Assessing environmental and anthropogenic drivers for the occurrence and extent of fires in high Andean Grasslands

Abstract

The grasslands of the southern Andes are critical ecosystems for the rural population, but they have been significantly affected by fires. While fire ignitions are anthropogenic, their occurrence and spread are shaped by climatic, vegetational, and topographic factors. This study identified the main environmental and human drivers of fire occur rence and extent in high Andean grasslands. We developed generalized linear models with 14 and 22 variables for the fire occurrence and extent model, respectively. Various metrics (e.g. AIC, AUC, pseudo-R²) were applied to validate the best-performing model and assess its performance. Our findings suggest that elevation, maximum temperature, soil adjusted vegetation index, and topographic position index are the primary drivers of fire occurrence. For fire extent, grass cover, elevation, topographic position index, and rock cover were the most influential factors. The models explained 21% and 60% of the variability in fire occurrence and extent, respectively. This study identifies key environmental factors influencing fire occurrence and extent, providing valuable insights for improving fire management strategies, particularly in fire-prone ecosystems such as grasslands. Since the temperature was a contributing factor to fire occurrence, this highlights the importance of prevention and reduction strategies in the context of climate change.