The Research On Restoration And Reconstruction Of Aquatic-terrestrial Ecological System

The aquatic-terrestrial ecotone is a kind of quite important inter-lands between the aquatic ecosystem and land terrestrial ecosystem. At present, the main research areas are always focused on soil ecosystem, wetland ecosystem, ocean ecosystem and aquatic ecosystem, while the studies on the aquatic-terrestrial ecosystem are very limited. Therefore in this paper, the definition, technology and application of restoration and reconstruction for aquatic-terrestrial ecotone are discussed at first. And then, taking Dongting Lake watershed for example, the results of implementation of the restoration and reconstruction engineering are simulated. It is hoped that such a work can awoke the attention of experts and academicians on the aquatic-terrestrial ecotone, and drive up the researches in this field as well.The whole paper consists of six parts, and the detailed contents of the parts are asfollows.Firstly, the paper gives the definition of aquatic-terrestrial ecotone, presents the basal connotation of restoration and reconstruction for aquatic-terrestrial ecotone, and addresses the goals, principles and some important theories, such as restoration legitimacy, ecology conservation theory, ecosystem health theory etc. Afterwards, it emphatically introduces the newest technologies utilized in the restoration and reconstruction of aquatic-terrestrial ecotone, and their effects on Dongting Lake watershed region.Secondly, the current ecological and environmental situations are performed upon some related investigations and reports, and the WNN (Wavelet Neural Network) is incorporated into the assessment procedure of sampling sites located in Dongting Lake watershed. Moreover, the effects of the running of three gorges project on the ecosystem and the water environmental capacity of regions are analyzed.Thirdly, based on the monitoring data from research reports on Dongting Lake, the water quality is analyzed considering the indices such as TN, TP, COD, Chla and so on. Also, WNN is used for assessment of the nutrition status of Dongting Lake.Fourthly, the east, south, and west parts of Dongting Lake watershed are studied, respectively, according to their special backgrounds. Upon the studying, industrial pollution, agricultural pollution, and anti-schistosomiasis pollution are regarded as the main polluted sources. Besides pollution index, natural disaster index and ecological index are simultaneously considered. Pollution index comprises nitrogenpollution index, phosphorus pollution index and heavy metal pollution index, while ecological index, in ecosystem itself, includes biological index, biodiversity index, species importance index, and ecological fragility index. All of these indices are integrated for regional ecological risk assessment of Dongting Lake watershed.Fifthly, as a typical technology, the dredging engineering is chosen for restoration and reconstruction of Dongting Lake watershed and its surrounding regions, and the watershed environmental quality before and after the dredging engineering is simultaneously simulated. Meanwhile, the benefits of the water environmental remediation, ecosystem restoration and anti-flood function are represented.Finally, on the ecological basis, the ecological planning for Dongting Lake and its surrounding regions is completed.