refugia

Refugia are locations that allow species, populations, or ecosystems to persist through periods of unfavorable climate, habitat loss, or other environmental stress. They function as reservoirs of genetic diversity and sources for recolonization when conditions improve, helping to maintain regional biodiversity over geological timescales.

Refugia come in several forms. Glacial refugia persisted during ice ages and similar cold spells, while climatic refugia endure during drought, warming, or other unfavorable phases. Microrefugia are small-scale pockets of suitable habitat or microclimate within a broader unsuitable area, enabling the survival of organisms with specific habitat needs. Aquatic refugia, such as ponds, springs, or river pockets, can maintain populations during droughts. Geographic refugia include mountain ranges, peninsulas, and other landscapes that shield populations from broad-scale climate impacts.

Examples commonly cited include temperate taxa that survived glaciations in southern Europe’s peninsulas (Iberian, Italian, Balkan) and similar refugia in other regions, as well as microrefugia in diverse habitats that supported localized persistence. Following adverse periods, refugial populations can expand and recolonize exposed areas, sometimes accompanied by genetic differentiation and speciation.

Understanding refugia informs conservation by highlighting regional sources of genetic diversity and potential resilience to climate change. Protecting refugial habitats, maintaining habitat heterogeneity, and integrating paleoecological and population-genetic data help identify critical refugia and guide management aimed at preserving evolutionary potential.