The Spatial-temporal Evolution Of Ecosystem Service Function And Its Driving Mechanism Based On Land Use Change In Anxi County

The rapid development of urbanization has exerted a profound impact on the natural,cultural and economic ecosystems in the regions,including coastal cities.How to achieve the coordinated development of economic,social and ecological benefits in the process of rapid urbanization has become a core issue in the study of land use/cover change in China,especially in the new era today.This study intended to take Anxi county of Quanzhou city,Fujian province as the research object.The land use change map was constructed by using geoscience information map and other methods,with the help of Landsat TM/OLI remote sensing image to obtain the land use data of the three time courses of 2010,1999 and 2019 under consideration and analyze the spatial-temporal change characteristics of land use in Anxi County and its 24 townships.At the same time,the key driving factors of land use type change are analyzed by using quantitative and qualitative methods such as canonical correspondence analysis,then by using the previous method of ecosystem value assessment,the equivalent factor was modified and the willingness to pay and the ability to pay were incorporated into the evaluation system,and the evaluation model conforming to Anxi county was reconstructed to calculate the value of ecosystem services（ESV）,then the impact of the spatial-temporal change pattern of land use on the value of ecosystem services and the coordination of economic development as well as its rules of action were analyzed At the same time,multiple regression,principal component analysis and path analysis were used to analyze the key factors and path relationship that affect the change of ecosystem service value to clarify the influence of land use change in Anxi County and its 24 subordinate towns on the formation of ecosystem service value and the internal law of mutual use.Then according to the analysis results including the socio-economic status of different townships and many other factors of the declined rate of ecosystem service values,etc.,Analysis hierarchy process（AHP）method was used to estimate the importance of the dual objectives of ecological compensation in all townships,and the priority weight of compensation time sequence and the key compensated townships were determined.Accordingly,the differentiated ecological compensation standards and its operation strategy by different compensating times were suggested and recommended to implement.The conclusions were made as follows:In the past 20 years,the land use types and spatial-temporal distribution of Anxi County have changed significantly,with the overall characteristics of three increases and four decreases,which was driven by the county’s social-economic index,geographical ecology and macro policy。However,the land use strategy and spatio-temporal evolution are also different in different townships due to the different natural endowment,geographical condition,economic levels.The results of this study showed that the land use types in Anxi County have changed significantly in the past 20 years.From 1999 to 2019,the cultivated land,grassland and water areas of the county have decreased by 36.82%,22.91%and 8.18%,respectively,while the construction land and unused land,woodland and garden areas（mainly tea garden）have increased by 10.37%,56.39%,206.08%and 90.14%,respectively.Further analysis shows that although the woodland as a whole has been improved,in the past decades（2009-2019）,1/3 of the 24townships in Anxi County showed a downward trend in woodland.Of which Chengxiang township mainly used the reduced wood land for urban construction,the other five townships such as Xianghua,Daping,Huqiu,Duping,and Futian mainly used reduced woodlands for tea development.This study found that land use change in Anxi County formed a significantly different spatial distribution pattern.In the northwest of Anxi County,the cultivated land showed a low-low agglomeration（LL）state,but in the east and northeast of Anxi County,the cultivated land showed a high-high agglomeration（HH）state,and the number of agglomeration grid decreased obviously with time.Grassland is high-high（HH）agglomeration in several townships in the north-central and south-western part of the county;The garden plots in the central and northern part of the county showed a high-high agglomeration（HH）state;The waters are mainly agglomerated in several townships on the northeast line of the county in high-high agglomeration and Construction land is mainly concentrated in the southeastern townships with high urbanization,showing a high-high agglomeration（HH）state.The change trend and distribution pattern are driven by social economic and and macroscopic policy and also result from geography ecological condition in county scale.As far as the driving force of land use change is concerned,the studies showed that among the 7 types of first-level land use,the proportion of water area and unused land type is relatively small,while the remaining 5types of land use change were mainly governed by the driving factors of social and economic indicators and macro policies in addition to geographical factors.Canonical correspondence analysis（CCA）showed that The total retail sales of consumer goods,GDP and the total output of tea were the key driving factors of land use change in Anxi County.At the township level,CCA analysis results also found that the spatial pattern difference of land use was significantly positively correlated with per capita GDP,gross output of agriculture,forestry,animal husbandry and fishery,agricultural output,and tea output in the first and second ordination axes.However,land use changes in different townships were driven by different factors.CCA analysis gave a clear evolution pattern of different township types based on the key driving factors of land use change.The overall characteristics of the 6 townships such as Changkeng,Daping,Gande,Bailai and Huqiu showed decrease of grassland in the past 10years.Among them,Changkeng,Gangde,Bailai,Jangdou and Hushang townships grassland decreased accompanying with the increase of woodland,Daping and Huqiu townships showed increases of grassland but decreaseof woodland.The change of land use type was driven by the gross output value of agriculture,forestry,animal husbandry and fishery（d）,agricultural output value（e）and tea production（j）.The four townships such as Shen chengxiang Fengcheng Shangqing,were characterized by the increase of construction land,the decrease or increase of woodland（such as Shangqing Township）,which was driven by animal husbandry output（f）,fishery output（g）,food output（m）and per capita GDP（K）.The 5townships such as Longmen,Kuidou Penglai,Hutou and Guanqiao showed a decrease in cultivated land,water area and unused land,which were driven by population（a,b,c）,fishery output value（h）and fruit output（l）.The characteristics of Jingu,Lantian,Lustian,Futian,Longjuan,Taozhou,Xianghua and Xiping were characterized by the increases of tea plantation area and the decreases of cultivated land area to different degrees in recent10 years.The land use change was strongly driven by the tea output value.Therefore,it was suggested that the evolution of land use in a County and its townships was driven by geographical ecology,social economy and macro policies.Different townships have slight differences in spatio-temporal evolution patterns of land use due to different natural resource endowments and development strategies.However,the rapid development of tea industry in Anxi county is still the key driving factor to induce the evolution of land use.The changes were akso driven by the multiple measures to carry out all kinds of forest ecological engineering construction launched by Anxi county government to emphasize afforestation work,which is in strict accordance with the overall requirements of“the construction of beautiful mountains and rivers of Tea Township and forest Anx”in 20a.At the same time,Anxi county government insists on taking tea industry as the most important livelihood and pillar industry in Anxi County,which plays a decisive role in promoting farmers’income,social and economic development.Therefore,the implementation of returning the farmland to tea plantation has produced the effect that the county tea planting area has always been maintained in more than 30%of Fujian province tea planting areas becoming the pillar industry of the regional economy indeed.However,this process also caused many ecological problems.（2）The pattern of land use changed the structure and function of the ecosystem,thus resulting in differential performances in the service value of the regional ecosystem,which is the reason why the coordination of social ecology and economy operates at a low level in this countyThe results showed that the overall ecosystem services in Anxi County showed a downward trend from 1999 to 2019,but the rate of decline was different in different time courses.The decline rate showed the faster in the first decade,then slowed down in post 10 years,which resulted from that the local government has paid attention to ecological and environmental protection in recent years.However,it impressed that the ecosystem structure of Anxi county was still fragile,which was the cascade reaction on ecosystem service resulting from the differences in potential drivers of land-use change in the county.Multivariate statistical analysis showed that the relationship between the ecosystem service value（Y）and seven types of land use mode,namely,arable land,woodland,grassland,tea garden,nonagricultural construction land,waters and unused land（Xi）performed significant multivariate linear regression,suggesting that in the other land use types were kept unchanged,increasing anyone of independent variables,such as arable land（X₁）,woodland（X₂）,grassland（X₃）or the waters（X₅）areas,could improve ecosystem service value.Reverse was true in the case of tea garden（X₄）and nonused land（X₇）.The result from Path analysis showed that the indirect path coefficient of X_i-X₄-Y was negative,that is,all other independent variables such as farmland,woodland,the waters etc,which were regulated to increase the garden area（mainly for tea plantation）,could lead to the reduction of ecosystem service value（ESV）.Opposite trend was observed in the case of X_i-X₂-Y,suggesting that increasing anyone of independent variables in the consideration was able to enhance ESV via increases of woodland.The findings suggested that the decline of ecosystem service value over time in Anxi County in the past two decades was closely related to the increases of tea garden land and the decreases of forest land and cultivated land area,which can be verified by the historical facts of the development of tea industry in Anxi County.However,due to different land use and development strategies,the ecosystem service value changes are different in different townships.The results of this study found that in the past 20years,the ecosystem service value of 24 townships in Anxi County decreased as a whole,and its change trend was consistent with that of the whole county.Among them,Thetownships of Longruixiang Huagande Futian and Changkeng contributed a great deal to the total value of ecosystem services in Anxi County,and the contribution rate of ecosystem services in the five towships reached 41.01%of the total values of ESV.In terms of its changing pattern and its developmental trend,the annual average decline rate of the township ecosystem service value in the pre10years from 1999 to 2019 is greater than that in the post 10 years,of which the annual decline rate is larger in 8 townships of Longjuan,Xianghua,Sende,Futian,Chang keng,Xiping,Taozhou and Huqiu.However,reverse was true in the other 8 townships at the post 10 years,showing the decline rate of ESV was slowed downin the case.This resulted from the resource endowment differences and development strategies of different townships.From the perspective of ecosystem service types,The result showed that the regulation service was the most important function in Anxi county,with an average value of 11.232 billion Yuan RM in the past of 20 years,accounting for 67.01%of the total ESV value,followed by the supporting service function,accounting for 23.02%,and cultural service function has the lowest value,occupying only 4.41%of the total ESV value.Further,PCA and cluster analysis were used to analyze the relationship between ESV and 7 land use types of data matrix（Xi）in 24 townships of Anxi County at the three time courses of 1999,2009 and 2019.The results showed that all Anxi townships could be generally classified into four groups,,that is,lower,middle-lower,middle and higher ESV groups,of which the lower ESV possed the smaller cultivated land,woodland,grassland and tea garden,the higher ESV group had more cultivated land,woodland,grassland and tea garden,but lower nonagricultural construction land,and the middle-lower and middle ESV groups had the higher nonagricultural construction land,but they standed in the middle place in the other land uses as compared with that in other groups.The findings suggested that the land-use mode and its changing patterns led to the structural and functional evolution of the ecosystem in county and its townships,and thus produced different ecosystem service values.The numerical characteristics revealed by this study that the value of ecosystem services in Anxi County has decreased over time in the past 20 years,which were obviously related to the increases of tea garden land and the decreases of forest and cultivated land area.Therefore,it is necessary to pay attention to the trade off and coordination between land use patterns in order to ensure a high ecosystem service value.（3）Exploring reasonable ecological compensation measures is the key to ensuring the sustainable use of land resources and promoting the balanced,coordinated and sustainable development of ecosystem services.This study found that,on the whole,the ecosystem service value of Anxi County was constantly changing in the whole ecological process,and this dynamic change was a reflection of the regional land use type and the coordination with social and economic development strategies.The author suggested that only reasonable construction of ecological compensation standards,the formulation and strict implementation of ecological compensation policies could ensure the coordinated development of regional ecosystem structure and function,promote to fully play the overall ecosystem service functions,thereby guarantee the sustainable and high-quality green development of regional economy,especially agricultural economy.Therefore,based on the fact of regional agricultural development dominated by tea industry in Anxi County,the author put forward the concept of ecological compensation by inter-temporal differences under the consideration of many factors such as the socio-economic conditions of different townships and the declined rated of ecosystem service values based on the ecosystem service value assessment results,and by adopting the method of analytic hierarchy process（AHP）to analyze the importance and priority weighting of the dual goal of ecological compensation,the priority sequence and ecological compensation standards of different townships were determined to implement differential ecological compensation by inter-temporal payment.In the design of inter-temporal compensation,the first stage is for the townships that choose the priority of ecological tea garden cost compensation.The essence of compensation is the increase of cost caused by the construction of ecological tea garden,which can be regarded as the cost of ecosystem service recovery undertaken by the government.However,the essence of the second phase of ecological compensation is that the beneficiary pays after the ecological benefit is increased.The main body of ecological tea plantation should voluntarily pay a certain fee for the benefit of ecosystem service.Therefore,the theoretical basis of the two-stage ecological compensation standard is different,which combines the opportunity cost theory with the ecosystem service value theory.The results suggested that inter-temporal ecological compensation was expected to effectively increase compensation fund use efficiency supported by the government and promote the transformation of ecological compensation by the way of blood transfusion to that of hematopoiesis,which is one of very important avenues to realize the green developmental idea of“Lucid waters and lush mountains are invaluable assets”.