Investigation And Analysis Of Species Composition And Community Character Of Riparian Forest In Central Districts Of Chongqing

Riparian forest is an important portion of riparian ecological corridors, taking on the important function of protecting river ecosystem and maintaining entironment and social environment in the urban riparian zone. The riparian zone of city areas of Chongqing is as long as several kilometers, but the riparian forest is destroyed by the effect of human disturbance such as urban construct, industrial and agricultural producing, and human living. As this result, the exchange of matter and energy between hydrophytic ecosystem and the terraneous ecosystem is not balance as nature, and even more the health of ecosystem and the terraneous ecosystem and the entironment of the urban riparian zone is deteriorated. With the aim of understanding more clearly the species compose and its character, diversity pattern, vegetation distributing pattern, landscape pattern, and the primary environment factor influencing them. This article investigated and researched the riparian forest in this area by using theoretics and methods of vegetation ecology, quantitative ecology and landscape ecology, and in finally bringed forward some strategies and suggestions to sustain the ecological resume in this areas.The results of investigation and research indicated: 1. There are 32 families 75 species woody plants in the researched area, incloud 17 families 31 species trees, 27 families 34 species trees, and 8 families 10 species trees woody vines. According to the layer-structure of community, there are 18 families 32 species in the tree-layer, 29 families 56 species in the shrub-layer, 6 families 6 species woody plant in the ground cover layer, and 9 families 9 species in the vines-layer; 2. The riparian forest in investigating area is separated into 17 community types by TWINSPAN, 13 of them is destroyed by human activity. The result of DCCA opens out: The vegetation distribution is mostly affected by human disturbance, elevation and river width, viz. along with disturbance intensity and river width increasing, and the elevation decreasing, the riparian forest is more and more unnatural and its species is more and more suitable for a deteriorated environment. 3. By the TWINSPAN, the main species in the tree-layer can be divided in 9 groups, and the species in the shrub-layer can be divided in to 12 groups. The DCCA result of the 2 layers opens out: the species in the shrub-layer mostly affected by human disturbance, but in the shrub-layer, this effect is more complex, and the elevation and river width are more important than other environment factors. 4. Such environment as human disturbance and elevation effect the pattern of riparian forest, viz. along with disturbance intensity increasing and the elevation decreasing, the species diversity decrease; thereinto, species diversity in the tree-layer is influenced by human disturbance, and in the shrub-layer, this effect is mostly by elevation. 5. Riparian forest can improve the environmental microclimate by playing down the temperature and illumination, increasing the humidity. This effect of riparian forest is correlated with the type of the vegetation, and it increase with the width of the riparian forest. As the width arrive to 50m, the illumination and temperature are played down 95% and 8%, and the humidity is increased by 8% in the bamboo forest; in the hardwood forest and the mixing forest of bamboo and hardwood, this value are 60%, 5.5%, 7% and 80%, 7%, 8%. 6. The landscape structure analysis is indicated: compared with riparian forest in suburb which is more natural, the riparian forest in urban is more fragmental, less connected, and its area and width is far lower.This article provided some suggestion for strategy of riparian forest ecological recovery: 1. The expanding area of urban to suburb is the key area of riparian forest ecology resume. 2. To rebuilt the plant community in this area should mainly choose the exist plant species, and in urban area, expanding area and suburb area, choosing plant species should be the species which adaptability is more better in this area. 3. Recover the environment of riparian species is important, especially in urban area and expanding area. 4. Some fostering needs in the initial stage of rebuilding, and an appropriate width of forest also needs. So the stability and eco-function can reform more soon. 5. Finally, we must think over the sight impression and the safety in this area.