Changes in plant species composition and diversity of alpine Kobresia (Kobresia pygmaea) steppe meadow at different stages of desertification in the North Tibetan plateau  

作　　者：XingHu Wei Ping Yang Sen Li YuXiang Dong ChunLai Zhang 

机构地区：[1]Department of Resources and Environmental of Foshan University,Foshan,Guangdong 528000,China [2]Resources and Environmental Bureau,Chinese Academy of Science,Lanzhou,Gansu 730000,China [3]Department of Geography of Zhongshan University,Guangzhou,Guangdong 510275,China [4]Beijing Normal University,Beijing 100875,China.

出　　处：《Research in Cold and Arid Regions》2009年第1期71-79,共9页寒旱区科学(英文版)

基　　金：financially supported by the National Natural Science Foundation of China (Grant No. 40271012);the Science & Technology Committee of the Tibet Autonomous Region (Grant No. 200101046);PHD foundation of Foshan university

摘　　要：The impacts of desertification on the vegetation composition, structure, and species diversity of alpine Kobresia steppe meadow were evaluated in an area of severe desertification in Anduo County, Tibet Autonomous Region, northern China. We investigated and analyzed the floristic features of communities at four different stages of desertification (slight desertification [SLD], moderate desertification [MD], severe desertification [SD], and very severe desertification [VSD]). The composition and structure of the alpine Kobresia steppe meadow at the SLD site differed significantly from that at the MD, SD, and VSD sites. Species that were more drought resistant and inedible by livestock were the dominant species at the SD site. No plants were found in the shifting dunes of the VSD site. Species diversity also decreased with increasing desertification. The SLD site had the largest mean number of species and individuals and the largest richness index; the MD grassland had the largest Shannon-Wiener index and evenness index, but the smallest Simpson’s index. The vegetation cover declined from 91.8% to 34.8% as desertification increased from SLD to SD, and reached 0% in VSD areas with shifting dunes.The impacts of desertification on the vegetation composition, structure, and species diversity of alpine Kobresia steppe meadow were evaluated in an area of severe desertification in Anduo County, Tibet Autonomous Region, northern China. We investigated and analyzed the floristic features of communities at four different stages of desertification (slight desertification [SLD], moderate desertification [MD], severe desertification [SD], and very severe desertification [VSD]). The composition and structure of the alpine Kobresia steppe meadow at the SLD site differed significantly from that at the MD, SD, and VSD sites. Species that were more drought resistant and inedible by livestock were the dominant species at the SD site. No plants were found in the shifting dunes of the VSD site. Species diversity also decreased with increasing desertification. The SLD site had the largest mean number of species and individuals and the largest richness index; the MD grassland had the largest Shannon-Wiener index and evenness index, but the smallest Simpson’s index. The vegetation cover declined from 91.8% to 34.8% as desertification increased from SLD to SD, and reached 0% in VSD areas with shifting dunes.

关 键 词：DESERTIFICATION alpine Kobresia steppe meadow DIVERSITY Tibet China 

分 类 号：S812[农业科学—草业科学]