ECOLOGICAL CORRELATES OF EXTINCTION PRONENESS IN AUSTRALIAN TROPICAL RAIN-FOREST MAMMALS

There is a dire need to predict the vulnerability of tropical forest biotas to habitat fragmentation. I tested the efficacy of seven ecological traits (body size, longevity, fecundity, trophic level, dietary specialization, natural abundance in rain forest, and abundance in the surrounding habitat matrix) for predicting responses of 16 nonflying mammal species to rain forest fragmentation in tropical Queensland, Australia. An ordination analysis revealed that most (84%) of the variation in traits was described by two axes, the first separating r- and K-selected species, and the second discriminating rare species with specialized diets from common species with generalized diets. Using multiple regression analysis, the two ordination axes explained 51.7% of variation in mammal extinction proneness (F = 9.96, P = 0.009). However, univariate tests revealed that a single trait, abundance in the matrix, was a better predictor of vulnerability (r2 = 63.8%, F = 24.69, P < 0.001). Partial correlations demonstrated that once the effects of matrix abundance were removed, no other traits or ordination axes were significant predictors of extinction proneness. These results highlight the importance of tolerance of modified habitats in determining survival of nonflying mammals in tropical forest fragments. Species that traverse or exploit modified habitats tend to remain stable or increase in fragments, whereas those that avoid these habitats often disappear. The implications of these findings for tropical forest conservation are discussed.