Using autonomous recorders and bioacoustics to monitor the globally endangered wildlife in the Annamite mountain landscape: A case study with crested argus in Song Thanh Nature Reserve

Abstract

In Southeast Asia, the Annamite mountains and Central Vietnam lowlands are two of the most prioritized areas for preventing the extinction of large populations of phasianids. Ground-feeding birds in Southeast Asia may be going extinct, both inside and outside the protected areas, due to habitat loss and poaching, especially, snaring. Being endemic to the mainland of Southeast Asia, the crested argus is one of the largest and most threatened species of Phasianidae. Indeed, the crested argus has recently been upgraded to the “endangered” category from the “near-threatened” category in the IUCN RedList. Quantitative data on the occurrence of the crested argus for guiding conservation efforts is poor. Additionally, information on the species’ ecology is limited. In this study, we used autonomous recorders to detect the presence of the crested argus and to estimate its occurrence probability in Song Thanh Nature Reserve, Vietnam. We also examined the effects of environmental variables on the species’ distribution in space. We used four Song Meter SM3 recorders to record the calls of the crested argus at 38 recording posts from February to April 2019. We used RAVEN software to analyze the sound data. We used the Occupancy Estimation in MARK to estimate the detection probability and the occurrence probability. Elevation had a slight negative effect on occurrence probability. The occurrence probability of the crested argus was high (0.88; CI: 0.60−0.97). The high occurrence probability in the Song Thanh Nature Reserve reveals the importance of this protected area in galliform species conservation in general and for the crested argus in particular.