The black-and-white snub-nosed monkey Rhinopithecus bieti is endemic to China, where its population is fragmented into 15 isolated groups and threatened despite efforts to protect the species. Here we analyse possible habitat connectivity between the groups reported in Yunnan, using genetic, least-cost path and Euclidean distances. We detect genetic isolation between the northern and southern groups but not among the northern groups. We show that genetic distance is better explained by human disturbance and land-cover least-cost paths than by Euclidian distance. High-quality habitats were found to be more fragmented in the southern part of the study area and interspersed with human-influenced areas unsuitable for black-and-white snub-nosed monkeys, which may explain the genetic isolation of the southern groups. Potential corridors are identified based on the least-cost path analysis, and seven sensitive areas are proposed for restoration. We recommend (1) that restoration is focused on the current range of the monkeys, with efforts to reduce human disturbance and human population pressure and increase public awareness, and (2) the development of a long-term plan for habitat restoration and corridor design in the areas between groups.

The black-and-white snub-nosed monkey Rhinopithecus bieti (Colobinae), categorized as Endangered on the IUCN Red List, is endemic to the Trans-Himalayas (the Hengduan Mountains) of north-west Yunnan and south-east Tibet. To evaluate the species’ current status in Tibet we surveyed six sites in Honglaxueshan National Nature Reserve, believed to be the area's only remaining location of R. bieti. Sites were identified from previous surveys and interviews with villagers and local officials. Three sub-populations, with a total of >300 individuals, were located in conifer and evergreen broad-leaf forests, which together comprise 971 km2. One of the sub-populations, in Zhina, is a new discovery, and is the northernmost known sub-population of R. bieti. Identified threats to the species include habitat destruction through wood extraction, uncontrolled grass fires, cutting of oak Quercus aquifolioides branches, inappropriate attitudes to R. bieti when people carry out economic activities in the forest, and hunting. Opportunities for conservation include the existence of sacred mountains, the limited possibilities for agriculture, and the economic dependency of villagers on the forest. We recommend the development of a sustainable ecosystem to reduce pressure on R. bieti and its forest habitat, including use of solar energy for heating and cheap electricity for cooking to minimize dependence on firewood, introduction of techniques for high crop yields to improve food supplies, and release of some farmland for planting grass, which can be used to raise livestock in enclosures and thus reduce the cutting of oak.