Research On The Emergy Value Of Ecosystem Services In Two Counties Of Zhoushan Islands

The assessment of ecosystem services is the basis for sustainable decision-making and natural protection.A careful analysis of the interaction between ecosystems and human activities can prevent ecosystems from being over-exploited,affecting current economic interests and the needs and well-being of future generations.Dinghai and Putuo District,which are representative areas of the Zhoushan Islands,are selected as the research area to explore the impact of human activities in this area on the island resources and environment.This research mainly includes two parts:based on emergy theory and ecosystem services,using Landsat series satellite image data of 2005-2019,and combining meteorological data and statistical data,to evaluate the impact of land use changes on the ecosystem service value of the study area,accounting of the regional ecosystem service value;based on the energy footprint model,the parameters of emergy ecological deficit/surplus,footprint diversity index（H）,social development pressure index（I）and economic coordination index（Q）were constructed,and the ecosystem sustainability of the region from 2005 to 2019 was evaluated.Starting from the island ecosystem service and its ecological value,construct an island ecosystem service value evaluation model.Considering the environmental support provided by nature directly and indirectly for resource generation,using emergy analysis to comprehensively analyze the ecological system and socio-economic system of the two counties in Zhoushan Islands,selecting four types of carbon sequestration,purification of air pollutants,reduction of soil erosion and climate regulation.This service integrates the geographic information system and emergy accounting to generate a spatial pattern map of the emergy value of ecosystem services.In view of the impact of human activities on the ecosystem,the sustainability evaluation index of the ecosystem is constructed from the natural,social and economic perspectives,and the time change law of the sustainability of the ecosystem is obtained by coupling the emergy footprint model and the sustainability evaluation index.Finally,on this basis,provide corresponding countermeasures and decision-making basis on how to promote the harmonious development of regional ecology and economy and improve the sustainable development of regional ecosystems.conclusion as below:（1）Urbanization is constantly changing the land use patterns in the region,and has a huge impact on the stability of the regional ecosystem.According to ENVI,the four phases of remote sensing image data from 2005 to 2019 were supervised and classified to obtain the results of land use/land cover changes.From 2005 to 2019,the continuous expansion of the scale of cities and towns led to a substantial increase in the area of construction land.In2005,the construction area was only 134 km².By 2019,it will increase to 314 km²,an increase of 133.5%;the area of water and arable land has shown a downward trend,the water area has decreased by 81.13%,and the area of arable land has decreased by 45.17%.From the perspective of land use,forest land,cultivated land,and grassland have the largest value of ecosystem services and the smallest construction land.The process of urbanization in this area has encroached on large areas of arable land and grassland,which will inevitably lead to a decline in ecosystem services.（2）The energy value of ecosystem services is generally on a downward trend.Affected by factors such as population,climate,and land use patterns,the emergy value of ecosystem services dropped from 1.83×10²⁴ sej in 2005 to 6.41×10²³ sej in 2019,a decrease of 64.96%.The four services all showed a decreasing trend.Among them,the air pollutant purification service decreased the most,with a decrease of 65.03%,followed by the carbon sequestration service,with a decrease of 64.77%;the third was the reduction of soil erosion service,with a decrease of 28.15%;Regulating climate services has the smallest decline at0.07%.（3）The emergy value of ecosystem services is generally on the rise.The emergy value of ecosystem services in 2019 is 1.92 times that of 2005.Compared with 2005,the value of various specific services has shown an increasing trend.Among them,climate regulation services have increased the most,increasing to 5.48 times;followed by services for reducing soil erosion,which has increased to 3.94 times;and thirdly,services for carbon sequestration have increased.To 1.93 times,and finally to clean up air pollution services,which increased to 1.92 times.On the one hand,this result shows that the economic strength of the region has increased and the emergy currency ratio has been reduced year by year,leading to an increase in the emergy value of ecosystem services.On the other hand,it shows that urbanization in this region has destroyed the integrity of the landscape,resulting in shrinkage of ecological land and impacts on the ecosystem.It has a huge impact,and the value of ecosystem services is further reduced,and ecosystem services become weaker,which further leads to more scarce ecosystem services and their value becomes higher and higher.（4）From 2005 to 2019,the emergy carrying capacity and emergy footprint of the two counties and districts of Zhoushan Islands showed an overall upward trend.Compared with2005,the per capita emergy ecological footprint has increased by 50.26 hm²,an increase of1.56 times;the per capita emergy carrying capacity has increased by 94.11 hm²,an increase of 1.95 times.Among them,the energy footprint generated by energy consumption has increased the most,and the socio-economic carrying capacity has increased the most,while the per capita natural carrying capacity has been maintained at about 0.02 hm².（5）During 2009-2011,the study area had an ecological deficit,and the rest of the year was in an ecological surplus.The ecological deficit in 2010 and 2011 increased faster than the previous year.Based on the ecological deficit in 2009,it increased by 128.01%in 2010and 388.36%in 2011.This is due to the rapid expansion of the scale of cities,the gradual increase in population,the occupation of cultivated land,grassland,and water areas for construction land,the rapid increase in the energy footprint of energy consumption,and the increasing pressure on the regional ecological environment.（6）The development status of the two counties in Zhoushan Islands is unsustainable.The regional footprint diversity index decreased from 1.01 to 0.39,indicating that the current land use method does not meet the requirements of sustainable development;the social development pressure index increased from 0.91 to 1.09 and then decreased to 0.73.Human activities are constantly changing the stability of the ecosystem;The low economic coordination index also further indicates that the regional development status is in an unsustainable state.