Forest fragmentation and edge influence on fire occurrence and intensity under different management types in Amazon forests

Abstract

The ecological characteristics of forest edges have been intensively studied in the Amazon region, but the occurrence and intensity of fires as large-scale edge effects are less well known, as is the role of different types of management in modifying this relationship. We used remote sensing techniques to examine the relationship between forest fragmentation, fire and management across NW Amazonia. Our study was based on forest data for 2005 and on active fire data from the MODerate-resolution imaging Spectro-radiometer (MODIS), with information on the occurrence and strength of fires based on fire radiative power (FRP) data. We analyzed the fragmentation and fire occurrence and intensity in a 50×50km grid. We also calculated the distance at which edge-related fires occur in the forest interior and outside the forest edge. Forest fragmentation had a significant impact on fire occurrence and fire intensity, supporting the hypothesis that the more fragmented a forest is, the higher the degree of biomass combustion. These results are in agreement with the occurrence of an edge effect on both the occurrence and the intensity of fire. The different types of management in the region influence the occurrence and intensity of fire, whereas fire as a large-scale edge effect occurs independent of the management type. Finally, we suggest that a high connectivity in protected areas and indigenous reserves and also in outside areas should be encouraged to minimize edge-driven fire processes.