Identifying Changes Of Production-Living-Ecological Spaces And Related Food Supply&Demand Under Rapid Urbanization

The reasonable configuration of landscape function spaces is the basis of maintaining economic growth and food supply-demand balance in rapidly urbanized areas.China is undergoing rapid urbanization,which refers to landscape evolution,population aggregation,industrialization and expenditure increase.However,urbanization changes land-based food production and population-based food demand,which can exacerbate food supply-demand imbalance.Therefore,it is of great significance to reveal the evolution of Production-Living-Ecological spaces(PLEs)based on the changes in land function,and to explore its relationship with food supply-demand imbalance.This study can be the scientific bases for coordinated development of social-economic-ecological systems and improvement of ecosystem services under the influences of land function change in rapidly urbanization areas.Ningbo is a typical rapid urbanization area in China with a high urbanization level and rapid economic development,which is a representative area to study the correlation between land function transformation and food supply-demand imbalance.In this study,(i)we revealed the coupling evolution of landscape patterns and the production-living-ecological functions from 1980 to 2035 based on the remote sensing and model simulation;(ii)we clarified the characteristics of food supply-demand imbalance and their correlations with the evolution of landscape functions based on the production and consumption data of grains,vegetables,livestock,and aquatic products;(iii)we analyzed the coupling degree of economic development and food supply-demand balance according to the food supply-demand efficiency and the land-use efficiency,and explored the optimal configuration of PLEs aimed at highly efficient use of landscape functional spaces and coordinated development of economic growth and food supply-demand balance.The results are as follows:(1)Rapid urbanization influenced the structures and evolutions of landscapes and their production-living-ecological functions.From 1980 to 2020,the Production space(PS)greatly reduced(～478 km~2),and the Living space(LS)expanded rapidly(～613km~2)in Ningbo.However,the Ecological space(ES)decreased slowly(～212 km~2).These changes were mainly characterized by the transformation from Agricultural Production space(APs)to Industrial Production space(IPs),Urban Living space(ULs),and Rural Living space(RLs),which was caused by the rapid urban expansion.Based on the model prediction,PLEs change slowly from 2020 to 2035.Economic and population growth were the important factors driving PLEs evolution from past to future.(2)The evolution of landscape functional spaces changed regional food supply and demand,which had spatial and temporal mismatches.From 1980 to 2020,the grain and meat supply could not meet the demand in the study area by coupling analysis of landscape evolution and social-economic data.The grain production decreased from1716.0 thousand tons to 663.3 thousand tons,while the demand increased from 876.0thousand tons in 2005 to 1135.2 thousand tons in 2020.The livestock production increased firstly and then decreased to 81.2 thousand tons in 2020,whereas the demand continuously increased to 345.5 thousand tons.In contrast,the supplies of vegetables and aquatic products could meet their demands,while their surpluses decrease.In general,the reduction of APs is the main factor limiting the supply-demand balance of grain and livestock production,and the area threshold of APs was 35%.In the process of economic development,the expansion of ULs promoted the supply and surplus of vegetables and aquatic products through the regulation of markets,and the area threshold of ULs was 5%.(3)The reasonable configuration of landscape functional spaces can promote economic growth and maintain food supply-demand balance,thus improving the landscape use efficiency.From 1980 to 2020,the supply-demand efficiencies of grains and livestock products in Ningbo increased firstly and then decreased,however,they were generally lower than 30%.Although there were similar temporal variations,the supply-demand efficiencies of vegetables and aquatic products were higher than 62%after 2000.From 2020 to 2035,the supply-demand efficiencies will increase for grains and livestock products,while will decrease for vegetables and aquatic products.In contrast,the land-use efficiencies generally decreased from 1980 to 2020 for grains,vegetables,livestock,and aquatic products,and the values were lower than 5%during recent a decade.Based on the coupling relationships between economic growth and land supply-demand efficiencies in responses to landscape functional patterns,we found that APs,RLs,and ULs had substantial impacts on their coupling relationships.The results suggested the fragmentation degree of APs should be lower than 0.023 and the dominance degree should be higher than 0.35,the landscape fragmentation degree of RLs should be lower than 0.13 and the patch area should be less than 8323 m~2,while the patch area of ULs should be greater than 4159 m~2.