Abstract

Batrachochytrium dendrobatidis (Bd) is the causative agent of chytridiomycosis, a disease of amphibians with significant global-scale implications. Bd has been found in the Southeastern United States, yet the potential impacts of chytridiomycosis on regional amphibian populations have not been fully elucidated. Occurrence of Bd in headwaters of large riverine systems also has considerable implications for downriver management and control of pathogen dissemination among amphibian populations in these watersheds. Determination of the presence and distribution of Bd in the environment and the fauna in headwater areas in the southern Appalachian streams would allow for development of management strategies such as monitoring programs or disinfection protocols to prevent the spread of the pathogen/disease in the immediate area as well as in managed areas downriver. The potential identification of other biotic reservoirs of infection or environmental variables that affect the ecology of the pathogen would also have implications for the detection and control of Bd throughout the Southeast region and beyond. This multi-year study investigates the presence of Bd among streamside salamanders and their habitat at 10 defined areas throughout the Southern Appalachian mountain range from southwestern North Carolina through northern Georgia to eastern Alabama. Streamside salamanders were collected and screened for presence of Bd by non-lethal external swab sampling at multiple sampling sites within each of the designated areas. In addition, 250-ml water samples were collected at each site for Bd screening via environmental DNA (eDNA) detection methodology, and external swab samples from crayfish cohabitating with salamanders in streams were likewise collected at selected sites. Samples were analyzed for the presence of BD using quantitative PCR. One of the ten areas screened, the Davidson River in southwestern North Carolina, yielded positive results through both salamander swabs and eDNA water samples tested. Neither salamander swabs nor water samples screened thus far from all additional sites have tested positive. Crayfish swab samples likewise have not tested positive for Bd from any site thus far evaluated. Preliminary results indicate that small volume water sample collection for eDNA analysis may prove a simple alternative to salamander swab collection to identify the presence of Bd in Southern Appalachian stream habitats. Further analysis is underway to test the replicability of results within the identified Bd-positive area of the Davidson River.

* Presenting author