Climate Contributors to Forest Mosaics: Ecological Persistence Following Wildfire

Abstract

It is hypothesized that climate impacts forest mosaics through dynamic ecological processes such as wildfires. However, climate-fire research has primarily focused on understanding drivers of fire frequency and area burned, largely due to scale mismatches and limited data availability. Recent datasets, however, allow for the investigation of climate influences on ecological patch metrics across broad regions independent of area burned and at finer scale. One area of particular interest is the distribution of fire refugia within wildfire perimeters. Although much recent research emphasis has been placed on high-severity patches within wildfires, unburned and low-severity patches provide critical remnant habitat and serve as seed sources to initiate colonization and succession in recently burned landscapes. These patches of persistence also may yield insights into approaches for developing fire-resilient landscapes by forest managers and communities seeking to reduce wildfire hazard. Here, we present results showing no decline in proportion of persistent patches in three study areas surrounding National Parks in the western United States, even as research and anecdotal information suggests that fires have become larger and more severe. We also show climate linkages to metrics of persistence that echo previous findings in climate-fire research, and we introduce a framework for addressing global change impacts on forest pattern more broadly. Specifically, we discuss the interactions of multiple drivers at landscape scales and the need to disaggregate relative influences using mixed methods that can address both social and ecological phenomenon.