Widespread changes to forested watersheds affected by the mountain pine beetle (Dendroctonus ponderosae Hopkins) epidemic across western North America raised concerns about the effects of this climate-induced disturba...Widespread changes to forested watersheds affected by the mountain pine beetle (Dendroctonus ponderosae Hopkins) epidemic across western North America raised concerns about the effects of this climate-induced disturbance on drinking water and natural resources. Effective communication and knowledge exchange across scientists and stakeholders (i.e., drinking water managers) is essential for constructively responding to such landscape scale disturbances, providing improved adaptive capacity through knowledge sharing. An assessment of stakeholder knowledge levels, information needs, primary concerns, and suggested communication strategies were conducted via an online elicitation survey and World Science Café workshops. Knowledge levels, assessed via a survey of local water managers and experts, were relatively low with approximately half of the respondents reporting little to no knowledge of the effects of mountain pine beetle on drinking water quality and quantity, thereby indicating limited knowledge exchange between scientists and drinking water stakeholders. Increased accessibility and dissemination of research findings pertinent to the mountain pine beetle epidemic’s effects on drinking water quality and quantity is necessary for natural resource management. Recommendations for improved communication among scientists and drinking water stakeholders in particular and forest health in general include dispersal of non-academic research summaries, information exchange through existing media and community resources, demonstration projects, and information clearinghouses. This information provides a better understanding of the challenges, concerns, and first-hand experience of stakeholders of a landscape disturbance issue to apply this knowledge to enhance land management practice and how researchers on this overall project enhanced science communication efforts.展开更多
Based on the three laws of dialectics of nature-the law of unity of opposites, the law of mutual change of quality and the law of negation of negation, this paper analyzes the relationship between the three laws and a...Based on the three laws of dialectics of nature-the law of unity of opposites, the law of mutual change of quality and the law of negation of negation, this paper analyzes the relationship between the three laws and agricultural development, and proposes making good use of the three laws to promote the better development of agriculture and realize agricultural modernization.展开更多
The water cycle and water resources within river basins under changing environmental conditions undergo profound changes, which have significant effects on the water environment of the river. Owing to the water resour...The water cycle and water resources within river basins under changing environmental conditions undergo profound changes, which have significant effects on the water environment of the river. Owing to the water resources demanded for economic and social development, water quantity and quality are becoming the core constraints of water resources development and utilization. In this paper, the dual attributes of water resources, progress into research regarding water quantity and quality joint assessment and simulation and the shortcomings associated with these techniques are summarized and described with respect to water quantity and quality. The results indicated that under the current environmental conditions, the method used for traditional water quality assessment of single water bodies cannot meet the requirements for water resources management. Moreover, a coupled hydrodynamic and water quality numerical model for river networks and lakes that applies to the river water environment system was developed for the river network flow and pollutant migration and transformation process and validated. This validation revealed that the error between the simulated values calculated by the model and the monitored values was small, meeting the application requirements and realizing the integrated and dynamic simulation of water quantity and quality of the river water environmental system. On this basis, the integrated simulation model was applied to the Luanhe River Basin.展开更多
The acceleration of urbanization has led to the occupation of more cropland, especially higher quality cropland, which could pose a huge threat to food security and have other implications for the inadequate cropland ...The acceleration of urbanization has led to the occupation of more cropland, especially higher quality cropland, which could pose a huge threat to food security and have other implications for the inadequate cropland resource supply in China. Though the spatial status of Chinese cropland quality has been assessed, its temporal changes since 2000 to 2015 are still not clear. An accumulated probability distribution method was used to determine the criteria of cropland quality using the net primary production data product(MOD17) from Moderate Resolution Imaging Spectroradiometer(MODIS). Then the cropland quality of higher, median and lower production was spatially mapped and its changes due to occupation by urbanization were analyzed through the land use changes(LUCC) data primarily from Landsat TM images in the three periods of 2000–2005, 2005–2010, and 2010–2015.The results showed that of the total cropland reduction area the proportion taken by urbanization increased from47.29% in the early stage to 77.46% in the recent period. The quality of Chinese cropland was dominated by lowand medium-yield fields, accounting for 40.81% and 48.74%, respectively, with high-yield fields accounting for only 10.44% of the total cropland in the country in 2000. The high-yield areas have been seriously threatened by the expansion of construction land fields, with the ratio of high-yield area to total area occupied by urbanization increasing from 9.71% in 2000–2005 to 15.63% in 2010–2015. Spatially, this phenomenon has been moving from eastern and southern China to central and western China, especially in Northwest China where the ratio has arrived at the highest proportion, with 52.97% of high-yield cropland in the total land taken by the expansion by 2015. This study not only provides a method to assess cropland quality but also reveals the threatening trend from the expansion of urbanization on high-quality cropland. More attention should be paid to the latter in land use planning and policies made to prevent threats to food security from declines in both cropland quantity and quality.展开更多
文摘Widespread changes to forested watersheds affected by the mountain pine beetle (Dendroctonus ponderosae Hopkins) epidemic across western North America raised concerns about the effects of this climate-induced disturbance on drinking water and natural resources. Effective communication and knowledge exchange across scientists and stakeholders (i.e., drinking water managers) is essential for constructively responding to such landscape scale disturbances, providing improved adaptive capacity through knowledge sharing. An assessment of stakeholder knowledge levels, information needs, primary concerns, and suggested communication strategies were conducted via an online elicitation survey and World Science Café workshops. Knowledge levels, assessed via a survey of local water managers and experts, were relatively low with approximately half of the respondents reporting little to no knowledge of the effects of mountain pine beetle on drinking water quality and quantity, thereby indicating limited knowledge exchange between scientists and drinking water stakeholders. Increased accessibility and dissemination of research findings pertinent to the mountain pine beetle epidemic’s effects on drinking water quality and quantity is necessary for natural resource management. Recommendations for improved communication among scientists and drinking water stakeholders in particular and forest health in general include dispersal of non-academic research summaries, information exchange through existing media and community resources, demonstration projects, and information clearinghouses. This information provides a better understanding of the challenges, concerns, and first-hand experience of stakeholders of a landscape disturbance issue to apply this knowledge to enhance land management practice and how researchers on this overall project enhanced science communication efforts.
文摘Based on the three laws of dialectics of nature-the law of unity of opposites, the law of mutual change of quality and the law of negation of negation, this paper analyzes the relationship between the three laws and agricultural development, and proposes making good use of the three laws to promote the better development of agriculture and realize agricultural modernization.
基金supported by the National Basic Research Program of China (2006CB403404 and 2010CB951102)the Funds for Creative Research Groups of China (51021066)the National Natural Science Foundation of China (51009150,40830637)
文摘The water cycle and water resources within river basins under changing environmental conditions undergo profound changes, which have significant effects on the water environment of the river. Owing to the water resources demanded for economic and social development, water quantity and quality are becoming the core constraints of water resources development and utilization. In this paper, the dual attributes of water resources, progress into research regarding water quantity and quality joint assessment and simulation and the shortcomings associated with these techniques are summarized and described with respect to water quantity and quality. The results indicated that under the current environmental conditions, the method used for traditional water quality assessment of single water bodies cannot meet the requirements for water resources management. Moreover, a coupled hydrodynamic and water quality numerical model for river networks and lakes that applies to the river water environment system was developed for the river network flow and pollutant migration and transformation process and validated. This validation revealed that the error between the simulated values calculated by the model and the monitored values was small, meeting the application requirements and realizing the integrated and dynamic simulation of water quantity and quality of the river water environmental system. On this basis, the integrated simulation model was applied to the Luanhe River Basin.
基金National Key Research and Development Program of China(2017YFC0503803)National Natural Science Foundation of China(41501428)Humanities and Social Sciences Foundation of the Ministry of Education(16YJCZH098)
文摘The acceleration of urbanization has led to the occupation of more cropland, especially higher quality cropland, which could pose a huge threat to food security and have other implications for the inadequate cropland resource supply in China. Though the spatial status of Chinese cropland quality has been assessed, its temporal changes since 2000 to 2015 are still not clear. An accumulated probability distribution method was used to determine the criteria of cropland quality using the net primary production data product(MOD17) from Moderate Resolution Imaging Spectroradiometer(MODIS). Then the cropland quality of higher, median and lower production was spatially mapped and its changes due to occupation by urbanization were analyzed through the land use changes(LUCC) data primarily from Landsat TM images in the three periods of 2000–2005, 2005–2010, and 2010–2015.The results showed that of the total cropland reduction area the proportion taken by urbanization increased from47.29% in the early stage to 77.46% in the recent period. The quality of Chinese cropland was dominated by lowand medium-yield fields, accounting for 40.81% and 48.74%, respectively, with high-yield fields accounting for only 10.44% of the total cropland in the country in 2000. The high-yield areas have been seriously threatened by the expansion of construction land fields, with the ratio of high-yield area to total area occupied by urbanization increasing from 9.71% in 2000–2005 to 15.63% in 2010–2015. Spatially, this phenomenon has been moving from eastern and southern China to central and western China, especially in Northwest China where the ratio has arrived at the highest proportion, with 52.97% of high-yield cropland in the total land taken by the expansion by 2015. This study not only provides a method to assess cropland quality but also reveals the threatening trend from the expansion of urbanization on high-quality cropland. More attention should be paid to the latter in land use planning and policies made to prevent threats to food security from declines in both cropland quantity and quality.
