Black Crested Gibbons Are All Endangered
The Number of Species Is Debated But The Declines Are Not
While some scientists contend that there are two species of black crested gibbon- Eastern (Nomascus nasutus) and Western (Nomascus concolor), others would separate the Eastern into two separate species. But the debate is, in many ways, a side issue. All black crested gibbons are endangered throughout Asia. Some may be closer to extinction than others; however, conservation of these endangered primates hinges on similar issues.
The Eastern Black Crested Gibbons
The Cao-Vit black crested gibbon (Nomascus nasutus nasutus) is found only in Cao Bang Province in northeastern Vietnam, which makes it geographically isolated from the Hainan black crested gibbon (Nomascus nasutus hiananus) found only on Hainan Island in China. In addition there are significant genetic differences between the two gibbons. This makes a good case for separating the eastern black crested gibbon into two species. Both are critically endangered with confirmed populations of less than fifty animals each. But only the Hainan black crested gibbon rated a place on the Top 25 Most Endangered Primates. The report did, however, express concern that, in Hainan, the two species survive in just one restricted area. Efforts now need to concentrate on involving the local community in the protection of their gibbons, as well as surveying to determine whether reports of gibbons in other parts of Hainan and Guangxi can be confirmed.
The Western Black Crested Gibbons
The western black crested gibbons are separated into four subspecies but genetic differences between them are not significant enough to justify separate species status.
The Endangered Laotian black crested gibbon (Nomascus concolor lu) is only now beginning to be studied in the wild and the most recent field study in Nam Kan Province held some good news. The indigenous people of the area do not hunt gibbons.
The Tonkin black crested gibbon (Nomascus concolor concolor) is believed to still inhabit Vietnam and the Yunnan Province in China. It is listed as Endangered. Its West Yunnan relative (Nomascus concolor furvogaster), found only in Yunnan Province is considered critically endangered, as is the Central Yunnan black crested gibbon (Namascus concolor jingdongensis).
Saving Black Crested Gibbons
Arboreal species like the black crested gibbons are particularly hard hit by deforestation and habitat fragmentation. They travel through the treetops, sleep in high nests and consume a diet of tree fruits. Finding mates and remaining safe from predators requires a healthy rainforest canopy.
Balancing the needs of a growing human population in Asia with the needs of these closely related species will not be an easy task but it is crucial to black crested gibbon survival. Traditional indigenous hunting practices must to be replaced with more sustainable activities. Incentives to maintain contiguous forested areas also need to be put in place for people to take an active role in endangered primate conservation locally.
