Orangutans count on stats for survival

Professor Kerrie Mengersen, from the School of Mathematical Sciences, is part of a study to guide efforts for saving the Indonesian primate whose name means "person of the forest."

Professor Mengersen said the study had found a quarter of villagers who lived side-by-side with orangutans did not know it was illegal under Indonesian law to kill the primates, and five per cent admitted to killing 1000 orangutans last year.

Professor Mengersen is participating in the study run by The Nature Conservancy (TNC) in their quest to protect orangutans in the Indonesian states of Borneo and Sumatra.

She designed and led the statistical analysis of the study's survey, which was completed by almost 7000 villagers.

In addition to learning about the location and abundance of remaining orangutans, the study investigated issues of conflict and hunting.

"Killing rates of more than one per cent of the orangutan population per year are thought to lead to certain extinction in local areas, but the survey results indicate rates of local killing may be much higher than this," Professor Mengersen said.

"Just over half of the killings were reportedly for food, followed by more than 10 per cent each for self-defence, crop protection and unspecified reasons.

"Very few reported killing for traditional medicine, selling orangutan babies for the pet trade, hunting for fun or being paid to kill."

Professor Mengersen said by identifying factors related to the killing, education campaigns could be tailored to specific areas and cultural groups.

"Not a single conservation program is effectively targeting orangutan hunting at present," she said.

"There appears to be a role for increased education about protection of orangutans under Indonesian law."

Professor Mengersen said the survey also found villagers felt overwhelming support for the forest, saying it contributed to their health and culture, but also appreciated the wealth, schools and health services provided where forest was cleared for industry, such as palm oil and eucalypt plantations.

"Through the work of TNC and others, and through the use of powerful statistical modelling, we can learn from the wealth of knowledge vested in these 'eyes and ears' of the forest and learn how to work more effectively towards goals for the conservation of orangutans," she said.

Professor Mengersen's findings have been published in the journal Significance, published by the Royal Statistical Society and the American Statistical Association.