Environmental determinants of the diets in François’ langurs (Trachypithecus francoisi)

Abstract

Exploring environmental determinants of the diet provides effective information to develop conservation for endangered species. Here, we collected dietary data of François’ langurs (Trachypithecus francoisi) to identify the environmental determinants of these langurs’ diets. Our results showed that the diets of François’ langurs were mainly dominated by leaves (69.9% ± 12.9%), followed by fruits (15.3% ± 6.6%), seeds (5.6% ± 4.7%), flowers (4.1% ± 2.8%), stems (1.2% ± 1.3%) and others (3.4% ± 3.2%). The model averaging results suggested that human interference and habitat fragmentation do not significantly affect the langurs’ dietary composition across geographical populations, which could be associated with the extreme habitat fragmentation and the intense anthropogenic disturbance within habitats. In addition, the results showed a significant negative effect of rainfall on the fruit consumption by langurs (β = - 0.45, Wip = 0.48), which may be related to the low fruit production in fragmented limestone forests. In addition, there was no significant geographical difference in the dietary composition of the langurs. Our results reveal the significant effects of habitat fragmentation on the diets of langurs and, as a response, the high flexibility in dietary composition in these langurs, providing insights into their adaptation to the fragmented limestone forest.