Ecological assessment of the limestone habitat of Vietnam's Critically Endangered primates: Trachypithecus poliocephalus, Rhinopithecus avunculus, Nomascus nasutus, and implications for conservation

Abstract

Non-human primates in Vietnam are facing increasing threats to their survival due to habitat destruction as a result of human expansion and development. As a biodiversity hotspot, Vietnam is home to a high density of non-human primate species, including some of the most Critically Endangered primates in the world. Three of these endangered primates - the cao vit gibbon (Nomascus nasutus), the Tonkin snub-nosed monkey (Rhinopithecus avunculus) and the Cat Ba langur (Trachypithecus poliocephalus) - are under serious threat due to habitat reduction and fragmentation. While occupying different ranges across northern Vietnam, these three species all inhabit limestone karst forest, an understudied and difficult to access habitat. Using a combination of in situ sampling and MaxEnt distribution analysis, this study compared the ecological profiles of each species and compared them to sites of potential habitat expansion to address the habitat fragmentation problem facing each species. Findings suggest that for the Cat Ba langur there may be viable corridor connections to increase connections between sub-populations, though suitability of this region for long-term settlement requires further investigation. Further work on overcoming potential corridor interruptions is also required. Results for the Tonkin snub-nosed monkey indicate that efforts to improve connections to the larger Du Gia is not recommended due to the high level of human activity is this region, including logging and mining. For the cao vit gibbon, results further support earlier recommendations by Fan et al. (2013) on the conservation prioritisation of an adjacent patch of forest as a potential habitat extension. Further recommendations for the cao vit gibbon include consideration of the introduction of an artificial corridor to supplement a discontinuous corridor between the two regions. Across all species, I recommend further long-term study of each area of potential expansion to further support conservation planning for these at-risk species. This research provides important information for conservation groups to plan for the future of these Critically Endangered species. Show more