新疆北屯绿洲弃耕农田的植被变化特征

在北屯绿洲选择了3组不同年限的次生盐渍化弃耕农田,分别计算了样地内每种植物的重要值,采用Shannon-Wiener指数、Pielou指数、Simpson指数测定了生物多样性.结果表明:3组群落组成存在显著差异,优势种更替明显.3组群落构成依次为,一年生草本、一年生草本 多年生小半灌木、多年生草本 灌木.物种多样性表现为2年群落＞5年群落＞13年群落;群落均匀度表现为2年群落＞5年群落,而5年与13年群落相当,但是生态优势度却表现出与物种多样性相反的趋势,即2年群落＜5年群落＜13年群落.

Study on the Succession of Vegetation in Farmlands Discarded from Cultivation in the Beitun Oasis, Xinjiang

In this study,some important values of each plant in 2-year,5-year and 13-year plant community plots in the farmlands discarded from cultivation for different years in the Beitun Oasis,Xinjiang,are calculated,and the values of biodiversity in the plots are measured,compared and lucubrated by applying Shannon-Wiener index,Pielou index and Simpson index.The results reveal that the community composition of the 3 groups of plant community plots in the farmlands discarded from cultivation for different years is significantly different,and the succession of dominant plant species is obvious.The community composition of the 3 groups is in an order of annual herbaceous plants,annual herbaceous plants perennial short half-shrubs,and perennial herbaceous plants shrubs.The succession of the plant communities is particular to a certain extent.There is a regularity in the change of biodiversity,the species diversity is in an order of 2-year community > 5-year community > 13-year community,the degree of homogeneity of 2-year community is higher than that of 5-year community,and the degree of homogeneity of 5-year community is similar to that of 13-year community.The trend of ecological predominance is contrary to that of species diversity,i.e.in an order of 2-year community < 5-year community < 13-year community.