内蒙古高原针茅草原群落α多样性研究

Study on α diversity of four Stipa communities in Inner Mongolia Plateau

用比较样地法调查了内蒙古高原 4类地带性针茅 (Stipa)草原 :贝加尔针茅 (S .baicalensis)草原、大针茅 (S .grandis)草原、克氏针茅 (S .krylovii)草原和小针茅 (S .klemenzii)草原群落的α多样性特征 ,结果表明 :群落物种数目同时受取样面积和样方形状的影响 ,对数模型S =alnA +b能够很好地表征群落的种 -面积关系 ,长方形样方可以获得与面积加倍的正方形样方相近的取样效果。同一尺度下 ,沿着降水量逐渐递减生态梯度 ,从贝加尔针茅群落到小针茅群落物种数目逐渐递减 ,群落丰富度指数 (群落物种数、Margalef指数 )逐渐降低。多样性指数中 ,Simpson指数逐渐增大 ,Shannon_Wiener指数逐渐降低 ,非常丰富种 (N2 )及丰富种 (N1 )的数量均不断减少。

The α diversity of four Stipa communities, i.e. S.baicalensis, S.grandis, S.krylovii, and S.klemenzii in the Inner Mongolia Plateau were studied using comparable plot methods. The results showed that the species number of four Stipa communities were affected by both the size and shape of quadrats. The species_area relationship could be characterized by a power function model,S=alnA+b.The difference between numbers of species obtained by oblong quadrats and by square quadrats with twice the size of the oblong quadrats was not significant. At the same scale the species number decreased along the ecological gradients from the S.baicalensis community to the S.klemenzii community. The richness indices, including species number of the communities and Margalef index, also declined from the S.baicalensis community to the S.klemenzii community. Diversity indices including Shannon_Wiener index and Hill's indices N 1 and N 2 , were also reduced.