Population status of a nocturnal primate (the Philippine tarsier – Carlito syrichta, Linnaeus, 1758) in an agricultural area of Subayon, Bilar, Bohol

Abstract

The destruction of wildlife habitats due to the exponential growth of human population and its encroachment into wild areas is a major threat to many species around the world. In order to understand the effects of human disturbance on the Philippine tarsier (Carlito syrichta), we evaluated its population status by quantifying the species’ population density in an agricultural habitat and assessed the degree of human disturbance in the area. We did the study in Subayon, Bilar, Bohol, where we surveyed 32 ha out of the total 115 ha of the village between April and June 2017. We predominantly used vocal activity to identify the presence and absence of tarsiers, supplementing the data with incidental sightings. In addition, human disturbances were assessed and described qualitatively. We estimated the population density on 75 individuals per square kilometer. The human disturbance was evidenced in 28 out of 32 plots, which indicates that the entire area has already been disturbed. This study showed that the Philippine tarsier could inhabit highly altered habitats such as agricultural landscapes and suggest that Subayon village might be important for the conservation of this species. We provided another example of the ecological flexibility of otherwise specialised nocturnal primates able to inhabit agricultural areas. To avoid conflicts with humans and to conserve such a species in the future, education, outreach and active involvement of local people are essential.