Ecosystem Services Assessment And Trade-offs And Synergies In The Lower Yellow River Floodplain Based On The InVEST Model

The rapid exploitation of urbanized and productive land resources interferes with the service structure of the ecosystem,causing a series of ecological and environmental problems,and certain ecosystem services are reduced as a result.At present,the conflict between human and land is becoming more and more serious,and land use and environmental protection are becoming more complicated.Therefore,how to maintain a sustainable supply of ecosystem services,achieve regional economic development and ecological balance "win-win",and promote the harmonious development of human-land relationship has become one of the key issues that need to be solved.The lower Yellow River floodplain are one of the representative areas of river wetlands in China,and in view of their high degree of land exploitation,it is facing serious river pollution,shrinkage and degradation of wetlands,and prominent vulnerability of the regional ecological environment,etc.Thus it is important to assess the value of ecosystem services in the lower Yellow River floodplain and conduct trade-offs and synergistic studies.This paper analyzed the dynamic characteristics of land use in the lower Yellow River floodplain in 1987,2004 and 2020 based on multi-source data such as remote sensing,meteorology,elevation and soil,using change dynamic attitude and transfer matrix.In addition,using the InVEST model,the changes and spatial and temporal distributions of four ecosystem service values of carbon storage,habitat quality,soil conservation and water purification in the lower Yellow River floodplain were simulated and evaluated,and the presentation of service values were analyzed under different land use types.Later the trade-off and synergistic characteristics among ecosystem services were explored by correlation analysis,trade-off synergy,root mean square deviation,ecosystem service importance zoning,and land class ecosystem service structure.The main research results are as follows:(1)The results of land use change characteristics showed that: rivers,beach and arable land adjacent to the beach were constantly being converted;the area of rivers first decreased and then increased,with an overall decrease;the beach distributed along the rivers in a band showed a more significant change in a continuous downward trend;forest land,residential land and canal ponds were scattered in the beach,mainly through the development of arable land continued to increase,of which the change in the attitude of canal ponds was significantly higher in 33 years.The arable land in general showed a more significant change of increasing first and then decreasing at a slower rate.(2)InVEST model evaluation results showed that: in terms of services characteristics changes among the integrated 33 years,carbon storage,habitat quality services had decreased,and along with the increase in the degree of habitat degradation,soil maintenance significantly increased,along with the actual degree of soil erosion significantly increased,water purification services had increased;at the same time,there was a certain heterogeneity in the spatial and temporal distribution patterns of the four services.Regarding the differences between different land use types and each service,carbon storage service had the strongest carbon sequestration capacity in beach,the strongest soil consolidation and highest habitat level in forest land in soil conservation and habitat quality,and the highest nitrogen and phosphorus output in arable land in water purification.The service structure of land types showed that forest land was mainly "carbon storage-habitat quality",and residential land evolved from "soil conservation-water purification" to "water purification" in 2020.The service structure of other land types was relatively homogeneous and stable.(3)The results of the trade-off and synergistic studies of ecosystem services showed that water purification had trade-off relationships with habitat quality,carbon storage,and soil conservation in the three years,and synergistic relationships existed among carbon storage,soil conservation,and habitat quality services.In the time periods of 1987-2004 and 2004-2020,there was a synergistic relationship between water purification and soil conservation,and the rest of the relationships were the same as the three years.In the period 1987-2020,the spatial distribution of carbon storage and water purification,soil conservation,and habitat quality were dominated by the non-significant trade-off synergistic relationship,the other three service pairs were dominated by the trade-off relationship;the mean value of trade-off intensity of habitat quality-carbon storage,habitat quality-water purification,and soil conservation-water purification service pairs increased,while the mean value of trade-off intensity of the other three service pairs decreased.In terms of importance zoning,the area of moderately important and extremely important zones decreased;the area of generally important,more important and highly important zones increased;as for the extremely important areas in space,beach and woodlands were dominant.