| The Yellow River Basin is an important ecological security barrier in China,but due to its poor ecological background and the impact of unreasonable human activities,it has been suffering from serious ecological security issues such as floods,reduced biodiversity,soil erosion,and decreased vegetation coverage for a long time.In order to improve the ecological environment of the Yellow River basin,China has invested a large amount of human and material resources,actively promoting a series of ecological improvement and restoration measures such as returning farmland to forests,consolidating ditches and protecting tableland,establishing ecological protection areas,soil and water conservation,and preventing and controlling desertification.As a result,in the past 30 years,significant changes have taken place in the land use structure,landscape ecological risks,and spatial layout of ecosystem services in the Yellow River basin,including the restoration of species diversity Significant results have been achieved in the prevention and control of soil erosion on the Loess Plateau and the control of suspended rivers in the lower Yellow River.Through studying the spatiotemporal evolution characteristics of land use,landscape ecological risks,and ecosystem services in the Yellow River basin over the past 30 years,it is possible to accurately grasp the changes in the background quality of the Yellow River basin,scientifically understand the impact of engineering measures on the ecological environment of the Yellow River basin,and provide reference suggestions for the ecological governance construction and risk management of the Yellow River basin.This paper takes the Yellow River Basin as the research area,using multiple periods of land use data,meteorological data,soil data,socio-economic data,MODIS data,etc.from 1990 to 2020,using improved landscape loss models,land use transformation/mode/frequency maps,heat map models,and Linkage Mapper models and methods,to determine the optimal granularity of landscape pattern analysis in the Yellow River Basin,The spatiotemporal evolution characteristics of land use,landscape ecological risk,and ecosystem service value in the Yellow River basin over the years were comprehensively explored,and the spatial agglomeration of landscape ecological risk and the trade-off and synergy between various ecosystem services were analyzed.The threshold characteristics of landscape ecological risk under different ecosystem services were quantified,and an ecological security pattern based on landscape ecological risk and ecosystem service results was constructed,And proposed risk management and control strategies for ecological sources,resistance surfaces,ecological corridors,and key and comprehensive zoning.The results show that:(1)According to the analysis of the granularity effect of landscape index,the evaluation of the loss of precision in landscape index conversion,and the evaluation of precision loss in landscape type area conversion,the best suitable granularity domain is obtained as(270450).The medium to small granularity in the suitable granularity domain is selected,so the optimal granularity is 270 m.(2)During the research period,the Yellow River Basin formed a complex land use structure of agriculture,forestry,and animal husbandry,with land use showing a trend of shrinking cultivated,unused,and water areas,and increasing forest,grassland,and construction land.The distribution of cultivated land grassland,unused land grassland,and cultivated land construction land is the most obvious in the land use transformation map.The map types of land use change patterns in the Yellow River Basin all exhibit a relatively obvious aggregation trend distribution feature,with only intermittent and continuous change types distributed more discretely.The spatial pattern of the Yellow River basin has always remained stable,with the largest area of the land use change frequency map with stable tillage and grassland.(3)In 2020,the proportion of areas at low,low,medium,high,and high risk was 11.84%,24.69%,26.81%,23.22%,and 13.44%,respectively.The study area as a whole was in a medium risk state,with a poor background ecological situation.Overall,the area of low value and medium risk areas has always maintained a downward trend,while the area of high value risk areas has continued to expand,increasing by 18321.3738 km in total ~2。 The landscape ecological risk in the Yellow River basin presents a distribution characteristic of "hot in the north and cold in the south",with high value aggregation areas mainly distributed in the Inner Mongolia section of the Yellow River basin and the Loess Plateau region;Low value accumulation areas are mainly distributed in the source areas of the three rivers and the Qinba Mountains.(4)The ecological service value of the upper reaches of the Yellow River Basin is generally good,with most areas at high and high values(>0.186),showing a very significant increase in 2020;The overall service value of the middle reaches of the Yellow River basin is relatively low,with the vast majority of the area at low and low values(<0.127).Since 1990,it has gradually shown a trend of contraction;The service value of the lower reaches of the Yellow River basin is relatively good,with most of them located in the middle equivalent region(0.127～0.186),and high and high value regions are also relatively common.Overall,the service value of the entire research area is constantly improving,with the largest increase in service value in 2020.(5)Soil conservation water supply(SC-WY)and food production water supply(CP-WY)have a strong synergistic correlation.Moran’s I for soil conservation carbon storage(SC-CS),soil conservation food production(SC-CP),soil conservation residential resource support(SC-RS),and carbon storage water supply(CS-WY)are all negative,showing a trade-off relationship,while other services exhibit weak synergy;From the operational results of the interactive probe,it can be seen that when water resources supply and other service types cooperate,they can further enhance the comprehensive interpretation of the value of integrated ecosystem services.(6)The RS with the most frequent human activities does not have a higher level of ecological regulation function.When the RS is between 100 and 500,it is most likely to generate a high level of landscape ecological risk value.With the RS greater than 500,the landscape ecological risk shows a downward trend.The combination of ecological regulation function services such as SC,CS,and WY is not prone to generate too high levels of landscape ecological risk.Under the condition of human interference,the competition between SC and RS,CS and RS will not generate higher landscape ecological risks.(7)This paper constructs an ecological security pattern in the Yellow River basin,including 113481 square kilometers of ecological source land,It is divided into different functional resistance surfaces of ecological buffer zone,ecological transition zone,and ecological blocking zone,540 ecological corridors,and 107 key nodes.According to the results of landscape ecological risk assessment and ecosystem service assessment,and in combination with the ecological security pattern of the Yellow River basin,implement a zoning and classification risk management and control strategy.On the whole,the Yellow River basin should take comprehensive ecological protection measures such as the conservation and intensive use of water resources,desertification prevention and control actions focused on drainage,effective improvement of flood control capacity,effective control of suspended rivers in the lower reaches,and improvement of disaster resistance stability,to build an ecological governance pattern centered on the "one belt,five regions,and multiple points" ecological network. |
PDF Full Text Request