Increased Wildfire Risk Driven by Climate and Development Interactions in the Bolivian Chiquitania, Southern Amazonia.

Tahia Devisscher,Liana O Anderson,Luis Galván,Yadvinder Malhi,Luiz E O C Aragão,Jorge Mpodozis

doi:10.1371/journal.pone.0161323

Abstract

Wildfires are becoming increasingly dominant in tropical landscapes due to reinforcing feedbacks between land cover change and more severe dry conditions. This study focused on the Bolivian Chiquitania, a region located at the southern edge of Amazonia. The extensive, unique and well-conserved tropical dry forest in this region is susceptible to wildfires due to a marked seasonality. We used a novel approach to assess fire risk at the regional level driven by different development trajectories interacting with changing climatic conditions. Possible future risk scenarios were simulated using maximum entropy modelling with presence-only data, combining land cover, anthropogenic and climatic variables. We found that important determinants of fire risk in the region are distance to roads, recent deforestation and density of human settlements. Severely dry conditions alone increased the area of high fire risk by 69%, affecting all categories of land use and land cover. Interactions between extreme dry conditions and rapid frontier expansion further increased fire risk, resulting in potential biomass loss of 2.44±0.8 Tg in high risk area, about 1.8 times higher than the estimates for the 2010 drought. These interactions showed particularly high fire risk in land used for ‘extensive cattle ranching’, ‘agro-silvopastoral use’ and ‘intensive cattle ranching and agriculture’. These findings have serious implications for subsistence activities and the economy in the Chiquitania, which greatly depend on the forestry, agriculture and livestock sectors. Results are particularly concerning if considering the current development policies promoting frontier expansion. Departmental protected areas inhibited wildfires when strategically established in areas of high risk, even under drought conditions. However, further research is needed to assess their effectiveness accounting for more specific contextual factors. This novel and simple modelling approach can inform fire and land management decisions in the Chiquitania and other tropical forest landscapes to better anticipate and manage large wildfires in the future.

Highlights

Wildfires in Amazonia are expected to increase as the region is exposed to higher temperatures and water stress over the 21st century [1,2,3,4]
Rather than studying Brazilian Amazonia, which is the usual focus of fire research in the Neotropics [47], we focus exclusively on a region located at the southern edge of Amazonia, the Chiquitania of Bolivia
We focused on the establishment of new DPAs in areas of high fire risk, because this category showed the smallest relationship with fire occurrence in the model (S5 Fig)

Summary

Introduction

Wildfires in Amazonia are expected to increase as the region is exposed to higher temperatures and water stress over the 21st century [1,2,3,4]. An increase in wildfire poses a threat to Amazon forests, affecting their structure and composition with the likelihood of a forest transition or dieback [14,15,16,17,18,19]. This in turn has effects on the global carbon balance further contributing to global warming [20,3]. Wildfires have implications for human health, livelihoods of local populations and economies of Amazon countries [22,23,24,25,26]

Methods

Results

Discussion

Conclusion