The growth of society and population has led to a range of water pollution issues.Among these,non-point source pollution assessment and treatment pose a particular challenge due to its formation mechanism.This has bec...The growth of society and population has led to a range of water pollution issues.Among these,non-point source pollution assessment and treatment pose a particular challenge due to its formation mechanism.This has become a focal point and challenge in water pollution treatment research.The study area for this research was the Huanghou basin in Guizhou Province,southwest China.The land use type of the basin was analyzed using remote sensing technology,and water quality data was collected by distributing points throughout the basin,based on source-sink landscape theory.The distribution map of the basin’s source-sink landscape and the results of water quality data accurately and efficiently identified the areas with high risk of non-point source pollution in the western and southwestern residential and agricultural areas of the upper basin.Hence,a strategy of“increasing sinks and decreasing sources”was proposed.The strategy was implemented at both macro and micro levels to address non-point source pollution in the basin using ecological remediation techniques.The work to control karst rocky desertification should continue at a macro level.The rocky desertification area in the basin should gradually transform into grassland and forested land,while increasing the overall area of the sink landscape.Ecological restoration techniques,such as slope planting,riparian zone vegetation restoration,increasing plant abundance,and restoring aquatic plants,can effectively control non-point source pollution at the micro level.Compared to traditional control methods,this remediation strategy focuses on source and process control.It is more effective and does not require large-scale water pollution control projects,which can save a lot of environmental control funds and management costs.Therefore,it has greater research significance and application value.展开更多
Exploring the relationships between landscape pattern and ecological processes is the key topic of landscape ecology,for which,a large number of indices as well as landscape pattern analysis model were developed.Howev...Exploring the relationships between landscape pattern and ecological processes is the key topic of landscape ecology,for which,a large number of indices as well as landscape pattern analysis model were developed.However,one problem faced by landscape ecologists is that it is hard to link the landscape indices with a specific ecological process.Linking landscape pattern and ecological processes has become a challenge for landscape ecologists.“Source”and“sink”are common concepts used in air pollution research,by which the movement direction and pattern of different pollutants in air can be clearly identified.In fact,for any ecological process,the research can be considered as a balance between the source and the sink in space.Thus,the concepts of“source”and“sink”could be implemented to the research of landscape pattern and ecological processes.In this paper,a theory of sourcesink landscape was proposed,which include:(1)In the research of landscape pattern and ecological process,all landscape types can be divided into two groups,“source”landscape and“sink”landscape.“Source”landscape contributes positively to the ecological process,while“sink”landscape is unhelpful to the ecological process.(2)Both landscapes are recognized with regard to the specific ecological process.“Source”landscape in a target ecological process may change into a“sink”landscape as in another ecological process.Therefore,the ecological process should be determined before“source”or“sink”landscape were defined.(3)The key point to distinguish“source”landscape from“sink”landscape is to quantify the effect of landscape on ecological process.The positive effect is made by“source”landscape,and the negative effect by“sink”landscape.(4)For the same ecological process,the contribution of“source”landscapes may vary,and it is the same to the“sink”landscapes.It is required to determine the weight of each landscape type on ecological processes.(5)The sourcesink principle can be applied to non-point source pollution control,biologic diversity protection,urban heat island effect mitigation,etc.However,the landscape evaluation models need to be calibrated respectively,because different ecological processes correspond with different source-sink landscapes and evaluation models for the different study areas.This theory is helpful to further study landscape pattern and ecological process,and offers a basis for new landscape index design.展开更多
The aim of this study was to quantitatively evaluate the influences of landscape composition and spatial structure on the transmission process of non-point source pollutants in different regions.The location-weighted ...The aim of this study was to quantitatively evaluate the influences of landscape composition and spatial structure on the transmission process of non-point source pollutants in different regions.The location-weighted landscape contrast index,using the hydrological response unit(HRULCI)as the minimum research unit,was proposed in this paper.Through the description of the endemic landscape types and various geographical factors in the basin,the index calculation can reflect the impact of the“source-sink”landscape structure on the non-point source pollution in different regions and quantitatively evaluate the contribution of different landscape types and geographical factors to non-point source pollution.This study constructed a method of geo-cognitive computing for identifying“source-sink”landscape patterns of river basin non-point source pollution at two levels.1)The basin level:the spatial distribution and landscape combination of the entire basin are identified,and the crucial“source”and“sink”landscape types are obtained to measure the differences in the non-point source pollutant transmission processes between the“source”and“sink”landscapes in the different watersheds.2)The landscape level:HRULCI is calculated based on multiple geographical correction weighting factors.By using the idea of intersecting geographic information system(GIS)and landscape ecology,the landscape spatial pattern and ecological processes are linked.Compared with the traditional method for studying landscape patterns,the calculation of HRULCI makes the proposed method more ecologically significant.Lastly,a case study was evaluated to verify the significance of the proposed research method by taking the Yanshi River basin,a sub-basin belonging to the Jiulong River basin located in Fujian Province,China,as the experimental study zone.The results showed that this method can reflect the spatial distribution characteristics of the“source-sink”types and their relationship with non-point source pollution.By comparing the resulting calculation based on HRULCI,the risk of nutrient loss and the influence of landscape patterns and ecological processes on non-point pollution in different catchments can be obtained.展开更多
Previous studies generally used land use and travel flow to investigate the efficiency of the railway system in Transit-Oriented Development(TOD)cities.Furthermore,to study the association of land use and jobs-housing...Previous studies generally used land use and travel flow to investigate the efficiency of the railway system in Transit-Oriented Development(TOD)cities.Furthermore,to study the association of land use and jobs-housing distribution of commuters,we can find out the potential development of rail commuting.In this research,four railway lines in Wuhan,China,were selected to explore the land use in promoting practical commuting population according to the smart-card data obtained.For land use issues,except the road density and building density,a Normalized Location-Weighted Landscape Index(NLWLI)based on the source-sink theory in landscape ecology was established to assess the jobs-housing land use around rail transit stations.Meanwhile,employment and housing details of commuters around rail transit stations were identified using smart-card data.We found that the generation of commuting flow was affected by building density and the land use of employment in the immediate vicinity of rail transit stations.The distribution of building density and commuters in a mature rail line was roughly a normal distribution.However,due to the inconsistency of land use and jobs-housing distribution around stations,the requirement of the balance of land use and jobs-housing distribution should be reduced at the scale of rail stations in the TOD planning systems.This study is the application of massive smart-card data in the field of urban research.It identifies land use issues that affect rail transit commuting flow,and can help urban planners improve the efficiency of rail transit through planning and design.展开更多
文摘The growth of society and population has led to a range of water pollution issues.Among these,non-point source pollution assessment and treatment pose a particular challenge due to its formation mechanism.This has become a focal point and challenge in water pollution treatment research.The study area for this research was the Huanghou basin in Guizhou Province,southwest China.The land use type of the basin was analyzed using remote sensing technology,and water quality data was collected by distributing points throughout the basin,based on source-sink landscape theory.The distribution map of the basin’s source-sink landscape and the results of water quality data accurately and efficiently identified the areas with high risk of non-point source pollution in the western and southwestern residential and agricultural areas of the upper basin.Hence,a strategy of“increasing sinks and decreasing sources”was proposed.The strategy was implemented at both macro and micro levels to address non-point source pollution in the basin using ecological remediation techniques.The work to control karst rocky desertification should continue at a macro level.The rocky desertification area in the basin should gradually transform into grassland and forested land,while increasing the overall area of the sink landscape.Ecological restoration techniques,such as slope planting,riparian zone vegetation restoration,increasing plant abundance,and restoring aquatic plants,can effectively control non-point source pollution at the micro level.Compared to traditional control methods,this remediation strategy focuses on source and process control.It is more effective and does not require large-scale water pollution control projects,which can save a lot of environmental control funds and management costs.Therefore,it has greater research significance and application value.
基金supported by the National Natural Science Foundation of China (Grant Nos.30570319 and 40621061).
文摘Exploring the relationships between landscape pattern and ecological processes is the key topic of landscape ecology,for which,a large number of indices as well as landscape pattern analysis model were developed.However,one problem faced by landscape ecologists is that it is hard to link the landscape indices with a specific ecological process.Linking landscape pattern and ecological processes has become a challenge for landscape ecologists.“Source”and“sink”are common concepts used in air pollution research,by which the movement direction and pattern of different pollutants in air can be clearly identified.In fact,for any ecological process,the research can be considered as a balance between the source and the sink in space.Thus,the concepts of“source”and“sink”could be implemented to the research of landscape pattern and ecological processes.In this paper,a theory of sourcesink landscape was proposed,which include:(1)In the research of landscape pattern and ecological process,all landscape types can be divided into two groups,“source”landscape and“sink”landscape.“Source”landscape contributes positively to the ecological process,while“sink”landscape is unhelpful to the ecological process.(2)Both landscapes are recognized with regard to the specific ecological process.“Source”landscape in a target ecological process may change into a“sink”landscape as in another ecological process.Therefore,the ecological process should be determined before“source”or“sink”landscape were defined.(3)The key point to distinguish“source”landscape from“sink”landscape is to quantify the effect of landscape on ecological process.The positive effect is made by“source”landscape,and the negative effect by“sink”landscape.(4)For the same ecological process,the contribution of“source”landscapes may vary,and it is the same to the“sink”landscapes.It is required to determine the weight of each landscape type on ecological processes.(5)The sourcesink principle can be applied to non-point source pollution control,biologic diversity protection,urban heat island effect mitigation,etc.However,the landscape evaluation models need to be calibrated respectively,because different ecological processes correspond with different source-sink landscapes and evaluation models for the different study areas.This theory is helpful to further study landscape pattern and ecological process,and offers a basis for new landscape index design.
基金funded by the National Key R&D Programs of China(Grant No.2017YFB0504201,2015BAJ02B02)the Natural Science Foundation of China(Grant No.61473286,61375002)the Natural Science Foundation of Hainan Province(Grant No.20164178).
文摘The aim of this study was to quantitatively evaluate the influences of landscape composition and spatial structure on the transmission process of non-point source pollutants in different regions.The location-weighted landscape contrast index,using the hydrological response unit(HRULCI)as the minimum research unit,was proposed in this paper.Through the description of the endemic landscape types and various geographical factors in the basin,the index calculation can reflect the impact of the“source-sink”landscape structure on the non-point source pollution in different regions and quantitatively evaluate the contribution of different landscape types and geographical factors to non-point source pollution.This study constructed a method of geo-cognitive computing for identifying“source-sink”landscape patterns of river basin non-point source pollution at two levels.1)The basin level:the spatial distribution and landscape combination of the entire basin are identified,and the crucial“source”and“sink”landscape types are obtained to measure the differences in the non-point source pollutant transmission processes between the“source”and“sink”landscapes in the different watersheds.2)The landscape level:HRULCI is calculated based on multiple geographical correction weighting factors.By using the idea of intersecting geographic information system(GIS)and landscape ecology,the landscape spatial pattern and ecological processes are linked.Compared with the traditional method for studying landscape patterns,the calculation of HRULCI makes the proposed method more ecologically significant.Lastly,a case study was evaluated to verify the significance of the proposed research method by taking the Yanshi River basin,a sub-basin belonging to the Jiulong River basin located in Fujian Province,China,as the experimental study zone.The results showed that this method can reflect the spatial distribution characteristics of the“source-sink”types and their relationship with non-point source pollution.By comparing the resulting calculation based on HRULCI,the risk of nutrient loss and the influence of landscape patterns and ecological processes on non-point pollution in different catchments can be obtained.
基金supported by the Innovative Post of Post-doctor in Hubei Province,China[grant number 2018(641)]National Natural Science Foundation of China[grant number 52078389]。
文摘Previous studies generally used land use and travel flow to investigate the efficiency of the railway system in Transit-Oriented Development(TOD)cities.Furthermore,to study the association of land use and jobs-housing distribution of commuters,we can find out the potential development of rail commuting.In this research,four railway lines in Wuhan,China,were selected to explore the land use in promoting practical commuting population according to the smart-card data obtained.For land use issues,except the road density and building density,a Normalized Location-Weighted Landscape Index(NLWLI)based on the source-sink theory in landscape ecology was established to assess the jobs-housing land use around rail transit stations.Meanwhile,employment and housing details of commuters around rail transit stations were identified using smart-card data.We found that the generation of commuting flow was affected by building density and the land use of employment in the immediate vicinity of rail transit stations.The distribution of building density and commuters in a mature rail line was roughly a normal distribution.However,due to the inconsistency of land use and jobs-housing distribution around stations,the requirement of the balance of land use and jobs-housing distribution should be reduced at the scale of rail stations in the TOD planning systems.This study is the application of massive smart-card data in the field of urban research.It identifies land use issues that affect rail transit commuting flow,and can help urban planners improve the efficiency of rail transit through planning and design.
