退化草原封育改良过程中植物种的多样性变化的研究

The Studies of Changes of Plant Diversity on Degenerated Steppe in Eeclosed Process

以冷蒿（Ａｒｔｅｍｉｓｉａｆｒｉｇｉｄａ）为建群种的退化羊草（Ｌｅｙｍｕｓｃｈｉｎｅｎｓｉｓ）草原变型封育过程中植物群落多样性特征及其变化趋势，１２年的研究结果如下：以冷蒿为建群种的退化羊草（Ｌｅｙｍｕｓｃｈｉｎｅｎｓｉｓ）草原变型尽管单位面积上的物种丰富度较低，但由于原有优势种群的生长受到抑制，因而比原生羊草草原具有较高的均匀性和多样性．退化草原１２年的封育过程中，多样性指数表现为具有峰值的总体下降趋势，其中峰值产生在群落组合发生根本变化的封育后第７年．物种分布的均匀度是影响多样性变化的主要因素，而物种丰富度对多样性指数的影响不大．羊草、冷蒿、冰草（Ａｇｒｏｐｙｒｏｎｍｉｃｈｎｏｉ）、变蒿（Ａｒｔｅｍｉｓｉａｃｏｍｍｕｔａｔａ）、双齿葱（Ａｌｉｕｍｂｉｄｅｎ－ｔａｔｕｍ）是造成群落多样性变化的主要植物种群。

\ \ Report on the changes of diversity in degenerated steppe of Leymus chinensis (steppe of Artemisia frigida) which was enclosed for restoration from 1983 to 1994 are researched.The results are as follows:The species richness of degenerated steppe were lower than natural steppe,because dominant population was restrained in degenerated steppe by grazing.The diversity index had peak value in middle stage of resteration succession (after enclosed 7th years).Apart from this,in the whole succession process,diversity index appeared to be overall declined.The main reason was species eveness.The species richness had a little influence to diversity index.The change of diversity of community was brought about by Leymus chinensis、Artemisia frigida、Agropyron michnoi、Artemisia commutata、Allium bidentatum.The correlation between diversity index and changes of population abundance (involve density,biomass) was significant.