| Human overdevelopment and exploitation of ecosystems have led to the degradation of ecosystem service(ES).The concentration of urban populations and the growth of industrial and agricultural production have increased human demand for ES,further exacerbating the supply-demand conflict of ES.In this article,the InVEST model was used to simulate and evaluate four ESs:carbon storage(CS),water yield(WY),soil conservation(SC)and food supply(FS)in Nanjing Jiangbei New Area in 2000,2010,and 2020.By analyzing the spatiotemporal evolution characteristics at both the regional and neighborhood scales,and combining with ecosystem service trade-off degree(ESTD)to reveal the trade-off/coordinated relationship of ES.The supply-demand ratio index(ESDR)was introduced to analyze the changes in ES and comprehensive ES supply and demand.This study provides scientific data support for the future urban ecological spatial planning and regional sustainable development decision-making of the Nanjing Jiangbei New Area.The research methods and results of this article also have reference significance for the evaluation and planning of ES in other regions.The results obtained were as follows:(1)From 2000 to 2020,the supply of WY,SC and FS in Nanjing Jiangbei New Area showed an increasing trend,while the supply of CS decreased year by year with a decrease of1.6%.The WY supply increased due to the increase of precipitation.The high value area was mainly located in the construction land such as Dachang Street,while the low value area was located in the waters along the Yangtze River.The spatial heterogeneity of SC supply was small,and the overall supply was low,which was lower than 1t/hm~2 in most streets.The spatial distribution pattern of CS and FS is similar,with the low value area is located in the construction land with frequent human activities.(2)At the global scale,the WY-CS interaction and SC-CS interaction presented mainly trade-offs,and the tradeoff was concentrated in the construction land along the Yangtze River.The SC-WY interaction and CS-FY interaction presented mainly synergy,the FS-WY interaction and FS-SC interaction presented synergy,accounting for nearly 60%.At the street scale,the CS-FS interaction and CS-SC interaction presented mainly trade-offs in more than50%of the streets.The WY-FS interaction presented synergy in more than 10 streets,mainly distributed in Ge Tang and nearby streets in the direct management area.The WY-CS interaction presented mainly trade-offs in most streets.The SC-WY interaction presented synergy in all streets.The SC-FS interaction presented mainly trade-offs between streets concentrated in high-tech development zones in the direct management area.(3)In Nanjing Jiangbei New Area,the multiple hotspots of ES are mainly level-1 and level-2 hot spots,accounting for more than 70%of the total area.Level-1 hot spots are concentrated in the urban construction land in the central part of the study area,level-2 hot spots are distributed in most parts of the region,and level-3 hot spots are mainly distributed in Maan and Jinniuhu subdistrict in the general area.However,non-hot spots and level-4 hot spots are scattered in the region.According to the proportion of hotspot areas in different streets,the hotspot areas of multi-ES in each street are mainly the level-1 and level-2 hotspot areas,and the streets with high proportion of non-hotspot areas are Jiangpu and Maan streets.Level-3 hot spots are mainly distributed in Maan and Zhuzhen.Most streets have virtually no level 4 hot spots and are negligible.(4)The demand of four ES increased significantly from 2000 to 2020.The high demand for SC,WY,FS and CS were almost distributed in the densely populated urban construction land such as Taishan and Dachang Street,and their demand was higher than the average level of the study area for many years.With the passing of time,the areas with high demand increased and gradually expanded to the periphery of the urban center.Low value areas are mainly distributed in remote suburbs or rural areas and sparsely populated Laoshan forest farm,pearl spring and other ecological areas.(5)The average ratio of CS,WY,SC,FY supply and demand in Nanjing Jiangbei New Area were-0.0147,0.0019,-0.0029 and 0.0371,respectively.The spatial pattern of supply and demand ratio of the four ES is relatively consistent.The urban construction land along the river in central area has a deficit problem,while the rural and remote suburban areas mainly show a surplus.From the perspective of street,the deficit streets with the supply of the four ES less than the demand are mostly located in Dachang and Getang streets in the direct management area.The WY and SC interaction present a high-supply and high-demand mode,while the CS and FS interaction present a low-supply and high-demand mode.(6)The comprehensive supply-demand ratios for ESs in the third phase of Nanjing Jiangbei New Area are negative,indicating a deficit in the supply of ES to meet the demand.This deficit is exacerbating the supply-demand imbalance,underscoring the urgent need to implement effective management and restoration measures in both surplus and deficit areas.These measures must prioritize the quality and quantity of ES,and optimize the allocation of different ESs,to achieve sustainable development goals. |
