Driven By Rapid Urbanization In Wuhan City Ecosystem Service Function Evaluation And Structure Optimization Research

Ecosystem service function is an important element for maintaining regional ecological security.Assessing the evolutionary dynamics of regional ecosystem service functions driven by rapid urbanization and exploring the mechanisms for optimizing the conservation of regional ecosystem patterns are of great significance for maintaining regional ecological security,but current research is insufficient.Taking Wuhan,a typical representative region of urbanization development in China,as a case study,the study selects land use data of five periods of rapid urbanization stage in Wuhan from 1980 to 2020,and firstly establishes three major categories of land use types under the two driving forces of socio-economic development and natural ecological conservation in rapid urbanization and the interaction:socio-economic land type,natural land type and productive land type.Secondly,the spatial and temporal distribution patterns of each land use type were analyzed and characterized by the land use transfer matrix,land use change trajectory and landscape pattern index method,and the five ecosystem service functions of grain yield,carbon storage,water purification,water production and habitat quality were simulated by the In VEST model.Finally,based on the system conservation planning theory and MARXAN model,we analyzed the optimization mechanism of regional ecosystem pattern conservation under rapid urbanization and proposed the priority conservation pattern with low cost and high ecological efficiency,and provided countermeasure suggestions for the construction of ecological security in Wuhan.The results of the study indicate that:(1)From 1980 to 2020,the area of socio-economic and natural land types in Wuhan increased by 171%and 11%,respectively,while the area of production land types decreased by 27%.2000-2020 saw the most obvious conversion of each land use type,with a dominant shift from production to socio-economic land types.Landscape fragmentation increased and aggregation and heterogeneity decreased in Wuhan during the four decades.The significant changes in spatial pattern are concentrated in and around the central city of Wuhan,with construction land occupying mainly the expansion of production land types,while natural land types are mainly distributed in the suburbs and are less affected,which intuitively reflects the rapid urbanization and expansion characteristics of Wuhan over the past 40 years of reform and opening up.(2)The five major ecosystem service functions of Wuhan city showed a general decreasing trend from 1980 to 2020,except for water production,food production,carbon storage,water purification and habitat quality services,which decreased by 16%,10%,32%and 7%,respectively.The spatial distribution of different ecosystem service functions tends to be consistent,with high values of carbon storage,water production and habitat quality concentrated in the southern and northern low mountain areas of Wuhan,and high values of grain yield output concentrated in the eastern and southern areas of the city,and high values of nitrogen output concentrated in the central and northern areas.(3)The synergistic relationship between each ecosystem service function occupies the upper peak,the habitat quality function and the remaining four service functions are trade-offs,and the remaining two-two combinations show synergy.The correlations between the three socio-economic,production and natural types and the five service functions range from 0.53-0.85,with an average correlation of 0.73.The correlations between the economic types and the remaining four service functions all reach 0.8 or more,indicating that the expansion of socio-economic types driven by rapid urbanization has a greater impact on the ecosystem service functions in Wuhan.(4)The evaluation results of ecosystem service function classes show that extremely important areas and low-level protected areas are relatively small in area,and are dominated by natural and socio-economic land types,respectively,while intermediate importance classes are dominated by production land types.This indicates that from the perspective of ecological function assessment only,natural types of land have the largest contribution to regional ecosystem service functions,followed by production types,and socio-economic types have the lowest.(5)Using five ecosystem service functions as conservation optimization targets,we simulated the conservation priority pattern with low cost investment and high ecological benefits under the scenarios of 10%,15%,20%,25%and 30%of regional service function conservation ratios,respectively.As the proportion of conservation targets increases,the proportion of productive land types in the conservation optimization pattern gradually increases and becomes dominant.Based on the simulation results,the priority conservation areas are 167 km~2,813.2 km~2 and 1309.5km~2 for the first,second and third classes respectively.Based on the optimization results,management suggestions are proposed with the goal of regional ecological security,which provide reference for the improvement of ecosystem service functions in Wuhan.