The black-crested gibbon is believed to be endangered throughout its range in China and northern Vietnam, where much of the original forest has been destroyed. The only reserves known to have substantial populations are the Ailao Mountain and Wuliang Mountain Natural Protected Areas in Yunnan Province, China, which together may have 1500 of an estimated total of 3500 black-crested gibbons in protected areas in China. Although they are probably the best protected, the gibbon populations of both reserves have been badly depleted by deforestation and hunting. Recent reports that roads will be constructed through the centres of the reserves, and that gold has been discovered in one of them, increase concern. The Ministry of Forestry has started new conservation measures, but further action is required.