关键词: 民勤, 绿洲荒漠过渡带, 群落特征, 重要值, 物种多样性

Abstract: [Objective] Along the evolution direction from oasis to desert in the Minqin oasis-desert ecotone,the position and function of each species in the community composition among different segments were investigated and analyzed.The results could provide the basis for the regional desertification control and ecological restoration. [Method] From oasis to desert (northwest-southeast),line transect method was used to investigate the vegetation types,volume,crown breadth,height and ground diameter,etc.The important value and species diversity index were calculated. [Results] There were 23 species in different sections in the area,belonging to 10 families and 23 genera.There were 6families 8species in shrubs and 8families 15 species in herbs.The largest important value of shrub (153.48%)was the Nitraria tangutorum in the sandbags area.The Chenopodiaceae dominated herb layer.There were no obvious differences in the diversity of shrub and herb based on important value in the different stages.The H',D and D_mc of shrub and herb decreased from oasis to desert transition.The J_sw value fluctuated due to individual advantage of Nitraria tangutorum. [Conclusion] In the study area,shrubs regeneration and growth was relatively stable.However,community structure was simple and species diversity was low.The growth of clonal plants,to some extent,accelerated the simplification of species diversity.

Key words: Minqin, oasis-desert ecotone, community characteristics, important value, species diversity