Resource selection of a nomadic ungulate in a dynamic landscape.

Area of Science:

• Ecology and Behavioral Biology
• Wildlife Ecology
• Conservation Biology

Background:

• Nomadic ungulate movements are driven by unpredictable resource availability.
• Understanding resource selection in dynamic environments is crucial for nomadic species.
• Mongolian gazelles (Procapra gutturosa) are nomadic ungulates inhabiting the Eastern Steppe of Mongolia.

Purpose of the Study:

• To examine the resource selection strategies of nomadic Mongolian gazelles.
• To investigate selection for forage (NDVI) during the growing season and snow cover in winter.
• To compare population-level and individual-level resource selection at various spatio-temporal scales.

Main Methods:

• Utilized daily GPS locations from 33 Mongolian gazelles tracked for up to 3.5 years.
• Employed resource selection functions (RSFs) at the population level.
• Used step-selection functions (SSFs) at the individual level across scales of 1 to 10 days.

Main Results:

• Population-level analysis revealed selection for higher Normalized Difference Vegetation Index (NDVI) during the growing season.
• In winter, gazelles selected for intermediate snow cover, balancing hydration and movement.
• Individual-level analyses (SSFs) detected selection in only a minority of gazelles, suggesting a random search strategy in homogeneous landscapes.

Conclusions:

• Mongolian gazelles exhibit population-level selection for optimal forage and snow conditions.
• Individual movement patterns may appear random at fine scales due to landscape characteristics and search strategies.
• Despite uncoordinated individual movements, the population collectively selects for similar vegetation and snow cover resources.