Declining Orangutan Encounter Rates from Wallace to the Present Suggest the Species Was Once More Abundant

• Erik Meijaard ,

  * E-mail: emeijaard@pnc-int.com

  Affiliations People and Nature Consulting International, Jakarta, Indonesia, School of Archaeology and Anthropology, Australian National University, Canberra, Australian Capital Territory, Australia

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• Alan Welsh,

  Affiliation Centre for Mathematics and its Applications, Mathematical Sciences Institute, Australian National University, Canberra, Australian Capital Territory, Australia

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• Marc Ancrenaz,

  Affiliation Kinabatangan Orangutan Conservation Project, Sandakan, Sabah, Malaysia

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• Serge Wich,

  Affiliations Anthropological Institute & Museum, University of Zurich, Zurich, Switzerland, Sumatran Orangutan Conservation Programme (PanEco-YEL), Medan, Sumatra, Indonesia

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• Vincent Nijman,

  Affiliations Zoological Museum Amsterdam, Amsterdam, The Netherlands, Department of Anthropology and Geography, School of Social Sciences and Law, Oxford Brookes University, Headington, Oxford, United Kingdom

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• Andrew J. Marshall

  Affiliation Department of Anthropology, Graduate Group in Ecology and Animal Behavior Graduate Group, University of California Davis, Davis, California, United States of America

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