Homogenization of terrestrial mammal assemblages in human-modified rainforests

Data on medium and large terrestrial mammal species was obtained in 22 forest patches and 4 continuous forest sites in the fragmented Lacandona rainforest, Chiapas, Mexico. We sampled mammals using camera-traps, ground tracks and direct sightings in 2011 and 2017. For each site, we measured metrics of landscape composition (i.e. percentage of forest cover and matrix openness) and landscape configuration (i.e. number of patches, edge density and mean inter-patch distance). We analyzed sample completeness in each site and removed sites with low sample coverage (Cn < 0.65). Thus, the analyses are based on 20 forest sites (16 patches and 4 continuous forest sites). We calculated changes in beta diversity from 2017 to 2011 and decomposed it into its turnover and nestedness components, using a presence-absence matrix. We analyzed the association between changes in landscape variables and changes in beta diversity using Mantel tests. Landscape metrics were measured across different landscape sizes (range of radii = 200 to 1400 m, at 200-m intervals).