Causal factors underlying the dramatic decline of the Sumatran orang-utan

The Sumatran orang-utan is in dramatic decline, including the population in its main stronghold, the Leuser Ecosystem, in Sumatra, Indonesia (C. P. va n Schaik et al. (2001) Oryx 35, 14-25). The major threats to the survival o f Sumatran orang-utans are identified as habitat loss (mainly from conversi on to oil palm plantations), habitat degradation and habitat fragmentation The immediate causes of this are identified as weak compliance with regulat ions and laws; weak law enforcement and the weak legal environment. Corrupt ion is identified as the ultimate causal factor underlying these three imme diate causal factors, along with a frontier mentality and bureaucratic cons traints. Together, the!: have resulted in the destruction of prime orang-ut an habitat. Several political actions are recommended to improve the effect iveness of habitat conservation for the orang-utan and several technical ch allenges are to be overcome once the policy context is right. The most cruc ial problem to solve is the lack of regular funds for enforcement operation s and establishing a new system of enforcement that is effective. In additi on, the Gunung Leuser National Park needs to be redesigned by enlarging it to cover all high biodiversity areas within the Leuser Ecosystem. Moreover, habitat corridors between important forest tracts need to be re-establishe d.