The Mongolian gazelle (Procapra gutturosa) is the main representative of the eastern Mongolian dry feather-grass steppe and one of the endemic ungulate species of Central Asia. Around 1 million Mongolian gazelles inhabit the eastern Mongolian steppe. The bulk of the population is located in Mongolia while a small resident herd has been reestablished in Russia after complete local extinction.
Gazelles no longer migrate to China because a fence was constructed along the Mongolian border leaving few openings for gazelles to cross. Migration and distribution are thought to relate to drought cycles and other climatic phenomena, and are affected by human activities including hunting. Oil exploration in the vast steppe area of eastern Mongolia and a planned railway through the steppe are the most pressing threats to gazelles. Construction of the Ulaanbaatar-Zamyn Uud railway blocked the main migration route to western provinces. As a result, herds west of the railway stopped breeding and their range and numbers fell sharply. The population in Mongolia north of the Kherlen River was never less than 100,000 head, and in the mid 1990s, the autumn population reached 200-230,000. The largest (maternal) summer group inhabited the left bank of the Kherlen not far from Choibalsan.
In the same region there was a calving ground or long-term area of mass calving of Mongolian Gazelles spreading from east to west. Every year in September the group migrated in separate herds to winter pastures. During autumn and spring migration and in winter gazelles are usually widely distributed and often penetrate into the Chita region of Russia.
During the last 10 years distribution of Mongolian gazelles shifted northwards to the southern border of the forest steppe across the Kherlen River. In the early 2000s, mostly due to drought, some gazelles from a maternity group in the north Kherlen population began to move to the northeast where a new large calving ground was formed near the China-Russia border. By 2004 there were more females there than in the main calving area. Timely monitoring of migrations and measures for protection of gazelles in the Daursky Zapovednik led to restoration of conditions for recovery of the species in Russia, and the breeding heard reached 700-900 individuals in 2007.