Land use intensity quantifies the impacts of human activities on natural ecosystems, which have become the major driver of global environmental change, and thus it serves as an essential measurement for assessing land...Land use intensity quantifies the impacts of human activities on natural ecosystems, which have become the major driver of global environmental change, and thus it serves as an essential measurement for assessing land use sustainability. To date, land-change studies have mainly focused on changes in land cover and their effects on ecological processes, whereas land use intensity has not yet received the attention it deserves and for which spa- tially-explicit representation studies have only just begun. In this paper, according to the de- gree and reversibility of surface disturbance by human activities, there are four main classes of land use intensity： artificial land, semi-artificial land, semi-natural land, and natural land. These were further divided into 22 subclasses based on key indicators, such as human pop- ulation density and the cropping intensity. Land use intensity map of China at a 1-km spatial resolution was obtained based on satellite images and statistical data. The area proportions of artificial land, semi-artificial land, semi-natural land, and natural land were 0.71%, 19.36%, 58.93%, and 21%, respectively. Human and economic carrying capacity increased with the increase of land use intensity. Artificial land supports 24.58% and 35.62% of the total population and GDP, using only 0.71% of the total land, while semi-artificial land supported 58.24% and 49.61% of human population and GDP with 19.36% of China＇s total land area.展开更多
森林具有气候调节、水源涵养、生物多样性保护等诸多生态服务功能（Millennium Ecosystem Assessment,2005;van der Werf et al.,2009）,同时减少毁林和森林退化也是减缓温室气体排放协议REDD＋的重要内容（DeF ries et al.,2007;Grassi...森林具有气候调节、水源涵养、生物多样性保护等诸多生态服务功能（Millennium Ecosystem Assessment,2005;van der Werf et al.,2009）,同时减少毁林和森林退化也是减缓温室气体排放协议REDD＋的重要内容（DeF ries et al.,2007;Grassi et al.,2008）。为了改善日益恶化的生态状况,提高森林资源的蓄积量,自20世纪70年代以来,中国实施了六大林业重点工程,包括天然林保护工程、“三北”和长江中下游地区等重点防护林体系建设工程、退耕还林还草工程、京津风沙源治理工程、野生动植物保护及自然保护区建设工程以及重点地区速生丰产用材林为主的林业产业建设工程。在森林砍伐和林业工程的双向驱动下，如何准确地监测中国森林覆盖度及其时空变化成为一大挑战。展开更多
In this paper,we mainly focused our research on northern Shaanxi district,which is a pilot area of the Grain for Green Project.We compared the spatial distribution patterns of croplands and their productivity for the ...In this paper,we mainly focused our research on northern Shaanxi district,which is a pilot area of the Grain for Green Project.We compared the spatial distribution patterns of croplands and their productivity for the past 20 years（from the end of the 1980 s to 2010）.Cropland dynamics for the past 20 years were interpreted from medium- and high-resolution remote sensing images（Landsat TM/ETM＋）.In addition,using the GLO-PEM and AGRO-VPM models with a medium resolution and long time series remote sensing dataset（AVHRR/MODIS）,net primary productivity（NPP） and its relationship with cropland were estimated.Finally,the effect of cropland change on productivity was analyzed.The results show that during the first decade of the research period,cropland area and productivity in northern Shaanxi experienced a small boost,while in the latter decade,both cropland area and NPP were significantly reduced.The main cause of the increase in cropland was the reclamation of large area of grassland and unutilized land to meet the food demands of the local population as well as to compensate for the occupation of urban constructions.While the main cause of the decrease in cropland was the implementation of the Grain for Green Project.In addition,urbanization was also a key factor.Overall,during the past 20 years,the total area of cropland in northern Shaanxi decreased by 42.56%,and cropland NPP dropped by 41.90%.This study is of great importance for the assessment of regional cropland security,food security and scientific planning of regional land use.展开更多
基金National Key Research and Development Program of China,No.2016YFC0503500,No.2016YFC0503700
文摘Land use intensity quantifies the impacts of human activities on natural ecosystems, which have become the major driver of global environmental change, and thus it serves as an essential measurement for assessing land use sustainability. To date, land-change studies have mainly focused on changes in land cover and their effects on ecological processes, whereas land use intensity has not yet received the attention it deserves and for which spa- tially-explicit representation studies have only just begun. In this paper, according to the de- gree and reversibility of surface disturbance by human activities, there are four main classes of land use intensity： artificial land, semi-artificial land, semi-natural land, and natural land. These were further divided into 22 subclasses based on key indicators, such as human pop- ulation density and the cropping intensity. Land use intensity map of China at a 1-km spatial resolution was obtained based on satellite images and statistical data. The area proportions of artificial land, semi-artificial land, semi-natural land, and natural land were 0.71%, 19.36%, 58.93%, and 21%, respectively. Human and economic carrying capacity increased with the increase of land use intensity. Artificial land supports 24.58% and 35.62% of the total population and GDP, using only 0.71% of the total land, while semi-artificial land supported 58.24% and 49.61% of human population and GDP with 19.36% of China＇s total land area.
文摘森林具有气候调节、水源涵养、生物多样性保护等诸多生态服务功能（Millennium Ecosystem Assessment,2005;van der Werf et al.,2009）,同时减少毁林和森林退化也是减缓温室气体排放协议REDD＋的重要内容（DeF ries et al.,2007;Grassi et al.,2008）。为了改善日益恶化的生态状况,提高森林资源的蓄积量,自20世纪70年代以来,中国实施了六大林业重点工程,包括天然林保护工程、“三北”和长江中下游地区等重点防护林体系建设工程、退耕还林还草工程、京津风沙源治理工程、野生动植物保护及自然保护区建设工程以及重点地区速生丰产用材林为主的林业产业建设工程。在森林砍伐和林业工程的双向驱动下，如何准确地监测中国森林覆盖度及其时空变化成为一大挑战。
基金National Basic Research Program of China(2010CB950900)National Key Technology R&D Program(2013BAC0304)
文摘In this paper,we mainly focused our research on northern Shaanxi district,which is a pilot area of the Grain for Green Project.We compared the spatial distribution patterns of croplands and their productivity for the past 20 years（from the end of the 1980 s to 2010）.Cropland dynamics for the past 20 years were interpreted from medium- and high-resolution remote sensing images（Landsat TM/ETM＋）.In addition,using the GLO-PEM and AGRO-VPM models with a medium resolution and long time series remote sensing dataset（AVHRR/MODIS）,net primary productivity（NPP） and its relationship with cropland were estimated.Finally,the effect of cropland change on productivity was analyzed.The results show that during the first decade of the research period,cropland area and productivity in northern Shaanxi experienced a small boost,while in the latter decade,both cropland area and NPP were significantly reduced.The main cause of the increase in cropland was the reclamation of large area of grassland and unutilized land to meet the food demands of the local population as well as to compensate for the occupation of urban constructions.While the main cause of the decrease in cropland was the implementation of the Grain for Green Project.In addition,urbanization was also a key factor.Overall,during the past 20 years,the total area of cropland in northern Shaanxi decreased by 42.56%,and cropland NPP dropped by 41.90%.This study is of great importance for the assessment of regional cropland security,food security and scientific planning of regional land use.
