Passive acoustic monitoring using smartphones reveals an alarming gibbon decline in a protected area in the central Annamite Mountains, Vietnam.

Autor: Vu TT; Department of Wildlife, Faculty of Forest Resource and Environment Management, Vietnam National University of Forestry, Hanoi, Vietnam., Doherty PF; Department of Fish, Wildlife, and Conservation Biology, Warner College of Natural Resources, Colorado State University, Fort Collins, Colorado, USA., T Nguyen H; Institute for Tropical biodiversity and Forestry, Hanoi, Vietnam., Clink DJ; Cornell Lab of Ornithology, K. Lisa Yang Center for Conservation Bioacoustics, Cornell University, Ithaca, New York, USA., Nguyen MD; Department of Wildlife, Faculty of Forest Resource and Environment Management, Vietnam National University of Forestry, Hanoi, Vietnam., Dong HT; Department of Wildlife, Faculty of Forest Resource and Environment Management, Vietnam National University of Forestry, Hanoi, Vietnam., Cheyne SM; Faculty of Humanities and Social Sciences, Oxford Brookes University, Headington Campus, Oxford, UK., Giang TT; Department of Wildlife, Faculty of Forest Resource and Environment Management, Vietnam National University of Forestry, Hanoi, Vietnam., Phan DV; Department of Wildlife, Faculty of Forest Resource and Environment Management, Vietnam National University of Forestry, Hanoi, Vietnam., Ta NT; Department of Wildlife, Faculty of Forest Resource and Environment Management, Vietnam National University of Forestry, Hanoi, Vietnam., Tran DV; Department of Wildlife, Faculty of Forest Resource and Environment Management, Vietnam National University of Forestry, Hanoi, Vietnam.
Jazyk: angličtina
Zdroj: American journal of primatology [Am J Primatol] 2023 Nov; Vol. 85 (11), pp. e23544. Date of Electronic Publication: 2023 Aug 12.
DOI: 10.1002/ajp.23544
Abstrakt: Monitoring populations is critical for understanding how they respond to anthropogenic disturbance and for management of protected areas. The use of passive acoustic monitoring can improve monitoring efforts as it allows for collection of data on vocal animals at spatial and temporal scales that are difficult using only human observers. In this study, we used a multiseason occupancy model to monitor occurrence, apparent extinction, and colonization probabilities of a northern yellow-cheeked gibbon, Nomascus annamensis population with acoustic data collected from mobile smartphones in Dakrong Nature Reserve, Vietnam. Forty-five sites were randomly selected for repeated surveys in 2019 and 2022. At each site, a mobile smartphone was attached to a tree and recorded sounds for 4.2 days and 3.89 days on average, in 2019 and 2022, respectively. We manually annotated spectrograms for the presence of gibbon calls, and we detected gibbons at 24 and 12 recording posts in 2019 and 2022, respectively. Estimated local apparent extinction from occupancy models was high with 67% of occupied sites in 2019 becoming unoccupied in 2022. Apparent colonization was low with ~25% of unoccupied sites in 2019 becoming occupied in 2022. As a result, the apparent occurrence probability declined from 0.58 in 2019 to 0.30 in 2022. If the absence of calls indicates that cells are unoccupied this would mean an alarming decline of the gibbon population in the nature reserve. We suggest that in the areas with high hunting pressure, monitoring intervals should be shortened to at least yearly. In addition, urgent actions, such as patrolling, or gun confiscation, should be implemented to conserve the gibbon populations in Dakrong Nature Reserve and other protected areas with the same management context.
(© 2023 Wiley Periodicals LLC.)
Databáze: MEDLINE
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