Study On The Tupu Characteristics And Ecosystem Service Value Variations With Land Use Change In The Taihu Lake Area Of Jiangsu Province

As an important factor of global environmental change,land use change plays a fundamental role in maintaining the ecosystem services,because it alters the structure and function of the ecosystem.In recent years,a series of ecological and environmental problems,including soil erosion,lake shrinkage,and the decline of biodiversity,have become prominent constraints for China’s high-quality economic development and people’s wish for a better life.The Taihu Lake area of Jiangsu,as a representative urban agglomeration in the Yangtze River Delta,has a highly developed economy,but disharmonious man-land relationship.Also,it’s an ecological sensitive area.It is significant to study ecosystem service value variations with land use change to improve the ecological environment,ease the resource constraints and improve the ecological compensation mechanism for the study area.Based on the raster data of land use types for years 1990,2000,2010 and 2018 in the Taihu Lake area of Jiangsu,this thesis uses geo-information Tupu to study the land use change visually and vividly.On this basis,according to the method of ecosystem service value proposed by Costanza and equivalent value per unit area modified by Xie Gaodi,etc.,this thesis constructs the ecosystem service value evaluation model to assess the ecosystem service value in the Taihu Lake area of Jiangsu.In addition,this thesis uses the sensitivity index to check the value coefficients.Finally,this thesis uses the spatial statistics method to analyze the changes of ecosystem service value from spatial perspective at county and municipal level cities and 5km×5km grid unit.The main contents are as follows:(1)During the study period,the spatial distribution of the land use change Tupu in the Taihu Lake area of Jiangsu evolved from dispersion to agglomeration.The structure of land use change changed from simple to complex,and eventually stabilized.However,land use in some local area’s is unstable,especially around the junction of traffic arteries,along the lake and the river,and at county junction.Research suggests that land use of the study area has undergone dramatic changes.From 1990 to 2010,the land use Tupu transformed mainly "from agricultural land to construction land" and"form agricultural land to waters".In addition,Tupu which was "from agricultural land to construction land" gradually showed the characteristics of "expanding along the Shanghai-Nanjing Expressway and spreading outward".The land use change Tupu from 2010 to 2018,transformed mainly "from agricultural land to construction land"and "form waters to agricultural land”.Also,the development intensity of construction was still relatively high in Suzhou Industrial Park and Kunshan City.(2)For years 1990,2000,2010 and 2018,ecosystem service value in the Taihu Lake area of Jiangsu first rose and then fell(The turning point appeared in 2010),with a total net increase of 1411.63 million.The increasing value of dry land,grassland and water bodies was beyond the decreasing value of other land types.However,research suggests that if the land use is not intervened in time,the value of ecosystem services will fall to80565.98 million by 2025;In 2018,water bodies,woodland and dry land had a higher contribution to the value of ecosystem services in the Taihu Lake aera of Jiangsu,and unused land had a minimum contribution;The ecosystem service value generated by a single ecosystem service function varied.The hydrological regulation,environmental purification and climate regulation had a greater contribution to the ecosystem service value;The expansion of construction land and the rapid development of social economy had a great negative impact on ecosystem service value.(3)During the study period,the ecosystem service value in Suzhou were higher than that of Wuxi and Changzhou.Although the total ecosystem service value increased,the overall level decreased.Wuzhong District had the highest rating,while Zhonglou District,Tianning District,Xinwu District,and Gusu District had low ratings;Generally,grid unit ecosystem service value levels were low,but Taihu,the Yangtze River,Yangcheng Lake,Gehu and Changdang Lake basins were well protected;The ecosystem service value of the study area had a positive spatial agglomeration effect.And hot spots with value-added areas of ecosystem service value were mainly in Liyang City,Wujiang District,and Wuzhong District;The Cold spots with loss value area of ecosystem service value were mainly in Wujin District,Suzhou Industrial Park,etc.While Wujiang District,Wuzhong District,and Taicang City included both hot spot value-added areas and cold spot loss areas,their land use changes were quite drastic.Last but not least,based on the results of the research,this thesis gives some suggestions on the land use,ecological environment improvement and green sustainable development for the Taihu Lake area of Jiangsu.