processes regulating geographic distributions of Plethodon salamanders in the Southern Appalachian Mountains

Abstract

Understanding how dispersal, adaptation to environmental characteristics, and interactions among species set the limits to species geographic distributions is one of the primary goals of biogeography. Evolutionary history of a species allows for a species to be adapted to a particular environment and is thought to have the greatest influence on where, geographically, a species can exist. However, often the species distribution is much smaller than its potential range based solely on environmental characteristics alone, and both local and regional ecological processes are responsible for this range restriction. For instance, the ability to disperse to suitable habitat and interspecific associations also factor in to the capability of a species to access and successfully colonize regions outside of its distribution. In this study, I assess patterns in trophic morphology, environmental characteristics, and spatially-explicit population models to assess the geographic distribution of Plethodon teyahalee. I find that the mechanisms regulating this species` distribution varies geographically, and that it is a combination of both environmental characteristics and interspecific competition which regulate this species` geographic range limits in this group. Further, this research also demonstrates that local processes, such as interspecific competition, can be important in understanding regional patterns such as species geographic distributions.