First characterization of fire refugia for a South American subtropical mountain forest

Abstract

Fire refugia play a key role in post-fire ecosystem recovery by preserving areas which represent persistent legacies on the landscape, and function as propagules sources for forest reestablishment. We investigated the factors that influence the presence and quality of fire refugia in the mountains of central Argentina, following extreme megafires. We assessed post-fire vegetation responses two years after the fire, applying five criteria to quantify fire refugia quality: burned tree cover, tree survival, scorched crown, resprouting rate and aerial resprouting presence, resulting in a quality index from 0 (no refuge) to 5 (high-quality refuge). We used field and GIS data to construct explanatory variables, and the refugia quality index as dependent variable. We used GLM and followed a model selection approach. We identified that high-quality fire refugia were strongly associated with high rock cover, steeper slopes, greater tree-to-grass cover proportions, and east-facing slopes, highlighting the influence of regional precipitation gradients. Contrary to expectations, refugia quality decreased at lower topographic positions and on rougher terrain. Our findings highlight the importance of topographic features and vegetation structure in shaping fire refugia, offering valuable insights for post-fire management and biodiversity conservation in mountain ecosystems.