First characterization of megafire refugia in a South American subtropical mountain forest

Abstract

Fire refugia play an important role in post-fire ecosystem recovery because they preserve areas that represent a persistent legacy in the landscape and serve as propagule sources for forest regeneration. Our objective was to identify the pre-fire topographic and land cover conditions that determine the presence and quality of megafire refugia in the mountains of central Argentina. In 208 1-ha field-based plots, we assessed pre-fire topographic and land cover variables along with post-fire vegetation responses two years after the megafires. Based on these assessments, we developed a fire refugia quality index ranging from 0 (no refugia) to 5 (high-quality refugia). Using ordinal logistic regression and a model selection approach, we found that high-quality fire refugia were associated with the more humid east mountain flank and east- and north-facing slopes, as well as with smooth terrain, high topographic positions, greater rock cover, steep slopes, and higher tree-to-grass cover proportions. Our findings highlight the importance of topographic and land cover variables in shaping fire refugia and provide insights into post-fire management and the conservation of biodiversity in mountain ecosystems.