Water Use of Asiatic Wild Asses in the Mongolian Gobi

Water is a key resource for most large bodied mammals in the world’s arid areas. With the growing human population, access to water for wildlife often becomes compromised. Equids are typical inhabitants of semi-arid to arid rangelands and need regular access to fresh water. However, their water needs are difficult to study under free-ranging conditions. In this study we investigated Asiatic wild ass (Equus hemionus) use of permanent water points in the Great Gobi B Strictly Protected Area (SPA) in south-western Mongolia. We combined observational data from one specific water point with high frequency GPS location data from one radio-collared Asiatic wild ass mare. Observations and GPS data revealed that wild asses come to drink during all 24-hours of the day without an apparent diurnal pattern. The majority of wild asses came to the water point alone or in small groups. Other ungulates were largely ignored by wild asses, but the arrival of humans and their transportation devices almost always resulted in flight behavior. The monthly drinking frequency varied from every 1.5 to 2.2 days during the hot and dry season in June and August to every 2.3 to 3.8 days in April, May and September. Longer intervals between successive visits to permanent water points may explain why Asiatic wild asses can make use of pastures further away from water than sympatric Przewalski’s horses (Equus ferus przewalskii). The lack of a clear diurnal pattern suggests that there is no specific time window in which wild ass are particularly vulnerable to disturbances at water points. However the high disturbance potential of humans and their transportation devices makes it desirable to restrict human impact at water points by re-routing transportation routes, or requiring a minimum distance from water for herder camps and wildlife viewing facilities