| Nowadays,the quantitative assessment of the ecological assets assessment is a hot topic and focus in the field of ecology and environmental economics.Based on combing summary of the theory of ecological assets assessment of value at home and abroad,this paper defines the concept of ecological assets,ecological assets are ecosystems that can provide natural resources and ecosystem services for human beings in a certain time and space,including natural ecosystems and artificial ecosystems,whose value includes the value of natural resources and ecosystem services.At the same time,based on remote sensing and GIS technology,this paper also analyzes ecosystem types and differences in quality of spatial and temporal,differentiates land cover types in the use of remote sensing images Landsat,uses vegetation net primary productivity and vegetation coverage to characterize the ecological adjustment factor of the quality status of the ecological system at that time.Combined with economic theory,this paper selects nutrient cycling value,hydrology adjustment value,soil conservation value,fixing carbon and releasing oxygen value,air purification value and spiritual and cultural value.Cities as remote sensing quantitative evaluation indexes in the urban regional ecological assets,establishes a quantitative evaluation model of urban ecological assets.Then,selecting the center region of Chengdu City as the study area,the ecological assets in the center region of Chengdu City in 2000,2004,2008,2012 and 2016 are measured quantificationally,and the five issues of the total ecological assets in the center region of Chengdu City are measured,for analyzing the temporal and spatial dynamic change of ecological assets and its driving force in the center region of Chengdu City from 2000 to 2016,through the establishment of CLUE-S model to simulate and analyze the changing trends of ecological assets in the central city of Chengdu,in order to provide effective protection for the sustainable development of the central city of Chengdu,as well as enrich and improve the standard system of the ecological assets.Selecting the central city of Chengdu as the study area,this paper applies image pre-processing and artificial interactive interpretation method and obtains four issues of land use classification diagrams in the center city of sing Landsat remote sensing images in2000,2004,2008,2012 and 2016,at the same time,this paper obtains changing data of land use in the center region of Chengdu City from 2000 to 2016,and then analyzes land use/cover change feature during the nearly 16 years in the center region of Chengdu City.On this basis,this paper chooses a single dynamic degree of land use type,land use comprehensive index and other mathematical models to thoroughly analyzes dynamics change information on the land use of the center region of Chengdu City during the nearly16 years from multiple perspectives,including structure,type,system space.Based on existing domestic and international theory and characteristics of ecological assets,this paper selects the appropriate assessment indicators ecological assets in the center region of Chengdu City and builds models.Using vegetation net primary productivity and vegetation coverage to characterize the ecological adjustment factor of the quality status of the ecological system at that time to reflect the dynamic changes of different dollar magnitude of value,this paper assesses and analyzes the regional ecological environment,optimizes and improves the evaluation system of urban ecological assets,chooses ecological assets quantitative evaluation index in the center region of Chengdu City,determines technical processes of the quantitative evaluation model of urban ecological assets,for the each ecosystem service value,uses mathematical methods and process simulation method is suitable for the center region of Chengdu City,and establishes the quantitative evaluation model of ecological assets of eco-by-pixel calculation.According to the quantitative evaluation model of urban ecological assets,this paper measures ecological assets in the center region of Chengdu City in 2000,2004,2008,2012and 2016 quantitatively,ecological assets are 14771.04×10~4yuan,10921.62×10~4yuan,10696.88×10~4yuan,10047.41×10~4yuan and 9800.36×10~4yuan in turn.There are three main characteristics of the changes in the ecological assets in the center region of Chengdu City:Firstly,from the time analysis,from 2000 to 2016,with the acceleration of urbanization,construction land increased sharply,occupying the areas of green vegetation and arable land which have relatively high ecological assets,the change trend of the ecological assets in the center region of Chengdu City is an overall decreasing trend,with a decrease rate of 33.65%,and a coefficient of variation of 15.02%;secondly,from the analysis of the constituent elements,changes in the area of green vegetation,waters and and arable land have a significant impact on the ecological capital of the center region of Chengdu City,at the same time,green vegetation,the waters and arable land of these three kinds of land use types provide more than 90%of ecological assets in the center region of Chengdu City,for different types of ecological assets,hydrology adjustment value and soil conservation value have a larger proportion,accounting for more than 20%of the total ecological assets,which are the most important components of the ecosystem service value in the center region of Chengdu City;thirdly,from the spatial analysis,the spatial distribution of ecological assets in the center region of Chengdu City presents a circle-like distribution characteristic,which increases with the increase of the linear distance from the urban center,the high value of the ecological assets is mainly concentrated in the area between the third ring road and the fourth ring road,and the low value is mainly concentrated in the third ring road,and as the year increases,the low value part is constantly scattering outward,with the trend of expansion.There are many driving forces for ecological assets changes in the center region of Chengdu City.Climate,human factors,policy and land use changes are influencing factors,and human factors play a leading role.According to the change of land use structure analyzed by land use transfer matrix,the land transferred by construction land has the largest area,resulting in a large reduction of land use type area with high ecological assets,which leads to a sharp decline of the ecological assets in the center region of Chengdu City.According to the principal component analysis,economic factors such as population,urbanization level,and GDP are the most important factors for the changes in ecological assets in the center region of Chengdu City.Based on remote sensing,GIS analysis and statistical analysis,this paper uses the CLUE-S model as its framework,and selects the five issues of the land use status map in2000,2004,2008,2012 and 2016 to test the accuracy of CLUE-S model applied to the land use scenario simulation,and Kappa of the simulation result is 0.781,indicating that using the CLUE-S model could better simulate the dynamic change of land use of the center region of Chengdu City and generally meet the requirements for prediction research of land use spatial distribution in the future.Based on the CLUE-S model,this paper acquires simulation results of land use spatial distribution of the center region of Chengdu City in2020 and 2024 under three kinds of scenarios,including the natural scenario,the ecological protection scenario and the comprehensive development scenario,after that,this paper estimates ecological assets of the central region of Chengdu City in 2020 and 2024 under different scenarios,combined with monetary value revised.The ecological assets in the ecological protection scenario is the highest ecological assets of the center region of Chengdu City in 2020 and 2024 among three different kinds of scenarios,and the ecological assets is 13854.14×10~4yuan and 14421.74×10~4yuan respectively,followed by the ecological assets in the comprehensive development scenario,and the ecological assets is 13376.99×10~4yuan and 13523.49×10~4yuan respectively,the ecological assets in the natural scenario is smallest,and the ecological assets is 9582.40×10~4yuan and 9394.39×10~4yuan respectively.The ecological assets in 2020 in the ecological protection scenario having an increase of 3.57%and 44.58%compares with the total ecological assets in the comprehensive development scenario and the total ecological assets in the natural scenario respectively.The ecological assets in 2024 in the ecological protection scenario having an increase of 6.64%and 53.51%compares with the ecological assets in the comprehensive development scenario and the ecological assets in the natural scenario respectively.The ecological assets of green vegetation,waters and arable land all have the largest proportion under three kinds of scenarios.The sort of individual ecological assets evaluation index value under three kinds of scenarios are that hydrological adjustment value>soil conservation value>air purification value>fixing carbon and releasing oxygen value>spiritual and cultural value>nutrient recycling value.As for comparison of the proportion of individual ecological assets evaluation index value,hydrology adjustment value,soil conservation value,air purification value and fixing carbon and releasing oxygen value of ecological value assessment of four values and the value of carbon sequestration and oxygen release have the larger proportion under three kinds of scenarios. |
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