The Appalachian Mountains are among the oldest mountains on Earth, and have had a massive impact on the development of the ecosystems and culture of people who settled under its rugged peaks. It is known as a biodiversity hotspot, and displays a wide range of climates and many types of unique ecosystems and species. 

Puerto Rico, an unincorporated US territory, is another biodiversity hotspot, with a wide variety of ecosystems ranging from tropical rainforest in the northern region to scrubland in the southern region. Many species on this island are endemic, and increasingly threatened especially due to climate change. 

Identifying key climate refugia within the southern portion of the Appalachians, and Puerto Rico, will help land managers prioritize ecosystems that will, in the face of contemporary climate change, continue to support important resources like unique species, ecological habitats, hydrological processes, and culturally-significant activities based in these two regions.

—  Priority Ecosystems in the southeast  —