Effects of Acid Deposition and Calcium Depletion on High Elevation Southern Appalachian Songbirds and Land Snails

R. Hylton, T. R. Simons, and K. Franzreb
USGS North Carolina Cooperative Fish and Wildlife Research Unit (1,2) and USDA Forest Service Southern Research Station 

Atmospheric pollution remains a critical environmental problem in the high elevation forests of North America, however we have a limited understanding of the long-term, landscape-level effects of acid precipitation on high elevation populations in terrestrial systems.  The objectives of our research are to quantify the effects of acid deposition and calcium depletion on high elevation songbird and snail populations both spatially and temporally.  Snails are of particular interest as they are the primary source of calcium for songbirds, and are sensitive to environmental contaminants.  We are comparing the calcium content of eggs and the nesting success of songbirds, and abundance, species richness, calcium content, and shell thickness of terrestrial land snails across a gradient of acid deposition in Great Smoky Mountains National Park, an area which faces some of the highest levels of air pollution in North America.  We are also conducting a retrospective study using museum specimens to determine if snail shell size, thickness, and calcium content have declined over time.  In subsequent years we will manipulate the availability of environmental calcium for songbirds at experimental study sites to examine the extent of calcium deficiency.  We anticipate expanding this research into adjacent high elevation sites on National Forest lands in subsequent years.  Our goal is to improve understanding of the connections between human-induced atmospheric pollution and the ecology of wild songbird and snail populations in the Southern Appalachians, and provide recommendations for environmental conservation and management.

corresponding author:
Southern Appalachians Cooperative Ecosystems Studies Unit
Department of Forestry
Wildlife and Fisheries
University of Tennessee
Knoxville, TN  37996
865-974-0932
kfranzreb@fs.fed.us