Bornean orangutan - Threats

No existing population can be considered safe

Past orangutan conservation failures demonstrate that no existing population, however large or seemingly well protected, should be considered safe and without need of strong protection efforts.

Habitat loss and degradation
Massive land conversion projects such as the disastrous Mega-Rice Project demonstrate how rapidly areas of orangutan habitat can be destroyed. In Kalimantan, one million hectares of peat-swamp forest was partly cleared and drained during 1995-97 for conversion to rice fields, despite the inadequacy of that land for agriculture.

As a result of the drainage of the proposed rice field area, and that of vast tracts of the surrounding forests, fires lit up and reached uncontrollable proportions, lasting for six months during 1997-98. Almost no forest remained for orangutans to seek refuge in and land changes prevented them from escaping. It is thought that up to 8,000 individuals could have perished in the fires.

P.p. pygmaeus, the most endangered of the three Bornean subspecies, has its core populations in four protected areas in western Borneo. Two of these, Lanjak Entimau and Batang Ai (Sarawak, Malaysia), suffer from being understaffed and from illegal logging and hunting, and probably cross-border logging from Kalimantan. Danau Sentarum and Betung Kerihun in West Kalimantan are being lost to illegal logging, and are also understaffed and underfunded.

Illegal logging has been controlled to some extent in Tanjung Puting and Gunung Palung National Parks. Generally however, the boundaries of protected areas are often not clearly delineated, which makes them difficult to patrol.

Consequently, shifting cultivators, oil palm companies and logging concessions have encroached into all the parks. Collateral problems include the spread of fire, hunting and human-animal conflict. Orangutans are shot when they enter some oil palm estates.

Because of the loss of their food base, many animals starve and die. Nevertheless, orangutans appear to survive in logged habitat at lower densities, and some of the populations remain surprisingly substantial.

Hunting
In low-hill forests, hunting is the likely cause of the very low estimated densities of orangutans, particularly in the upper reaches of the Katingan and Barito rivers in Central Kalimantan and Pawan river in West Kalimantan. The slightest hunting pressures can cause a steep decline in numbers, even in good quality habitat. Hunting intensity would seem to vary from one region to another, a phenomenon probably explained by cultural and religious differences.