Evaluation of Plant Species Compositional Changes during the Recent Decades in Mongolian Steppe

Abstract

To qualitatively assess vegetation degradation, degradation indicator species have been developed by comparing vegetation structures between areas near to and far away from livestock camps and water points in Mongolia. However, the development of qualitative degradation indicators cannot evaluate whether vegetation has degraded in areas far from livestock camps and water points over time. Thus, we aimed to identify changes in plant species composition over time using historical data collections in the area. Between 2013 and 2015, we recorded plant species compositions in 12 plots located in the steppe zone around Ulaanbaatar, and compared these with historical data collected from the same zone including the locations around Ulaanbaatar during the 1960s-1980s. Ordination analysis showed that the compositional similarity between the current and historical data was low. Moreover, current species compositions were more similar to those of areas neighboring livestock camps and water points (i.e. Heavily grazed areas). Specifically, decreases in the appearance frequency of Koeleria macrantha, Poa attenuata, and Bupleurum bicaule seemed to contribute to compositional differences between current and historical data.