The Study On The Change Of Land Use/Cover And Ecosystem Health Assessment In Yellow River Delta

The Yellow River Delta(YRD) is the most typical estuary ecosystem in the warm temperate zone. It is usually productive and can provide diverse ecosystem services, however, it is vulnerable to the effects of human activities.The resource degradation、environmental deterioration and the trend of serious damage to the ecological environment has appeared. Therefore, on the basis of the comprehensive land use/cover study, effective assessment of YRD ecosystem health can provide the scientific basis for understanding the status and sustainability of the ecosystem.The main content and results of this paper include the following parts:Firstly, we extracted the land use/cover information. With the support of ENVI software, we adopted the decision tree classification mythology to interpret remote sensing images of 1995,2004 and 2013. The land use types of YRD were finally classified as six categories including cultivated land、grassland、waters、construction land、coastal wetlands and saline-alkali soil, and the results were validated with filed work.Secondly, we studied the land use/cover change characteristics. We analyzed the changes of the area number, the land use process, the degree of land use and the changes of landscape pattern during 1995-2013 on the basis of remote sensing interpretation. The result revealed that the number and structure of the YRD land use/cover type changed greatly, meanwhile, the landscape fragmentation of the YRD region was rising under the influence of human disturbance.Thirdly, we calculated the ecosystem services value. Based on the provisioning, regulation, cultural and supporting ecosystem services, food production, raw material affordance, biodiversity protection and entertainment culture were chosen as the main functions of the ecosystem service function of YRD. And by using ecosystem services equivalent factor tables, the dynamic changes of the ecosystem services value was evaluated. The results showed that the ecosystem services value had a first increasing then descending tendency in general from 1995 to 2013, and on the spatial characteristics, the ecosystem services value increased gradually from the inland to the shallow for the changes of wetlands.Finally, we assessed ecosystem health. Combining the actual conditions of the YRD, the paper selected pressure-state-response (PSR) model to construct the evaluation index system of the ecosystem health, then used principal component analysis (PCA) to evaluate ecosystem health by means of SPSS software. The results showed that the ecological health index of YRD were respectively 0.3880、0.5229、0.4330 in 1995、2004 and 2013. It means that the YRD is relatively better in 1995 and normal in 2004 and 2013.To sum up,we has performed a thorough research for the land use/cover of YRD, which can provide a reference for urban construction, and gradually realizing the coordinated development of urban development and ecological environment,and ultimately achieving the harmony of man and nature.