风蚀沙化对草原植被生物多样性的影响——以呼伦贝尔草原为例

Effects of wind erosion desertification on the biodiversity of grassland vegetation of Hulunbeir steppe

通过对呼伦贝尔草地沙化过程中不同演替阶段植被物种组成和生物多样性研究,结果表明:草地沙化,灌丛化明显,群落结构趋于简单化;群落α多样性急剧下降,其中物种丰富度、多样性、均匀性,严重沙化草地分别比潜在沙化草地减少59.4%、54.0%和31.4%,而生态优势度增加44.9%,说明草地沙化后,群落物种数减少,优势种更加突出。群落相似性,四类沙化草地与未沙化草地比较,相似系数分别为0.8649、0.6486、0.2593和0.1200,而β多样性变化,四类沙化草地均呈明显增长趋势,其中严重沙化草地比潜在沙化草地高14.6倍,说明β多样性增大,群落相似性降低,生境异质性加大,预示草地沙化程度严重。

In this paper species composition and species diversity of communities in different succession stages in desertification process of Hulunbeir steppe were studied.The results showed that desertification of grassland results in simplification of community structure,and invasion of shrubs which is adapted to desert environment.In this process,α-diversity of communities also decrease rapidly as the ecological environment worsen,and the indices of species richness,diversity and evenness decrease by 59.4%,54.0% and 31.4% respectively,but ecological dominance index increase by 44.9%.It is illustrated that species quantity decrease gradually and dominance species becomes more and more prominent in succession processes of grassland desertification.The similarity coefficients of community of 4-type desertification grasslands are 0.8649,0.6486,0.2593 and 0.1200 respectively compared to steppe,but the β-diversity index the serious one increases 14.6 times than the potential desertificated land.It indicates that the habitat heterogeneity becomes the largest and the grade of grassland desertification will be more and more serious.