The local extinction of the proboscis monkey Nasalis larvatus in Pulau Kaget Nature Reserve, Indonesia

The population of the threatened proboscis monkey Nasalis larvatus, a Bornean endemic, in the Pulau Kaget Nature Reserve, South Kalimantan, Indonesia, is extinct. Until 1997, this small, isolated population, estimated at c. 300 individuals, had been pushed towards the fringes of the reserve by illegal agricultural expansion. As food sources became depleted, the population apparently exceeded the decreasing carrying capacity of the reserve and was reported to be starving to death. As a solution, 84 animals were translocated to nearby, unprotected sites, resulting in 13 fatalities. An additional 61 animals were taken to a zoo, where 60 per cent died within 4 months of their capture. There was neither a proper pre-translocation assessment of the suitability of the release sites, nor a proper post-translocation monitoring programme for the released animals. We conclude that the Pulau Kaget reserve and its proboscis monkeys have been poorly managed. We provide some suggestions to improve the effectiveness of conservation efforts in Indonesia.