The degradation of tropical forests is progressing rapidly and its ecological effects on wild animals are a global concern. We evaluated the hypothesis that small mammals in highly degraded forest occupy higher trophic levels than those in somewhat degraded forests, as indicated by diets high in consumers such as insects, in a tropical rain forest in Sarawak, Malaysia. After correcting for differences in the δ15N values for primary production among the study sites, the δ15Ncorrected values for rats and mice (Muridae) differed significantly among forest types. Rats and mice in more degraded forest had higher δ15N corrected values than those in less degraded or primary forest; in contrast, treeshrews (Tupaiidae) and squirrels (Sciuridae) showed no significant differences in the δ15Ncorrected values among forest types. We found significant positive correlations between canopy openness and the δ15NCOrrected values for one species of squirrel and two species of rats. This hypothesis was supported for small mammals that have normal dietary preferences for plants, i.e., omnivorous rodents, but not for those that normally prefer insects, i.e., treeshrews. The δ15N values for omnivorous mammals may be useful as an indicator of changes in food-web structure in response to forest disturbance.
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics
- Animal Science and Zoology