Effects of spatiotemporal heterogeneity of forage availability on annual range size of Mongolian gazelles

We analyzed the effects of forage amount and its spatiotemporal heterogeneity on the annual range size of Mongolian gazelles by tracking 20 gazelles over a wide range of their distribution in Mongolia and by applying the normalized difference vegetation index (NDVI). Annual ranges were separated into four regions. The maximum individual annual range size was more than 40 times the minimum (range: 900-37000km(2)). Annual range size was increased with increasing forage amount and spatial heterogeneity and seasonal change in forage amount. Many tracked gazelles changed their range locations between summer and winter, and these ranges occupied only small parts of their annual ranges. The smaller annual range size in the areas with smaller forage amount was explained by the smaller seasonal change and spatial heterogeneity of forage amount. Knowledge of such variations of movements and environments in a continuous distribution can improve our understanding of movement ecology.