Abstract: Aims The study of species diversity patterns is useful in understanding community structure and resource allocation patterns in the succession process in alpine meadows. The present study aims to explore: 1) the changes in community species-abundance relationships in alpine meadows of the Qinghai-Xizang Plateau with mountain slopes; and 2) the difference between the abundances of common and rare species, and their roles in the ecological mechanisms. Methods Field investigation was carried out in alpine meadows of the Qinghai-Xizang Plateau followed by lab analyses in Lanzhou. RAD was used to analyze the difference in environmental factors and plant communities among different slope aspects. Important findings Soil water content increased gradually from the south to north slopes (from 0.18 g·g ^-1 on the south slope to 0.31 g·g ^-1 on the north slope), while soil temperature and light intensity showed the opposite trends (from 22.33 ℃ and 744.15 lx on the south slope to 18.13 ℃ and 681.93 lx on the north slope, respectively). The species abundance and species diversity increased, while the slope of species abundance curves decreased from the south to north slopes. Among the six species abundance fitting models, the ecological niche model best explained the species abundance curves followed by the random distribution model. Further analysis showed that the overall resource allocation pattern of species was mainly fixed distribution. In addition, the resource allocation pattern of the rare species was mainly random, while that of the common species was mainly deterministic.

Key words: Gannan alpine meadow, slope gradient, species-abundance, common species, rare species