Large-Scale Forest Responses to Fire in Amazonia

Abstract:

Fire is an ecological process that is fundamental in determining global biome distributions and carbon dynamics. Some biomes – such as savanna and some Mediterranean ecosystems – are fire maintained; they are characterized by frequent or at least regular fires that have driven the evolution of fire-tolerant and fire-dependent flora. The role of fire is less often considered in other biomes, such as tropical forest, that are less flammable and where fires are less frequent. However, recent work has suggested that fires are increasing in prevalence in some tropical forests, including in the southern Amazon. These fires can have unparalleled impacts on forest community dynamics and on forest carbon stocks, but quantification of fire impacts on Amazonian forests is restricted to a few sites and estimates of their extent are thus largely anecdotal. Here, we present traits data from a set of sites throughout the Amazon that aim to examine how fire-related traits vary with respect to large-scale climatic gradients in order more broadly to estimate the distribution of fire susceptibility across the Amazon basin. Combined with maps of fire potential, these results have yielded basin-wide estimates of fire impacts in the Amazon that can be used for comparison with modeled results.