Abstract: The research results indicate that:It shows a certain law that space evolvement from grassland to field community. All plant community can be clustered three kinds:field community、ecotone and grassland community; biodiversity index H′, Richess index R¹、R², evenness index and spices number all show a common change law from low to high then to low. The disturbance of human cause a change of soil, but the growth of grass was restrained by crop growth strongly this is the main reason for community evolvement from grassland to field.

Key words: <Keywords>Grassland, Field, Community, Evolvement, Ecotone, Similarity coefficient

摘要： 研究结果表明,从农田—天然草地群落的空间演变表现出-定的规律,即植物群落可明显聚为三类:农田群落、交错群落和天然草地群落;群落多样性指数(香农H′)、丰富度指数(R¹、R²)、均匀度指数(E1)及物种数量均表现出由低→高→低的变化规律。人类的频繁扰动(耕作)导致土壤理化性状的变化,作物的强烈生长又抑制了-些草原植物的生长,是天然草地—农田群落空间演变的主要原因。

关键词: 草原, 农田, 群落, 演变, 交错带, 相似系数