Study On Plant Diversity Of Restoration Succession Series Of Degraded Leymus Chinensis Meadow In Horqin

Succession is the process from the beginning of plant settlement to the formation of stable plant communities.Ecologists call each characteristic stage set of community succession process a succession series.Due to the influence of human activities,natural grassland vegetation has degraded,patch fragmentation also occurs in habitats.,Resulting in a significant reduction in plant diversity.Therefore,it is of great significance to explore the spatial and temporal patterns of plant diversity in restored succession series and patch habitats.In this paper,37 different types of plant communities in 4 succession series and 9 patches of plant communities in 4 succession series were studied to discuss the effects of habitat fragmentation on the structure of plant community and the changes of plant diversity in the process of restoration and succession.IThe results are as follows::1.In the four stages of restoration succession,88 species belonging to 23 families and 60 genera were recorded.In the process of succession from annual halophyte community(8 species)to Leymus chinensis community(71 species),the community species composition tended to be composed of a few widespread species.Moreover,the ecological types tend to be composed of straight root,branching and ground bud plants.Species richness gradually increases,and some endemic species begin to appear.At the same time,the more evenly the community is,the more rare the species will be.2.At the level of Leymus chinensis patch assemblage community,all six diversity indices of flora composition and life form have similar pattern changes.With the increase of area,the change of growth rate among floristic composition is relatively small,but only among ecological types is relatively large.Higher taxonomic units such as families and genera are more sensitive to the size of habitats than life forms.Based on the above results,a new analytical method for spatial pattern of plant diversity can be proposed.That is to say,families and genera can be included in the spatial analysis of plant diversity.However,the environment has a greater impact on the ecological types of species in the community,which can be used as an auxiliary means of analysis.3.From the view of species richness change law,With the increase of patch area,all 9 communities showed linear function curve in the process of restoration succession,and 5 of them reached very significant level(p < 0.01).Therefore,the function curve can quantitatively describe the change of species diversity in habitat fragmentation,and the indicators with stability and certain regularity can be applied in practice.In this study,species richness is more intuitive and reliable than Shannon-Wiener index in describing community characteristics.4.With the increase of patch fragmentation,patches area decreases and the proportion of species loss increases.The number and area of species in different communities were linearly fitted.It was found that for every 10% decrease in habitat area,the number of species in Leymus chinensis community decreased the most(37.49%),while the patches in community decreased about 10-20% in the initial stage of restoration succession.This shows that the higher the degree of restoration succession,the higher the species richness of the community,the greater the impact of the habitat area.From the perspective of plant diversity,the community with higher species richness should be protected first.