Things are finally looking up for the Hainan gibbon. There are fresh hopes for the world’s rarest primate after conservationists confirm the presence of a newly formed pair outside of their known range, bringing the species' population and family group numbers to the healthiest they've been in many decades.
The Hainan gibbon (Nomascus hainanus) is a critically endangered primate found in a small pocket of forest on the tropical islands of Hainan in the South China Sea. The males have a jet black coat, which is why the species is sometimes called the Hainan black-crested gibbon, while the fur of females turns a rich golden color after they reach maturity.
Historical documents from the 17th century suggest the species were once widespread across much of mainland China. In more recent times, the gibbons became restricted to the lowland forests of Hainan Island, before deforestation drove species to higher altitudes where food is scarce and conditions are generally less favorable.
In the 1950s, there were an estimated 2,000 Hainan gibbons living in tropical forests across 12 counties in Hainan, but poaching and habitat destruction rapidly took their toll on the species. The species was on the precipice of extinction by the 1970s with fewer than 10 individuals left in a small patch of the Bawangling forest. One of the latest surveys of the population in 2013 found there were still just 13 individuals formed of two groups.
Things are starting to look up for the species, however. Reporting in the journal Oryx, researchers at the Kadoorie Farm and Botanic Garden (KFBG) and Hainan Wildlife Conservation and Management Bureau reveal the discovery of a newly formed pair of Hainan gibbons some 8 kilometers (5 miles) north of their expected range, showing they are expanding territory. Local villagers first spotted the pair in October 2019 and their presence was later confirmed by scientists who documented the distinctive calls of the gibbons, including a “duet” between the male and female.
The discovery of the new pair and their location suggests the population of Hainan gibbons has now formed at least five different family groups, vital for genetic diversity, made up of more than 30 individuals. Although the species still has a long way to go, the future is certainly more promising than it was just a few years ago.
The slow but steady recovery has not come easy. Conservationists at the KFBG have spent years helping the Hainan gibbons with a number of planned and coordinated conservation strategies on the island. In one of these measures, the KFBG and members of the local community looked to tempt back the species with their favorite food by planting some 80,000 seedlings from 51 native tree species in the degraded lowland forest of Hainan. This small but significant victory shows their efforts were well spent.
“Our key conservation measures include funding and training two gibbon monitoring teams, sponsoring researchers to study the species, conducting annual population census, planting the species’ favorite native food trees produced by a local nursery, promoting sustainable agriculture and conducting awareness-raising activities amongst the local community,” Philip Lo, senior conservation officer at KFBG in charge of the Hainan Gibbon conservation project, said in a statement.
“With our concerted efforts, the population of Hainan Gibbon has been gradually recovering, with a third and fourth family group formed in 2011 and 2015, respectively.”
Now, with a fifth, this is the largest number of family groups recorded for the species in 40 years.