Floristic changes induced by fire frequency in Chaco Serrano.

Abstract

Floristic changes induced by fire frequency in Chaco Serrano. The Sierras Chicas from Córdoba is the mountain range with the highest fire frequency in central Argentina. However, the response to fire frequency of Chaco Serrano plant communities has not yet been assessed. Based on 23-year fire history, we surveyed all vascular plants in unburned, low and high fire frequency sites in the Chaco Serrano district located on Sierras Chicas from Córdoba. We found that fire frequency induces changes in vegetation structure, plant richness, and composition. Specifically, we observed a decrease in total plant richness at sites with a higher number of fire events. All life forms showed decreases in richness to the effects of fire, except the graminoids that showed no changes. In addition, we recorded a change in the species composition between the burned sites (both frequencies) and unburned sites, evidenced through the emergence of indicator species that define both conditions. These results indicate that fire is a strong ecological process that shapes plant communities, selecting species with life history traits (i.e., resprouting and lifespan) that confer adaptative value to new environmental conditions imposed by the regime of high fire frequency.