Aquatic Ecosystems Represented By AQUATOX Model And Watershed Eco-function Regionalization Of Dongting Lake

Dongting Lake is loacated on the south of middle reaches of Yangtze River, which fulfill many important ecological service functions, such as: water retention, flood control and storage, biodiversity protection and human economic utilization on developing agriculture, which acts as an important role on watershed ecological conservation and water equilibrium. Ecosystem-based Dongting Lake watershed management is namely to strengthen sustainable development capability, and thus it is important to analyze the relation between Dongting Lake and its branches, divide the watershed of Dongting Lake into defferent area base on ecosystem function of each area. According the type of ecosystem and ecological niche of different regions, and brought forth proper measures for each region.This research took Muping Lake– the main part of West Dongting Lake as an example, simulated its aquatic ecosystem, by the analytical tools of AQUATOX model, which combines hydrodynamic model, water quality model, and ecological model, with more complete ecosystem representation and more realistic simulation competence, studied the eutrophic and aquatic ecological process, explicited the relation among the compartment of the Muping Lake ecosystem and each driving factor.The eco-function regions of Dongting Lake Area includes 4 regions: water body ecological landscape function are, lake wetland conservation area, wetland restoration area, and peripheral Area for economic development. From the view of supervising Dongting Lake based on the whole watershed area,the eco-function regions of outside peripheral Dongting Lake Area were divided. Take Changsha city for example, according to the heterogeneity among ecological function units and the similarity of interior units, divided Changsha city into 5 ecological function regions on the platform of ARCMAP/INFO software, with utilizing Landsat TM/ETM remote sensing image interpreted, 1:250000 digital elevation model, social and economic development data, population of Changsha city. For the sake of conservation and rational using the resource of Dongting Lake, this paper described the character of each region.