Abstract
Context With the ongoing biodiversity crisis and the continued loss of species, it becomes crucial to find practical solutions to monitor threatened animal populations for wildlife conservation and management. However, in practice, monitoring is especially challenging for elusive, rare, and wide-ranging species, where estimating abundance is often expensive and time-consuming. Alternatively, estimating occupancy (i.e. detection/non-detection data) may be less resource-intensive, while still providing useful information for monitoring population trends. Aims We aimed to describe a new field method, the random walk grid survey, to conduct a habitat selection study on elusive diurnal forest-dwelling primates. We explored how to improve occupancy estimates when detection probability is low and determined the minimal effort needed for reasonable estimates on the species habitat selection by using site-occupancy models. Methods We collected data to assess the northern pigtailed macaques’ (Macaca leonina) occupancy and detection probability using a random walk survey of degraded forest fragments in Sakaerat Biosphere Reserve in Northeast Thailand. We ran simulations to identify what is required for minimum survey efforts to obtain reasonable estimates of occupancy and detection probability on small or relatively large spatial scales, covering a small primate community in Southeast Asia. Key results Simulations showed that the probability of detecting macaques increased dramatically with an increased survey effort. However, compared with similar line-transect survey methods, the random walk grid survey was less time-consuming. Additionally, the occupancy and habitat selection estimates were similar to our knowledge of macaque distribution within the study area. Conclusions Our findings suggest that the new random walk grid survey method is effective to assess the elusive northern pigtailed macaques’ occupancy, and to provide reliable data on habitat selection where there is low macaque abundance and detection probability in a degraded forest fragment. Implications Our survey protocol could be used as a starting point to target high location occupancy to start habituation processes, but also for further intensive studies on primate behaviour and habitat use of primate communities. Finally, combining the random walk grid survey with automated recording devices (e.g. camera traps or passive acoustic surveys) could help improve occupancy and detection probability estimates for long-term monitoring programs and over large spatial scales.
Funder
Thailand Graduate Institute of Science and Technology
Fonds De La Recherche Scientifique - FNRS
Subject
Management, Monitoring, Policy and Law,Ecology, Evolution, Behavior and Systematics
Reference78 articles.
1. Akaike H (1973) Information theory and an extension of the maximum likelihood principle. In ‘International symposium on information theory’. (Eds BN Petrov, F Czáki) pp. 267–281. (Akademiai Kiado: Budapest, Hungary)
2. Albert A (2012) Feeding and ranging behavior of northern pigtailed macaques (): impact on their seed dispersal effectiveness and ecological contribution in a tropical rainforest at Khao Yai National Park, Thailand. PhD. Thesis, University of Liège, Belgium. Available at
3. Considerations for using occupancy surveys to monitor forest primates: a case study with sclater’s monkey ().;Population Ecology,2011
4. Habituation of wild chimpanzees () of the South Group at Taï Forest, Côte d’Ivoire: empirical measure of progress.;Folia Primatologica,2008
5. Using multiple data types and integrated population models to improve our knowledge of apex predator population dynamics.;Ecology and Evolution,2017