Refining conservation strategies using distribution modelling: A case study of the Endangered Arabian tahr Arabitragus jayakari

Abstract

The Endangered Arabian tahr Arabitragus jayakari is a rare and little known mountain ungulate, endemic to the 650 km mountain chain of northern Oman and the United Arab Emirates. To investigate the species' status and distribution we conducted a systematic camera-trap survey across its entire range. We used occupancy modelling to quantify habitat associations and create a predictive distribution model for the species. We found that tahr preferred steep, rugged mountain habitats, and occupancy was much higher in protected areas. Arabian tahr were subject to anthropogenic threats, with occupancy decreasing with closer proximity to villages, and with increasing numbers of domestic goats. Tahr occupancy was also negatively associated with elevation and rainfall, with peak occupancy at 800-1,000 m. Although previous assessments have associated the entire Hajar Mountain range with the Arabian tahr, we found that only 23.9%, or 6,986 km2, of the mountain range was occupied. This reduction in area of occupancy reflects recent population declines, but also our improved methods of assessment. Based on our findings, future conservation efforts should focus on creating more protected areas, control measures to partition goats from core habitats of the Arabian tahr, and restoration and captive reinforcement within suitable habitats unoccupied by Arabian tahr. As infrastructure development is a threat to the Arabian tahr, our occurrence probability map provides a useful tool for spatial planning of developments to reduce impacts on the species.