The fate of the Southern Appalachian salamanders


Whether you once caught salamanders as a child, used them for bait, or have never seen one, salamanders are reclusive yet an important part of the natural heritage of the Southern Appalachians. More salamander species exist here than anywhere else in the world and researchers are still discovering new species. Over 50 species of red, green, gold, and intricately patterned salamanders live exclusively in the Western North Carolina Mountains. These salamanders are also abundant – researchers suspect that in many forested areas, the biomass of salamanders (their total weight in a given area) could exceed that of birds and mammals combined.

Salamanders in Western North Carolina are unique because most don’t have lungs with which to breathe. They breathe exclusively by absorbing oxygen through their moist skin. Salamanders are well adapted to this region’s moderate temperatures and high humidity, which allow them to breathe and be active without risking desiccation. These traits also explain why they can be difficult to find. Underground habitats are cooler than air during the summer, warmer during the winter, and remain moist year-round. Therefore, salamanders remain underground or under cover until local climatic conditions allow them to become active on the forest floor or in streams.

Salamanders have many other traits that make them sensitive to changes in the environment. Their presence in watersheds is often indicative of high water quality and habitat quality for a variety of native Appalachian species. Researchers at the Coweeta LTER are examining how salamanders that breed in streams are distributed throughout the upper Little Tennessee River basin. Many of you have welcomed us onto your properties to survey salamanders and compare populations in streams surrounded by forest, agriculture, lawns, homes, and commercial buildings. As past columns have discussed, changes to watershed vegetation by these land uses can change many important stream conditions such as temperature or habitat availability.

We found that salamanders are most abundant in forested areas near streams the entire watershed, regardless of any other human activities within the watershed. Forests adjacent to streams provide cover from the sun that keep these streams at cool temperatures, provide woody debris for refuge, and provide leaves that fuel the food webs of streams. Further investigations found that salamanders are even unwilling to move through streams that lack riparian vegetation. Therefore, open stream reaches isolate populations of stream salamanders, making them more susceptible to local extinction.

Because salamanders are very sensitive to temperature and precipitation patterns, researchers are increasingly concerned about how climate change will make it more difficult for salamanders to survive in the region. In disturbed streams, salamanders are more likely to be flushed far downstream during floods, where they become prey for larger fish species. Alternatively, droughts decrease habitat availability and increase stream temperatures, which both negatively impact stream salamander populations.

Land uses and climate are going to change, but well-preserved riparian zones may be the key to helping stream salamanders survive and remain healthy even during these changes. Our research shows that it is particularly important that riparian corridors remain forested throughout the watershed; otherwise, many stream and terrestrial species will lose movement corridors that they depend on throughout their life cycle. Ultimately, forested riparian zones are essential for preventing degradation of the biological, chemical, and physical properties of the area’s streams and rivers and buffering them from future change.

 

This column is produced by members of the Coweeta Listening Project (CLP), a branch of the Coweeta Long Term Ecological Research Program. Views expressed here are not representative of the USDA Forest Service or the Coweeta Hydrologic Lab. Please share questions, comments, or suggestions for future topics at cwtlistn@uga.edu or Coweeta Listening Project, UGA, 210 Field St., Room 204, Athens, Georgia 30602.

 

Original Citation: The Coweeta Listening Project. Franklin Press. Column on "Science, Public Policy, Community." Page B4. July 19, 2013.