The potential distribution and disappearing of Yunnan snub-nosed monkey: Influences of habitat fragmentation

Abstract

Analysis of environmental variables and organism occurrence records offers insight that can be used to predict potential distribution areas and habitat fragmentation. For large landscapes, modeling is the most convenient and effective way to conduct habitat research. Two species distribution models, BIOMOD2 and FRAGSTATS 4.2, were given data on environmental variables and organism occurrence records as input and used to predict the potential suitable habitat and habitat fragmentation for the Yunnan snub-nosed monkey (Rhinopithecus bieti). Our results estimated the total area of potentially suitable habitat for R. bieti as 7412.82 km2, but only 4164.58 km2 was found to be inhabited by R. bieti. We found that the main land cover type in the potential suitable distribution area of R. bieti was evergreen needle-leaf forest (6153.95 km2, 83.02%). Comparison of inhabited and suitable but uninhabited habitats showed that areas actually inhabited by R. bieti had a lower patch density (PD) and higher largest patch index (LPI) than uninhabited habitats only in evergreen needle-leaf forest. The potential suitable habitats of R. bieti has increased significantly, but the actual distribution has shrunk from 1997 to 2017. Although the government has made great progress in protecting R. bieti, logging that took place before the regulations and the boundary effect of roads and rivers resulted in the local extinction of R. bieti in some potentially suitable areas. In view of this, we propose to establish a national park for Yunnan snub-nosed monkeys. We also suggest protecting the potentially suitable but currently empty habitats for later release of R. bieti. Successfully reintroducing R. bieti into areas where it formerly lived will require continual and careful habitat monitoring.