Accounting for the gains and losses of ecological assets holds scientific significance in sustaining human well-being.Based on related research on ecological assets,we established a county-scale ecological asset accou...Accounting for the gains and losses of ecological assets holds scientific significance in sustaining human well-being.Based on related research on ecological assets,we established a county-scale ecological asset accounting technology system by analyzing the temporal and spatial variations of county-level ecological assets in China from 1990 to 2018 and clarified the factors which caused the gains and losses of ecological assets.On these bases,optimization and promotion pathways were proposed.The results show that the number of counties dominated by farmland and forest ecological resources accounted for about 45%and 37%of the total counties,respectively.From 1990 to 2018,the quality of county-level ecological stock assets showed an increasing trend,while the water conservation volume decreased in nearly 70%of the counties.The number of counties with the gains(47%)and losses(37%)of ecological flow assets demonstrated spatial patterns which showed the same segmentation characteristics as the“Hu Huanyong Line”,that is,the counties in the vastness of northwest China experienced significant gains,while decreases were widespread in eastern and southern China.The change of ecological assets in more than 70%of the counties was driven by climate change and human activities.The average degree of impact of human activities driving the ecological asset gains in counties was about 80%,while that of climate change causing the ecological asset losses was about 60%.According to various ecological resource types,gain and loss status,and its driving factors,counties in China can be classified into five types:climate change mitigation,climate change adaptation,ecological resources restoration,ecological resources protection,and ecological resources management.Our results indicate that differentiated optimization and promotion pathways can be adopted to achieve desired ecological asset gains.展开更多
The study of the spatial patterns and temporal changes of cropland is important to understand the underlying factors and the functional effects of the agricultural landscape. On the other hand, crop dynamics mapping i...The study of the spatial patterns and temporal changes of cropland is important to understand the underlying factors and the functional effects of the agricultural landscape. On the other hand, crop dynamics mapping is essential to know the overall agro-spatial diversity of the area. Therefore, this paper addressed a spatio-temporal analysis of cropland and cropping pattern change in the Bogra district of Bangladesh over the last 16 years （between 1988/89 and 2004/05）. In this paper, crop mapping from multi-temporal and multi-sensor satellite images was described. Landsat TM and IRS P6 LlSS Ⅲ satellite images were used with GIS for spatial dynamics of cropland and cropping pattern change analysis. First, seasonal cropland maps were derived from object-based classification of satellite images, then two-date classified image differencing with GIS overlay technique and decision rules were applied. Cropping pattern change was analyzed in a spatial and quantitative way for the 16 years and for this, Integrated Land and Water Information System （ILWIS） and Land Change Modular （LCM） of IDRISl Andes were used. The results showed that in the area, mono crop cultivation was found in summer, but in winter, areas under different crop cultivation had changed dramatically. Change analysis showed that the changes mainly occurred in the north northwest and southwest of the areas, and during the time the highest change area was found under the rice-potato pattern.展开更多
基金The Strategic Priority Research Program of the Chinese Academy of Sciences,No.XDA23020202。
文摘Accounting for the gains and losses of ecological assets holds scientific significance in sustaining human well-being.Based on related research on ecological assets,we established a county-scale ecological asset accounting technology system by analyzing the temporal and spatial variations of county-level ecological assets in China from 1990 to 2018 and clarified the factors which caused the gains and losses of ecological assets.On these bases,optimization and promotion pathways were proposed.The results show that the number of counties dominated by farmland and forest ecological resources accounted for about 45%and 37%of the total counties,respectively.From 1990 to 2018,the quality of county-level ecological stock assets showed an increasing trend,while the water conservation volume decreased in nearly 70%of the counties.The number of counties with the gains(47%)and losses(37%)of ecological flow assets demonstrated spatial patterns which showed the same segmentation characteristics as the“Hu Huanyong Line”,that is,the counties in the vastness of northwest China experienced significant gains,while decreases were widespread in eastern and southern China.The change of ecological assets in more than 70%of the counties was driven by climate change and human activities.The average degree of impact of human activities driving the ecological asset gains in counties was about 80%,while that of climate change causing the ecological asset losses was about 60%.According to various ecological resource types,gain and loss status,and its driving factors,counties in China can be classified into five types:climate change mitigation,climate change adaptation,ecological resources restoration,ecological resources protection,and ecological resources management.Our results indicate that differentiated optimization and promotion pathways can be adopted to achieve desired ecological asset gains.
文摘The study of the spatial patterns and temporal changes of cropland is important to understand the underlying factors and the functional effects of the agricultural landscape. On the other hand, crop dynamics mapping is essential to know the overall agro-spatial diversity of the area. Therefore, this paper addressed a spatio-temporal analysis of cropland and cropping pattern change in the Bogra district of Bangladesh over the last 16 years （between 1988/89 and 2004/05）. In this paper, crop mapping from multi-temporal and multi-sensor satellite images was described. Landsat TM and IRS P6 LlSS Ⅲ satellite images were used with GIS for spatial dynamics of cropland and cropping pattern change analysis. First, seasonal cropland maps were derived from object-based classification of satellite images, then two-date classified image differencing with GIS overlay technique and decision rules were applied. Cropping pattern change was analyzed in a spatial and quantitative way for the 16 years and for this, Integrated Land and Water Information System （ILWIS） and Land Change Modular （LCM） of IDRISl Andes were used. The results showed that in the area, mono crop cultivation was found in summer, but in winter, areas under different crop cultivation had changed dramatically. Change analysis showed that the changes mainly occurred in the north northwest and southwest of the areas, and during the time the highest change area was found under the rice-potato pattern.
