The responses of leaf litter ant communities to wildfires in the Brazilian Amazon: a multi-region assessment

Abstract

Fire is frequently used as tool for land management in the Amazon, but often escapes into surrounding forests, with potentially severe impacts for forest biodiversity. We investigated the effects of single wildfires on ant communities in four geographically distinct regions of the Brazilian Amazon (Roraima, Pará, Acre and Mato Grosso) where forests had burned between 8 months and 10 years before our sampling. We established 7–12 transects, 500 m each, in burned and unburned forests in each region to investigate the effects of fire on forest structure and leaf litter ant communities, which were sampled using Winkler sacks. Fire effects on forest structure were more drastic in the most recently burned forests in Acre and Mato Grosso, while the impacts of older burns in Roraima and Pará were more subtle. Ant species richness was not different between burnt and unburned areas, but community composition differed between burned and control forests in all regions except Mato Grosso. At the species level, indicator species analysis showed that a limited number of species were significant indicators of unburned control forests in all regions, except Acre. Forests structure variables and leaf litter volume were all important in shaping ant communities, but their relative importance varied between regions. Our results indicate that burned forest have different ant species communities from unburned forests, and those differences are still apparent 10 years after the disturbance, highlighting the importance of effective policies for fire management in Amazon.