Ecological service is the environmental condition and effectiveness for the development of ecology system and the maintenance of human survival and development. The loss and degeneration of ecological service will greatly impact human happiness and directly threaten the regional or global sustainable development and ecology safety. Taihu Lake catchment is located at the core of Yangtze River delta, with the highest density of population, most developed economy, greatest land intensity and fastest changes of land use in China. Besides, the contradiction between human and land and the problems of the environment and ecology there are most outstanding. In recent 30 years, the fast and large-scaled urbanization in the catchment of Taihu Lake has greatly disturbed the land ecological system of the catchment, which affecting the ecology safety of the ecological system and regions. The main changes of adjustment and supplying service include that the increasing output of nitrogen and phosphorous nutrient strengthen the eutrophication of lakes; the weakening of water quantity adjustment function worsens flood; the changes of carbon budget process and carbon fluxes affects the climate; the reduction and decreasing quality of farmland threatens the food safety. How the catchment land use changes and how they affect the degeneration of ecological service have been the carbon hot sport generally being noticed and the urgent need to optimize the use of land and protect the ecology.

Based on the support of the key project of National Natural Science Foundation of China, “Mechanism and Evaluation of the Effect of Taihu Lake Catchment Land Use Changes on Ecological Service”, the deputy researcher Xu Xibao and other member of our institute selected four key ecological services from the land ecological system of Taihu Lake (water quality adjustment, water quantity adjustment, carbon fixation, food production) and established a comprehensive risk evaluation mold (figure 1) for the degeneration of the ecological service of Taihu Lake on the basis of PETAR evaluation framework and by combining the four ecological process molds, DNDC,SWAP, Biome-BGC and AEC with the prediction moldl of land use changes GWML-CA. For typical land ecological system categories, they obtained constant field observation data by carrying out the field experiment of runoff plot, taking water samples, observing relevant carbon/water fluxes of vorticity, and controlling farmlands. Besides, they improve and calibrate the DNDC, SWAP, Biome-BGC and AEZ mold on point-to-point scale. Based on the land use data of remote sensing between 1985 and 2010 and the prediction of land use situations in 2020 (figure 2), they respectively simulated and evaluated the ecological degeneration risk of Taihu Lake catchment from 1985 to 2010 and from 2010 to 2020 and identified the high-risk area of ecological service degeneration in Taihu Lake catchment (figure 3).The research shows that from 1985 to 2010, about two third of Taihu Lake catchment ecological service had the trend to degenerate, among which 10.7% faced severe degeneration trend and mainly spread in rapidly developing urban including Shanghai, Suzhou, Wuxi, Jiangyin, Zhangjiagang and Kunshan. In 2020, the area with ecological service degeneration risk is predicted to increase by 12%. Besides of some economically developed big and medium cities, some small cities (Yixing, Tongxiang, Danyang, Jintan and Changshuo) also will face rather high degeneration risks of ecological service. In addition, through analyzing the spatial structure of ecological service in two periods and the spatial dependence of the four degeneration risks of the ecological service, it is found that the two ecological services, water quantity adjustment and carbon fixation, have a coordinating relationship in space while the water quality adjustment and food production have a trade-off relationship.

Additionally, the research also points out that it is needed to strengthen the research on the degeneration risk evaluation of the ecological service of the urban ecological system and water ecological system, the risk indicators system and balance of ecological service and the prediction of multiple situations of land use, which will provide more comprehensive decisions and supports for the land use of Taihu Lake catchment and the optimizing adjustment of the ecological service. The research is supported by key programs and of National Natural Science Foundation of China, general programs of National Natural Science Foundation of China, and the front programs in 135 fields. The research result is published in the mainstream journal of the environmental science “Science of the Total Environment (4.099)".

　　Xibao Xu*, Guishan Yang, Yan Tan, Qianlai Zhuang, Hengpeng Li, Rongrong Wan, Weizhong Su, Jian Zhang. Ecological Risk Assessment of Ecosystem Services in the Taihu Lake Basin of China from 1985 to 2020. Science of the Total Environment, 2016, 554-555:7-16.

Xibao Xu*, Guishan Yang, Yan Tan, Qianlai Zhuang, Hengpeng Li, Rongrong Wan, Weizhong Su, Jian Zhang. Ecological Risk Assessment of Ecosystem Services in the Taihu Lake Basin of China from 1985 to 2020. Science of the Total Environment, 2016, 554-555:7-16.

    Link: http://www.sciencedirect.com/science/article/pii/S0048969716303308