Protecting the forest homes of orangutans is the most cost-effective way of boosting the great apes' chances of survival in the long-run, international scientists have found.
New research at the ARC Centre of Excellence for Environmental Decisions (CEED) has established the best strategies for maintaining orangutan populations for more than 20 years on a limited budget.
"The International Union for Conservation of Nature (IUCN) has listed the Sumatran orangutan as critically endangered, and the Bornean species as endangered," says Professor Hugh Possingham of CEED and The University of Queensland (UQ). "Unless we act quickly, most orangutan populations that don't have adequate protection face a dire future."
Currently, the two main strategies to conserve orangutans are rehabilitating and reintroducing ex-captive or displaced animals, and protecting their forest habitat to decrease threats such as deforestation and hunting, Prof. Possingham explains.
In the study, the researchers analysed which strategy or combination of strategies, and under what conditions, is the most cost-effective at maintaining wild orangutan populations.
"Money is limited in conservation, and it is important to know how best to spend it," says Dr Howard Wilson of CEED and UQ. "We found that the choice between habitat protection and rehabilitation depends on the cost of rehabilitation per orangutan and the rate of deforestation."
"If we want to maintain orangutan populations for less than 20 years, then reintroduction is best," says Dr Wilson. "But if we're aiming for long-term species conservation, protecting their habitat is by far the best strategy.
"This is because reintroduction costs twelve times as much per animal compared with protecting its habitat, so rehabilitation is only a cost-effective strategy at very short timescales."
Prof. Possingham says the study suggests that the Indonesian and Malaysian governments as well as non-governmental organisations should allocate as much of their resources as possible to protecting orangutan habitats, rather than rehabilitating individual animals.
"There's another option – sustainable logging practices and protecting orangutans from hunting in timber production forests is intermediate in cost-effectiveness between habitat protection and reintroduction," he says.
"These findings are really important", says, Dr Erik Meijaard, one of the co-authors of the study and a long-term orangutan conservation expert. "Although we don't know how much money is being spent on rehabilitation and how much on the protection of wild habitats, it is clear that the balance may need to be shifted."
"Orangutans live in the forests of Borneo and Sumatra. The conversion of orangutan habitats is ongoing, as we speak," Meijaard continues, "and mopping up orangutans in areas that are being converted for oil palm is good for orangutan welfare, but is a very expensive way to contribute to saving the species. The government may need to rethink its objectives on this."
The scientists say that most people in Indonesia and Malaysia want orangutans to survive as a long-term part of the country's natural heritage. "The choice is ours and we need to be smart in deciding the best way to secure the species' future, then go and do it effectively."
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Wilson HB, Meijaard E, Venter O, Ancrenaz M, Possingham HP (2014) "Conservation Strategies for Orangutans: Reintroduction versus Habitat Preservation and the Benefits of Sustainably Logged Forest." PLoS ONE 9(7): e102174. DOI: 10.1371/journal.pone.0102174