A landscape-scale framework to identify refugia from multiple stressors.

From a conservation perspective, quantifying potential refugial capacity has been predominantly focused on climate refugia, which is critical for maintaining the persistence of species and ecosystems. However, protection from other stressors, like human-induced changes in fire and hydrology, that cause habitat loss, degradation and fragmentation are also necessary to ensure that conservation efforts focused on climate are not undermined by other threats. Thus, conceptual and methodological advances for quantifying potential refugia from multiple anthropogenic stressors are important to support conservation efforts. We propose a new conceptual approach, the domains of refugia, to assess refugial capacity, identifying areas where exposure to multiple stressors is low. Our framework uses patterns of environmental variability, thresholds of resilience, and extent and intensity of stressors to identify areas of potential refugia from a suite of ongoing anthropogenic stressors. To demonstrate the utility of this framework, we illustrate how refugial conditions can be characterized and identified using a Southern California landscape. Sites with high refugial capacity, the super-refugia sites, have on average 30% less frequent extremely warm summers, 20% less frequent fire events, 10% less exposure to altered channels and riparian areas, and 50% fewer trails than the surrounding landscape. Our results suggest that super-refugia sites (∼ 8,200 km2 ) for some natural communities are under-represented in the existing protected area network, a finding that can inform efforts to expand protected areas. Our case study highlights how considering exposure to multiple stressors can inform planning and practice to conserve biodiversity in a changing world. This article is protected by copyright. All rights reserved.