Natural history of the Peaks of Otter salamander (Plethodon hubrichti) along an elevational gradient
Document Type Article
ABSTRACT - The Peaks of Otter salamander, Plethodon hubrichti, is a montane species found at elevations above 442 m within a 117 km2 area of the Blue Ridge Mountains in central Virginia, USA. In areas of this species’ range where the Eastern Red-backed salamander Plethodon cinereus, a potential competitor, is absent, surface-active salamander density was hypothesised to decrease at lower elevations due to increased temperatures and lower humidities, which may adversely affect salamander reproductive output and survival rates. Eggs/female, % gravid females, surface-active salamander density, temperature and relative humidity were recorded from nine sites ranging in elevation from 488 to 1143 m. Survival rates and growth rates were estimated at three of these sites. Surface-active salamander densities, survival rates, growth rates, eggs/female and reproductive output decreased with elevation. Decreases were correlated with increases in temperature and a decrease in relative humidity associated with decline in elevation. Other habitat factors such as % canopy closure did not decrease with elevation at the study sites. Peaks of Otter salamanders had greater dehydration rates and lower critical thermal maxima than the wider-ranging Eastern red-backed salamanders, which reflects their adaptation to montane environments. These results support the importance of conserving mature hardwood forests, particularly at lower elevations, which represent marginal environments for montane species of salamanders.