Study On Community And Diversity Of Nature Regeneration Community After Clear Cutting Of Phyllostachys Edulis Forest In Tianmu Mountain

The invasion of phyllostachys pubescens occurs from time to time in nature reserves in China,phyllostachys edulis is expanding rapidly in Tianmu Mountain nature reserve.The loss of biodiversity in the reserve has become an important issue,This paper is based on the survey data of 70 5m×5m quadrat of woody and herbaceous layers in the natural regeneration community after clear cutting and under unclear cutting,Natural renewal communities were analyzed in terms of species composition,community structure,community classification and alpha diversity,The results show that:(1)A total of 314 species of plant species were found in this survey through statistical analysis of the families and species of recorded plants,it belongs to 93 families,222 genera,there are many kinds of plants after natural renewal,the number of rose species is 24,the family contains the most species.(2)The analysis of the life type and growth type of the woody plants in the natural renewal community showed that the highest important value of deciduous trees was 51.1,the second is deciduous shrub 23.08,evergreen shrub 17.3,the lowest value of evergreen trees was 8.52.Zanthoxylum molle is the only tree species with more than 10 important values in the woody layer of the community.At present,deciduous species occupy the dominant position in the regeneration community,combined with the average annual growth and density analysis of major tree species,it is expected that deciduous broad-leaved forests will be formed first in cleared areas in a few years,however,it needs a longer succession time to restore the zonal evergreen broad-leaved forest.(3)It was found that the Gleason richness index at each level of the natural renewal community was the most significant,shannon diversity index and Simpson diversity index increased significantly,this is related to the adverse effect of phyllostachys edulis on the surrounding plant diversity and the abundance of various resources(such as light)after clearing,it indicates that all species grow rapidly after clear cutting of phyllostachys edulis forest,biodiversity recovery is better.(4)The 55 samples were divided into 11 community types by TWINSPAN analysis,the same quadrangle appears but the classification is not in the same community type,it may be due to the different microtopographic units in the sample plot,and the presence of tall uncleared trees,the formation of heterogeneous habitats leads to the differentiation of vegetation.(5)According to the classification results,there are significant differences in alpha diversity between different types,which may.be related to different resource gradients(such as elevation)between sample lands.RDA analysis of alpha diversity and environmental factors at all levels of the community sample was conducted,and it was found that among the three topographic factors,elevation,slope direction and slope,elevation was the main factor determining the alpha diversity differentiation of vegetation.The alpha diversity of the community decreased with elevation.