Nomadic Movement of Mongolian Gazelles Identified through the Net Squared Displacement Approach

Abstract

The Mongolian gazelles (Procapra gutturosa) that inhabit Mongolia's steppe and semi-desert travel several hundred kilometers each year. Their movement pattern has been considered nomadic, but the details of their movement patterns remain unclear. The aim of this study is to gain an overall perspective of the movement of Mongolian gazelles, which experience diverse environmental conditions with large interannual variations across their continuous distribution range. Based on net squared displacement (NSD) modeling approach, the mixed migration type was the most observed type in the statistical assignment among five movement types, and some movements were assigned into the migration or sedentary. However, NSD seasonal change was irregular in the most annual movements of gazelles, suggesting the nomadic movements of individuals. Most gazelles tracked for more than a year changed their movement types annually, and the movement period differed among individuals. These results also support nomadic movement of the species, although some difficulties of modeling nomadism by the NSD approach were revealed.