| Ecosystem services are the environmental and material basis for the development of national and regional socio-economic development and ecological civilization.It is a hot issue of scholars’ attention and research in recent decades.Urbanization has played a positive role in promoting China’s economic development and improving the people’s living standard.But at the same time,a tremendous pressure was conducted on the local ecological environment along with China’s rapid urbanization.The continuous expansion of the city requires the establishment of a new management model for the socio-economic-natural complex ecosystem coupling.How to realize the effective evaluation of social economy and natural resources in the complex ecosystem,and the estimation of the value of ecosystem services according to land use change will be an important guarantee for the sustainable development of China’s sustainable development under the background of new urbanizationThis study analyzed the land-use/land-cover change(LUCC)of Dongying city and the corresponding variation in ecosystem services.Dongying city was chosen as the study area for its typicality.Dongying city owns the Yellow River delta national nature reserve that has rich animal and plant resources and is also the core city of the Yellow River Delta High-efficient Eco-Economic Zone(YRDHEZ).The local government is subjected to considerable stress during urbanization because of the need to consider ecosystem protection and economic development at the same time.It is necessary to study the LUCC caused by urbanization and to quantify the damage caused to ecosystem services,which may provide useful scientific references for policy making and a sustainable development method.In this study,we investigated LUCC during 1995-2015 and generated LUCC maps for 1995,2004 and 2015.The areas of grassland,farmland,water and bare land were reduced by 21.43%,38.72%,7.36%and 22.54%,respectively,while the area of built-up land was increased by 347.34%.In addition,a simulation LUCC map for 2025 was also obtained.The result indicated that the area of built-up land will continue to increase in 2025.Landscape metrics at a class level were calculated to quantify land-use changes with the help of FRAGSTATS 4.2 software.The result showed a sharp increase in built-up land in Dongying city.The results revealed that land use of Dongying city changed dramatically according to urbanization.As other types of landscape changed into built-up land during rapid urbanization,LUCC strongly affected ecosystem services.This paper also presents a social-economic-natural approach to measure regional sustainability in the Yellow River Delta region of China based on emergy theory.In this study,Dongying,as the core city of the Yellow River Delta High-efficient Eco-Economic Zone(YRDHEZ)in China,was chosen as the study area.The reason we chose this city is because of its fast economicg growth,quick urbanization,and rich natural capital.Using GIS technology,we assessed the emergy of the study area in the year 2009 as well as 2015 with consideration of natural capitals.Compared with many previous emergy studies on the urban and regional levels,the natural capital especially the Net Primary Production(NPP)of the ecosystem were included rather than only assessing the natural capitals based on statistical data of agriculture products.The results showed that total emergy used(U)of Dongying was 1.14E+23 solar emergy joule(sej)in 2009.While the emergy value of NPP was 1.95E+22 sej accounting for 60%of Indigenous renewable production(Ri).In 2015,total emergy used(U)of Dongying was 1.83E+23 solar emergy joule(sej),while the emergy value of NPP was 1.78E+22 sej accounting for 52%of Indigenous renewable production(Ri).A series of indices based on emergy flows of Dongying were also calculated.The Emergy Sustainable Index(ESI)of Dongying was 0.79 in 2009 and down to 0.63 in 2015,indicating that the sustainability of Dongying was declining.But the values of ESI were still higher than several other cities from previous studies.The emergy money ratio(EMR)decreased from 4.53E+12 sej/$ in 2009 to 3.92E+12 sej/$ by 2015,representing a decrease of 13.47%,which means that the amount of emergy required to produce a unit of monetary value is declining,indicating that the overall development of Dongying’s social economy has improved in 2015.However,the biggest proportion among all used sources was the nonrenewable source(N)which indicated that its economic development relied heavily on the consumption of N.The results of this study may provide a reference standard for measuring regional sustainability and also provide policy makers with a reference for adjusting regional developing policies ’with systematic consideration of the social-economic-natural complex system.The urbanization of Dongying has had a great impact on ecosystem services.From the results of the ecosystem services emergy calculation,the emergy value of carbon sequestration services in 2015 decreased by 8.92%compared with that in 2009,mainly due to the reduction of the area of grassland and cultivated land,resulting in the net primary productivity of ecosystems from 1.73E+12gC in 2009 reduced to 1.57E+12gC by 2015,the emergy savings of the local ecosystem’s carbon fixation services decreased;the value of soil conservation services decreased by 19.52%in2015 compared with 2009,and the soil was eroded for the main reason that the original vegetation cover was destroyed,leading to soil erosion;nutrient retention service value in 2015 decreased by 20.61%than in 2009,soil erosion also lead to the loss N,P,K and other nutrients,and the reduction of soil conservation services affected the nutrient conservation.The emergy value of water conservation services in 2015 increased by 49.85%compared with that in 2009,mainly due to the annual precipitation was 634.1 mm in 2009 and 684.7 mm in Dongying in 2015,respectively.The annual precipitation is significantly higher in 2015 than in 2009.The total value of ecosystem services in 2015 decreased by 10.89%than in 2009.The reduction of emergy of ecosystem services reflects the large change of land use in Dongying during the urbanization process,and the damage to the local ecosystem,which affects the ecosystem services.At the same time,in order to further evaluate the value and change of ecosystem service in Dongying City,this study combined with the emergy analysis method to calculate the material quality,emergy value and economic value of indirect ecosystem services in Dongying City.Quantitative assessments of regional ecosystem services are achieved.Furthermore,the spatial analysis of the results is carried out by spatial analysis technology,and the quantitative evaluation and spatial visualization analysis of regional ecosystem services are realized,which provide scientific reference for the development and utilization and protection of ecosystem services for regional government.Prediction of ecosystem service value is conducted based on the results of ecosystem service value evaluation and forecast of land use change,the results show a further decrease of quality and emergy of ecosystem service,its economic value will be increased indicating that the ecosystem service will become more precious in the future.Based on the results of land use classification of Dongying in 2009 and 2015,this paper extracts the value of ecosystem services for different land use types in 2009 and 2015,combined with the results of ecosystem services value calculation in 2009 and 2015,the annual change in monetary value of ecosystem service is obtained.The ecosystem services values of different land use types as well as the total value of Dongying in 2025 are calculated.The results show that the total value of Dongying’s ecosystem services was 6.22E+08$ in 2009 and 6.41E+08$ in 2015,the growth rate was 3.05%.According to the forecast results,the total value of ecosystem services in Dongying will increase to 7.75E+08$ in 2025,increased by 20.90%compared with 2015.The specific value of ecosystem services showed an increasing trend compared with 2015.The results of this study indicating that the expansion of construction land in the process of urbanization caused regional landscape fragmentation and the loss of ecological land,and the ecosystem services will be greatly affected.The quantity and emergy of ecosystem services will be further reduced,while ecosystem services are becoming increasingly scarce,leading to an increase in the economic value of ecosystem services.Ecosystem service will become more and more valuable on the macroeconomic level.The results of the above studies show that under the influence of rapid urbanization,the land use change of Dongying is larger,the area of construction land is increasing,and the area of ecological land such as grassland and farmland is declining.The pressure on regional ecological environment increases,ecosystem service is significantly affected.In the process of regional socio-economic development,we should strengthen the overall planning and macro-control of land use and promote the rational development of land use.More attention should be given to the protection of local ecosystem services,formulate reasonable ecological control policies and ensure that regional ecosystem services as well as the value is not reduced.The results of this study will provide scientific reference for the development of sustainable urbanization and the construction of eco-economic zone. |
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