The population has declined up to one hundred fold since the late 19th Century, coinciding with the arrival of colonial powers on the island of Borneo and accelerated timber extraction. The research is among the first to link species decline with colonial deforestation, as opposed to when humans first appeared in the region.
"This is the first time that an alarming and recent human related decline of a great ape population has been demonstrated using genetic data," said Dr Benot Goossens, Cardiff School of Biosciences.
"The research used a new, innovative analysis that meant we could distinguish between population decline that happened thousands of years ago and much more recently".
The team of researchers sampled the faeces from two hundred orang-utans in the Kinabatangan Wildlife Sanctuary in Sabah, northern Borneo and DNA profiling was used to discover the most likely history of the population that would give rise to their genetic profiles.
"It is clear that the remaining population of Orang-utans in Sabah is a very small fraction of what originally existed, and more importantly, if the decline continues at the same speed, the population will be extinct within a few decades," said Dr Goossens.
Normally the genetic effects of recent events such as colonial deforestation would be obscured by ancient demographic events. However, humans have so devastated orang-utan populations that the genetic signature of the recent bottleneck may have overshadowed any previous population fluctuations.
"The results of the study underscores the need to act now to protect the long term survival of the species. The animals still possess enough genetic diversity to stabilise if immediate action is taken to halt further decline", said Professor Michael Bruford, Cardiff School of Bio
Contact: Professor Michael Bruford