The effects of various forest uses on small mammal communities in Sarawak, Malaysia

The ecological effects of anthropogenic deforestation on wild animals in tropical regions are a global concern. We investigated the effects of various forest uses on small mammal communities, in Sarawak, Malaysia, by comparing 20 study plots in six forest types: fragmented primeval forest, abandoned fallow at three developmental stages (new, young, and old), rubber plantation, and primary forest. An analysis of forest microhabitat structure revealed three distinctive groups: primary forest, new fallow, and other forests. These were characterized by canopy openness, the basal area, density, and species richness of trees, and vegetation types within a 600-m radius of each plot. In total, 283 individuals of small mammals from 22 species were captured. Small mammals in new fallow formed a distinctive group in an analysis of species composition, with high emergence of human-associated rats and arboreal treeshrews. However, small mammal communities in the other five forest types did not differ considerably. Rubber plantation patches affected the populations of a rodent and a treeshrew. Our results suggest that the various forest uses studied here, except for new fallow, do not have severe effects on small mammal communities. However, the invasion of human-associated species into primary forest may cause unfavorable or unexpected consequences, such as negative effects on natural forest and animal diversity.