Winner–loser species replacements increase rodent diversity in landscape mosaics exposed to slash-and-burn agriculture

Abstract Context Slash-and-burn agriculture creates heterogeneous landscapes composed of old-growth forests, secondary forests, and agricultural lands. In these mosaics, some species are extirpated (loser species) and replaced by disturbance-adapted species (winners). However, the community-level outcome of this winner–loser species replacement and its local and landscape drivers remain poorly understood. Objectives We assessed the effect of local land-use type and the surrounding old-growth forest cover on small rodent populations and communities in landscape mosaics exposed to slash-and-burn agriculture. We hypothesized that winner–loser species replacements may contribute to maintaining or increasing rodent diversity. Methods Using Sherman traps, we sampled small rodents in 14 sites (5 old-growth forests, 5 secondary forests, and 4 agricultural lands) from the Mayan forest, Mexico. We then evaluated the effect of land-use type and landscape forest cover on species-specific abundance, total abundance, and species richness. Results We recorded 428 rodents from 6 native species and one exotic ( Rattus rattus ). Total abundance was weakly related to both predictors. Yet, one species ( Ototylomys phyllotis ) decreased in abundance in agricultural lands (loser species), and three species ( Heteromys gaumeri , Peromyscus yucatanicus , and Sigmodon toltecus ) followed the opposite pattern (winner species), which increased species richness in agricultural lands. The abundance of Heteromys gaumeri and Peromyscus leucopus also increased with old-growth forest loss, increasing species richness in more deforested landscapes. Conclusions Our findings indicate that slash-and-burn agriculture promotes winner–loser species replacements, which maintain rodent abundance, but increase species richness. However, to prevent the extirpation of forest-dependent species, we must preserve old-growth forests.