Studies On Forest Plant Community Structure And Biodiversity In Chongqing Simian Mountain

Based on the date from 27 plants plots in Chongqing Simian Mountains.The flora,vegetation community characteristics and species diversity of plantations community were studied in this paper. Then the biodiversity characteristics of 5 deposition model plantations were discussed.Further more,it was researched such as community structures,species composition,niche,interspecific association and spatial pattern of Cunning hamia lanceolata forest.It can be learned the local species and the vegetation types,estimated the growth status of different deposition model plantations.Then the research put forward the better deposition model plantations in Simian Mountains.The characteristics spatial structure was mastered by the study of pattern of Cunning hamia lanceolata forest,which can provide reference to forestation of three gorges reservoir area.Based on the understanding of vegetation type of Simian Mountains,the results provide scientific basis for selection of high efficiency soil and water conservation vegetations.Main conclusions were as follows:Totally,261 species of plants were recorded at Simian Mountains,and they distributed in 77 families and 153 genera.The dominant genera was the tropics distribution in the floristic elements of Simian Mountains.The second was temperate distribution type.The results showed by using the two-way indicator species analysis(TWINSPAN) and the detrended correspondence analysis(DCA) that the researchful area could be individed into 9 vegetation types.Cunninghamia lanceolata+Castanopsis fargesii+Castanopsis orthacantha forest had the highest species diversity in these nine vegetation types.The next were Cunninghamia lanceolata+Clethra fargesii forest,Liquidambar formosana forest,Castanopsis carlesii var.spinulosa forest,Cunninghamia lanceolata forest which including many evergreen broadleaves,Castanopsis orthacantha forest,Toona sinensis forest and Cunninghamia lanceolata forest,Schima superba forest had the lowest species diversity.The distribution of diameter-class of nine vegetation communities basically presented inverse-J type,this indicated these communities had better natural regeneration.The species diversity of growth form showed most communities were shrub layer>tree layer>herb layer.The results showed by species diversity analysis of five different plantations in Simian Mountains, among five plantations—Deutzia scabra Thunb +Schima superba+Lithocarpus glaber+Cinnamomum camphora mixed forest,Lithocarpus glaber+Schima superba mixed forest,Cunninghamia lanceolata +Pinus massoniana+Schima superba mixed forest,Cunninghamia lanceolata+Pinus massoniana mixed forest and Cunninghamia lanceolata,Deutzia scabra Thunb+Schima superba+Lithocarpus glaber+ Cinnamomum camphora mixed forest had the highest species diversity.During the farmland afforestation,it was suggested that choose tree-shrub mixed model with the main of evergreen broadleaved forest and conifer-broadleaved mixed forest in Simian Mountains and similar ecosystem areas.So than it can increase plantation's species diversity and realize perfect function of soil and water conservation forest.The size-class structure of Cunninghamia lanceolata forest in Dawopu were categorized into five types:Unimodal,Sporadic,Inverse-J,L and Unibar type.Cunninghamia lanceolata took on unimodal type.Other companion species,mainly L type,they had more bigger developmental potential.Studies on the relationship of species showed that overall association of Cunninghamia lanceolata forest was significant positive correlation and the community was at a stable stage.In 22 species,7 species pairs exhibited highly significant positive or negative association.The results of niche analysis showed niche breadths of dominant populations were all low,the most biggerst was Eurya loquaiana,the lowest was Sassafras tzumu.The populations with high value of niche breadths had high niche overlap.Otherwise the populations of high niche breadths with the populations of low niche breadths may have more higher niche overlap,whereas low.The point pattern analysis of Cunninghamia lanceolata forest showed mostly populations presented aggregated distribution.Among seven familiar trees,six presented aggregated,and most trees with aggregated turned into random with the increasing along with the dimensions.The interspecific relationships of mostly populations represented negative correlation in 25 meter.It was primarily because of under this dimensions,the growth of the crown of tree layer usually avoided overlaying each other,therefore caused the negative connection.Other weak shade tolerance populations,they were in the place between sub-tree layer and shrub layer,they existed hard.Under this dimensions,the biggest negative connection usually appeared in the tree layer,sub-tree layer and shrub layer.So the result that the main populations in Cunninghamia lanceolata forest presented negative connection may be also for this reason.