An airborne survey of endangered orangutans in Sabah, the Malaysian state in the north-east of Borneo has found that populations have stabilised within well-managed forests but are still in decline in areas with extensive palm oil plantations.
The study was carried out by the World Wide Fund for Nature and is the largest, most comprehensive survey of orangutans in Borneo to date.
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The large areas of lowland forest is Sabah is the ideal habitat for orangutans. However, over the past 50 years extensive logging and land clearance for agriculture has led to a drastic decline in their numbers.
In the study, the researchers surveyed an area almost 5,500 km wide. Based on the number of tree-borne nests counted they estimate that there are almost 10,000 orangutans living in the area. This includes more than 1,500 previously undiscovered animals spread out in small widely dispersed groups.
The bulk of the orangutans, around 5,550, were found living within sustainably managed forests or in the central uplands away from the loggers. The numbers in this area have remained stable since 2002, suggesting that conservation efforts are proving successful. By contrast, orangutan numbers in forests surrounded by extensive areas of palm oil plantations have fallen by as much as 30 per cent.
“A recent survey on orangutan populations in Sabah, North-east Borneo showed a mixed picture from different regions,” said the World Wide Fund for Nature’s Donna Simon. “However, overall the research shows that they have maintained the same numbers over the last 15 years and can remain so as long as proper conservation management measure continues to be put in place.”