RESUMEN
Expectations of increases in human population growth and accelerated habitat loss, along with the realization that efforts to provide protection for ecosystems that sustain primates have met with limited success, make it critical that conservation plans are grounded firmly in scientific observation. Studies of the diet breadth and feeding behavior of endangered species, therefore, are critical for understanding ecological adaptations and developing a conservation strategy. The diet and feeding ecology of gray snub-nosed monkeys (Rhinopithecus brelichi) were studied in the Fanjingshan National Nature Reserve, Guizhou, China. The monkeys were found to consume 107 different species of trees, shrubs, and ground plants from 58 genera and 28 families. Food items included young leaves, mature leaves, flowers, fruits/seeds, buds, and insects. Among these food items, there were at least 13 evergreen species of tree and liana, 3 species of grasses, and at least 2 kinds of invertebrates collected from decayed wood. Diet varied markedly throughout different seasons. Overall, diet composition (based on feeding records) was 15.3% buds, 25.5% young leaves, 21.8% mature leaves, 9.4% flowers, 21.6% fruits/seeds, and 6.3% other items. The monkeys feed mainly on young leaves and flowers in spring, unripe fruits/seeds and young leaves in summer, ripe fruits/seeds in autumn, and mature leaves and buds in winter. We propose that when inhabiting forests of lower elevation and greater vegetation complexity, R. brelichi is characterized by expanded diet breadth and includes a greater diversity of food types and plant species in its diet. One food type that appears critical to the diet of this species, especially during the winter, are the buds of Magnolia sprengeri. To protect this resource we advocate working with local communities to limit the collection of M. sprengeri, which is used in traditional Chinese medicine and has high economic value for people in the reserve.