Vegetation restoration is a critical strategy for mitigating debris flow hazards by stabilizing slopes and modifying hydrological processes.Effective planning of priority restoration areas is particularly essential in...Vegetation restoration is a critical strategy for mitigating debris flow hazards by stabilizing slopes and modifying hydrological processes.Effective planning of priority restoration areas is particularly essential in dry-hot valley regions,where extreme hydrothermal conditions pose significant challenges.This study presents a novel framework that integrates microclimatic variables,such as temperature lapse rates,to enhance the spatial precision of revegetation efforts.The Reshuihe watershed in Southwest China,a representative dry-hot valley,was chosen as the study area.By analyzing hourly temperature and rainfall across an elevation gradient,a quadratic relationship between temperature lapse rates and weak rainfall events was identified,underscoring the role of microclimatic processes in influencing rainfall distribution and plant-available water.Rainfall peaks were observed when the temperature lapse rate was approximately 4.5°C/km.This relationship was incorporated into a cost-based restoration framework using the Marxan model,optimizing the spatial allocation of priority areas for revegetation.Results demonstrated that integrating microclimatic variables significantly improved the effectiveness of revegetation strategies,particularly for reducing debris flow risks.The lowest restoration costs were observed between elevations of 3200 m and 3300 m,where strong correlations between temperature lapse rates and rainfall were recorded.Priority restoration areas covered 41 km^(2),targeting zones with high debris flow risks.These findings highlight the value of incorporating microclimatic data into revegetation planning,enabling cost-effective and ecologically sustainable hazard mitigation in regions vulnerable to hydrological hazards.展开更多
Labor migration to urban centers is a common phenomenon in the Panxi region of the southwestern mountainous region of China, mainly owing to inadequate livelihood capital in rural areas. Numerous studies have been con...Labor migration to urban centers is a common phenomenon in the Panxi region of the southwestern mountainous region of China, mainly owing to inadequate livelihood capital in rural areas. Numerous studies have been conducted to explore the relationship between labor migration and its causes, such as individual and family characteristics, but few studies have focused on livelihood capital. This paper examines the impact factors on labor migration employment location selection and duration from a household livelihood capital perspective. A case study of 279 households from 10 villages in the area was carried out in February 2016. We used both qualitative and quantitative methods to analyze the data. On the basis of the 279 questionnaires, the proportion of households with non-labor migration is 48.4%, whereas households with labor migration within a local city and migration across regions account for 28.7% and 22.9%, respectively. Social, financial, and human capitals are the primary factors that influence migrants' employment location choice positively. Among them, social capital has a significant impact on both migration within a local city and across regions; each of the regression coefficients is 1.111 and 1.183. Social, human, and financial capitals also have a positive impact on the duration of labor migration, and similarly, social capital is the highest coefficient with 2.489. However, physical capital only partly impacts labor migration across regions, whereas the impact of labor migration within a local city, and the duration, are not significant. Furthermore, the impact of household natural capital on migration space and time are all negative relationships, especially for labor migration across the regions and duration, with coefficient scores of 4.836 and 3.450, respectively. That is to say, a laborer is inclined to migrate within a local city for a short term, or not migrate at all, if natural capital is abundant. Our analysis results show that household livelihood capital has a strong spatio-temporal impact on labor migration.展开更多
Post-disaster recovery and reconstruction provide an effective way to reduce the disaster vulnerability of, and promote leapfrog development in, an affected area. To date, studies that have used administrative boundar...Post-disaster recovery and reconstruction provide an effective way to reduce the disaster vulnerability of, and promote leapfrog development in, an affected area. To date, studies that have used administrative boundaries to investigate the reconstruction of settlement space have not been able to clearly define the real boundaries of land use changes or quantify the degree of response to the ‘Build-Back-Better’ initiative, and have lacked any consideration of the fourth reconstruction stage–development period(10 years). This study constructed a mountain settlement niche and analyzed the characteristics, spatial reconstruction, and drivers of rural settlements during 2009–2019 in the upper reaches of the Minjiang River, southwest China. The results showed the following:(1) Natural factors were the basis for the formation and development of mountain settlement niches. The scale of the settlement niche and its land use structure depended on the physical geography features and the ethnic farming and grazing traditions. The settlement niche provided a realistic boundary for the spatial reconstruction.(2) The layout of residential land around cropland was the common feature of the mountain settlement niche. Of all the land use types, the roads and rural residential lands showed the most change over the 10 years;13,860 residential patches increased in size and 4,742 patches were abandoned.(3) The area of orchards, planted to reconstruct the economy in the mountains, increased by nearly 2.5 times.(4) Collapses, landslides, and debris flow disasters and the ecological red line influenced the spatial reconstruction. While the main focus of post-disaster recovery is spatial reconstruction, initiatives should include economic and spiritual recovery, and should also achieve sustainable development of the region.展开更多
Identifying the impacts of climate change is important for conservation of ecosystems under climate change, particularly in mountain regions. Holdridge life zone system and Koppen classification provide two effective ...Identifying the impacts of climate change is important for conservation of ecosystems under climate change, particularly in mountain regions. Holdridge life zone system and Koppen classification provide two effective methods to assess impacts of climate change on ecosystems, as typical climate-vegetation models. Meanwhile, these previous studies are insufficient to assess the complex terrain as well as there are some uncertainties in results while using the given methods. Analysis of the impacts of the prevailing climate conditions in an area on shifts of ecosystems may reduce uncertainties in projecting climate change. In this study, we used different models to depict changes in ecosystems at 1 km × 1 km resolution in Sichuan Province, China during 1961-2010. The results indicate that changes in climate data during the past 50 years were sufficient to cause shifts in the spatial distribution of ecosystems. The trend of shift was from low temperature ecosystems to high temperature ecosystems. Compared with K？ppen classification, the Holdridge system has better adaptation to assess the impacts of climate change on ecosystems in low elevation（0-1000 m）. Moreover, we found that changed areas in ecosystems were easily affected by climate change than unchanged areas by calculating current climate condition.展开更多
Debris flow hazards seriously threaten thesafety and sustainable development of mountainousareas. Numerous debris flow mitigation measures havebeen implemented worldwide;however, acomprehensive assessment of the speci...Debris flow hazards seriously threaten thesafety and sustainable development of mountainousareas. Numerous debris flow mitigation measures havebeen implemented worldwide;however, acomprehensive assessment of the specific disasterreduction effects of these measures and their economic,social and ecological benefits is yet to be performed.The western region of Sichuan Province frequentlysuffers from geohazards such as debris flow, and thegovernment has adopted many mitigation measures.This study assessed the benefits of debris flowmitigation measures and identified the key influencingfactors via a field-based study conducted in 81 villagesin western Sichuan province, China. A framework forthe evaluation of the benefits of rural debris flowmitigation measures was constructed andquantitatively evaluated using a survey. Snowballsampling was performed to recruit 81 village leadersand 468 farmers. The results showed that managementand engineering measures were the main methodsused to mitigate debris flow;ecological measures wereauxiliary. The average satisfaction scores of farmers forthese three types of measures were 4.07, 3.90, and 3.56,respectively (as measured on a five-point Likert scale).In contrast, in terms of the benefits of these mitigationmeasures, only a small proportion of villages (11.11%)obtained a high level of comprehensive benefits fromthe debris flow mitigation measures, while the majority(88.89%) received medium to low-level benefits. Toimprove this situation, we further studied and foundthat the main factors that restricted villages fromachieving high-level comprehensive benefits were theunpredictable nature of debris flows, labour forceoutflow and remoteness. Effective control measures, agood economic environment and strong governmentassistance were reported as crucial factors forimproving these comprehensive benefits. This studyprovides socio-scientific references for decisionmakingon rural debris flow mitigation measures while keeping villages at the centre of economic development.展开更多
Preparation and characterization of the YBCO superconducting films by chemical solution route with polyethylene glycol(PEG200)and Cu(NO3)2 as precursors are presented.It was found that PEG200 and sucrose were novel ch...Preparation and characterization of the YBCO superconducting films by chemical solution route with polyethylene glycol(PEG200)and Cu(NO3)2 as precursors are presented.It was found that PEG200 and sucrose were novel chelates and Cu(NO3)2 was an alternative precursor for the preparation of YBCO superconducting film by chemical solution route.The precursor solution was prepared by mixing yttrium trifluoroacetate,barium trifluoroacetate,and copper nitrate in solvent of methanol with chelates including PEG200 and sucrose.YBCO films were prepared by coating the precursor solution on LaAlO3 single crystal substrate,following vacuum drying,rapid calcining,firing and oxygen annealing.The prepared films were characterized by optical microscope(OM),X-ray diffraction(XRD)and scanning electron microscopy(SEM).The results showed that films were crack-free and homogeneous,stronger tendency of(00l)texture,uniform with less pore,pure c-axis orientation.The films showed good superconducting properties,with Tc of 90 K and critical current density(Jc)of 1 MA/cm2(77 K,0 T).This work demonstrates that the developed method is a promising method for preparation of YBCO superconducting film which has a fine superconducting characterization with advantages of simple and rapid.展开更多
基金supported by the National Natural Science Foundation of China for General Program(42171118)the National Natural Science Foundation of China for Distinguished Young Scholars(41925030)the Special Funding Projects of Talents of Yunnan Province(YNWR-QNBJ-2020-099).
文摘Vegetation restoration is a critical strategy for mitigating debris flow hazards by stabilizing slopes and modifying hydrological processes.Effective planning of priority restoration areas is particularly essential in dry-hot valley regions,where extreme hydrothermal conditions pose significant challenges.This study presents a novel framework that integrates microclimatic variables,such as temperature lapse rates,to enhance the spatial precision of revegetation efforts.The Reshuihe watershed in Southwest China,a representative dry-hot valley,was chosen as the study area.By analyzing hourly temperature and rainfall across an elevation gradient,a quadratic relationship between temperature lapse rates and weak rainfall events was identified,underscoring the role of microclimatic processes in influencing rainfall distribution and plant-available water.Rainfall peaks were observed when the temperature lapse rate was approximately 4.5°C/km.This relationship was incorporated into a cost-based restoration framework using the Marxan model,optimizing the spatial allocation of priority areas for revegetation.Results demonstrated that integrating microclimatic variables significantly improved the effectiveness of revegetation strategies,particularly for reducing debris flow risks.The lowest restoration costs were observed between elevations of 3200 m and 3300 m,where strong correlations between temperature lapse rates and rainfall were recorded.Priority restoration areas covered 41 km^(2),targeting zones with high debris flow risks.These findings highlight the value of incorporating microclimatic data into revegetation planning,enabling cost-effective and ecologically sustainable hazard mitigation in regions vulnerable to hydrological hazards.
基金Under the auspices of the National Natural Science Foundation of China(No.41471469,41601141)the National Key Basic Research Program of China(No.2015CB452706)+1 种基金the Humanities and Social Sciences Youth Project of Ministry of Education in China(No.14YJCZH130)Youth Talent Team Program of the Institute of Mountain Hazards and Environment,Chinese Academy of Sciences(No.SDSQB-2015-01)
文摘Labor migration to urban centers is a common phenomenon in the Panxi region of the southwestern mountainous region of China, mainly owing to inadequate livelihood capital in rural areas. Numerous studies have been conducted to explore the relationship between labor migration and its causes, such as individual and family characteristics, but few studies have focused on livelihood capital. This paper examines the impact factors on labor migration employment location selection and duration from a household livelihood capital perspective. A case study of 279 households from 10 villages in the area was carried out in February 2016. We used both qualitative and quantitative methods to analyze the data. On the basis of the 279 questionnaires, the proportion of households with non-labor migration is 48.4%, whereas households with labor migration within a local city and migration across regions account for 28.7% and 22.9%, respectively. Social, financial, and human capitals are the primary factors that influence migrants' employment location choice positively. Among them, social capital has a significant impact on both migration within a local city and across regions; each of the regression coefficients is 1.111 and 1.183. Social, human, and financial capitals also have a positive impact on the duration of labor migration, and similarly, social capital is the highest coefficient with 2.489. However, physical capital only partly impacts labor migration across regions, whereas the impact of labor migration within a local city, and the duration, are not significant. Furthermore, the impact of household natural capital on migration space and time are all negative relationships, especially for labor migration across the regions and duration, with coefficient scores of 4.836 and 3.450, respectively. That is to say, a laborer is inclined to migrate within a local city for a short term, or not migrate at all, if natural capital is abundant. Our analysis results show that household livelihood capital has a strong spatio-temporal impact on labor migration.
基金financially supported by the National Natural Science Foundation of China (Grant No. 42171085)The Second Tibetan Plateau Scientific Expedition and Research Program (STEP) (Grant No.2019QZKK0307)。
文摘Post-disaster recovery and reconstruction provide an effective way to reduce the disaster vulnerability of, and promote leapfrog development in, an affected area. To date, studies that have used administrative boundaries to investigate the reconstruction of settlement space have not been able to clearly define the real boundaries of land use changes or quantify the degree of response to the ‘Build-Back-Better’ initiative, and have lacked any consideration of the fourth reconstruction stage–development period(10 years). This study constructed a mountain settlement niche and analyzed the characteristics, spatial reconstruction, and drivers of rural settlements during 2009–2019 in the upper reaches of the Minjiang River, southwest China. The results showed the following:(1) Natural factors were the basis for the formation and development of mountain settlement niches. The scale of the settlement niche and its land use structure depended on the physical geography features and the ethnic farming and grazing traditions. The settlement niche provided a realistic boundary for the spatial reconstruction.(2) The layout of residential land around cropland was the common feature of the mountain settlement niche. Of all the land use types, the roads and rural residential lands showed the most change over the 10 years;13,860 residential patches increased in size and 4,742 patches were abandoned.(3) The area of orchards, planted to reconstruct the economy in the mountains, increased by nearly 2.5 times.(4) Collapses, landslides, and debris flow disasters and the ecological red line influenced the spatial reconstruction. While the main focus of post-disaster recovery is spatial reconstruction, initiatives should include economic and spiritual recovery, and should also achieve sustainable development of the region.
基金Under the auspices of National Basic Research Program of China(No.2015CB452702)
文摘Identifying the impacts of climate change is important for conservation of ecosystems under climate change, particularly in mountain regions. Holdridge life zone system and Koppen classification provide two effective methods to assess impacts of climate change on ecosystems, as typical climate-vegetation models. Meanwhile, these previous studies are insufficient to assess the complex terrain as well as there are some uncertainties in results while using the given methods. Analysis of the impacts of the prevailing climate conditions in an area on shifts of ecosystems may reduce uncertainties in projecting climate change. In this study, we used different models to depict changes in ecosystems at 1 km × 1 km resolution in Sichuan Province, China during 1961-2010. The results indicate that changes in climate data during the past 50 years were sufficient to cause shifts in the spatial distribution of ecosystems. The trend of shift was from low temperature ecosystems to high temperature ecosystems. Compared with K？ppen classification, the Holdridge system has better adaptation to assess the impacts of climate change on ecosystems in low elevation（0-1000 m）. Moreover, we found that changed areas in ecosystems were easily affected by climate change than unchanged areas by calculating current climate condition.
基金supported by the Science and Technology Research Program of the Institute of Mountain Hazards and Environment,Chinese Academy of Sciences(Grant No.IMHE-ZDRW-08)the Sichuan Science and Technology Program(Grant No.2022JDR0209).
文摘Debris flow hazards seriously threaten thesafety and sustainable development of mountainousareas. Numerous debris flow mitigation measures havebeen implemented worldwide;however, acomprehensive assessment of the specific disasterreduction effects of these measures and their economic,social and ecological benefits is yet to be performed.The western region of Sichuan Province frequentlysuffers from geohazards such as debris flow, and thegovernment has adopted many mitigation measures.This study assessed the benefits of debris flowmitigation measures and identified the key influencingfactors via a field-based study conducted in 81 villagesin western Sichuan province, China. A framework forthe evaluation of the benefits of rural debris flowmitigation measures was constructed andquantitatively evaluated using a survey. Snowballsampling was performed to recruit 81 village leadersand 468 farmers. The results showed that managementand engineering measures were the main methodsused to mitigate debris flow;ecological measures wereauxiliary. The average satisfaction scores of farmers forthese three types of measures were 4.07, 3.90, and 3.56,respectively (as measured on a five-point Likert scale).In contrast, in terms of the benefits of these mitigationmeasures, only a small proportion of villages (11.11%)obtained a high level of comprehensive benefits fromthe debris flow mitigation measures, while the majority(88.89%) received medium to low-level benefits. Toimprove this situation, we further studied and foundthat the main factors that restricted villages fromachieving high-level comprehensive benefits were theunpredictable nature of debris flows, labour forceoutflow and remoteness. Effective control measures, agood economic environment and strong governmentassistance were reported as crucial factors forimproving these comprehensive benefits. This studyprovides socio-scientific references for decisionmakingon rural debris flow mitigation measures while keeping villages at the centre of economic development.
基金National High Technology Research and Development Program of China("863"Program)(2009AA03Z203)
文摘Preparation and characterization of the YBCO superconducting films by chemical solution route with polyethylene glycol(PEG200)and Cu(NO3)2 as precursors are presented.It was found that PEG200 and sucrose were novel chelates and Cu(NO3)2 was an alternative precursor for the preparation of YBCO superconducting film by chemical solution route.The precursor solution was prepared by mixing yttrium trifluoroacetate,barium trifluoroacetate,and copper nitrate in solvent of methanol with chelates including PEG200 and sucrose.YBCO films were prepared by coating the precursor solution on LaAlO3 single crystal substrate,following vacuum drying,rapid calcining,firing and oxygen annealing.The prepared films were characterized by optical microscope(OM),X-ray diffraction(XRD)and scanning electron microscopy(SEM).The results showed that films were crack-free and homogeneous,stronger tendency of(00l)texture,uniform with less pore,pure c-axis orientation.The films showed good superconducting properties,with Tc of 90 K and critical current density(Jc)of 1 MA/cm2(77 K,0 T).This work demonstrates that the developed method is a promising method for preparation of YBCO superconducting film which has a fine superconducting characterization with advantages of simple and rapid.
