The Qinba Mountains are climatically and ecologically recognized as the north-south transitional zone of China.Analysis of its phenology is critical for comprehending the response of vegetation to climatic change.We r...The Qinba Mountains are climatically and ecologically recognized as the north-south transitional zone of China.Analysis of its phenology is critical for comprehending the response of vegetation to climatic change.We retrieved the start of spring phenology(SOS)of eight forest communities from the MODIS products and adopted it as an indicator for spring phenology.Trend analysis,partial correlation analysis,and GeoDetector were employed to reveal the spatio-temporal patterns and climatic drivers of SOS.The results indicated that the SOS presented an advance trend from 2001 to 2020,with a mean rate of−0.473 d yr^(−1).The SOS of most forests correlated negatively with air temperature(TEMP)and positively with precipitation(PRE),suggesting that rising TEMP and increasing PRE in spring would forward and delay SOS,respectively.The dominant factors influencing the sensitivity of SOS to climatic variables were altitude,forest type,and latitude,while the effects of slope and aspect were relatively minor.The response of SOS to climatic factors varied significantly in space and among forest communities,partly due to the influence of altitude,slope,and aspect.展开更多
The emergence of smart grids in India is propelled by an intricate interaction of market dynamics,regulatory structures,and stakeholder obligations.This study analyzes the primary factors that are driving the widespre...The emergence of smart grids in India is propelled by an intricate interaction of market dynamics,regulatory structures,and stakeholder obligations.This study analyzes the primary factors that are driving the widespread use of smart grid technologies and outlines the specific roles and obligations of different stakeholders,such as government entities,utility companies,technology suppliers,and consumers.Government activities and regulations are crucial in facilitating the implementation of smart grid technology by offering financial incentives,regulatory assistance,and strategic guidance.Utility firms have the responsibility of implementing and integrating smart grid infrastructure,with an emphasis on improving the dependability of the grid,minimizing losses in transmission and distribution,and integrating renewable energy sources.Technology companies offer the essential hardware and software solutions,which stimulate creativity and enhance efficiency.Consumers actively engage in the energy ecosystem by participating in demand response,implementing energy saving measures,and adopting distributed energy resources like solar panels and electric vehicles.This study examines the difficulties and possibilities in India’s smart grid industry,highlighting the importance of cooperation among stakeholders to build a strong,effective,and environmentally friendly energy future.展开更多
Osyris lanceolata is heavily and illegally exploited in East Africa for its essential oils, yet little is known about its population status and ecological requirements. This study examined its population structure and...Osyris lanceolata is heavily and illegally exploited in East Africa for its essential oils, yet little is known about its population status and ecological requirements. This study examined its population structure and environmental factors influencing its distribution in the semi-arid Karamoja sub-region, Uganda. We surveyed 388 plots (5 m radius) at different altitudes, recording life stages, stem diameters, and regeneration patterns, and analyzed soil samples. Multivariate analyses, including Canonical Correspondence Analysis (CCA), Detrended Correspondence Analysis (DCA), Non-metric Multidimensional Scaling (NMDS), and Multiple Regression Modeling (MRM), identified key environmental factors affecting its distribution. Findings show that O. lanceolata populations in Moroto, Nakapiripirit, and Amudat districts are severely degraded due to overexploitation. The species is primarily regenerating through coppicing rather than seedlings, with an exploitation intensity of 56.6%. Population densities are low, distribution is irregular, and sustainable harvesting is not viable. Soil properties, particularly Ca2+, N, P, K+, Na+, and organic matter, significantly influence its abundance. Conservation efforts should focus on identifying suitable provenances for genetic preservation and plantation establishment. Areas with at least 9 trees per hectare in Moroto, Nakapiripirit, and Amudat could serve as potential sites for ex-situ plantations. Further research should explore how biotic interactions, genetic diversity, and morphology affect oil yield and quality to support restoration, breeding, and domestication initiatives.展开更多
In recent years,soil acidification has been expanding in many areas of Asia due to increasing reactive nitrogen inputs and industrial activities,which may seriously affect the performance of various ecosystem function...In recent years,soil acidification has been expanding in many areas of Asia due to increasing reactive nitrogen inputs and industrial activities,which may seriously affect the performance of various ecosystem functions.However,the underlying patterns and processes of ecosystem multifunctionality(EMF)are largely unknown at different levels of pH,limiting our understanding of how EMF respond to drivers.This study aims to explore threshold of pH on changes in EMF and differences in the drivers for the changes in EMF on either side of each of the determined pH thresholds.We collected nutrient and environmental databases for raster-level sampling data,totaling 4,000 sampling points.Averaging and cluster-multiple-threshold approach were used to calculate EMF,then quadratic and generalized additive models and Mann-Whitney U were used to determine and test the pH thresholds for changes in EMF,structural equation modellings and variance partitioning analysis were used to explore the main drivers on changes in EMF.The pH threshold for EMF changes in Chinese terrestrial ecosystems is 6.0.When pH<6.0,climate was consistently more important in controlling the variation of EMF than other variables;when pH≥6.0,soil was consistently more important in controlling the variation of EMF than other variables.Specifically,when pH<6.0,mean annual temperature was the main factor in regulating the EMF variation;when pH≥6.0,soil moisture was the main factor in regulating the EMF variation.Our study provides important scientific value for the mechanism of maintaining EMF under global change.For example,with further increases in global nitrogen deposition,leading to increased soil acidification,there are different impacts on EMF in different regions.It may lead to a decrease in EMF in acidic soils and an increase in EMF in alkaline soils.This suggests different management strategies for different regions to maintain EMF stability in the context of future global changes.In the future,more attention should be paid to the biological mechanisms regulating EMF.展开更多
Accelerating the transition from old to new economic drivers(TONED)is fundamental to building a modernized economic system,and the digital economy(DE)has the potential to expedite this process.This study uses panel da...Accelerating the transition from old to new economic drivers(TONED)is fundamental to building a modernized economic system,and the digital economy(DE)has the potential to expedite this process.This study uses panel data that encompassed 273 prefecturelevel cities in China from 2011 to 2020,to empirically examine the effect and underlying mechanisms of the DE on the TONED.The findings indicate that both the DE and TONED exhibit a distinct spatial differentiation,characterized by significantly higher development in the eastern regions compared to the western regions.Furthermore,the robustness test conducted to address the endogeneity problem verifies that DE has a significant positive driving effect on the TONED.In addition,industrial structure upgrading is a significant channel for DE to influence the TONED.Under the constraint of the level of economic development,DE exhibits a non-linear impact on the TONED,and the marginal effect is incremental after passing a specific threshold.Moreover,in the eastern region,non-resource cities,and urban agglomeration areas,DE has a more significant favorable effect on the TONED.The findings provide robust empirical evidence supporting the role of the DE in facilitating the TONED and offer valuable policy insights for developing countries aiming to advance economic transformation.展开更多
As drivers age, roadway conditions may become more challenging, particularly when normal aging is coupled with cognitive decline. Driving during lower visibility conditions, such as inclement weather, is especially ch...As drivers age, roadway conditions may become more challenging, particularly when normal aging is coupled with cognitive decline. Driving during lower visibility conditions, such as inclement weather, is especially challenging for older drivers due to their sensitivity to glare and reduced visibility. As a result, older drivers may adjust their behavior during adverse weather. This paper explores the differential impacts of weather on older drivers with cognitive decline compared to older drivers with normal cognitive function. Data were from a naturalistic driving study of older drivers in Omaha, Nebraska. Driver speed and weather data were extracted and the correlation between speed compliance, road weather conditions, and the cognitive/neurological status of the drivers was examined. Speed compliance was used as the surrogate safety measure since driving at lower speeds can indicate that the driver is challenged by roadway or environmental conditions and can therefore indicate a risk. The percentage of time during a trip when drivers were 16.1 kph under the speed limit was modeled as the dependent variable using beta regression. The variables that resulted in the best fit model were mild cognitive impairment (MCI), age group, traffic density, and weather. Results indicated that the youngest group of older drivers (young-old) spent less time driving at impeding speeds and had the least variability compared to the other two age groups. The middle group of older drivers (middle-old) had the highest amount of time driving at impeding speeds and had more variability than young-old drivers. The oldest group of older drivers (old-old) were the most likely to drive at impeding speeds and had the most variability. In general, older drivers were more likely to drive at impeding speeds during peak hours than during non-peak hours. Additionally, in most cases, older drivers spent less time below the speed limit when the weather was clear than in adverse conditions. Results indicate that older drivers are impacted by weather conditions, and distinct patterns were noted between older drivers who were cognitively impaired compared to drivers with normal cognition.展开更多
The Southern Ocean is a critical component in the Earth system by dominating the global heat and anthropogenic carbon uptake and supplying heat to melt the largest ice sheet.Variability and changes in the water masses...The Southern Ocean is a critical component in the Earth system by dominating the global heat and anthropogenic carbon uptake and supplying heat to melt the largest ice sheet.Variability and changes in the water masses of the Southern Ocean are thus important to the global energy and water cycles,carbon cycling,and sea-level change.In this article,we review the recent progress on understanding the variability and changes in the four major water masses in the Southern Ocean,including Subantarctic Mode Water,Antarctic Intermediate Water,Circumpolar Deep Water and Antarctic Bottom Water.Subantarctic Mode Water and Antarctic Intermediate Water show statistically significant strong circumpolar shoaling,warming,and density reductions since 1970s,indicating that signals of global warming have entered the interior ocean.Meanwhile,strong regional variability of Subantarctic Mode Water and Antarctic Intermediate Water responding to surface buoyancy forcing and westerly winds is attracting more attention.Circumpolar Deep Water is an important modulator of heat content and nutrient concentrations on continental shelves around Antarctica and has made significant contributions to the basal melting of Antarctic ice shelves.Since the late 1950s,a long-term freshening trend in Antarctic Bottom Water in the Ross Sea and its downstream region has been observed and is mainly attributed to the accelerated basal melting of ice shelves in West Antarctica.The shrinking of Antarctic Bottom Water in the Weddell Sea during 1992–2020 has also been revealed and is attributed to reduced sea ice production over the southern Weddell continental shelf related to the Interdecadal Pacific Oscillation and the variability in the Amundsen Sea Low.Though significant advances have been achieved,there is an urgent need to enhance and improve both observations and model performances for better understandings and projections of the formation,transformation,and transport of the water masses in the Southern Ocean.展开更多
Invasive alien plant species(IAPS)pose severe threats to global biodiversity conservation.Effective management of IAPS requires mapping their distribution and identifying the environmental factors that drive their spr...Invasive alien plant species(IAPS)pose severe threats to global biodiversity conservation.Effective management of IAPS requires mapping their distribution and identifying the environmental factors that drive their spread.The Gaoligong Mountains,a renowned biodiversity hotspot in southwestern China,currently face the dual challenges of IAPS invasion and climate change.However,we know little about the distribution patterns,key environmental drivers,and sensitivity of IAPS to future climate change in this region.In this study,we mapped IAPS richness distribution and identified invasion hotspots throughout the Gaoligong Mountains.In addition,we assessed the relative importance of environmental variables in shaping the spatial distribution of IAPS richness and projected potential shifts in IAPS richness under various climate change scenarios.We identified 161 IAPS,primarily concentrated in the low-elevation tropical and subtropical regions along river valleys,forming belt-like invasion hotspots.The key factors shaping IAPS richness included disturbance complexity,elevation,seasonal precipitation,and vegetation types.Notably,IAPS richness significantly declined with increasing elevation and latitude but increased with higher disturbance complexity.Moreover,IAPS were more prevalent in grasslands and shrublands than in forested areas.Ensemble modeling of future climate scenarios predicted that the distribution of IAPS richness would shift to progressively higher elevations.These findings provide valuable insights for managing IAPS in mountainous regions that play a crucial role in global biodiversity conservation.展开更多
The present study aimed to identify risk factors among older adult drivers from realistic data in order to stimulate the development of appropriate safety measures in the future.For this purpose,N=400 archived case fi...The present study aimed to identify risk factors among older adult drivers from realistic data in order to stimulate the development of appropriate safety measures in the future.For this purpose,N=400 archived case files from the driving authority in Dresden(Germany),were systematically analysed.The risk criterion was the outcome of the fitness to drive(FTD)assessment required by the authority.The results show that there are several significant risk factors(aged over 80,dementia,multi-morbidity and involvement into complex accidents)that can serve as cues for being unfit to drive.The practical measures for enhancing traffic safety are discussed.展开更多
<span style="font-family:""><span style="font-family:Verdana;">Flood is a natural process generated by the interaction of various driving fac</span><span style="font-...<span style="font-family:""><span style="font-family:Verdana;">Flood is a natural process generated by the interaction of various driving fac</span><span style="font-family:Verdana;">tors. Flood peak flows, flood frequency at different return periods, and potential driving forces are analyzed in this study. The peak flow of six gauging stations, with a catchment area ranging from 169 -</span></span><span style="font-family:""> </span><span style="font-family:""><span style="font-family:Verdana;">124,108 km</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;"> and sufficient observed streamflow data, was selected to develop threshold (3</span><sup><span style="font-family:Verdana;">rd</span></sup><span style="font-family:Verdana;"> quartile) magnitude and frequency (POTF) that occurred over ten years of records. Sixteen Potential climatic, watershed and human driving factors of floods in the study area were identified and analyzed with GIS, Pearson’s correlation, and Principal Correlation Analysis (PCA) to select the most influential factors. Eight of them (MAR, DA, BE, VS, sand, forest AGR, PD) are identified as the most significant variables in the flood formation of the basin. Moreover, mean annual rainfall (MAR), drainage area (DA), and lack of forest cover are explored as the principal driving factors for flood peak discharge in Wabi-Shebele River Basin. Fi</span></span><span style="font-family:""><span style="font-family:Verdana;">nally, the study resulted in regression equations that helped plan and design different infrastructure works in the basin as ungauged catchment empirical</span><span><span style="font-family:Verdana;"> equations to compute Q</span><sub><span style="font-family:Verdana;">MPF</span></sub><span style="font-family:Verdana;">, Q</span><sub><span style="font-family:Verdana;">5</span></sub><span style="font-family:Verdana;">, Q</span><sub><span style="font-family:Verdana;">10</span></sub><span style="font-family:Verdana;">, Q</span><sub><span style="font-family:Verdana;">50</span></sub><span style="font-family:Verdana;">, and Q</span><sub><span style="font-family:Verdana;">100</span></sub><span style="font-family:Verdana;"> using influential climate, watershed, and human driving factors. The results of these empirical equations are </span></span><span style="font-family:Verdana;">also statistically accepted with a high significance correlation (R</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;"> > 0.9).展开更多
Understory plants are important components of forest ecosystems and play a crucial role in regulating community structures,function realization,and community succession.However,little is known about how abiotic and bi...Understory plants are important components of forest ecosystems and play a crucial role in regulating community structures,function realization,and community succession.However,little is known about how abiotic and biotic drivers affect the diversity of understory species in cold temperate coniferous forests in the semiarid climate region of North China.We hypothesized that(1)topographic factors are important environmental factors affecting the distribution and variation of understory strata,and(2)different understory strata respond differently to environmental factors;shrubs may be significantly affected by the overstory stratum,and herbs may be more affected by surface soil conditions.To test these hypotheses,we used the boosted regression tree method to analyze abiotic and biotic environmental factors that influence understory species diversity,using data from 280 subplots across 56 sites in cold temperate coniferous forests of North China.Elevation and slope aspect were the dominant and indirect abiotic drivers affecting understory species diversity,and individual tree size inequality(DBH variation)was the dominant biotic driver of understory species diversity;soil water content was the main edaphic factors affecting herb layers.Elevation,slope aspect,and DBH variation accounted for 36.4,14.5,and 12.1%,respectively,of shrub stratum diversity.Shrub diversity decreased with elevation within the range of altitude of this study,but increased with DBH variation;shrub diversity was highest on north-oriented slopes.The strongest factor affecting herb stratum species diversity was slope aspect,accounting for 25.9%of the diversity,followed by elevation(15.7%),slope(12.2%),and soil water content(10.3%).The highest herb diversity was found on southeast-oriented slopes and the lowest on northeast-oriented slopes;herb diversity decreased with elevation and soil water content,but increased with slope.The results of the study provide a reference for scientific management and biodiversity protection in cold temperate coniferous forests of North China.展开更多
Competitive use of transboundary freshwater resources is becoming one of the key factors influencing regional peace and political relationship among states.In China, 18 major international river basins are concentrate...Competitive use of transboundary freshwater resources is becoming one of the key factors influencing regional peace and political relationship among states.In China, 18 major international river basins are concentrated in three regions, of which the total annual outflow at the border is 7320×108 m3, occupying 26.8% of the total annual runoff of China, and the inflow at the border is only 172×108 m3.In this paper, we analyzed the major drivers affecting shared water vulnerability in China, namely:(1) changes in physical conditions affecting the availability of water;(2) competing objectives between economic development and ecological conservation;(3) lack of emergency response mechanisms;(4) unsound administrative institutions;and(5) shortcomings in the development of regional cooperation based on transboundary waters.We concluded by identifying four pathways for reducing vulnerability:(1) encouraging scientific research cooperation;(2) constructing information-sharing channels;(3) establishing early-warning mechanisms;and(4) promoting further coordination and negotia-tion.展开更多
A whole circuit model of a linear transformer drivers （LTD） module composed of 60 cavities in series was developed in the software PSPICE to study the influence of switching jitter on the operational performances of...A whole circuit model of a linear transformer drivers （LTD） module composed of 60 cavities in series was developed in the software PSPICE to study the influence of switching jitter on the operational performances of LTDs. In the model, each brick in each cavity is capable of operating with jitter in its switch. Additionally, the manner of triggering cables entering into cavities was considered. The performances of the LTD module operating with three typical cavity-triggering sequences were simulated and the simulation results indicate that switching jitter affects slightly the peak and starting time of the output current pulse. However, the enhancement in switching jitter would significantly lengthen the rise time of the output current pulse. Without considering other factors, a jitter lower than 10 ns may be necessary for the switches in the LTD module to provide output current parameters with an acceptable deviation.展开更多
This paper proposes two lattice traffic models by taking into account the drivers＇ delay in response. The lattice versions of the hydrodynamic model are described by the differential-difference equation and differenc...This paper proposes two lattice traffic models by taking into account the drivers＇ delay in response. The lattice versions of the hydrodynamic model are described by the differential-difference equation and difference-difference equation, respectively. The stability conditions for the two models are obtained by using the linear stability theory. The modified KdV equation near the critical point is derived to describe the traffic jam by using the reductive perturbation method, and the kink-antikink soliton solutions related to the traffic density waves are obtained. The results show that the drivers＇ delay in sensing headway plays an important role in jamming transition.展开更多
The high environmental pollution load caused by the massive pollutant emissions and the accumulation of endogenous and cross-regional pollution has become an important obstacle to the current ecological civilization c...The high environmental pollution load caused by the massive pollutant emissions and the accumulation of endogenous and cross-regional pollution has become an important obstacle to the current ecological civilization construction in the Yangtze River Economic Belt(YREB)in China.Taking the YREB as an example,by using four environmental pollutant emission indicators,including chemical oxygen demand(COD),ammonia nitrogen(NH_(3)-N),sulfur dioxide(SO_(2)),and nitrogen oxides(NO_(x)),this paper established an environmental pollution load index(EPLI)based on the entropy-based measurement.Moreover,the Spatial Durbin Model was used to quantitatively analyze the drivers and spatial effects of environmental pollution load.Finally,specific scientific references were provided for formulating environmental regulations of pollution source control in the YREB.The results showed that:1)During2011-2015,the EPLI in the YREB was reduced significantly and the environmental pollution load increased from upstream to downstream.Among them,the pollution load levels in the Upper Mainstream subbasin,Taihu Lake subbasin,and Lower Mainstream subbasin were the most prominent.2)The environmental pollution load situation in the YREB was generally stable and partially improved.High load level areas were mainly concentrated in the Yangtze River Delta Region and the provincial borders in upstream,midstream,and downstream areas.The high load level areas already formed in Chengdu and Chongqing were also the key regulatory points in the future.3)The degree of local environmental pollution load was apparently affected by the adjacent cities.The population size,industrialization level,and the fiscal decentralization not only drove the increase of the local environmental pollution load level,but also affected the adjacent areas through the spatial spillover effects.The land development intensity mainly drove the increase in the local EPLI in the YREB.While factors such as economic development level and agricultural economic share could only act on the environmental pollution load process in adjacent cities.4)According to the differentiation characteristics of drivers of each city,the YREB was divided into seven zones based on k-medoids cluster method,and targeted zoning control policy recommendations for alleviating environmental pollution load in the YREB were proposed.展开更多
The world is marching into a new development period when the digital technology,physical technology,and biological technology have achieved an unprecedented development respectively in their own fields,and at the same...The world is marching into a new development period when the digital technology,physical technology,and biological technology have achieved an unprecedented development respectively in their own fields,and at the same time their applications are converging greatly.These are the three major technological drivers for the Fourth Industrial Revolution.This paper discusses the specific technology niches of each kind technological driver behind the Fourth Industrial Revolution,and then evaluates impacts of the Fourth Industrial Revolution on global industrial,economic,and social development.At last this paper proposes possible measures and policies for both firms and governments to cope with the changes brought by the Fourth Industrial Revolution.展开更多
Topography, especially altitude, will influence the way, process and characteristics of land cover changes in mountainous area, simultaneously, the vertical difference of land cover changes will affect soil quality an...Topography, especially altitude, will influence the way, process and characteristics of land cover changes in mountainous area, simultaneously, the vertical difference of land cover changes will affect soil quality and regional ecological environment. Therefore, the gradient relationship analysis between land cover changes and altitude is very important for regional sustainability. This study investigated land cover dynamics based on land cover data from a typical mountainous area in the Guizhou-Guangxi karst mountain area, China, in 2000 and 2010, then explored the relationship between altitude and land cover change and analyzed different drivers of land cover change at different altitudes. Our findings are as follows. 1) From 2000 to 2010, the total area of land cover transition was 7167.04 km^2 or 2.8% of the region. The increasing area of build-up land(926.23 km^2) was larger than that of forest(859.38 km^2), suggesting that the urban construction speed was higher than that of reforestation. 2) Intensity of land cover transition in northwestern Guizhou-Guangxi karst mountain area was much larger than that of southeast part and their transition trend was also significantly different, which was consistent with regional population and economy. 3) Human activity was the most dramatic at altitudes between 0–500 m. For 500–1000 m, grassland mainly converted to forest and build-up land. Area of land cover transition was the greatest between 1000–1500 m, while above 1500 m, the transition of grassland was the most obvious. 4) The drivers of land cover change varied. Land cover change was positively correlated with gross domestic product and population density but was inversely related to relief amplitude. There were correlations between land cover change and distance to roads and rivers, and their correlations varied with altitude. By revealing patterns and causes of land cover changes in different altitudes, we hope to understand the vertical dependence of land cover changes, so as to improve land productivity and protect land ecological environment scientifically.展开更多
Transition from old to new economic drivers(TONED) is of great significance for optimizing economic structures. Using a combination of methods including entropy weight technique for order preference by similarity to i...Transition from old to new economic drivers(TONED) is of great significance for optimizing economic structures. Using a combination of methods including entropy weight technique for order preference by similarity to ideal solution, geospatial analysis, and optimal parameter geodetector, this study investigates the patterns and mechanisms of China's TONED in the prefecture-level cities from 2011 to 2020. The findings reveal that(1) the TONED exhibited a spatial distribution characterized by higher levels in the east and lower levels in the west, along with a pyramidal hierarchy of levels. The distribution of hot and cold spots roughly followed the Heihe-Yulin line.(2) The informatization levels, openness to the outside world, and urbanization played a dominant role in the TONED. The types of dual-factor interactions exhibited both dual-factor enhancement and non-linear enhancement effects.(3) The eastern and central regions were more likely to promote the TONED through enhanced informatization levels, whereas the western region relied more on increasing openness. This study finds that the TONED results from the combined effects of three geographical natures, each playing a distinct role. The recommendations provided can serve as a reference for China and other developing countries to implement the TONED in the context of deglobalization.展开更多
Revealing the drivers and scale effects of water pollutant discharges is an important issue in the study of the environmental consequences during urban agglomeration evolution.It is also a prerequisite for realizing c...Revealing the drivers and scale effects of water pollutant discharges is an important issue in the study of the environmental consequences during urban agglomeration evolution.It is also a prerequisite for realizing collaborative water pollutant reduction and environmental governance in urban agglomerations.This paper takes 305 counties in the Yangtze River Delta(YRD)as an example and selects chemical oxygen demand(COD)and ammonia nitrogen(NH_(3)–N)as two distinctive pollutant indicators,using the Spatial Lag Model(SLM)and Spatial Error Model(SEM)to estimate the drivers of water pollutant discharges in 2011 and 2016.Then the Multiscale Geographically Weighted Regression(MGWR)model is constructed to diagnose the scale effect and spatial heterogeneity of the drivers.The findings show that the size of population,the level of urbanization,and the economic development level show global-level increase impacts on water pollutant discharges,while the level of industrialization,social fixed assets investment,foreign direct investment,and local fiscal decentralization are local-level impacts.The spatial heterogeneity of local drivers presents the following characteristics:Social fixed assets investment has a strong promoting effect on both COD and NH_(3)–N discharges in the Hangzhou–Jiaxing–Huzhou region and the coastal area of the YRD;industrialization has a promoting effect on COD discharges in the Taihu Lake basin and Zhejiang province;foreign direct investment has a local inhibitory effect on NH3–N discharge,and the pollution halo effect is more prominent in the marginal areas of the YRD such as northern Jiangsu,northern Anhui,and southern Zhejiang;local fiscal decentralization has a noticeable inhibitory effect on COD discharge in the central areas of the YRD,reflecting the positive impacts on improved local environmental awareness and stronger constraints of multilevel environmental regulations in the urban agglomeration.Therefore,it is recommended to guide greener development to reduce the water pollutant discharge;to embed an environmental push-back mechanism in the fields of industrial production,capital investment,and financial income and expenditure;and to establish a high-quality development pattern of urban agglomerations systematically compatible with the carrying capacity of the water environment.展开更多
Deforestation and forest degradation has been observed to be rampant in Masito-Ugalla ecosystem, Kigoma Region, western part of Tanzania. This paper therefore, intended to assess the extent of deforestation and forest...Deforestation and forest degradation has been observed to be rampant in Masito-Ugalla ecosystem, Kigoma Region, western part of Tanzania. This paper therefore, intended to assess the extent of deforestation and forest degradation in the area, and to determine their causes. A total of 101 respondents were considered as the sample size for this study. The methods used for data collection were household questionnaire interviews, in-depth interviews, focus group discussions, analysis of satellite images and direct observation. The findings indicated that deforestation was occurring in the study area. Satellite data revealed diminished closed woodland, bushed grassland, forest and thickets between 1990 and 2014. On the contrary, settlement area, cultivated land and open woodland had increased during the same time frame. Proximate factors causing deforestation and forest degradation included agricultural expansion, wood extraction and expansion of settlement area. Underlying factors included population growth, poverty, poor levels of education, lack of employment, corruption and embezzlement of public funds by politicians and senior government officials;and high demand for fuel-wood. Biophysical drivers like incidences of unplanned wildfires and socio trigger events notably civil strife were also important. In order to minimize the problem and based on the factors augmenting deforestation and forest degradation in the Masito-Ugalla ecosystem and their coupled negative consequences, effective environmental conservation education, increased patrols, effective law enforcement and provision of alternative energy sources are necessary.展开更多
基金National Key Research and Development Program of China,No.2023YFE0208100,No.2021YFC3000201Natural Science Foundation of Henan Province,No.232300420165。
文摘The Qinba Mountains are climatically and ecologically recognized as the north-south transitional zone of China.Analysis of its phenology is critical for comprehending the response of vegetation to climatic change.We retrieved the start of spring phenology(SOS)of eight forest communities from the MODIS products and adopted it as an indicator for spring phenology.Trend analysis,partial correlation analysis,and GeoDetector were employed to reveal the spatio-temporal patterns and climatic drivers of SOS.The results indicated that the SOS presented an advance trend from 2001 to 2020,with a mean rate of−0.473 d yr^(−1).The SOS of most forests correlated negatively with air temperature(TEMP)and positively with precipitation(PRE),suggesting that rising TEMP and increasing PRE in spring would forward and delay SOS,respectively.The dominant factors influencing the sensitivity of SOS to climatic variables were altitude,forest type,and latitude,while the effects of slope and aspect were relatively minor.The response of SOS to climatic factors varied significantly in space and among forest communities,partly due to the influence of altitude,slope,and aspect.
文摘The emergence of smart grids in India is propelled by an intricate interaction of market dynamics,regulatory structures,and stakeholder obligations.This study analyzes the primary factors that are driving the widespread use of smart grid technologies and outlines the specific roles and obligations of different stakeholders,such as government entities,utility companies,technology suppliers,and consumers.Government activities and regulations are crucial in facilitating the implementation of smart grid technology by offering financial incentives,regulatory assistance,and strategic guidance.Utility firms have the responsibility of implementing and integrating smart grid infrastructure,with an emphasis on improving the dependability of the grid,minimizing losses in transmission and distribution,and integrating renewable energy sources.Technology companies offer the essential hardware and software solutions,which stimulate creativity and enhance efficiency.Consumers actively engage in the energy ecosystem by participating in demand response,implementing energy saving measures,and adopting distributed energy resources like solar panels and electric vehicles.This study examines the difficulties and possibilities in India’s smart grid industry,highlighting the importance of cooperation among stakeholders to build a strong,effective,and environmentally friendly energy future.
文摘Osyris lanceolata is heavily and illegally exploited in East Africa for its essential oils, yet little is known about its population status and ecological requirements. This study examined its population structure and environmental factors influencing its distribution in the semi-arid Karamoja sub-region, Uganda. We surveyed 388 plots (5 m radius) at different altitudes, recording life stages, stem diameters, and regeneration patterns, and analyzed soil samples. Multivariate analyses, including Canonical Correspondence Analysis (CCA), Detrended Correspondence Analysis (DCA), Non-metric Multidimensional Scaling (NMDS), and Multiple Regression Modeling (MRM), identified key environmental factors affecting its distribution. Findings show that O. lanceolata populations in Moroto, Nakapiripirit, and Amudat districts are severely degraded due to overexploitation. The species is primarily regenerating through coppicing rather than seedlings, with an exploitation intensity of 56.6%. Population densities are low, distribution is irregular, and sustainable harvesting is not viable. Soil properties, particularly Ca2+, N, P, K+, Na+, and organic matter, significantly influence its abundance. Conservation efforts should focus on identifying suitable provenances for genetic preservation and plantation establishment. Areas with at least 9 trees per hectare in Moroto, Nakapiripirit, and Amudat could serve as potential sites for ex-situ plantations. Further research should explore how biotic interactions, genetic diversity, and morphology affect oil yield and quality to support restoration, breeding, and domestication initiatives.
基金This work was supported by the Tianshan Programme of Excellence(2022TSYCCX0001)the National Key Program for Basic Research and Development(973 Program)(2012CB417101)。
文摘In recent years,soil acidification has been expanding in many areas of Asia due to increasing reactive nitrogen inputs and industrial activities,which may seriously affect the performance of various ecosystem functions.However,the underlying patterns and processes of ecosystem multifunctionality(EMF)are largely unknown at different levels of pH,limiting our understanding of how EMF respond to drivers.This study aims to explore threshold of pH on changes in EMF and differences in the drivers for the changes in EMF on either side of each of the determined pH thresholds.We collected nutrient and environmental databases for raster-level sampling data,totaling 4,000 sampling points.Averaging and cluster-multiple-threshold approach were used to calculate EMF,then quadratic and generalized additive models and Mann-Whitney U were used to determine and test the pH thresholds for changes in EMF,structural equation modellings and variance partitioning analysis were used to explore the main drivers on changes in EMF.The pH threshold for EMF changes in Chinese terrestrial ecosystems is 6.0.When pH<6.0,climate was consistently more important in controlling the variation of EMF than other variables;when pH≥6.0,soil was consistently more important in controlling the variation of EMF than other variables.Specifically,when pH<6.0,mean annual temperature was the main factor in regulating the EMF variation;when pH≥6.0,soil moisture was the main factor in regulating the EMF variation.Our study provides important scientific value for the mechanism of maintaining EMF under global change.For example,with further increases in global nitrogen deposition,leading to increased soil acidification,there are different impacts on EMF in different regions.It may lead to a decrease in EMF in acidic soils and an increase in EMF in alkaline soils.This suggests different management strategies for different regions to maintain EMF stability in the context of future global changes.In the future,more attention should be paid to the biological mechanisms regulating EMF.
基金Under the auspices of National Natural Science Foundation of China(No.42371188)National Social Science Foundation of China(No.20BJL104)+3 种基金Major Bidding Program of Key Research Base of Humanities and Social Sciences of the Ministry of Education(No.22JJD790016)Major Applied Research Program of Philosophy and Social Sciences in Universities of Henan Province(No.2023-YYZD-03)Special Research Project of Think Tanks in Universities of Henan Province(No.2025ZKYJ07)Funding Program for Young Talents in Publicity,Ideology and Culture,Publicity Department of the CPC Central Committee(No.2021QNYC073)。
文摘Accelerating the transition from old to new economic drivers(TONED)is fundamental to building a modernized economic system,and the digital economy(DE)has the potential to expedite this process.This study uses panel data that encompassed 273 prefecturelevel cities in China from 2011 to 2020,to empirically examine the effect and underlying mechanisms of the DE on the TONED.The findings indicate that both the DE and TONED exhibit a distinct spatial differentiation,characterized by significantly higher development in the eastern regions compared to the western regions.Furthermore,the robustness test conducted to address the endogeneity problem verifies that DE has a significant positive driving effect on the TONED.In addition,industrial structure upgrading is a significant channel for DE to influence the TONED.Under the constraint of the level of economic development,DE exhibits a non-linear impact on the TONED,and the marginal effect is incremental after passing a specific threshold.Moreover,in the eastern region,non-resource cities,and urban agglomeration areas,DE has a more significant favorable effect on the TONED.The findings provide robust empirical evidence supporting the role of the DE in facilitating the TONED and offer valuable policy insights for developing countries aiming to advance economic transformation.
文摘As drivers age, roadway conditions may become more challenging, particularly when normal aging is coupled with cognitive decline. Driving during lower visibility conditions, such as inclement weather, is especially challenging for older drivers due to their sensitivity to glare and reduced visibility. As a result, older drivers may adjust their behavior during adverse weather. This paper explores the differential impacts of weather on older drivers with cognitive decline compared to older drivers with normal cognitive function. Data were from a naturalistic driving study of older drivers in Omaha, Nebraska. Driver speed and weather data were extracted and the correlation between speed compliance, road weather conditions, and the cognitive/neurological status of the drivers was examined. Speed compliance was used as the surrogate safety measure since driving at lower speeds can indicate that the driver is challenged by roadway or environmental conditions and can therefore indicate a risk. The percentage of time during a trip when drivers were 16.1 kph under the speed limit was modeled as the dependent variable using beta regression. The variables that resulted in the best fit model were mild cognitive impairment (MCI), age group, traffic density, and weather. Results indicated that the youngest group of older drivers (young-old) spent less time driving at impeding speeds and had the least variability compared to the other two age groups. The middle group of older drivers (middle-old) had the highest amount of time driving at impeding speeds and had more variability than young-old drivers. The oldest group of older drivers (old-old) were the most likely to drive at impeding speeds and had the most variability. In general, older drivers were more likely to drive at impeding speeds during peak hours than during non-peak hours. Additionally, in most cases, older drivers spent less time below the speed limit when the weather was clear than in adverse conditions. Results indicate that older drivers are impacted by weather conditions, and distinct patterns were noted between older drivers who were cognitively impaired compared to drivers with normal cognition.
基金The Independent Research Foundation of Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)under contract Nos SML2023SP201 and SML2021SP306the Natural Science Foundation of Guangdong Province of China under contract No.2024A1515012717+5 种基金the Initial Research Foundation of Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)under contract Nos 313021004,313022009,and 313022001the National Natural Science Foundation of China under contract No.41706225the National Key R&D Program of China under contract No.2018YFA0605701the Impact and Response of Antarctic Seas to Climate Change under contract No.IRASCC 1-02-01Bthe Shenlan Program funded by Shanghai Jiao Tong University under contract No.SL2020MS021the fund from Shanghai Frontiers Science Center of Polar Research.
文摘The Southern Ocean is a critical component in the Earth system by dominating the global heat and anthropogenic carbon uptake and supplying heat to melt the largest ice sheet.Variability and changes in the water masses of the Southern Ocean are thus important to the global energy and water cycles,carbon cycling,and sea-level change.In this article,we review the recent progress on understanding the variability and changes in the four major water masses in the Southern Ocean,including Subantarctic Mode Water,Antarctic Intermediate Water,Circumpolar Deep Water and Antarctic Bottom Water.Subantarctic Mode Water and Antarctic Intermediate Water show statistically significant strong circumpolar shoaling,warming,and density reductions since 1970s,indicating that signals of global warming have entered the interior ocean.Meanwhile,strong regional variability of Subantarctic Mode Water and Antarctic Intermediate Water responding to surface buoyancy forcing and westerly winds is attracting more attention.Circumpolar Deep Water is an important modulator of heat content and nutrient concentrations on continental shelves around Antarctica and has made significant contributions to the basal melting of Antarctic ice shelves.Since the late 1950s,a long-term freshening trend in Antarctic Bottom Water in the Ross Sea and its downstream region has been observed and is mainly attributed to the accelerated basal melting of ice shelves in West Antarctica.The shrinking of Antarctic Bottom Water in the Weddell Sea during 1992–2020 has also been revealed and is attributed to reduced sea ice production over the southern Weddell continental shelf related to the Interdecadal Pacific Oscillation and the variability in the Amundsen Sea Low.Though significant advances have been achieved,there is an urgent need to enhance and improve both observations and model performances for better understandings and projections of the formation,transformation,and transport of the water masses in the Southern Ocean.
基金supported by the Second Tibetan Plateau Scientific Expedition and Research(STEP)Program(Grant No.2019QZKK0502)National Natural Science Foundation of China(Grant No.U23A20160)Shanghai Science and Technology Innovation Action Plan(Grant No.23015810100).
文摘Invasive alien plant species(IAPS)pose severe threats to global biodiversity conservation.Effective management of IAPS requires mapping their distribution and identifying the environmental factors that drive their spread.The Gaoligong Mountains,a renowned biodiversity hotspot in southwestern China,currently face the dual challenges of IAPS invasion and climate change.However,we know little about the distribution patterns,key environmental drivers,and sensitivity of IAPS to future climate change in this region.In this study,we mapped IAPS richness distribution and identified invasion hotspots throughout the Gaoligong Mountains.In addition,we assessed the relative importance of environmental variables in shaping the spatial distribution of IAPS richness and projected potential shifts in IAPS richness under various climate change scenarios.We identified 161 IAPS,primarily concentrated in the low-elevation tropical and subtropical regions along river valleys,forming belt-like invasion hotspots.The key factors shaping IAPS richness included disturbance complexity,elevation,seasonal precipitation,and vegetation types.Notably,IAPS richness significantly declined with increasing elevation and latitude but increased with higher disturbance complexity.Moreover,IAPS were more prevalent in grasslands and shrublands than in forested areas.Ensemble modeling of future climate scenarios predicted that the distribution of IAPS richness would shift to progressively higher elevations.These findings provide valuable insights for managing IAPS in mountainous regions that play a crucial role in global biodiversity conservation.
文摘The present study aimed to identify risk factors among older adult drivers from realistic data in order to stimulate the development of appropriate safety measures in the future.For this purpose,N=400 archived case files from the driving authority in Dresden(Germany),were systematically analysed.The risk criterion was the outcome of the fitness to drive(FTD)assessment required by the authority.The results show that there are several significant risk factors(aged over 80,dementia,multi-morbidity and involvement into complex accidents)that can serve as cues for being unfit to drive.The practical measures for enhancing traffic safety are discussed.
文摘<span style="font-family:""><span style="font-family:Verdana;">Flood is a natural process generated by the interaction of various driving fac</span><span style="font-family:Verdana;">tors. Flood peak flows, flood frequency at different return periods, and potential driving forces are analyzed in this study. The peak flow of six gauging stations, with a catchment area ranging from 169 -</span></span><span style="font-family:""> </span><span style="font-family:""><span style="font-family:Verdana;">124,108 km</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;"> and sufficient observed streamflow data, was selected to develop threshold (3</span><sup><span style="font-family:Verdana;">rd</span></sup><span style="font-family:Verdana;"> quartile) magnitude and frequency (POTF) that occurred over ten years of records. Sixteen Potential climatic, watershed and human driving factors of floods in the study area were identified and analyzed with GIS, Pearson’s correlation, and Principal Correlation Analysis (PCA) to select the most influential factors. Eight of them (MAR, DA, BE, VS, sand, forest AGR, PD) are identified as the most significant variables in the flood formation of the basin. Moreover, mean annual rainfall (MAR), drainage area (DA), and lack of forest cover are explored as the principal driving factors for flood peak discharge in Wabi-Shebele River Basin. Fi</span></span><span style="font-family:""><span style="font-family:Verdana;">nally, the study resulted in regression equations that helped plan and design different infrastructure works in the basin as ungauged catchment empirical</span><span><span style="font-family:Verdana;"> equations to compute Q</span><sub><span style="font-family:Verdana;">MPF</span></sub><span style="font-family:Verdana;">, Q</span><sub><span style="font-family:Verdana;">5</span></sub><span style="font-family:Verdana;">, Q</span><sub><span style="font-family:Verdana;">10</span></sub><span style="font-family:Verdana;">, Q</span><sub><span style="font-family:Verdana;">50</span></sub><span style="font-family:Verdana;">, and Q</span><sub><span style="font-family:Verdana;">100</span></sub><span style="font-family:Verdana;"> using influential climate, watershed, and human driving factors. The results of these empirical equations are </span></span><span style="font-family:Verdana;">also statistically accepted with a high significance correlation (R</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;"> > 0.9).
基金supported by the National Natural Science Foundation of China(Grant No.31470630)Shanxi Forestry Science and Technology Innovation Project
文摘Understory plants are important components of forest ecosystems and play a crucial role in regulating community structures,function realization,and community succession.However,little is known about how abiotic and biotic drivers affect the diversity of understory species in cold temperate coniferous forests in the semiarid climate region of North China.We hypothesized that(1)topographic factors are important environmental factors affecting the distribution and variation of understory strata,and(2)different understory strata respond differently to environmental factors;shrubs may be significantly affected by the overstory stratum,and herbs may be more affected by surface soil conditions.To test these hypotheses,we used the boosted regression tree method to analyze abiotic and biotic environmental factors that influence understory species diversity,using data from 280 subplots across 56 sites in cold temperate coniferous forests of North China.Elevation and slope aspect were the dominant and indirect abiotic drivers affecting understory species diversity,and individual tree size inequality(DBH variation)was the dominant biotic driver of understory species diversity;soil water content was the main edaphic factors affecting herb layers.Elevation,slope aspect,and DBH variation accounted for 36.4,14.5,and 12.1%,respectively,of shrub stratum diversity.Shrub diversity decreased with elevation within the range of altitude of this study,but increased with DBH variation;shrub diversity was highest on north-oriented slopes.The strongest factor affecting herb stratum species diversity was slope aspect,accounting for 25.9%of the diversity,followed by elevation(15.7%),slope(12.2%),and soil water content(10.3%).The highest herb diversity was found on southeast-oriented slopes and the lowest on northeast-oriented slopes;herb diversity decreased with elevation and soil water content,but increased with slope.The results of the study provide a reference for scientific management and biodiversity protection in cold temperate coniferous forests of North China.
基金The National Key Project for Basic Research on Ecosystem Changes in Longitudinal Range-Gorge Region and Transboundary Eco-security of Southwest China,No.2003CB415105
文摘Competitive use of transboundary freshwater resources is becoming one of the key factors influencing regional peace and political relationship among states.In China, 18 major international river basins are concentrated in three regions, of which the total annual outflow at the border is 7320×108 m3, occupying 26.8% of the total annual runoff of China, and the inflow at the border is only 172×108 m3.In this paper, we analyzed the major drivers affecting shared water vulnerability in China, namely:(1) changes in physical conditions affecting the availability of water;(2) competing objectives between economic development and ecological conservation;(3) lack of emergency response mechanisms;(4) unsound administrative institutions;and(5) shortcomings in the development of regional cooperation based on transboundary waters.We concluded by identifying four pathways for reducing vulnerability:(1) encouraging scientific research cooperation;(2) constructing information-sharing channels;(3) establishing early-warning mechanisms;and(4) promoting further coordination and negotia-tion.
基金supported partly by National Natural Science Foundation of China(Nos.50637010,51077111)partly by the State Key Laboratory of Electrical Insulation and Power Equipment of Xi'an Jiaotong University of China(EIPE09207)
文摘A whole circuit model of a linear transformer drivers （LTD） module composed of 60 cavities in series was developed in the software PSPICE to study the influence of switching jitter on the operational performances of LTDs. In the model, each brick in each cavity is capable of operating with jitter in its switch. Additionally, the manner of triggering cables entering into cavities was considered. The performances of the LTD module operating with three typical cavity-triggering sequences were simulated and the simulation results indicate that switching jitter affects slightly the peak and starting time of the output current pulse. However, the enhancement in switching jitter would significantly lengthen the rise time of the output current pulse. Without considering other factors, a jitter lower than 10 ns may be necessary for the switches in the LTD module to provide output current parameters with an acceptable deviation.
基金Project supported by the National Basic Research Program of China (Grant No 2006CB705500)the National Natural Science Foundation of China (Grant No 10532060)+1 种基金the Natural Science Foundation of Ningbo (Grant Nos 2008A610022 and 2007A610050)K. C. Wang Magna Fund in Ningbo University, China
文摘This paper proposes two lattice traffic models by taking into account the drivers＇ delay in response. The lattice versions of the hydrodynamic model are described by the differential-difference equation and difference-difference equation, respectively. The stability conditions for the two models are obtained by using the linear stability theory. The modified KdV equation near the critical point is derived to describe the traffic jam by using the reductive perturbation method, and the kink-antikink soliton solutions related to the traffic density waves are obtained. The results show that the drivers＇ delay in sensing headway plays an important role in jamming transition.
基金Under the auspices of National Natural Science Foundation of China(No.41971164,41530634)Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA23020101)Second Tibetan Plateau Scientific Expedition and Research Program(No.2019QZKK0406)。
文摘The high environmental pollution load caused by the massive pollutant emissions and the accumulation of endogenous and cross-regional pollution has become an important obstacle to the current ecological civilization construction in the Yangtze River Economic Belt(YREB)in China.Taking the YREB as an example,by using four environmental pollutant emission indicators,including chemical oxygen demand(COD),ammonia nitrogen(NH_(3)-N),sulfur dioxide(SO_(2)),and nitrogen oxides(NO_(x)),this paper established an environmental pollution load index(EPLI)based on the entropy-based measurement.Moreover,the Spatial Durbin Model was used to quantitatively analyze the drivers and spatial effects of environmental pollution load.Finally,specific scientific references were provided for formulating environmental regulations of pollution source control in the YREB.The results showed that:1)During2011-2015,the EPLI in the YREB was reduced significantly and the environmental pollution load increased from upstream to downstream.Among them,the pollution load levels in the Upper Mainstream subbasin,Taihu Lake subbasin,and Lower Mainstream subbasin were the most prominent.2)The environmental pollution load situation in the YREB was generally stable and partially improved.High load level areas were mainly concentrated in the Yangtze River Delta Region and the provincial borders in upstream,midstream,and downstream areas.The high load level areas already formed in Chengdu and Chongqing were also the key regulatory points in the future.3)The degree of local environmental pollution load was apparently affected by the adjacent cities.The population size,industrialization level,and the fiscal decentralization not only drove the increase of the local environmental pollution load level,but also affected the adjacent areas through the spatial spillover effects.The land development intensity mainly drove the increase in the local EPLI in the YREB.While factors such as economic development level and agricultural economic share could only act on the environmental pollution load process in adjacent cities.4)According to the differentiation characteristics of drivers of each city,the YREB was divided into seven zones based on k-medoids cluster method,and targeted zoning control policy recommendations for alleviating environmental pollution load in the YREB were proposed.
基金Under the auspices of National Natural Science Foundation of China(No.41671120,41401125)
文摘The world is marching into a new development period when the digital technology,physical technology,and biological technology have achieved an unprecedented development respectively in their own fields,and at the same time their applications are converging greatly.These are the three major technological drivers for the Fourth Industrial Revolution.This paper discusses the specific technology niches of each kind technological driver behind the Fourth Industrial Revolution,and then evaluates impacts of the Fourth Industrial Revolution on global industrial,economic,and social development.At last this paper proposes possible measures and policies for both firms and governments to cope with the changes brought by the Fourth Industrial Revolution.
基金supported by the National Key Basic Research Program of China (973Program, 2015CB452706)the youth talent team program of the Institute of Mountain Hazards and Environment, CAS (SDSQB-2015-01)+1 种基金the National Natural Science Foundation of China (41401198 and 41571527)the Youth Innovation Promotion Association, CAS(No. 2016332)
文摘Topography, especially altitude, will influence the way, process and characteristics of land cover changes in mountainous area, simultaneously, the vertical difference of land cover changes will affect soil quality and regional ecological environment. Therefore, the gradient relationship analysis between land cover changes and altitude is very important for regional sustainability. This study investigated land cover dynamics based on land cover data from a typical mountainous area in the Guizhou-Guangxi karst mountain area, China, in 2000 and 2010, then explored the relationship between altitude and land cover change and analyzed different drivers of land cover change at different altitudes. Our findings are as follows. 1) From 2000 to 2010, the total area of land cover transition was 7167.04 km^2 or 2.8% of the region. The increasing area of build-up land(926.23 km^2) was larger than that of forest(859.38 km^2), suggesting that the urban construction speed was higher than that of reforestation. 2) Intensity of land cover transition in northwestern Guizhou-Guangxi karst mountain area was much larger than that of southeast part and their transition trend was also significantly different, which was consistent with regional population and economy. 3) Human activity was the most dramatic at altitudes between 0–500 m. For 500–1000 m, grassland mainly converted to forest and build-up land. Area of land cover transition was the greatest between 1000–1500 m, while above 1500 m, the transition of grassland was the most obvious. 4) The drivers of land cover change varied. Land cover change was positively correlated with gross domestic product and population density but was inversely related to relief amplitude. There were correlations between land cover change and distance to roads and rivers, and their correlations varied with altitude. By revealing patterns and causes of land cover changes in different altitudes, we hope to understand the vertical dependence of land cover changes, so as to improve land productivity and protect land ecological environment scientifically.
基金National Natural Science Foundation of China,No.42371188National Social Science Foundation of China,No.20BJL104+2 种基金Major Project of Key Research Bases of Humanities and Social Sciences,Ministry of Education,No.22JJD790016Major Project of Applied Research in Philosophy and Social Sciences at Colleges and Universities in Henan Province,No.2023-YYZD-03Program of Excellence for Graduate Students of Henan University,No.SYLYC2023123。
文摘Transition from old to new economic drivers(TONED) is of great significance for optimizing economic structures. Using a combination of methods including entropy weight technique for order preference by similarity to ideal solution, geospatial analysis, and optimal parameter geodetector, this study investigates the patterns and mechanisms of China's TONED in the prefecture-level cities from 2011 to 2020. The findings reveal that(1) the TONED exhibited a spatial distribution characterized by higher levels in the east and lower levels in the west, along with a pyramidal hierarchy of levels. The distribution of hot and cold spots roughly followed the Heihe-Yulin line.(2) The informatization levels, openness to the outside world, and urbanization played a dominant role in the TONED. The types of dual-factor interactions exhibited both dual-factor enhancement and non-linear enhancement effects.(3) The eastern and central regions were more likely to promote the TONED through enhanced informatization levels, whereas the western region relied more on increasing openness. This study finds that the TONED results from the combined effects of three geographical natures, each playing a distinct role. The recommendations provided can serve as a reference for China and other developing countries to implement the TONED in the context of deglobalization.
基金National Natural Science Foundation of China,No.41971164Strategic Priority Research Program of the Chinese Academy of Sciences,No.XDA23020101。
文摘Revealing the drivers and scale effects of water pollutant discharges is an important issue in the study of the environmental consequences during urban agglomeration evolution.It is also a prerequisite for realizing collaborative water pollutant reduction and environmental governance in urban agglomerations.This paper takes 305 counties in the Yangtze River Delta(YRD)as an example and selects chemical oxygen demand(COD)and ammonia nitrogen(NH_(3)–N)as two distinctive pollutant indicators,using the Spatial Lag Model(SLM)and Spatial Error Model(SEM)to estimate the drivers of water pollutant discharges in 2011 and 2016.Then the Multiscale Geographically Weighted Regression(MGWR)model is constructed to diagnose the scale effect and spatial heterogeneity of the drivers.The findings show that the size of population,the level of urbanization,and the economic development level show global-level increase impacts on water pollutant discharges,while the level of industrialization,social fixed assets investment,foreign direct investment,and local fiscal decentralization are local-level impacts.The spatial heterogeneity of local drivers presents the following characteristics:Social fixed assets investment has a strong promoting effect on both COD and NH_(3)–N discharges in the Hangzhou–Jiaxing–Huzhou region and the coastal area of the YRD;industrialization has a promoting effect on COD discharges in the Taihu Lake basin and Zhejiang province;foreign direct investment has a local inhibitory effect on NH3–N discharge,and the pollution halo effect is more prominent in the marginal areas of the YRD such as northern Jiangsu,northern Anhui,and southern Zhejiang;local fiscal decentralization has a noticeable inhibitory effect on COD discharge in the central areas of the YRD,reflecting the positive impacts on improved local environmental awareness and stronger constraints of multilevel environmental regulations in the urban agglomeration.Therefore,it is recommended to guide greener development to reduce the water pollutant discharge;to embed an environmental push-back mechanism in the fields of industrial production,capital investment,and financial income and expenditure;and to establish a high-quality development pattern of urban agglomerations systematically compatible with the carrying capacity of the water environment.
文摘Deforestation and forest degradation has been observed to be rampant in Masito-Ugalla ecosystem, Kigoma Region, western part of Tanzania. This paper therefore, intended to assess the extent of deforestation and forest degradation in the area, and to determine their causes. A total of 101 respondents were considered as the sample size for this study. The methods used for data collection were household questionnaire interviews, in-depth interviews, focus group discussions, analysis of satellite images and direct observation. The findings indicated that deforestation was occurring in the study area. Satellite data revealed diminished closed woodland, bushed grassland, forest and thickets between 1990 and 2014. On the contrary, settlement area, cultivated land and open woodland had increased during the same time frame. Proximate factors causing deforestation and forest degradation included agricultural expansion, wood extraction and expansion of settlement area. Underlying factors included population growth, poverty, poor levels of education, lack of employment, corruption and embezzlement of public funds by politicians and senior government officials;and high demand for fuel-wood. Biophysical drivers like incidences of unplanned wildfires and socio trigger events notably civil strife were also important. In order to minimize the problem and based on the factors augmenting deforestation and forest degradation in the Masito-Ugalla ecosystem and their coupled negative consequences, effective environmental conservation education, increased patrols, effective law enforcement and provision of alternative energy sources are necessary.
