| Bijie City is located in the karst area of southwest China and it is a typical city with low level of economic development and fragile ecology.In the past few decades,a series of Ecological Restoration Projects(ERPs)have been implemented in the region,including Grain to Green Program(GGP)and Rocky Desertification Control(RDC))Wait.The implementation of ecological restoration projects will cause changes in regional ecosystem services(ESs).In the context of the implementation of ecological restoration projects,it is urgent to understand the effectiveness of regional ecosystem service restoration to guide the construction of subsequent ecological restoration projects.This paper takes Bijie City as the research area to analyze the effect of ERPs on the spatiotemporal evolution of ESs in Bijie City.It will provide a scientific basis for the implementation of ERPs and the construction of ecological security patterns in the region in the future.This study takes Bijie City as the research area,aiming to quantify the changes of ecosystem services in Bijie City before(1990-2000)and after(2000-2019)the implementation of the ERPs,and analyze the time and space of the ESs in Bijie City caused by the implementation of the ERPs.The influence of evolution characteristics provides a scientific basis for the implementation of ERPs and the construction of ecological security patterns in the region in the future.Based on high-precision remote sensing data of time series,this study uses the Continuous Change Detection and Classification(CCDC)algorithm to invert the Land Use and Land Cover(LULC)of Bijie City from 1990 to 2019,and then analysed the temporal and spatial evolution characteristics of land use in the study area.The ESs of Bijie City from 1990 to 2019 assessed based on the results of LULC,and the Consumer Price Index(CPI)was used to adjust the price in 2019,using the consumer price index(CPI)as the benchmark in 2019 to adjust the ESs value in Bijie from 1990 to 2019.Using hotspot analysis,correlation analysis,Sen Slope and Mann-Kendall(MK)and other methods,the temporal and spatial evolution characteristics of ESs in Bijie City in the past 30 years were analyzed.And discusse the change areas of hotspot of four types of ESs in Bijie,including soil conservation(SC),water conservation(WY),carbon storage(CS),and oxygen release(OR).And analysis the trade-offs and synergistic among these ESs,then analusis the impact of ERPs on the changing trends of ecosystem services was revealed.The main conclusions are as follows:(1)From 1990 to 2019,the land use of Bijie City was mainly forest(about 55%)and cropland(about 45%).Among them,cropland mainly distributed in Weining,Dafang and Qianxi,while forests mainly distributed in in Qixingguan,Jinsha,Dafang,Hezhang,Nayong and Zhijin.Cropland,forest,water body and impervious surface are the main changing land types,among which,cropland shows a continuous decreasing trend,while forest,water body and impervious surface show a continuous increasing trend..(2)There is spatial heterogeneity in ESs in Bijie City.Among them,water conservation,oxygen release,and carbon storage all showed a distribution pattern of"high in the east and low in the west",while the spatial distribution of soil conservation did not change significantly..(3)After the implementation of the ERPs,soil conservation,carbon storage,oxygen release and air purification all show an increasing trend while water conservation show a decreasing trend.Among them,soil conservation increased from 20.02 billion tons to 31.27 billion tons with an increase of 56.24%,carbon storage increased from 650 million tons to 1.06 billion tons with an increase of 63.47%,and water conservation decreased from 15.5 billion tons to 15.3 billion tons with a decreased by 1.29%,and the air purification volume increased from 570 million tons to 5.82 tons with an increase of 2.26%.The amount of oxygen released increased from 90 million tons to 1.15 tons with an increase of 31.16%.(4)After the implementation of the ERPs,the total value of ESs in Bijie City has increased by more than 4 times.Among them,the value of supply services increased from 11.7 billion to 76.8 billion with an increase of 359.59%;the value of regulation services increased from 410.74 billion to 1,330.32 billion with an increase of 123.17%;the value of cultural services increased from 12 million to 110.7 billion with an increase of 91 387.6%.(5)Under the background of the implementation of the ERPs,the four ESs,soil conservation,water conservation,carbon storage and oxygen release in Bijie,are mainly synergistic relationships(multi-year average correlation coefficient is greater than 0 and significant).The correlation coefficient between ESs generally showed an increasing trend,with fluctuations that first increased and then decreased.This study uses high-precision,long-term remote sensing data to quantitatively assess the impact of the implementation of the ERPs on the changes in ESs in Bijie City,which fills the time series of existing research on changes in ESs in poor and ecologically fragile areas.Monitoring gaps and confirming that the implementation of ERPs can enhance ESs.This study provides a comprehensive framework for studying the effects of ESs and ERPs in economically underdeveloped and ecologically fragile areas. |
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