Abstract: To explain effects of rare and endangered primates on plant community structure, we analyzed the impact of the blackand-white snub-nosed monkey（Rhinopithecus bieti）on forest structure by comparing plant communities in an existing Rhinopithecus bieti habitat in Longma Mountain（Mt. Yongma）and an historical suitable habitat in Tianzi Mountain（Mt. Tianzi）. We collected plant community data in both sites using sampling methods from January 1th to 15th in 2014. Results showed that in the existing habitat of Mt.Yongma, hemlock trees had lower heights and larger crowns（t = 2.60, df = 236, P = 0.01; t = 10.49, df = 236, P < 0.001）, Pinus armandi had larger crown（t = 7.46, df = 190, P < 0.001）, and other tree species had lower heights and smaller diameter at breast height（t = 7.19, df = 527, P < 0.001; t = 4.11, df = 527, P < 0.001）. Shrubs showed lower height and smaller coverage, while herbs also had lower height in the existing habitat than in the historical suitable habitat（Z = 4.78, P < 0.001; Z = 6.24, P < 0.001; Z = 3.71,P < 0.001）. No significant differences were found in the diversity index, the Pielou index and the value of importance of plants. These findings confirmed the impact of black-and-white snub-nosed monkeys on vegetation structure and its role in the process of ecology succession. However, Rhinophitecus bieti's impact on plant diversity was not obvious.

Key words: black-and-white snub-nosed monkey（Rhinopithecus bieti）, plant community structure, dominant species, plant diversity, functional ecology