Truly enigmatic declines in terrestrial salamander populations in Great Smoky Mountains National Park


Correspondence: Nicholas M. Caruso, Department of Biology, University of Maryland, 1210 Biology-Psychology Building, College Park, MD 20742, USA.




Woodland salamanders (genus: Plethodon) declined synchronously across many protected areas in Eastern North America by the mid-1980s, but no cause was attributed to these declines. We hypothesized that the rapid, synchronous loss of several populations of many species was consistent with the invasive pathogen Batrachochytrium dendrobatidis ( Bd), and we resurveyed historic sites to search for Bd in current populations.


Great Smoky Mountains National Park.


We surveyed 35 sites 2–4 times between March and November 2009, quantified community composition and abundance of 72 populations of six species and three hybrids of Plethodon salamanders, and collected 665 skin swabs to detect Bd.


At 22 of the 35 sites, we were unable to find one or more species that were historically present. Plethodon glutinosus and P. teyahalee and their hybrids were less abundant than historically found, P. jordani x metcalfi and P. ventralis were more abundant and the remaining three species fluctuated but showed no net change. Yet, only one of the 665 salamanders was positive for Bd.

Main conclusions

Declines were not associated with particular localities, but occurred in particular species. We conclude that over collecting, logging, and acid rain are unlikely to have caused these population declines, but we were unable to rule out disease or climate change as contributing factors. Population declines of Plethodon salamanders in the Park are substantial and have persisted for 30 years. Determining the cause and the extent of these declines is important for managing this area of global salamander biodiversity.