Scientifically assessing the suitability, safety and resilience of urban development is the premise for high-quality regional development in China. Here we developed a high-precision coupling model for comprehensive a...
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Scientifically assessing the suitability, safety and resilience of urban development is the premise for high-quality regional development in China. Here we developed a high-precision coupling model for comprehensive assessing the spatially explicit adaptation, and livability and safety of urban development, based on urban expansion and nine types of natural disaster risks data in 1990–2020. Through remote sensing and big data mining methods, we revealed spatial differentiation characteristics of urban development's spatial adaptation and livability safety levels over the past three decades, diagnosing the expansion status of cities at varying potential safety risk levels. The results indicate that urban development was primarily concentrated in medium to high suitability level areas(83.23%, 5.23×10~4 km2) from 1990 to 2020, with 14.46% of urban expansion occurring in the lowest suitability areas, predominantly in the eastern coastal and western regions. From the safety aspect, urban development predominantly occurred in areas with medium to highest safety levels(49%), yet 13% of urban expansion areas exhibit relatively high safety risks. In the eastern coastal regions, the primary threat is water-related risks, with urban expansion in these risk areas accounting for 62% of total expansion. The western region is mainly threatened by geological earthquake risks, with urban expansion area in these risk zones exceeding by more than four times of that in the eastern, central, and northeastern regions. The central region is primarily at risk from high-temperature disaster, while the northeastern region faces risks from low-temperature and snow-related disasters. Overall, urban development in China over the past three decades has displayed a pattern of the highsuitability and high-expansion in the eastern regions, medium-suitability and medium-speed expansion in the central region, lowsuitability and low-expansion in the western region, and the high-suitability and slow-ex
The Hengduan Mountains region(HMR)is one of the most densely distributed and severe flash flood disaster-prone areas in southwest *** is also a key area for major engineering projects and beautiful countryside constru...
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The Hengduan Mountains region(HMR)is one of the most densely distributed and severe flash flood disaster-prone areas in southwest *** is also a key area for major engineering projects and beautiful countryside construction in Southwest ***,previous studies have not systematically summarized the development characteristics and formation modes of flash flood disasters in the HMR,which limits the development of theoretical and technical system for flood *** this study,we focused on the physical processes of flash flood disasters in the HMR,including generation,movement,and disaster formation,and clarified the dominant disaster-inducing conditions(multiple humid monsoon circulation,high potential energy and high heterogenous underlying surface)and disaster development characteristics(high spatio-temporal heterogeneity,highly concentrated energy,chain and cascading effects,and clustered occurrence)of flash floods in the *** on the entire processes of flash flood disasters,three major formation modes have been summarized:the runoff generation mode of vegetation-hydrology-soil coupling dominated by high hydraulic gradient in mountainous areas,strong flow-sediment coupling movement,and serious disaster losses due to high exposure of disaster bearing ***,based on the issues in previous research,four future research challenges for flash flood disaster in the HMR were *** study provides insights into disaster prevention and reduction research,including fundamental theoretical system,precise risk assessment of regional disasters,and accurate early warning and forecasting of flash floods.
Meeting the increasing food demand in a manner that ensures both resources and environmental sustainability poses a global *** conceptual framework of planetary boundaries(PBs)has emerged as a crucial reference in the...
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Meeting the increasing food demand in a manner that ensures both resources and environmental sustainability poses a global *** conceptual framework of planetary boundaries(PBs)has emerged as a crucial reference in the study of sustainable food system,with specific focuses on key dimensions such as land use change,freshwater use,nitrogen(N)and phosphorus(P)cycles,and greenhouse gas(GHG)*** this study,we summarized the threshold applications of PBs in sustainable food system research at both the global and national(China)*** on these thresholds,we evaluated the sustainability conditions of the food system,considering resources such as cropland,freshwater,N and P applications,as well as environmental impacts including N and P losses,and GHG *** addition,we explored the impacts of single or combined management strategies on sustainable food *** strategies included dietary changes,improvements in technologies and management,reductions in food loss and waste,and optimization in agricultural production ***,we outlined future research directions in sustainable food system,including enhancing research on the interaction mechanisms among PBs elements within food systems,conducting downscaling studies of PBs elements at national and regional levels,and ensuring the rationality of policy-making for sustainable food systems in *** study can provide a theoretical foundation and strategies guidance for sustainable food system and agricultural land use management in the future both globally and in China.
This study investigates the distribution,geochemical behavior,and potential anthropogenic influences of rare earth elements(REEs)in the surface sediments of Qinghai Lake,the largest saline lake in China.A total of 36 ...
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This study investigates the distribution,geochemical behavior,and potential anthropogenic influences of rare earth elements(REEs)in the surface sediments of Qinghai Lake,the largest saline lake in China.A total of 36 surface sediment samples were analyzed for REE concentrations with a combination of self-organizing maps(SOM)and positive matrix factorization(PMF).Results indicate distinct enrichment patterns,with light REEs(LREEs)exhibiting higher concentrations than heavy REEs(HREEs),reflecting natural abundances and geochemical *** minimum value was found in Lu as low as 0.091 mg/kg,and the maximum concentration was exhibited in Ce at 78.877 mg/*** index(I_(geo))analysis reveals minor to moderate enrichment of specific REEs of Sm and Nd,suggesting possible localized anthropogenic inputs,particularly near river *** analysis using inverse distance weighting(IDW)and self-organizing maps(SOM)highlights significant correlations between REE distributions and riverine inputs,underscoring fluvial transport's role in sedimentary REE *** identifies mixed natural and anthropogenic sources,with agricultural and industrial activities contributing to elevated REE levels in *** findings provide critical insights into the geochemical behavior of REEs in saline lake systems and off er a foundation for pollution control and sustainable resource management in sensitive environments like Qinghai Lake.
Spatial and temporal changes in ecosystem services(ESs)are driven by two types of factors:environmental factors and trade-offs/synergies between *** the ecological conservation red line(ECRL)area,in which national eco...
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Spatial and temporal changes in ecosystem services(ESs)are driven by two types of factors:environmental factors and trade-offs/synergies between *** the ecological conservation red line(ECRL)area,in which national ecological security and social sustainable development are guaranteed,it is particularly important to clarify the driving mechanism of ESs for the management of *** this study,soil conservation,water yield,and carbon sequestration in Beijing’s ECRL area are quantified,and GeoDetector is used to identify the factors influencing the trade-offs/synergies between ***,partial correlation analysis is used to calculate the net trade-offs/synergies and compare them with the extent to which environmental variables contribute to *** results are as follows:environmental variables and trade-offs/synergies have different effects on the changes in ESs,and their interactions can enhance the determinative power of the corresponding individual *** land use intensity is an extremely important factor affecting the trade-offs/synergies between the three services,indicating that rational land use planning in Beijing’s ECRL area is crucial for avoiding the negative impacts of trade-offs and enabling coordinated optimization of *** the elimination of the cross-influence of environmental variables,the trade-offs/synergies change significantly,and the impact of environmental variables on ESs is compared with the net trade-offs/*** variables are the driving forces of the spatiotemporal changes in soil *** and carbon sequestration have similar effects on water *** changes in carbon sequestration are closely related to the other two services,with smaller influences from environmental variables.
This paper studied the fertilizer rate(FR), fertilizer use efficiency(FUE) and fertilizer overuse rate(FOR) of rice, corn and wheat in China from 1998 to 2018 and briefly analysed the reasons why farmers were willing ...
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This paper studied the fertilizer rate(FR), fertilizer use efficiency(FUE) and fertilizer overuse rate(FOR) of rice, corn and wheat in China from 1998 to 2018 and briefly analysed the reasons why farmers were willing to apply more fertilizers.(1) The FR of grain in China reached 373.7 kg/ha in 2018, an increase of 26.8% compared to that in 1998. In 2018, the FR for corn was the highest, at 411.2 kg/ha, compared to the values of 338.3 kg/ha for rice and 371.7 kg/ha for wheat.(2) In recent years, the FUE of grain in China has obviously improved, with values of 32.9% in 1998, 36.7% in 2008, and 39.3% in 2018. In 2018, the FUE for rice was the highest(41.2%), followed by that for corn(39.9%), and the FUE for wheat was the lowest(36.0%).(3) By 2018, fertilizer was overused in all zones of rice, corn and wheat. In 2018, the average FOR for wheat reached 69.0%, which was 35.9% higher than that for corn and 42.8% higher than that for rice.(4) The lower price of chemical fertilizers was the main reason leading to overapplication.(5) Establishing market mechanisms and adjusting regional planting structures can be effective in reducing the application of chemical fertilizers.
Historical forest and grassland cover changes not only are critical indicators for quantifying ecological and environmental change processes but also serve as fundamental data for long-term climate change simulations ...
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Historical forest and grassland cover changes not only are critical indicators for quantifying ecological and environmental change processes but also serve as fundamental data for long-term climate change simulations and terrestrial ecosystem carbon emission ***,because of limitations in historical data,quantitative estimations and spatially gridded reconstructions of these changes remain challenging,necessitating further methodological *** study focused on China's present-day land area over the past millennium,objectively capturing the characteristics and drivers of forest and grassland cover *** this basis,using the forest transition theory and the space-for-time substitution method,we depicted the historical deforestation process as an inverted“S”curve and developed a model to reconstruct historical forest area changes based on the functional relationship between the forest area and population size ***,a gridded forest allocation model was established on the basis of deforestation *** the grassland cover,we implemented regionspecific methods,such as the cropland area deduction method and the habitat constraint method,to quantitatively reconstruct historical ***,we obtained provincial forest and grassland area changes over the past millennium and mapped 10-km-resolution gridded data of forest and grassland *** results indicated the following.(1)The methods developed using population data as a proxy objectively reproduced the spatiotemporal evolution of forest and grassland cover in China over the past *** feasible methods offer a novel pathway for the quantitative reconstruction of historical forest and grassland cover changes.(2)The data indicated that China's forest area generally decreased over the past millennium,characterized by a“decrease-then-increase”*** forest area experienced three distinct phases:a slow decline(AD 1000–1650),a rapid decline(AD 16
The vulnerability curve is a key method for assessing flood loss risk,which contributes to the improvement of flood prevention and relief ***,existing vulnerability curves are typically developed on a large spatial sc...
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The vulnerability curve is a key method for assessing flood loss risk,which contributes to the improvement of flood prevention and relief ***,existing vulnerability curves are typically developed on a large spatial scale,and intraregional variations in vulnerability are *** study aims to quantify the spatial heterogeneity of vulnerability within a region and elucidate the impact of vulnerability on flood *** Hubei and Hunan provinces in China as case study areas,vulnerability curves are constructed using a mixed-effects *** curves are then combined with flood intensities across various return periods to estimate flood *** addition,the influence of vulnerability and flood intensity on flood losses is *** results indicate that the mixed-effects model is effective in constructing distinct vulnerability curves for smaller-scale administrative units(***)while also assessing the overall vulnerability of the study area,and it achieves high accuracy(R^(2)>0.75).The disparities in loss rates between cities increase under longer return ***,the variation in vulnerability between cities is the primary factor influencing flood losses for short return periods,whereas differences in hazard intensity have a greater impact on city flood losses during longer return *** study provides methods and recommendations for systematic flood risk reduction and proposes pathways for enhancing climate resilience.
It is crucial to investigate the characteristics of fire danger in the areas around Beijing to increase the accuracy of fire danger monitoring,forecasting,and *** meteorological data from 17 national meteorological st...
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It is crucial to investigate the characteristics of fire danger in the areas around Beijing to increase the accuracy of fire danger monitoring,forecasting,and *** meteorological data from 17 national meteorological stations in the areas around Beijing from 1981−2021,this study calculated the fire weather index(FWI)and analyzed its spatiotemporal *** was found that the high and low fire danger periods were in April−May and July−August,with spatial patterns of“decrease in the northwest−increase in the southeast”and a significant increase throughout the areas around Beijing,***,the contributions of different meteorological factors were quantified by the multiple regression *** found that during the high fire danger period,the northern and southern parts were affected by precipitation and minimum relative humidity,***,most areas were influenced by wind speed during the low fire danger ***,comparing with the FWI characteristics under different SSP scenarios,we found that the FWI decreased during high fire danger period and increased during low fire danger period under different SSP scenarios(i.e.,SSP245,SSP585)for periods of 2021−2050,2071−2100,2021−2100,except for SSP245 in 2071−2100 with an increasing trend both in high and low fire danger *** study implies that there is a higher probability of FWI in the low fire danger period,threatening the ecological environment and human ***,it is necessary to enhance research on fire danger during the low fire danger period to improve the ability to predict summer fire danger.
Latitudinal patterns of treeβ-diversity reveal important insights into the biogeographical processes that influence forest *** previous studies have extensively documentedβ-diversity within relatively small spatial ...
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Latitudinal patterns of treeβ-diversity reveal important insights into the biogeographical processes that influence forest *** previous studies have extensively documentedβ-diversity within relatively small spatial extents,the potential drivers ofβ-diversity along latitudinal gradients are still not well understood at larger spatial *** this study,we determined whether treeβ-diversity is correlated with latitude in forests of southeastern China,and if so,what ecological processes contribute to these patterns of treeβ-*** specifically aimed to disentangle the relative contributions from interspecific aggregation and environmental filtering across various spatial *** delineated regional communities comprising multiple nearby national forest inventory(NFI)plots around random focal *** number of NFI plots in a regional community served as a surrogate for spatial *** also used a null model to simulate randomly assembled communities and quantify the deviation(β-deviation)between observed and expectedβ-*** found thatβ-diversity decreased along a latitudinal gradient and that this pattern was clearer at larger spatial *** addition,latitudinal patterns ofβ-deviation were explained by the degree of species spatial *** also identified environmental factors that driveβ-deviation in these forests,including precipitation,seasonality,and temperature *** larger spatial extents,these environmental variables explained up to 84%of theβ-*** results reinforce that ecological processes are scale-dependent and collectively contribute to theβ-gradient in subtropical *** recommend that conservation efforts maintain diverse forests and heterogeneous environments at multiple spatial extents to mitigate the adverse effects of climate change.
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