Managing climate change refugia for climate adaptation
The concept of refugia has been discussed from theoretical and paleontological perspectives to address how populations persisted during periods of unfavorable climate. Recently, several studies have applied the idea to contemporary landscapes to identify locations that are buffered from climate change effects so as to favor greater persistence of valued resources relative to other areas. Refugia are now being discussed among natural resource agencies as a potential adaptation option in the face of anthropogenic climate change. Here I review the latest literature on definitions and identification of climate change refugia, based on a California LCC-funded collaboration involving expert researchers and natural resource managers from across the western United States. I distinguish between ecological and physical definitions and delineate how climate change refugia can fit into the existing framework of federal management practice. I will then illustrate their utility through a montane meadow example. Genetic data and surveys of Belding’s ground squirrel (Urocitellus beldingi) populations in California were used to conduct a rare test of whether particular habitats are acting as climate change refugia.
As predicted, refugial meadows showed higher rates of occupancy and lower rates of extirpation over time. Populations found in meadows where the magnitude of climate change was small had higher genetic diversity, indicating that they had persisted longer. Moreover, I used these species data to show that connectivity among sites increased gene flow and genetic diversity. Although no panacea, managing climate change refugia could be an important strategy for prioritizing habitats in order to conserve populations, including genetic diversity and evolutionary potential.