Projected future changes in the geographic distributions of the threatened Plethodon nettingi and a potential competitor

The Central Appalachian region contains several high-elevation endemic woodland salamanders, which are thought to be particularly vulnerable to climate change due to their restricted distributions and low vagility. In West Virginia, there is a strong management focus on protection and recovery of the federally threatened Cheat Mountain salamander Plethodon nettingi . To support this focus, there is a need for improved understanding of the occurrence-habitat relationships and spatially explicit projections of fine-scale contemporary and potential future habitat quality to inform management actions. In addition, there is concern among natural resource managers that climate change may increase habitat quality at high elevations for potential competitors of P. nettingi , particularly the eastern red-backed salamander P. cinereus , potentially resulting in increased competition pressure for P. nettingi . To address these knowledge gaps concerning future habitat availability and competition, we created ecological niche models using the random forest classification algorithm and used the estimated occurrence-habitat relationships to assess ecological niche overlap between the species and project fine-scale contemporary and potential future habitat availability and quality. We estimated that the ecological niches of P. nettingi and P. cinereus were 80.5% similar. For P. nettingi , we estimated that the amount of high-quality habitat will be reduced by mid-century and potentially lost by end-of-century, but that moderate and low-quality habitat will persist. For P. cinereus , we estimated that the amount of high-quality habitat will increase through end-of-century, and that high elevations will become more suitable for this species, indicating that potential competition pressure for P. nettingi is likely to increase.