Pyrodiversity begets taxonomic and functional richness of tropical mammals

Understanding how species respond to the environmental heterogeneity created by fire (i.e., pyrodiversity) is essential to protect biodiversity in the face of current changes in the natural fire regime. Pyrodiversity is hypothesized to promote biodiversity, but this hypothesis has mixed support and has never been tested for medium- and large-sized mammals in a neotropical savanna. Here, we investigated how mammalian communities respond to fire frequency, fire age, and spatiotemporal variations in these fire regime elements (pyrodiversity) at multiple spatial scales (from 0.8 to 78.5 ha). We sampled medium- and large-sized mammals using camera traps distributed on 30 sites in grassland and typical savanna formations. We applied multiple regression analysis to describe the relationships between fire regime variables and mammal communities. Mammals responded to the fire regime only when the spatiotemporal variation was considered. Taxonomic and functional mammal richness increased with variations in fire age, but mammal diversity and functional dispersion were greater at intermediate pyrodiversity. Moreover, mammal abundance responded positively to diversity of fire frequency but negatively to fire age diversity. Our results indicate that pyrodiversity can lead to taxonomically and functionally rich communities, probably due to more forage, shelter, and movement opportunities for different species in heterogeneous environments. Nonetheless, its effect on abundance seems limited. We recommend focusing fire management in savanna landscapes on the diversity of fire age mosaics, at least for medium and large mammals. Moreover, management conducted on intermediate scales (~ 80 ha) is sufficient to generate pyrodiversity that affects mammal communities.