There are more than twice as many orangutans on the Indonesian island of Sumatra as we thought, according to a new survey. But deforestation and development could still see their numbers plummet over the next decade.
A team led by , a primatologist at Liverpool John Moores University in the UK, scoured the Sumatran forest and found evidence that there were more than 14,600 apes living there, more than double the previous estimate of 6600.
A second species of orangutan, which lives on Borneo, numbers about 54,000, although that figure could also change when a new population estimate for them appears later this year.
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These apes are among our closest relatives, exhibiting evidence of culture, and we are still uncovering insights into their complex behaviour.
The Sumatran population estimate grew mainly because Wich鈥檚 team found orangutans in places they hadn鈥檛 looked before, such as at higher elevations, in logged forests, and in a remote area west of Lake Toba.
鈥淚t takes enormous effort, and cost, to get to these areas,鈥� he says. 鈥淟ast time we didn鈥檛 have the funding.鈥�
Having more accurate population figures helps focus conservation efforts where they can do the most good, says Wich. 鈥淚t helps us determine which areas have sufficient concentrations to be viable,鈥� he says. 鈥淪ometimes trade-offs have to be made.鈥�
Adaptable
The increased estimate is good news for this critically endangered species, because of what it implies for their adaptability, too. 鈥淚t changes my perception of how flexible Sumatran orangutans are,鈥� says Wich. 鈥淭he fact that they occur in logged areas means it is possible to have some timber harvesting and keep the orangutans.鈥�
But the larger population doesn鈥檛 mean that the species is out of the woods.
, a primatologist at Simon Fraser University in Vancouver, Canada, says that 14,000 is a 鈥渕inuscule鈥� population scattered over a wide area, and Sumatran orangutans are still on the verge of extinction.
鈥淚 don鈥檛 think this changes the conservation picture all that much. The threats are the same as what they were before,鈥� she says. 鈥淚n the end, it鈥檚 not the absolute numbers that matter, but how fast they are disappearing.鈥�
And they could disappear very fast. Wich analysed a series of potential habitat changes over the next few decades, based on both historical changes and local development plans. The government of Aceh province, which is home to around 80 per cent of Sumatran orangutans, is planning to open up large areas of forest to oil-palm plantations, mining and new roads, which Wich says could result in the loss of almost a third of the apes by 2030.
鈥淭he Acehnese plan is by far the largest single threat to the orangutans,鈥� he says. He hopes, though, that it could be made less damaging. 鈥淲e鈥檙e not asking for something unreasonable,鈥� he says. 鈥淭here are ways to develop in much more environmentally friendly ways than what the government is proposing.鈥�
Read more: Apps for apes: Orang-utans want iPads for Christmas
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