甘南玛曲高寒草甸草地沙化的研究

Study on alpine meadow grassland desertification in Maqu,Gannan

以甘南玛曲高寒草甸生态系统植物群落样地调查资料为基础,对不同沙化程度植物群落结构及物种多样性特征进行了研究分析。结果表明:随着草地沙化程度的加剧,植物群落多样性指数,均匀度指数及丰富度指数下降,优势度指数增加;禾草地上植物量减少,杂草、莎草地上植物量增加,其中,莎草增加最快。中度沙化阶段是植物群落丰富度、多样性、优势度、地上植物量和均匀度变化的一个转折点,演替早期群落多样性,均匀度及地上总植物量最高,在极度沙化阶段,地上总植物量最低,优势度指数最大。

Basing on the sampling data of sample survey from plant community of alpine meadow ecosystem in Maqu, Gansu, the degree of grassland deserification,the characteristics of plant communities and the diversity of plant species were studied in this article. The results indicate that, with the increasing of degree of grassland desertification,the three indexes of species richness, evenness and biodiversity redused, the index of dominance increased. The abover-ground biomass of gramanoids reduced, however, above-ground biomass of sedges and forbs increased, especially sedges increased most quickly. The stage of moderate desertification was the turn- ing point of changes for indexes of species richness, evenness, biodiversity and dominance. At the early stage of succession, the indexes of species biodiversity, evenness and above-ground biomass were the highest. However,in the extreme desertification stage, the above-ground biomass became the lowest and the dominance index the highest.