One-Sided Barrier Impact of an International Railroad on Mongolian Gazelles

Abstract: We conducted a carcass census of Mongolian gazelles (Procapra gutturosa) along the Trans-Mongolian railroad in June 2005. We counted 241 gazelles that had died within the previous 12 months. Carcass numbers were greater on the southwestern side in the northern 3 zones, but we found carcasses only on the northeastern side in the southernmost zone. It suggests that impact of the railroad was stronger on one side and that the strength of this impact varied among regions.     

Food overlap between Mongolian gazelles and livestock in Omnogobi,southern Mongolia

Botanical and particle size compositions of the feces of sympatric Mongolian gazelles, sheep/goats, and horses collected in southern Mongolia in autumn 2002 were analyzed. The botanical composition of Mongolian gazelles was similar to that of sheep/goats where dicotyledonous plants (64.6% for Mongolian gazelles, 65.6% for sheep/goats), particularly woody fibers were important (39.5% for Mongolian gazelles, 19.5% for sheep/goats). In contrast, horse feces were exclusively composed of graminoids (93.2%). Consequently, food overlap was great between Mongolian gazelles and sheep/goats (Piankas index: 0.977) but was small between Mongolian gazelles and horses (0.437) and sheep/goats and horses (0.421). Particle size distributions were also similar between Mongolian gazelles and sheep/goats, whereas they were different between horses and Mongolian gazelles and horses and sheep/goats. These results support our expectation based on the Jarman-Bell principle. Although interspecific competition cannot be inferred from a mere food overlap, our analyses suggest that sheep and goats are potential competitors for Mongolian gazelles. Therefore, the increase in the numbers of domestic sheep/goats might pose a risk for Mongolian gazelle populations.