FIRST PLACE - SESSION A (Botony, Zoology, Geology and Geography)

Eastern hellbenders Cryptobranchus alleganiensis (Cryptobranchidae) are the largest salamander in the United States, and recent studies indicate that they are declining over most of their range. We are mapping the current distribution of hellbenders in the Cherokee National Forest and Great Smoky Mountains National Park in Tennessee and North Carolina, which represent much of the highest quality habitat for hellbenders in the southern Appalachians. When a population is identified, we are assessing the age structure and population viability, and investigating potential environmental stressors. We have identified just two rivers in which all size classes are represented, including gilled larvae (indicating current reproduction and recruitment). Preliminary tissue analyses revealed the presence of DDT metabolites and mercury residues; however the levels are very low, and unlikely to be biologically significant. We found four additional rivers containing hellbenders, however population densities appear relatively low, and as yet there is no evidence of current reproduction. Our data confirm that hellbenders have declined across their historical range in southeast Tennessee. Likely causes include habitat fragmentation, siltation and dam construction