内蒙古退化草原恢复演替进程中植物群落特征的分析

<正> 生态环境的恶化是当今世界所面临的重大问题,而草地生态系统的退化是其中重要问题之一。内蒙古草原面积的1/3,大约4.6亿亩已经退化。在退化草场上,优良牧草的数量减少,质量变劣,生境恶化,已成为畜牧业生产的严重障碍。因此,退化草原的恢复与治理已成为当务之急。

THE RESEARCH ON THE DYNAMICS OF COMMUNITY CHARACTERS OF DEGENERATED LEYMUS CHINENSE STEPPE DURING RECOVERING SUCCESSION

According to the important values of the species, the ecological diversity and theevenness index of the community in Leymus chinense steppe which was enclosed for recov-ery from 1983 to 1991, we discussed dynamics of the species component and their communi-ty roles, saturation degree of species, structure of synusiae, productivity and synthetic char-acteristics. The results showed the recovering succession of degenerated steppe was a kindof halfway succession process. During the recovering process, the component of main spe-cies in the community was not changed obviously. But the community was changedalternatively by function of different species groups. The community function of the zonalspecies obviously increased. During the recovering succession process, these species formedthe raising species group including Leymus chinense, Stipa grandis and Agropyron cristatumetc.13 species. However. Artemisia frigida, Potentilla acaulis, Caragana microphylla etc. 13species which were dominated during the period of degeneration formed a species group,the roles of which declined annually. The roles of the other 10 species were not changedclearly and formed a constant accompanying group. These species were Allium bidentatum,Potentilla bifurca and Saposhnikovia divaricata etc.. During the initial stage of recoveringsuccession, the subshrub synusia of Artemisia frigida and Kochia prastrata was dominant inthe community. Then, 5 years later, the dominant subshrub synusia was substituded byrhizome geophyte synusia (L. chinense) and rosette plant synusia (S. grandis, Koeleriacristata). Otherwise, on the whole; succession process, the saturation degree of the speciesdeclined annually, the diversity and the evenness of community basically maintained stable,but the height of the plants and the aboveground biomass of the community increased annu-ally. All of these was a reflection of the dynamics of the degenerated steppe community'scharaterastics in halfway recovering succession.