Abstract: Data of vegetation and soil physicochemical properties were collected from 55 quadrats in a typical semi-arid grassland in Ewenke Tribe Autonomous Qi (Flag), Hulunbuir, easternInner Mongolia, China. The effects of soil physicochemical properties on the spatial distribution of vegetation community were analyzed by canonical correspondence analysis (CCA). With respect to its spatial distribution, the vegetation was slightly degraded. The degraded communities showed the characteristics of high biomass and low diversity. The transitional communities showed the characteristics of high diversity and low biomass, and the original communities showed an intermediate state. Soil physical properties, such as particle composition and bulk density, had little spatial variation. In contrast, there were substantial spatial variation in the contents of soil organic matter, total phosphorus, total nitrogen, and soil moisture. The horizontal change of plantcommunity structure was mainly driven by soil moisture, total phosphorus, organic matter andtotal nitrogen contents, with soil moisture being the most important factor. The moisture of surface soil (0-20 cm) was the most important factor affecting community structure (with a contribution rate of 38%), followed by the moisture of deep soil (60-80 cm) (with a contribution rate of 36.4%). Such a result indicated that plant community structure was affected not only by shortterm precipitation but also by longterm climate. In conclusion, soil moisture was the most important factor driving the spatial variation of plant community structure in the semi-arid grassland, followed by soil organic matter, total nitrogen  and total phosphorus contents.

Key words: diploid male production, Apis cerana, polyandry, balancing selection, thelytoky.