Abstract: By using quadrat method, this paper studied the structure, species diversity, and population productivity of representative plant communities in eastern Aerjin Mountain Nature Reserve, Northwest China, with the relationships between these plant communities’ characteristics and environmental factors analyzed. The species diversity of the plant communities was in the order of eroded steppe at Kaerqiuka > wet meadow at Abatiba > steppe at Kaerdun > steppe at Yixiekepati Central Station > desert at Yixiekepati. The diversity indices of the plant communities were negatively correlated to slope and soil pH, and positively correlated to soil moisture. The analysis on the biomass of different functional groups of the plant communities showed that Cyperaceae distributed mostly in wet meadow, while Poaceae distributed mainly in the steppe near Yixiekepati Central Station. Leguminosae only appeared in the steppe at Kaerdun. Since the distribution of plant resources limited the herbivores’ selection for foods, the steppe near Yixiekepati Central Station and the wet meadow at Abadiba should be strictly protected as the key food sources and habitats for wildlife.

Key words: spatial pattern, slope aspect, Potentilla fruticosa, subalpine meadow, spatial correlation.