From Refugia to Resilience: Wildfires, Changing Climate, and Landscape Transformation in the Southwestern U.S.

In ecosystems of the southwestern US intensifying wildfires and climatic shifts are causing widespread tree mortality and slowed recovery after fires. Ecological refugia are areas that retain intact biological features or ecological processes after disturbance. These refugia are essential for the survival of a wide array of species and communities and aid in ecosystem recovery by repopulating surrounding areas. Researchers supported by this Southwest CASC project are using complex ecological modeling to study the effects of changing climate and wildfire regimes on ecological refugia, to provide useful information for conservation planning. This study (a) identifies future refugia and the biological and physical processes that create them; (b) examines the role of refugia in promoting ecosystem recovery, and (c) identifies potential management actions that may protect and promote refugia.

In the southwestern US, rising temperatures, prolonged megadroughts, and accumulated fuels and novel fuel types are shifting fire regimes away from ecological norms, resulting in widespread tree mortality and slowed post-fire recovery across large landscapes. In these settings, ecological refugia are critical for the persistence and recovery of ecosystems, habitats, and species. Fire refugia are areas less affected by fire, often due to microclimates, topographic barriers to fire spread, or long-established fire patterns, and are essential for the survival of a wide array of species and for repopulating surrounding areas after fires. Understanding how changing climate and fire regimes affect the presence and persistence of refugia is important for ensuring ecosystem resilience.

As climate and disturbance patterns shift, historical data become less relevant benchmarks for understanding potential future landscape and ecosystem dynamics. Researchers supported by this project are using the FireBGCv2 landscape-fire succession model to study the effects of changing climate and wildfire regimes on ecosystem processes and to assess the resilience and vulnerability of landscapes to ecological transformation. Specifically, the project team will answer: (1) Where and under what future climate conditions and fire regimes may refugia persist? (2) How and how quickly do refugia promote recovery after disturbances? (3) Can management actions protect or promote refugia?

Outcomes from this project include identifying when and where fire refugia are likely to occur and which habitats and distributions of plant species and communities are likely to remain buffered from regional climate extremes and wildfire impacts. Resulting information provides an important focus for science and conservation planning.