The 2016–2017 introduction of peste des petits ruminants virus (PPRV) into livestock in Mongolia was followed by mass mortality of the critically endangered Mongolian saiga antelope and other rare wild ungulates. To assess the nature and population effects of this outbreak among wild ungulates, we collected clinical, histopathologic, epidemiologic, and ecological evidence. Molecular characterization confirmed that the causative agent was PPRV lineage IV. The spatiotemporal patterns of cases among wildlife were similar to those among livestock affected by the PPRV outbreak, suggesting spillover of virus from livestock at multiple locations and time points and subsequent spread among wild ungulates. Estimates of saiga abundance suggested a population decline of 80%, raising substantial concerns for the species’ survival. Consideration of the entire ungulate community (wild and domestic) is essential for elucidating the epidemiology of PPRV in Mongolia, addressing the threats to wild ungulate conservation, and achieving global PPRV eradication.

Habitat loss and habitat fragmentation caused by anthropogenic activities are the main factors that constrain long-distance movement of ungulates. Mongolian gazelles (Procapra gutturosa) and Asiatic wild asses (Equus hemionus) in Mongolia are facing habitat fragmentation and loss. To better understand how their movements respond to potential anthropogenic and natural barriers, we tracked 24 Mongolian gazelles and 12 wild asses near the Ulaanbaatar–Beijing Railroad and the fenced international border between Mongolia and China between 2002 and 2012. None of the tracked gazelles crossed the railroad, even though gazelles were captured on both sides of the tracks at the start of the study. Similarly, we did not observe cross-border movements between Mongolia and China for either species, even though some animals used areas adjacent to the border. The both species used close areas to the anthropogenic barriers more frequently during winter than summer. These results suggest strong impacts by the artificial barriers. The construction of new railroads and roads to permit mining and other resource development therefore creates the threat of further habitat fragmentation, because the planned routes will divide the remaining non-fragmented habitats of the ungulates into smaller pieces. To conserve long-distance movement of the ungulates in this area, it will be necessary to remove or mitigate the barrier effects of the existing and planned roads and railroads and to adopt a landscape-level approach to allow access by ungulates to wide ranges throughout their distribution.

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1. Conservation of nomadic species presents significant conservation challenges because of unpredictability in their movements and space use. Long-term studies on nomadic species offering insights into the variability in space use within and between years are largely missing but are necessary to develop effective conservation strategies.2. We examined the temporal variability in space-use of Mongolian gazelle, a nomadic species. We tracked 22 individuals for 1-3 years with GPS and used the resulting movement patterns to evaluate conservation strategies associated with their nomadic movements in the intact open plain grasslands of Mongolia.Individuals exhibited a high degree of variability in space use within and between years, often using different wintering areas in different years. The individual range size varied as much as threefold between years, with an estimated average annual individual range size of ~19,000 km 2 and a lifetime range of ~100,000 km 2 . Comparing simulated and empirical GPS trajectories for the Mongolian gazelleshowed that they avoided disturbed areas (e.g. oil fields) and did not prefer protected areas. Importantly, no single protected area in the region was large enough to cover the annual range of any of the tracked gazelle.4. Because of their wide-ranging movements, the presence of linear infrastructure and the resulting barrier effects are a particular concern. We found that fences along the national border were absolute barriers affecting movements of about 80% of all tracked individuals. When gazelle encounter the border fence, they moved a median distance of 11 km along fences, suggesting frequent crossing options are needed to make barriers permeable.

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