Climate refugia: Archive and source of biodiversity

Background/Question/Methods

Climate refugia are those localities that have allowed relict populations to persist through periods of elevated environmental stress resulting from changes in climate. They typically contain physiographic settings that contribute to decouple local microclimates from regional trends and mitigate the impact of extreme climatic events. It has early been recognized that climate refugia play an important role for the long-term survival of species and the geographic distribution of biodiversity. However, recent years have seen a rapid accumulation of empirical evidence and great progress in our understanding of the particular character of climate refugia and the relict populations they harbor. This knowledge is providing important insights regarding the response of species and lineages to past climatic changes and their conservation in a future warmer world.

Results/Conclusions

Here I present a brief overview of three major types of climate refugia: i) glacial, ii) postglacial (also commonly termed interglacial) and iii) long-term refugia. I compare their respective environmental constraints, distribution and significance for the conservation of species' genetic identity and evolutionary history. Relict populations have persisted despite episodes of great stress, irregular recruitment, and a low carrying capacity imposed by their habitat. The mechanisms to cope with these constraints vary among refugium types and partly also between plants and animals because of differences in their growth strategies, trophic level, and mobility.
Although future climate change represents an undeniable threat for the continued existence of many postglacial and long-term refugia, other drivers of global change - in particular, changed land use - may represent even more immediate causes of population extinction. An improved knowledge of how climate relict populations are formed and maintained within their refugia will substantially increase our understanding of the likely impacts of modern climate change on species distributions and our ability to conserve those populations that are most at risk.