Friday, November 23, 2012

Decline of orang utans in Borneo began over 2,000 years ago

KOTA KINABALU The decline of Borneo's orang utan population is not just due to recent deforestation but had begun to occur over 2,000 years.

A scientific paper study published in Plus One journal by a team experts found that the Borneo orang utans begun experiencing a major demographic decline from about 2,000 years ago based on samples collected in six different study sites in Sabah and Kalimantan.

This was the main conclusion by a team of scientists from the Instituto Gulbenkian de Cincia (IGC, Portugal), the Anthropological Institute and Museum of the University of Zrich (Switzerland), the CNRS (France), Cardiff University (UK) and the Danau Girang Field Centre (DGFC, Sabah).

"The recent loss of habitat and its dramatic fragmentation has affected the patterns of genetic variability and differentiation among the remaining populations of orang utans and increased the extinction risk of the most isolated ones," Dr Reeta Sharma from IGC, the lead author of the paper said.

"We used orang utans samples collected in six different study sites in Sabah (Kinabatangan and Danum Valley) and Kalimantan and genetic markers to identify signals of population decline," added Sharma.

"The dating of the population decline varied across sites but was always within the 200-2,000 years period," Dr Benoit Goossens, director of DGFC and a co-author on the paper.

"This suggests that in some sites at least, orang utan populations were affected by demographic events (like climate change and arrival of modern humans) that started much before the recent human impact on environment in Borneo," added Dr Goossens.

"However, these results do not mean that the recent forest exploitation did not leave its genetic mark on orangutans but suggests that the genetic pool of orang utans is also impacted by more ancient events," suggested Goossens.