退化羊草草原浅耕翻处理植物群落恢复演替的研究

The Study on Restoration Succession of Community on Degenerated Steppe of Leymus chinensis after Shallow Ploughing

对退化羊草草原浅耕翻处理后植物群落恢复演替动态的研究结果进行了报道．１１年的变化结果如下：处理群落种的丰富度增加．群落种多样性指数在１１年中的分布符合方程Ｄ＝２．４３－０．４９ｔ＋０．０４ｔ２，均匀性指数分布符合方程Ｅ＝１．４３－０．８５ｔ＋０．０２７ｔ２．群落密度和生物量均较处理前有显著的增加．羊草是造成群落密度和生物量变化的最主要种群，其重要值在１１年中分布符合方程Ｉ＝２０２．９－７８．４／ｔ－０．２２／ｔ２，表明在演替开始的前几年羊草恢复较快，随着时间的延长，增加变缓并保持在一定的水平．１１年的恢复过程可划分为羊草＋少年生杂类草、冰草群落（１—４年）；羊草群落（５—８年）和羊草＋冰草＋多年生杂类草群落（９—１１年）三个群落阶段．１１年的恢复处理群落并未恢复到原生羊草草原群落的水平。

An result that an analysis study on restoration succession of community in degenerated steppe of L.chinensis after shallow ploughing (1983￣1993) is reported.The results are as follow:The species richness per unit area (1￣20 m 2) increased as pernnial plant increased during restoration succession.The community density and aboveground biomass have incrcased obviouly than degenerated stepp.The diversity index of species in restoration community appears an open up parabola for 11 years,the regression equation is D=2.43-0.49t+0.04t(r=0.77). Homogeneity index appears an open up parabola for 11 years,the regression reason that changes of density and biomass were changes of L.chinensis population.The regression equation of important value of L.chinensis can be expressed as I=202.9-78.4/t-0.22/t 2(r=0.933 9). This result make know that an repid increase of L.chinensis population from 1 to 7 year after shllow ploughing,then slow decrease in 8 year later and it will be keep an higher level than degenerated steppe.The restoration succession of community may be devided into three stages.The first stage is community of L.chinensis, annual plant,A.michnoi (for 1￣4 year after ploughing);The second stage is community of L.chinensis (for 5￣8 year after ploughing);The third stage is community of L.chinensis+A.michnoin+perenniol plant (for 9￣11 year after ploughing).The direction of succession is oriented to the primary vegetation of natural steppe of L.chinensis at the seventh year after ploughing and the restoration succession will be continue.