关键词: 风成沉积物, 跃移, 绿洲-沙漠过渡带, 粒度

Abstract: In this paper, we studied the characteristics of plant functional groups in Stipa klemenzii desert steppe in China and Mongolia, including community average height, coverage, importance value, species number, diversity and ecological niche. Results showed that the average coverage and importance value of perennial community were lower under the settled grazing than under fourseason nomadic grazing, while the average coverage and importance value of annual community were opposite. The proportions of annual plant and shrub were significantly higher under the settled grazing than under fourseason nomadic grazing. Moreover, xerophytes dominated in the community and the proportion of xerophytes was lower under the fourseason nomadic grazing (77.1%) than under the settled grazing (78.6%). However, compared with the settled grazing, both Shannon and Simpson indexes were higher while Pielou index was lower in life form and ecological functional groups under the fourseason nomadic grazing. There was a significant positive correlation between Shannon and Simpson indexes, and Pielou index had a negative correlation with Shannon and Simpson indexes, respectively. Niche breaths of annual and perennial plants were higher, with a niche overlap of 0.965; niche breaths of xerophytes and mesoxerophytes were 0.999 and 0.987, respectively, with a niche overlap of 0.985.

Key words: grain size, saltation, oasis-desert ecotone, aeolian deposit