Meeting Abstract

20.2  Saturday, Jan. 4 13:45  High and Dry: Responses of Evaporative Water Loss Along an Elevational Gradient for Two Species of Lungless Salamanders RIDDELL, EA*; SEARS, MW; Clemson University; Clemson University eriddel@clemson.edu

With rapidly changing climates, many specialist organisms will need to acclimatize, adapt, migrate, or risk extinction. To forecast the impacts of climatic change, species distribution models incorporate relationships between organisms and their environments. However, these models operate under the assumption that organisms do not adjust behavior or physiology to changing conditions. Plethodontid salamanders are a model organism to understand such responses to environments because they have limited dispersal ability and, lacking lungs, they are restricted to relatively wet environments to breathe. Along typical elevational gradients, populations experience microclimates ranging from cool, wet conditions on mountaintops to warmer, drier conditions at lower elevations. Thus, salamanders may respond to these environmental conditions along an elevational gradient by modifying cutaneous water loss (CWL). Here, we investigated CWL for two species, Plethodon metcalfi and P. teyahalee, collected over their elevational limits near Cullowhee, NC. Cutaneous water loss was determined in the lab using a flow-through system at two temperatures (12°C, 18°C) and at three vapor pressure deficits (0.2 kPa, 0.35 kPa, 0.5 kPa). Both vapor pressure deficit and surface area of the individual significantly influenced CWL for both species. Interestingly, CWL for P. metcalfi was influenced by the elevation at which the individual was captured, suggesting either acclimation or adaptation to local conditions, whereas CWL for P. teyahalee was insensitive to elevation at capture. Our results suggest that the abilities to tolerate changing climates will be species specific and dependent on the capacities for individuals to acclimate or adapt.