Study On The Trade-offs And Synergies Of Land Use Functions In Rapid Urbanizing Regions

The emergence of land change science has led to the research's focus of land use shifted from land use/land cover change to the change of land use functions and the relationship among functions.Land use functions(LUFs)are the benefits obtained from land-use systems,which is a valuable concept that allows for more integrated assessments of land system change.Identifying the change of LUFs and the relationships among multiple LUFs is crucial for land-based spatial planning that can guide targeted land use and planning policy-making in complex socio-ecological systems such as rapidly urbanizing landscapes.However,previous studies on LUFs have primarily focused on natural ecosystems,ignoring the impacts of human-dominated complex socio-ecological systems.Also,the existing studies maily focused on the LUFs assessment at the administrative district level,few studies have,unfortunately,have spatialized the LUFs at grid scale and examined the interactions among multiple LUFs.Under the guidance of land use multifuctionality and ecosystem services trade-offs,this study proposed a classification framework and evaluation index system for LUFs considering the associations and impacts of different land-uses in complex socio-ecological systems from the perspective of land-based spatial planning and management.We applied the framework to a rapidly urbanizing region,Jiangsu Province,and quantified the different LUF in the years of 2000,2005,2010,2015 in Jiangsu Province at 1-km2 scale using In VEST model and spatialization methods.We also analyzed the temporal and spatial dynamic of the LUFs from 2000 to 2015.Then,we revealed the trade-offs and synergies among the LUFs and their spatial-temporal variation from the perspective of ecological security,as well as the impacts of land use/land cover change on the trade-offs and synergies of LUFs.Finally,we identified the distinct LUF restriction zones and their dominat functional restriction types using k-means clustering analysis at the county level,as well as proposed some suggestions for land use multi-functional management.The study is of theoretical and practical significance for the development of land change science and for land-based spatial planning and landmanagement policy-making.The main conclusions of this study are as follows:(1)LUFs are divided into three functions:(agricultural)production function(AP),(urban)living function(UL),and ecological(maintenance)function(EM).Also,the ecological functions are further divided into four sub-functions,i.e.,water conservation(WC),climate regulation(CR),biodiversity conservation(BC),and cultural service(CS).,AP mainly showed the trend of increasing in the northern Jiangsu and decreasing in the southern Jiangsu between 2000 and 2015.UL showed increased trend in the study period,however,UL decreased in the center of most cities in Jiangsu Province from 2005 to 2010.Increased and decreased WC between 2000 and 2015 mainly concerntrated in the southern Jiangsu and northern Jiangsu,respectively.Increased and decreased WC between 2000 and 2015 mainly concerntrated in the northern Jiangsu and southern Jiangsu,respectively.BC was mainly characterized by a continuous decline between 2000 and 2015,and had more prominent decrease in southern Jiangsu along the Yangtze River.CS mainly showed increase between 2000 and 2015,and increased more prominently in the center of each city in Jiangsu.(2)AP and WC showed an increased trade-off between 2000 and 2015.AP had a significant and stable synergy with CR,and have decreased trade-offs with both BC and CS between 2000 and 2015.Increased synergy occurred between UL and WC,also,UL had stable trade-offs with both CR and BC between 2000 and 2015.UL and CS showed a low level and slightly decreased synergy during the study period.WC and CR showed a significantly increased trade-off,and WC also had decreased synergies with both BC and CS between 2000 and 2015.CR and BC showed a low level and gradually decreased trade-off,and a steady increased trade-off occurred between CR and CS between 2000 and 2015.BC and CS had a low-level and stable synergy between 2000 and 2015.In addition,during the study period,the trade-offs and synergies between AP and multiple EMs present various spatial differentiation characteristics,which is the same for UL and multiple EMs as well as for EMs themselves.The southern and northern Jiangsu,the costal and inland areas of Jiangsu showed significant spatial differences,respectively.(3)The interconversion among different land use/land cover types will make different types of LUFs change,i.e.,increase or decrease,that will impact the trade-offs and synergies among multiple LUFs.The impacts on the trade-offs and synergies among LUFs are more prominent for the interconversion of farmland and built-up land,farmland and grassland,woodland,water body,as well as built-up land and grassland,woodland,water body,grassland and water body.Trade-offs and synergies of some LUFs also varied in the areas where land use/land cover types remain stable.This mainly due to the decrease of AP,UL,WC,BC and the increase of CR during the study period.The main reason of the decrease for AP,WC,BC is the degradation of farmland,grassland and woodland resulted from extensive urban expansion,and the low utilization efficiency of built-up land and the insufficient exploitation of internal potential of built-up land will lead to the decrease for UL.The increase of CR can be attribute to the stability of land use/land cover types.Changes in LUFs further have impacts on the relationships among functions.(4)Jiangsu Province includes four distinct types of LUF restriction zones,i.e.,zone of synergistic decrease for agricultural production-urban living-biodiversity conservation in hilly areas of southwest Jiangsu,zone of synergistic decrease for agricultural production-climate regulation-biodiversity conservation in the plain around Taihu Lake,zone of synergistic decrease for agricultural production-ecological maintenace and trade-off for urban living-ecological maintenace in eastern coastal plain of Jiangsu,zone of synergistic decrease for water conservation-biodiversity conservation in northern plain of Jiangsu.Dominant restriction types are vary among different zones.And we also proposed planning and management suggestions for promoting the coordinated development of multiple LUFs.