Behavioral Flexibility and the Conservation Value of Howler Monkey Populations in Small Habitat Patches

Species occupying small habitat patches and exhibiting behavioral and ecological flexibility are more likely to persist in fragmented landscapes. However, when isolated populations are not self-sustaining in the long term, translocation may be required, making an understanding of their behavior critical. Howler monkeys (Alouatta spp.) show high tolerance to habitat restriction, which has been linked to a highly folivorous diet and the exploitation of non-tree plant and non-native species as food sources. We assessed how the size of the habitat patch influences home range size, day range, time spent feeding, young leaf and fruit consumption, and diet richness, the relationships between these behaviors, and the effect of group size and study length on them using Generalized Linear Mixed Models and full model averaging based on a dataset of 97 studies conducted at 62 locations on the behavior of 124 groups representing nine species. Habitat patch size predicted home range size, which showed a positive effect on fruit consumption. Diet richness increased with increasing mean day range. No variable predicted day range, feeding time, and young leaf consumption. The limited and uncertain predictive power of habitat patch size for most variables reflect the unpredictability of the behavioral and ecological responses of howler monkeys to varying conditions of habitat quality. Our findings are consistent with the possibility that the behavioral flexibility enabling howler groups to survive in small, isolated, low quality habitat patches could enhance their value in metapopulation management strategies aimed at promoting long-term persistence of the species in human-modified landscapes.