Ecosystem Health Assessment And Optimization Path Of The Yellow River Basin In Shandong Province Based On Emergy Analysis

The Yellow River Basin(YRB)is an important ecological shelter zone and economic belt in China.Given the background of national strategy for ecological protection and high-quality development of the YRB and the goal of carbon peak and carbon neutrality,how to realize the sustainable development of the YRB has become an urgent issue.Shandong is the only coastal province in the YRB.Its total economic output and population accounts for 32.1%and 23.9%of the YRB respectively,which plays a key role in the national strategy of ecological protection and high-quality development of the YRB.The Yellow River flows through Heze,Jining,Tai’an,Liaocheng,Jinan,Dezhou,Binzhou,Zibo and Dongying in Shandong Province.It’s of key significance for this region to make the utmost of mutual advantages and construct a new development pattern full of collaborative linkage and complementary advantages among the cities.As a complex system composed of natural,economic and social elements,regional ecosystem is a network with multiple interactions.This paper takes the nine cities of the YRB in Shandong Province as the research object.The dynamic trend of regional ecosystem health level is evaluated and the optimization path is designed in accordance with the research approach of "retrospective evaluation-health diagnosis-path optimization" and local conditions.In the part of retrospective evaluation,the ecological service emergy needed to dilute pollutants and the emergy equivalent loss on ecosystem quality and human health damage caused by pollutants and CO2 emissions are taken into consideration in emergy flow accounting,and the emergy evaluation indicator system is constructed.With respect to health diagnosis,the regional ecosystem health evaluation indicator system based on "driving force-pressure-state-impact-response"(DPSIR)model is constructed.The indicators are weighted by triangular fuzzy analytic hierarchy process,entropy weight method and combined weight method based on game theory.Technique for Order Preference by Similarity to an Ideal Solution(TOPSIS)model is used to diagnose the health level of ecosystem.In the part of path optimization,the synergy degree model and the obstacle degree model are introduced to analyze the factors limiting the health level of ecosystem from the perspective of region and city,and targeted optimization paths are put forward for the nine cities.The retrospective evaluation results reveal that the sustainable development indicators(ESI)of Tai’an,Heze,Dezhou and Liaocheng range from 1 to 10,which have the great potential for sustainable development.The ESI values of Jinan,Jining,Zibo,Dongying and Binzhou are less than 1,which indicate that these cities are under high ecological pressure.The value of emergy indicators for sustainable development(EISD)of all cities show a downward trend and the sustainable development level of the region is weakened,but it represents the downward trend is slowing down in recent years.Through health diagnosis,it is found that the health levels of nine city have been continuously improved from 2010 to 2019.The health comprehensive index of Dongying is the highest but that of Heze is the lowest,and a high-value area centered on Jinan has gradually formed.In addition,Dezhou and Liaocheng make the most significant progress and the comprehensive health indexes of them increase by 0.193 and 0.145 respectively.Tai’an and Binzhou have no obvious variation compared with 2010.The path optimization results reveal that the health synergy degrees of the nine cities range from-0.009 to 0.080,which indicate that the health regional synergy of this region is still at a low level.Moreover,the key obstacle factors have changed greatly from 2010 to 2019.In details,the factors changed from the indicators focusing on the driving force layer in 2010 to the indicators focusing on the state layer and response layer in 2019.From the macro perspective,it has shifted from the social economic development to the structure of energy and resources and the quality of ecological environment.Finally,this paper designs the optimization path of ecosystem health from the perspective of regional synergy,energy and resources,and ecological environment based on the research results and actual condition of different cities.