Refuges for biodiversity conservation: A review of the evidence

Refuges and refugia are important to conservation management because of their potential to protect species from difficult-to-manage threats such as changing climate, extreme events (e.g., drought, fire) and biotic threats (e.g., disease, invasive species). To provide conservation managers with an evidence-based approach to identifying refuges and refugia, we ask: which places have been observed to function as refuges/refugia, with results reported in the scientific literature? We systematically reviewed the past 20 years of research into refuges/refugia. To provide an objective picture of the evidence for different refuges/refugia, we analysed each study using the framework of: (a) the place providing protection and its environmental characteristics; (b) the threat; and (c) the biota being protected. We identified 16 categories of places which functioned as refuges/refugia. These places occurred at spatial scales varying from within-habitat elements (e.g., crevices and burrows) to regions, and functioned at temporal scales from minutes to millennia. Most studies focused on large-scale, geographically specific places (mainly glacial refugia) or small-scale within-habitat refuges; relatively few studies described environmental characteristics of the refuges/refugia. However, three landscape elements: rocky environments, montane environments and riparian areas (and other terrestrial wet-spots), were identified as refuges/refugia for multiple species and threats. Conservation managers seeking to increase the resistance of local biodiversity can act now to protect these places within their sphere of influence. Clearly describing of refuges/refugia in terms of place (and environmental characteristics), threat and biota protected, enables application of research findings beyond individual study sites, and provides direction for evidence-based conservation management.