Remote Sensing Assessment And Spatiotemporal Evolution Mechanism Analysis Of Ecological Assets In Karst Rocky Desertification Area

Since the 20th century,with the understanding of the value of natural capital and the deepening of the study of sustainable development mechanism,it is increasingly urgent to estimate the ecological assets with natural resources and ecosystem services as the core.Due to the limitation of the complex surface and the extreme lack of optical satellite images.For a long time,regional ecological remote sensing has faced the bottleneck problems such as the serious mixed pixel phenomenon and the lack of high quality optical remote sensing images.The traditional quantitative remote sensing research methods based on pixel/grid scale cannot meet the needs and objectives of accurate assessment of regional ecological assets,mining of spatio-temporal evolution mechanism and ecological restoration decision support.This paper chooses Guanling-Zhenfeng Hua Jiang rocky desertification control demonstration area as the typical karst rocky desertification research area.Guided by the concept of "map coupling" in remote sensing map cognitive theory and the methodology of intelligent calculation model of geographical map spot,the evaluation framework of spatial-temporal evolution of ecological assets in karst rocky desertification area is constructed from the two dimensions of ecological asset quality and ecological asset service function.According to the linear cognitive process of " space-time-attribute ",the basic geospatial unit of ecological assets deeply integrated into geomorphologic zoning control is deconstructed,the key ecological factor inversion calculation and spatial and temporal dynamic evaluation of ecological assets are carried out in multi-source data collaboration,and the classical geospatial analysis method is used to explore the spatial and temporal evolution pattern and driving mechanism of ecological assets.The understanding of location-structure-index-evolution of ecological assets in the past 20 years is realized.Progress in the study is as follows:(1)From the point of view of evaluating and excavating the spatial and temporal evolution mechanism of ecological assets in karst rocky desertification area in the past 20 years,this paper constructs a framework for the spatiotemporal evolution evaluation of ecological assets based on remote sensing map cognitive theory and geographical map spot intelligent calculation model,and puts forward some key issues,such as the deconstruction of geographical units of ecological assets,the spatiotemporal dynamic assessment of ecological assets coordinated by multi-source data,the understanding of spatial and temporal evolution pattern of ecological assets based on geoscience spatial analysis and the revelation of driving mechanism,which provides a theoretical foundation for the research of the spatial and temporal evolution mechanism of ecological assets according to the dimension of "space-time-attribute".(2)Based on the analysis of the long-standing problems and shortcomings of the traditional quantitative remote sensing study of ecological environment based on pixel,the necessity of studying the spatial and temporal evolution mechanism of ecological assets in karst rocky desertification area based on the basic spatial unit with clear geographical significance is discussed.Based on high-precision DEM and high-resolution remote sensing images,the deconstruction of three-level basic spatial units of regional geomorphology unit,geographical unit and geographical map geo-parcel is realized.(3)On the basis of the theory connotation of "stock(stock)" and " flow(flow)" of ecological assets and the idea of system evaluation of devalue,the evaluation model of ecological assets quality and service function and the evaluation model of ecological assets comprehensive index are constructed based on the characteristics of fragile ecological environment in karst rocky desertification area,which are driven by ecosystem type and quantity,net primary productivity of NPP vegetation,rock exposure rate and vegetation coverage,The classification of ecological asset quality and service function in different monitoring periods and the comprehensive evaluation of ecological assets on regional geographical unit scale from 2000 to 2018 were completed respectively.(4)Focusing on the objective of understanding the temporal and spatial evolution mechanism of ecological assets in karst rocky desertification areas,taking geographical units and geomorphological units as the basis,introducing the most representative geographical spatial analysis method into the study of spatial and temporal evolution mechanism of ecological assets.From the aspects of spatial and temporal change pattern of ecological assets and spatial change driving mechanism of ecological assets,the author superimposes the "map" of ecological assets change from 2000 to 2018 and the "map" of driving using model calculation,spatial analysis and logical reasoning.The evolution pattern and driving mechanism of ecological assets in karst rocky desertification areas at different time stages and different spatial scales are expounded and revealed,which provides theoretical basis and scientific and technological support for regional ecological management and restoration.