Meeting Abstract
Character displacement, or the evolution of differences that reduce competition, provides one mechanism through which closely related species can coexist. The introduction of nonnative species provides a valuable system for studying character displacement, as novel interactions between native and nonnative species may alter the evolutionary trajectory of the native species. Gray-cheeked salamanders (Plethodon montanus) were introduced to Mountain Lake Biological Station (MLBS), Pembroke VA approximately 80 years ago. To our knowledge, this is the only human-introduced lungless salamander to have successfully established outside of its native range. Today, this nonnative salamander successfully coexists with several closely related species, including the highly abundant red-backed salamander (Plethodon cinereus). In the presence of competitors, other populations of red-backed salamanders have developed larger jaws to better obtain food, space, and other resources. We were interested in whether character displacement has occurred in P. cinereus in order to reduce competition with the newly established species. Using geometric morphometrics, we compared skull and jaw shape of P. cinereus from sites where P. montanus is either absent, introduced, or native. We predicted that skulls and jaws of P. cinereus would be larger in the presence of P. montanus. If this is the case, we expect that P. cinereus from the introduction site will represent a “transition” in skull and jaw morphology in response to the newly introduced competitor. The results of our study will shed light on the mechanisms underlying species coexistence, and will provide insight to the effects of novel species interactions caused by climate-related range shifts.
