Spatial interactions between Mongolian saiga and domestic sheep in western Mongolia: a historical GPS-telemetry baseline

The endangered Mongolian saiga ( Saiga tatarica mongolica ) inhabits the desert–steppe of western Mongolia within landscapes used by livestock, yet their spatial interactions have rarely been quantified using telemetry. We used GPS data from saiga and domestic sheep collared in Sharga Nature Reserve during 2006–2007 to assess individual-level movement patterns, home-range size, seasonal spatial overlap, and proximity to livestock and roads. Saiga occupied substantially larger annual ranges (1,676–3,990 km 2 ) than sheep (225–403 km 2 ) and exhibited higher cumulative movement distances. Seasonal analyses showed moderate spatial overlap, peaking in autumn and winter and remaining low from spring through summer. Fine-scale analyses revealed no consistent spatial attraction between saiga and sheep, whereas saiga strongly avoided roads. These results indicate spatial co-occurrence without clear evidence of displacement under the grazing conditions present during the study period. This study represents the first GPS-based assessment of saiga across their Eurasian range at the time of data collection. The data, collected in the early 2000s, provide a historical baseline of saiga spatial ecology, before the major increases in livestock numbers and infrastructure development. Such baselines are essential for evaluating future changes in movement behavior and informing long-term conservation planning for wide-ranging ungulates in rapidly changing rangelands.