Studies On The Plant Biodiversity In Danjiangkou Reservoir Area

The paper studied aims at studying the community diversity in Danjiangkou reservoir district and its ecological restoration.Studied the present situation of its plant diversity through investigating the major resource of plant species and plant community in this district,Studied the relationship between environmental factors and diversity through examining the environmental factors such as soil.Based on these two researches,The paper suggested a restoration model and some protection measures of forest vegetation suitable for the local site conditions.It could provide for the Danjiangkou reservoir district with certain reliable reference regarding ecological restoration.The major research results are as follows:1.There are 581 species of vascular plants belonging to 116 families and 339 genera. Pteridophyte takes up a total of 9 families,13 genera and 21 species.Gymnosperm 7 families,14 genera and 20 species.Angiosperm 100 families,312 genera and 540 species.2.With reference to the field investigation and Chinese Vegetation,the paper manage to classify the community.There are 3 vegetation type groups,6 vegetation types,8 formations and 18 associations.The 6 vegetation types are:temperate coniferous forest、deciduous broad-leaved forest、warm coniferous forest、shrubs、Shrub-grassland.temperate coniferous forest takes up the biggest proportion,followed by deciduous broad-leaved forest and shrubs.Platycladus orientalis forest takes up the largest proportion among the association.3.The results from community diversity analysis reveal that: Regarding diversity,it’s herb layer＞shrub layer＞tree layer;regarding evenness,it’s shrub layer＞herb layer＞tree layer;regarding integral diversity,it’s evergreen broad-leaved forest＞mixed forest of coniferous and broad-leaved forest＞coniferous forest＞shrub-grassland;regardingβdiversity,the mixed forest of Quercus Variabilis and Platycarya strobilacea has the highestβdiversity compared with other forest communities,while Oriental arborvitae forest and other forest communities have the lowestβdiversity.4.The correlation degree r of diversity and environmental factors is:soil pH rate＞Community Density＞slope＞altitude＞soil thickness;the correlation degree of evenness and environmental factors is:soil pH rate＞slope＞Community Density＞soil thickness＞altitude;the correlation degree of diversity and soil nutrient is:total n＞available p＞available k＞organic matter.The paper get to the conclusion that soil pH rate and the total n are dominant factors of environmental factors,soil nutrients and correlation diversity.5.Based on the field investigation toward sample field’s environmental factors,this paper choose the dominant factors and confirm the major site type of that district.Taking soil pH rate as the dominant factor,classifisd the site into 5 types,and further classify it into more than ten minor types,and then sort out the native species suitable for different site types in accordance with 19 communities.6.Based on the site type classification,the paper design 20 models for plant communities in different site types.Also,study some afforestation technology.Suggested unified planning with respect to community types,and maked research into the demonstration area in the district,absorb the best practices,find out the problems that need to be worked on and put the lessons in practice to build a new demonstration area.