Wildfire smoke linked to vocal changes in wild Bornean orangutans
Wendy M. Erb,
Elizabeth J. Barrow,
Alexandra N. Hofner,
Jessica L. Lecorchick,
Tatang Mitra Setia,
Erin R. Vogel
Affiliations
Wendy M. Erb
K. Lisa Yang Center for Conservation Bioacoustics, Cornell Lab of Ornithology, Cornell University, Ithaca, NY 14850, USA; Department of Anthropology, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA; Corresponding author
Elizabeth J. Barrow
Department of Social Sciences, Oxford Brookes University, Headington, Oxford OX3 0BP, UK; Gunung Palung Orangutan Conservation Program, West Kalimantan, Ketapang 78811, Indonesia
Alexandra N. Hofner
Department of Integrative Conservation, University of Georgia, Athens, GA 30602, USA; Department of Anthropology, University of Georgia, Athens, GA 30602, USA
Jessica L. Lecorchick
K. Lisa Yang Center for Conservation Bioacoustics, Cornell Lab of Ornithology, Cornell University, Ithaca, NY 14850, USA
Tatang Mitra Setia
Fakultas Biologi, Universitas Nasional, Jakarta 12520, Indonesia; Primate Research Center, Universitas Nasional, Jakarta 12520, Indonesia
Erin R. Vogel
Department of Anthropology, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA; Center for Human Evolutionary Studies, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA
Summary: Tropical peatlands are the sites of Earth’s largest fire events, with outsized contributions to greenhouse gases, toxic smoke, and haze rich with particulate matter. The human health risks from wildfire smoke are well known, but its effects on wildlife inhabiting these ecosystems are poorly understood. In 2015, peatland fires on Borneo created a thick haze of smoke that blanketed the region. We studied its effects on the long call vocalizations of four adult male Bornean orangutans (Pongo pygmaeus wurmbii) in a peat swamp forest. During the period of heavy smoke, orangutans called less often and showed reduced vocal quality—lower pitch, increased harshness and perturbations, and more nonlinear phenomena—similar to changes in human smokers. Most of these changes persisted for two months after the smoke had cleared and likely signal changes in health. Our work contributes valuable information to support non-invasive acoustic monitoring of this Critically Endangered primate.
