• 1 The University of Queensland, School of Biological Sciences, Brisbane, QLD, Australia.
  • 2 Borneo Futures, Bandar Seri Begawan, Brunei Darussalam
  • 3 The University of Queensland, School of Biological Sciences, Brisbane, QLD, Australia
  • 4 Anthropology Program, University of Wisconsin Oshkosh, Oshkosh, WI, USA
  • 5 School of Biological Sciences, University of Aberdeen, Zoology Building, Tillydrone Avenue, Aberdeen, AB24 2TZ, United Kingdom
  • 6 Yayasan IAR Indonesia, Bogor, 16001, Indonesia
  • 7 Department of Anthropology, Stanford University, Stanford, California, USA
  • 8 Orangutan Tropical Peatland Project, The Center for International Cooperation in the Sustainable Management of Tropical Peatlands (CIMTROP), University of Palangka Raya, Central Kalimantan, Indonesia
  • 9 Departments of Anthropology and Biological Sciences, Program in Integrative and Evolutionary Biology (IEB), University of Southern California, Los Angeles, USA
  • 10 GFA/KWF, Kapuas Hulu Program, West Kalimantan, Indonesia
  • 11 Organisms and Environment Division, Cardiff School of Biosciences, Cardiff University, Cardiff, United Kingdom
  • 12 The Nature Conservancy (TNC) Indonesia, Jakarta, Indonesia
  • 13 Research Centre in Evolutionary Anthropology, and Palaeoecology, School of Natural Sciences and Psychology, Liverpool John Moores University, Byrom Street, Liverpool, L3 3AF, United Kingdom
  • 14 Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103, Leipzig, Germany
  • 15 Kinabatangan Orang-utan Conservation Programme, Sandakan, Sabah, Malaysia
  • 16 Orangutan Foundation, London, United Kingdom
  • 17 Department of Anthropology, Program in the Environment, and School for Natural Resources and Environment, University of Michigan, Ann Arbor, MI, 48109, USA
  • 18 Biology Faculty, Universitas Nasional (UNAS), Jakarta, Indonesia
  • 19 Science and Engineering Faculty, Queensland University of Technology, Brisbane, QLD, Australia
  • 20 Austindo Nusantara Jaya Tbk, Jakarta 12910, Indonesia
  • 21 College of Arts and Social Sciences, The Australian National University, Canberra, ACT, Australia
  • 22 Borneo Orangutan Survival Foundation (BOSF), Nyaru Menteng, Central Kalimantan, Indonesia
  • 23 World Wide Fund for Nature-Indonesia (WWF-Indonesia), Central Kalimantan Program, Indonesia
  • 24 The Indonesian Association of Primatologists (PERHAPPI), Bogor, Indonesia
  • 25 Flora and Fauna International-Indonesia, Ragunan, Jakarta, Indonesia
  • 26 Faculty of Veterinary Medicine, Gadjah Mada University (UGM), Yogyakarta, 55281, Indonesia
  • 27 Lembaga Living Landscapes Indonesia (LLI), Pontianak, West Kalimantan, Indonesia
  • 28 Psychology Department, Glendon College of York University, 2275 Bayview Avenue, Toronto, M4N 3M6, ON, Canada
  • 29 Yayasan Orangutan Indonesia (YAYORIN), Pangkalan Bun, Central Kalimantan, Indonesia
  • 30 Restorasi Habitat Orangutan Indonesia (RHOI), Bogor, West Java, Indonesia
  • 31 World Wide Fund for Nature-Indonesia (WWF-Indonesia), West Kalimantan Program, Indonesia
  • 32 Anthropological Institute and Museum, University of Zurich, Zurich, Switzerland
  • 33 ARC Centre of Excellence for Environmental Decisions, The University of Queensland, Brisbane, QLD, Australia
Sci Rep, 2017 07 07;7(1):4839.
PMID: 28687788 DOI: 10.1038/s41598-017-04435-9


For many threatened species the rate and drivers of population decline are difficult to assess accurately: species' surveys are typically restricted to small geographic areas, are conducted over short time periods, and employ a wide range of survey protocols. We addressed methodological challenges for assessing change in the abundance of an endangered species. We applied novel methods for integrating field and interview survey data for the critically endangered Bornean orangutan (Pongo pygmaeus), allowing a deeper understanding of the species' persistence through time. Our analysis revealed that Bornean orangutan populations have declined at a rate of 25% over the last 10 years. Survival rates of the species are lowest in areas with intermediate rainfall, where complex interrelations between soil fertility, agricultural productivity, and human settlement patterns influence persistence. These areas also have highest threats from human-wildlife conflict. Survival rates are further positively associated with forest extent, but are lower in areas where surrounding forest has been recently converted to industrial agriculture. Our study highlights the urgency of determining specific management interventions needed in different locations to counter the trend of decline and its associated drivers.

* Title and MeSH Headings from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.