Mammals Of the Southern Appalachian Sky Islands: The Boreal-Deciduous Ecotone as a Possible Climate Change Refugia

Global biodiversity is threatened by anthropogenic climate change. Sky islands are among the most biodiverse ecosystems in the world and face a disproportionately high threat of climate change. This in part is because these high-elevation ecosystems are at their altitudinal limit and are predicted to severely contract in response to increased temperatures. The identification and conservation of climate change refugia is an increasingly popular technique to protect biodiversity associated with imperiled ecosystems. I examined the boreal-deciduous ecotone as a possible refugia for high-elevation mammals in the Southern Appalachian red spruce-Fraser fir sky islands. I conducted live-trapping, remote camera trapping, and ultrasonic acoustic recording surveys to describe mammal communities across spruce-fir, ecotone, and northern hardwood forests on two sky islands. I found that mammal species richness, alpha diversity, and bat activity were highest in the ecotone. High-elevation mammal species occurred more frequently in the spruce-fir and ecotone forests than in the northern hardwood forests. The results suggest that the ecotone may be serving as a refugia for high-elevation mammal species that are associated with spruce-fir sky islands. Therefore, habitat conservation efforts aiming to protect high-elevation mammal diversity should consider focusing on the boreal-deciduous ecotone in addition to the adjacent spruce-fir forest.