Some of the most striking examples of altered-disturbance regimes involve changes in fire regimes. In summer 2015 a wildfire outbreak took place in southern Chile, with a magnitude not seen in the recent history, which devastated large portions of natural forests within protected areas (PAs). One of the most affected areas in La Araucania Region was the China Muerta National Reserve (CMNR), in which fire was active for 22 days and burned ca. 3,000 hectares of natural forests of Araucaria araucana. Plant species of these forests are less adapted to withstand intense fires, so fire can negatively affect the entire plant community. These changes could potentially alter the ecosystem functioning in a permanent way. The main goal of this research is to evaluate the impact of fire on the plant community (both native and exotic species) within burned areas of the CMNR. One year after fire, we established 10 permanent plots of 10x10 m within Araucaria forests across two fire levels: severe and moderate. An unburned area served as control. Within each sampling plot we measured abundance, percentage cover, and growth for all native and exotic plants.
Results/Conclusions
Fire severity had a significant effect on plant recovery after the wildfire, with greater abundance and cover in the moderate-fire plots. Moderate-fire plots were dominated by shrubs (Gaultheria spp.), whereas in high-fire plots annuals (Alstroemeria spp.) were more dominant. Araucaria trees presented resprouting of branches at the top of the crown in the moderate-fire plots. In high-fire plots Araucaria trees were all carbonized, but slight vegetative sprouting was observed in juvenile saplings. Exotic species only appeared in the high-fire plots, with Rumex acetosella being the most common species. Our results show that vegetation of the CMNR responded differently to fire severity, with rapid recovery of native plant species in moderate fire severity conditions, but slow recovery in high fire severity plots. Furthermore, exotic species were only detected in this latter condition. As a natural reserve, CMNR provides ecosystem services for local communities (timber and non-timber forest products), but with altered fire regimes occurring in the area, this provision might be threaten over time. Long-term monitoring of vegetation response to different levels of fire severity is needed for better understanding and informing land managers in regard of conservation of natural forest resources.