A Preliminary Rehabilitation Study Upon A Riparian Ecosystem Damaged By Concrete Construction

This study took spillway flowing by Jingyue campus of Northeast Normal University asan object to construct patchy environment favorable to the survive of biology on the concretebank, to rehabilitate the terrestrial ecosystems and aquatic ecosystem, which were separatedby the concrete protecting bank. Simultaneously, the study examined whether the constructedpatchy environment provided living space for biology, whether the constructed ecosystemdeveloped in succession, and what's the effect of the ecological rehabilitation. The purpose ofthe study is to explore the technique and theoretical foundation of rehabilitation of thedamaged concrete bank, which is approaching nature, low cost, high benefit, and suitable tocurrent conditions in China.(1) Density of frog and dragonfly: Plot A (constructed patchy environment)>PlotB(nature exposed bank)>Plot C(concrete bank). The relationship between species of SoilMacrofauna, Benthos, density, diversity index: Plot A>Plot B>Plot C. The change oftemperature in experimental plot: Plot A﹤Plot B﹤Plot C. The results show that theconstructed riparian patchy environment could provide suitable habitats for multiplying andinhabitation of frogs, dragonflies, Soil Macrofauna, and Benthos etc.(2) The results of the experiment about the arrangements of root system of plants in thepatchy environments: the anti-draught force of the root system increases with the expandingof the average diameter,and they took on the close relation of power function andpolynomials, and preferable correlation. The integrated function of the root system of plantsand the fibre bags strengthened the anti-flood intensity of the patchy environments.(3) Anti flood eroding. The eroding of the constructed patchy environment is less seriousthan that of the natural exposed bank, and there is no eroding in the concrete riparian. Theresult is: Plot A< Plot B< Plot C (the rate of eroding is zero).(4) In recent two years, the observation of the indexes in the constructed patchyenvironment showed that the growth of the arranged plants is preferable and in accord with acertain function relationship and with a high correlation. All these indicate that theenvironment of the soil in the constructed ecosystem is good.(5) Economical benefit. The cost of the bank-protecting project which adopts thestructure of "frame + plant fibre bags +plants" is RMB 55 per square meter, while the costof the bank of concrete and stone, which is very common in China, is more than RMB 120 persquare meter. The former can bring not only the less cost but also the additional ecologicaland view value.