Assessing Plethodon cinereus (Red-backed Salamander) Skin Microbiome Differences Across Northern NY

Abstract

The role of global climate change in increasing the prevalence of amphibian disease, including chytridiomycosis, is well known. The skin microbiome is considered an important component of the amphibian immune system. Specific bacterial taxa and high skin microbial diversity are factors that are known to boost amphibian disease resistance. In this study, we explored the impact of environmental conditions on Plethodon cinereus (Red-backed Salamander) skin microbial abundance and diversity at a variety of different sites in New York’s North Country. We surveyed P. cinereus specimens from 5 sites varying in elevation and dominant vegetation type. Salamander skin microbiomes were subsequently sampled via sterile swab, plated and characterized by visual inspection of colony morphology. We performed DNA extractions and PCR to prepare samples for genetic sequencing to determine bacterial species identity. In total, 31 unique bacterial taxa were collected from the 5 sites. The highest and lowest bacterial diversity were observed at the Paul Smiths’ Visitor Interpretive Center’s Forest Ecosystem Research and Demonstration Area (FERDA) sites single tree and control silviculture stands, respectively. Beta diversity tests also indicated that the skin microbial communities at these 2 sites were most similar to each other and noticeably different from that of the Altona Flat Rock and Rugar Woods sites. These results indicate that site conditions are important determinants of P. cinereus skin microbial community diversity patterns. Although the identity of bacterial species (pathogenic, non-pathogenic) are yet to be confirmed, this study has added support to the concept that environmental conditions alter salamander skin microbiomes, which in turn can influence salamander disease resistance.