呼伦贝尔草地风蚀沙化植被生物多样性研究

Studies on the Bio-diversity in the Wind Eroded and Desertified Vegetation of Hulunbeir Steppe

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。四类沙化草地群落相似性与未沙化草地比较,相似系数分别为0.8649、0.6486、0.2593和0.1200,而四类沙化草地β多样性变化均呈明显增大趋势,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。

The species composition and species diversity of communities with different succession stages were studied in desertification process of Hulunbeir steppe.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 decreased by 59.4%,54.0% and 31.4% respectively compared with the potential desertification grassland,but ecological dominance index increased 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 were 0.8649,0.6486,0.2593 and 0.1200 respectively compared to steppe,but the β-diversity index increased by 14.6 times desertification than the serious one.It indicated that the habitat heterogeneity becomes the largest and the grade of grassland desertification will be more and more serious.