Hidden treasure of the Gobi: understanding how water limits range use of khulan in the Mongolian Gobi

John C Payne,Petra Kaczensky,Bayarbaatar Buuveibaatar,Chris Walzer,Diana E Bowler,Kirk A Olson

doi:10.1038/s41598-020-59969-2

Abstract

Most large herbivores in arid landscapes need to drink which constrains their movements and makes them vulnerable to disturbance. Asiatic wild ass or khulan (Equus hemionus) were widespread and abundant throughout the arid landscapes of Central Asia and Mongolia, but have undergone dramatic population declines and range constrictions; denying khulan access to water is believed to have played a major role. Mongolia’s South Gobi Region now houses the world largest remaining khulan population, but is undergoing rapid land use changes. Khulan water use is poorly understood, largely due to the difficulty of mapping waterpoints used by khulan throughout their exceptionally large ranges, prone to high variations in precipitation. We used the special movement path characteristics of GPS tagged khulan to show us where water is located. We identified 367 waterpoints, 53 of which were of population importance, characterized the seasonal and circadian use, and identified snow cover as the most important variable predicting khulan visits during the non-growing season, and vegetation greenness during the growing season. Our results provide a data layer to help guide a regional khulan conservation strategy, allow predictions for other part of the global khulan range, and illustrates the overall importance of waterpoints for dryland herbivores.

Highlights

Most large herbivores in arid landscapes need to drink which constrains their movements and makes them vulnerable to disturbance
Understanding the factors affecting water use in space and time is a precondition for understanding movement strategies and habitat use of large herbivores in arid ecosystems
Revisits to waterpoints by wild and domestic herbivores result in movement patterns that are typically associated with central-place foragers, in which grazing is constrained by the need to return to a central resource[18,19]

Summary

Introduction

Most large herbivores in arid landscapes need to drink which constrains their movements and makes them vulnerable to disturbance. Central-place foraging depletes forage available close to the central resource, resulting in wild and domestic herbivores selecting foraging areas away from water and encouraging them to switch between water sources[20]. Perpetuating such movement patterns requires high landscape permeability. Located or unmitigated linear infrastructure such as fences, railways, or roads can block wildlife access to water and thereby reduce the area of pasture functionally available to wildlife This can increase the dependence, and pressure, on the remaining accessible waterpoints[21,22,23]. Identifying important waterpoints is essential for wildlife friendly land-use planning and the mitigation of infrastructure[25]

Methods

Results

Conclusion