With the continuous increase of rapid urbanization and population growth,sustainable urban land-use planning is becoming a more complex and challenging task for urban planners and decision-makers.Multi-objective land-...With the continuous increase of rapid urbanization and population growth,sustainable urban land-use planning is becoming a more complex and challenging task for urban planners and decision-makers.Multi-objective land-use allocation can be regarded as a complex spatial optimization problem that aims to achieve the possible trade-offs among multiple and conflicting objectives.This paper proposes an improved Non-dominated Sorting Biogeography-Based Optimization(NSBBO)algorithm for solving the multi-objective land-use allocation problem,in which maximum accessibility,maximum compactness,and maximum spatial integration were formulated as spatial objectives;and space syntax analysis was used to analyze the potential movement patterns in the new urban planning area of the city of Kigali,Rwanda.Efficient Non-dominated Sorting(ENS)algorithm and crossover operator were integrated into classical NSBBO to improve the quality of non-dominated solutions,and local search ability,and to accelerate the convergence speed of the algorithm.The results showed that the proposed NSBBO exhibited good optimal solutions with a high hypervolume index compared to the classical NSBBO.Furthermore,the proposed algorithm could generate optimal land use scenarios according to the preferred objectives,thus having the potential to support the decision-making of urban planners and stockholders in revising and updating the existing detailed master plan of land use.展开更多
Long-term droughts,temperature rise,and extreme weather events cause changes in runoff,evaporation,and transpiration in basins.These changes are more severe in arid and semi-arid regions.Since 2007,the discharge of ba...Long-term droughts,temperature rise,and extreme weather events cause changes in runoff,evaporation,and transpiration in basins.These changes are more severe in arid and semi-arid regions.Since 2007,the discharge of baseflow of the Zagros Mountain has decreased and made the supply of agricultural,industrial,and drinking water a big challenge.In this investigation,utilizing data from weather stations,the output of CORDEX,and the WetSpass model,the impact of climate change on river discharge in the Great Karun Basin(GKB)was examined.The temperature and precipitation projections for the period 2019-2040 were analyzed using the Coupled Model Intercomparison Project Phase Six(CMIP6)under scenarios SSP2-4.5 and SSP5-8.5.The findings reveal that the minimum and maximum temperatures are expected to increase by 0.2℃ to 5.1℃ and 0.1℃ to 3.6℃,respectively.Annual precipitation will decrease between 1.3%and 16.7%in scenario SSP2-4.5 and 23.4%in scenario SSP5-8.5.The results of the WetSpass Model for predicting future scenarios indicate a decrease in direct flow(5%),total discharge(27%),and interception(15%).As evapotranspiration will increase by 15%due to climate change,it will be more difficult to predict the water resources’volume of the Karoun Basin for the next decades.Adapting to climate change is the appropriate solution to solve this problem.Changes in temperature and precipitation in these areas pose major challenges to water resources.展开更多
River confluences represent an integral component of the fluvial system,with the potential to disrupt downstream longitudinal trends in the main river through inputs of water,sediments,and other materials,such as wood...River confluences represent an integral component of the fluvial system,with the potential to disrupt downstream longitudinal trends in the main river through inputs of water,sediments,and other materials,such as woody debris.These various inputs at confluence zones result in a high degree of morphological and,consequently,ecological diversity.This study examines the potential relationship between the spatial characteristics of the catchment and the parameters of the confluence hydrodynamic zones(CHZs).A total of 15 tributaries and their adjacent CHZs were selected for analysis along a 50 km reach of the VsetínskáBečva River in the Javorníky and Hostýn-Vsetín Mountains in the Czech part of the Outer Western Carpathians.The VsetínskáBečva River is highly channelized,with the majority of channelization efforts involving riverbank stabilization,weirs,or grade control structures.The study hypothesized a correlation between the spatial arrangement of the channel,as indicated by the channel width symmetry ratio,and the angle between the tributary and main-stem river,and the increased morphological activity,evidenced by changes in average bed depth at the CHZs.The correlation coefficient(r)and p significance were employed to describe the relationships among the parameters.The results indicated a significant correlation between channel width and the catchment area symmetry ratio(r=0.747,p=0.001),likely influenced by channel regulation works(e.g.,channel shape or size),which are often artificially adjusted to accommodate local hydrological conditions and flood discharges for flood protection.A significant inverse correlation between channel width symmetry ratio and average main-stem channel depth was also found(r=-0.584,p=0.022).展开更多
Water scarcity in Khuzestan Province,Iran,has attracted growing concerns despite the region's abundant water resources.The province predominantly relies on surface water,prompting an assessment of groundwater'...Water scarcity in Khuzestan Province,Iran,has attracted growing concerns despite the region's abundant water resources.The province predominantly relies on surface water,prompting an assessment of groundwater's potential to supplement water supplies during surface water shortages.This study assesses the province's groundwater availability and quality under increased exploitation conditions.Between 2008 and 2018,data on groundwater quantity and quality were collected from 204 exploration wells and 70 piezometric wells across 19 aquifers.The analysis revealed that 53%of aquifers in the eastern and northeastern regions experienced declining groundwater levels.Hydrochemical assessments indicated low concentrations of major ions in the northeastern,while high levels were observed from the central region towards the southeast.These variations were attributed to agricultural and industrial activities,seawater intrusion,and the influences of evaporation and geological factors.The dominant hydrochemical facies identified were of the Ca-Cl type.Water quality classification showed that 48%of groundwater samples fell within the C4S4-C4S1 category,primarily in the western,central,and southern regions,while 27%were classified as C3S2,C3S1,and 25%as C2S1,mainly in the northern and eastern regions.The Irrigation WWater Quality(IWQ)index indicated that many samples were suitable for irrigation.Additionally,the analysis potable groundwater was primarily found in the northern,northeastern,and eastern aquifers,with quality declining toward the south.The study highlights that certain aquifers in the northern and eastern regions offer greater potential for sustainable groundwater exploitation during water shortages.These findings provide valuable insights for on how to implement effective land and water management strategies to mitigate future water crises.展开更多
Doline susceptibility mapping(DSM)in karst aquifer is important in terms of estimating the vulnerability of the aquifer to pollutants,estimating the infiltration rate,and infrastructures exposed to the development of ...Doline susceptibility mapping(DSM)in karst aquifer is important in terms of estimating the vulnerability of the aquifer to pollutants,estimating the infiltration rate,and infrastructures exposed to the development of dolines.In this research,doline susceptibility map was prepared in Saldaran mountain by generalized linear model(GLM)using 14 affecting parameters extracted from satellite images,digital elevation model,and geology map.Only 8 parameters have been inputted to the model which had correlation with dolines.In this regards,306 dolines were identified by the photogrammetric Unmanned Aerial Vehicles(UAV)method in 600 hectares of Salderan lands and then,these data were divided into the training(70%)and testing(30%)data for modelling.The results of DSM modeling showed that classified probability of doline occurrences in the Saldaran mountain were as follow:16.5%of the area high to very high,72%in the class of low to very low,and 5%in the moderate class.Also,locally,in Saldaran mountain,the Pirghar aquifer has the highest potential for the doline development,followed by Bagh Rostam and Sarab aquifers.Also,the precipitation,digital elevation model,Topographic Position Index,drainage density,slope,TRASP(transformed the circular aspect to a radiation index),Snow-Covered Days and vegetation cover index are of highest importance in the DSM modeling,respectively.Accurate evaluation of the model using the Receiver Operating Characteristics(ROC)curve represents a very good accuracy(AUC=0.953)of the DSM model.展开更多
A new renewable material by use reed biochar(Phragmites autralis);a species strong grows and very high biomass,it can be exploit a renewable resources for agriculture and environmental treatment.People often used rice...A new renewable material by use reed biochar(Phragmites autralis);a species strong grows and very high biomass,it can be exploit a renewable resources for agriculture and environmental treatment.People often used rice husks as materials for organic fertilizers in agriculture.This study is a new discovere to made of reed biochar to filter N,P,K of chemical mineral fertilizer and pig urine use to provide bio-organic fertilizer for rice plant(ST 25).Methods:(1)Made of biochar by use the local method;(2)analyse the chemical indicators of locations on trunks,leaves,flowers;(3)identify chemical indicators of peatland on locations of experiment;(4)adsorpting chemical fertilizer(nitrogen,phosphorus and potash),pig urine filter by reed biochar,analize its chemical indicators;(5)use fomulas of reed plant biochar mixed peat and mineral inorganic fertilizer.Results:Made of reed biochar and it can adsorpted as ammonium,nitrate,nitrogen,phosphorus and kalium the pig urine and it also adsorpted inorganic fertilizer as nitrogen,phosphorus and Kalium.Thus it used for environmental treatment in the region polluted and planting local rice ST 25 in the experiment area.Conclusion:Biochar of reed can use to environment treatment and agriculture fertilizer;chemical indicators of bichar indentified;the mixed biochar,peat and inorganic in formulas in 5 days and 10 days were not differences;biochar can adsorb some chemical components of pig urine and nitrogen,phosphorus and kalium;biochar can mixed peat and inorganic mineral to planting rice ST 25 in Mekong Delta.展开更多
The intertwined challenges of climate change, resource scarcity, and conflict require innovative integrated solutions that address both environmental and societal vulnerabilities. Technological innovation offers a tra...The intertwined challenges of climate change, resource scarcity, and conflict require innovative integrated solutions that address both environmental and societal vulnerabilities. Technological innovation offers a transformative pathway for climate change adaptation and peacebuilding, with emphasis on a holistic approach to managing resource conflicts and environmental challenges. This paper explores the synergies between emerging technologies and strategic framework to mitigate climate-induced tensions and foster resilience. It focuses on the application of renewable energy systems to reduce dependence on contested resources, blockchain technology to ensure transparency in climate finance, equitable resource allocation and Artificial Intelligence (AI) to enhance early warning systems for climate-related disaster and conflicts. Additionally, technologies such as precision agriculture and remote sensing empower communities to optimize resource use, adapt to shifting environmental conditions, and reduce competition over scares resources. These innovations with inclusive governance and local capacity-building are very primordial. Ultimately, the convergence of technology, policy, and local participation offers a scalable and replicable model for addressing the dual challenges of environmental degradation and instability, thereby paving the way for a more sustainable and peaceful future.展开更多
Compared to lake area and water level,lake storage capacity more intuitively reflects regional climate changes.In this study,we first derived lakebed elevation profiles for individual ICESat-2 tracks based on the unde...Compared to lake area and water level,lake storage capacity more intuitively reflects regional climate changes.In this study,we first derived lakebed elevation profiles for individual ICESat-2 tracks based on the underwater stratification of laser photons,then integrating all valid elevation tracks within the water body to interpolate the bathymetry.On this basis,we calculated the capacity and its time series directly,with the aid of lake boundaries and water levels obtained from optical imagery and CryoSat-2 data.Next,we also applied an empirical formula to estimate the water volume changes of Bangdag Co by combining the area and water levels from 2010 to 2023.Finally,we compared the results of Bangdag Co's water volume changes obtained from the two different methods and conducted a detailed analysis of their performance and regional applicability.The bathymetric map of Bangdag Co reveals a distinct spatial pattern,with the northeastern part significantly deeper(with a maximum depth of 35.27 m)and the southwestern part shallower.The average depth of the lake is 13.99 m.We further estimated that the lake storage capacity in November 2023 was 2.95 km^(3).Water volume changes estimated using the empirical formula were highly consistent with those derived from the lake storage capacity time series(from 2010 to 2023,the lake storage capacity increased by 1.04 km^(3)).Our comparison revealed that the empirical formula method reflects only changes in water volume.In contrast,while our method can accurately estimate lake storage capacity,it is constrained to shallow,clear,and elongated east-west lakes(e.g.,Ayakkum Lake).In summary,the ICESat-2 laser altimetry data,which do not rely on measured water depths,offer an essential complement to underwater topography detection and provide a novel perspective on lake volume estimation research.展开更多
This study investigates the impact of vegetation-climate feedback on the global land monsoon system during the Last Interglacial(LIG,127000 years BP)and the mid-Holocene(MH,6000 years BP)using the earth system model E...This study investigates the impact of vegetation-climate feedback on the global land monsoon system during the Last Interglacial(LIG,127000 years BP)and the mid-Holocene(MH,6000 years BP)using the earth system model EC-Earth3.Our findings indicate that vegetation changes significantly influence the global monsoon area and precipitation patterns,especially in the North African and Indian monsoon regions.The North African monsoon region experienced the most substantial increase in vegetation during both the LIG and MH,resulting in significant increases in monsoonal precipitation by 9.8%and 6.0%,respectively.The vegetation feedback also intensified the Saharan Heat Low,strengthened monsoonal flows,and enhanced precipitation over the North African monsoon region.In contrast,the Indian monsoon region exhibited divergent responses to vegetation changes.During the LIG,precipitation in the Indian monsoon region decreased by 2.2%,while it increased by 1.6%during the MH.These differences highlight the complex and region-specific impacts of vegetation feedback on monsoon systems.Overall,this study demonstrates that vegetation feedback exerts distinct influences on the global monsoon during the MH and LIG.These findings highlight the importance of considering vegetation-climate feedback in understanding past monsoon variability and in predicting future climate change impacts on monsoon systems.展开更多
Studying runoff characteristics and quantifying human activities’impact on northern Shaanxi,a crucial mineral resource area in China,is crucial to alleviate water resource contradictions.In this study,hydrological el...Studying runoff characteristics and quantifying human activities’impact on northern Shaanxi,a crucial mineral resource area in China,is crucial to alleviate water resource contradictions.In this study,hydrological element trends were analyzed using theβ-z-h three-parameter indication method.The Mann-Kendall,Pettitt,moving T,and Yamamoto methods were used to test the mutation point of hydrological elements.The Budyko framework was used to quantitatively assess the impacts of climate change and multiple human activities on runoff reduction.The results showed that(1):Precipitation(PRE),potential evapotranspiration(E0),and temperature(TEM)showed increasing trends;runoff in the Huangfuchuan,Gushanchuan,Kuye River,Tuwei River,Wuding River,Qingjian River,and Yanhe River catchments showed decreasing trends(HFC,GSC,KYR,TWR,WDR,QJR,YR);whereas runoff in the Jialu River(JLR)catchment showed a“V-shaped”trend from 1980 to2020.(2)Runoff was positively correlated with PRE and negatively correlated with E0and the subsurface index(n),with the elasticity coefficients of PRE,E0,and n showing an increasing trend in the change period.(3)Human activities were a key factor in runoff reduction,although the impact of different human activities showed spatial variations.This study provides a scientific foundation for achieving the sustainable development of water resources in mining areas.展开更多
Soil capacity to support life and to produce economic goods and services is strongly linked to the maintenance of good soil physical quality(SPQ). In this study, the SPQ of citrus orchards was assessed under three dif...Soil capacity to support life and to produce economic goods and services is strongly linked to the maintenance of good soil physical quality(SPQ). In this study, the SPQ of citrus orchards was assessed under three different soil managements, namely no-tillage using herbicides, tillage under chemical farming, and no-tillage under organic farming. Commonly used indicators, such as soil bulk density,organic carbon content, and structural stability index, were considered in conjunction with capacitive indicators estimated by the Beerkan estimation of soil transfer parameter(BEST) method. The measurements taken at the L'Alcoleja Experimental Station in Spain yielded optimal values for soil bulk density and organic carbon content in 100% and 70% of cases for organic farming. The values of structural stability index indicated that the soil was stable in 90% of cases. Differences between the soil management practices were particularly clear in terms of plant-available water capacity and saturated hydraulic conductivity. Under organic farming, the soil had the greatest ability to store and provide water to plant roots, and to quickly drain excess water and facilitate root proliferation.Management practices adopted under organic farming(such as vegetation cover between the trees, chipping after pruning, and spreading the chips on the soil surface) improved the SPQ. Conversely, the conventional management strategies unequivocally led to soil degradation owing to the loss of organic matter, soil compaction, and reduced structural stability. The results in this study show that organic farming has a clear positive impact on the SPQ, suggesting that tillage and herbicide treatments should be avoided.展开更多
This study investigated the relationship between climate and biophysical variables in burned areas in Iran.The fire burned area(FBA)product(Fire CCI 5.1.1),land surface temperature(MOD11C3C),vegetation index(MOD13A1),...This study investigated the relationship between climate and biophysical variables in burned areas in Iran.The fire burned area(FBA)product(Fire CCI 5.1.1),land surface temperature(MOD11C3C),vegetation index(MOD13A1),and climate variables such as temperature,wind speed,relative humidity,and volumetric soil moisture from the ERA5 reanalysis dataset were used.Pearson correlation coefficient was used to determine the relationship between biophysical and climate variables and fire occurrence.The results show that FBA increased by 1.7 hectares/decade from 2001 to 2020.The high FBA in 2010(the black summer of Iran)was due to high temperatures and significant heatwaves that led to extensive wildfires.Although anthropogenic activities are considered a significant cause of wildfires,several variables,including increased temperatures,less precipitation,relative humidity,and wind speed and direction,contribute to the extent and occurrence of wildfires.The country’s FBA hotspot is in the Arasbaran region during the summer season.Temperature and relative humidity are the most significant variables influencing the occurrence of wildfires.The results show the vulnerability of Iran s forests and their high potential for fires.Considering the frequency of fire occurrences in Iran and the limited equipment,fire prevention plans should be carried out by applying proper management in high-risk regions.展开更多
Nature-based coastal protection is increasingly recognised as a potentially sustainable and cost-effective solution to reduce coastal flood risk.It uses coastal ecosystems such as mangrove forests to create resilient ...Nature-based coastal protection is increasingly recognised as a potentially sustainable and cost-effective solution to reduce coastal flood risk.It uses coastal ecosystems such as mangrove forests to create resilient designs for coastal flood protection.However,to use mangroves effectively as a nature-based measure for flood risk reduction,we must understand the biophysical processes that govern risk reduction capacity through mangrove ecosystem size and structure.In this perspective,we evaluate the current state of knowledge on local physical drivers and ecological processes that determine mangrove functioning as part of a nature-based flood defence.We show that the forest properties that comprise coastal flood protection are well-known,but models cannot yet pinpoint how spatial heterogeneity of the forest structure affects the capacity for wave or surge attenuation.Overall,there is relatively good understanding of the ecological processes that drive forest structure and size,but there is a lack of knowledge on how daily bed-level dynamics link to long-term biogeomorphic forest dynamics,and on the role of combined stressors influencing forest retreat.Integrating simulation models of forest structure under changing physical(e.g.due to sea-level change)and ecological drivers with hydrodynamic attenuation models will allow for better projections of long-term natural coastal protection.展开更多
In the context of global warming,escalating water cycles have led to a surge in drought frequency and severity.Yet,multidecadal fluctuations in drought and their multifaceted influencing factors remain inadequately un...In the context of global warming,escalating water cycles have led to a surge in drought frequency and severity.Yet,multidecadal fluctuations in drought and their multifaceted influencing factors remain inadequately understood.This study examined the multidecadal changes in drought characteristics(frequency,duration,and severity)and their geographical focal points within China's north-south transitional zone,the Qinling-Daba Mountains(QDM),from 1960 to 2017 using the Standardized Precipitation Evapotranspiration Index(SPEI).In addition,a suite of eight scenarios,correlation analysis,and wavelet coherence were used to identify the meteorological and circulation factors that influenced drought characteristics.The results indicate the following:(1)From 1960 to 2017,the QDM experienced significant interdecadal variations in drought frequency,duration,and severity,the climate was relatively humid before the 1990s,but drought intensified thereafter.Specifically,the 1990s marked the period of the longest drought duration and greatest severity,while the years spanning 2010 to 2017 experienced the highest frequency of drought events.(2)Spatially,the Qinling Mountains,particularly the western Qinling Mountain,exhibited higher drought frequency,duration,and severity than the Daba Mountains.This disparity can be attributed to higher rates of temperature increase and precipitation decrease in the western Qinling Mountain.(3)Interdecadal variations in droughts in the QDM were directly influenced by the synergistic effects of interdecadal fluctuations in air temperature and precipitation.Circulation factors modulate temperature and precipitation through phase transitions,thereby affecting drought dynamics in the QDM.The Atlantic Multidecadal Oscillation emerges as the primary circulation factors influencing temperature changes,with a mid-1990s shift to a positive phase favoring warming.The East Asian Summer Monsoon and El Ni?o-Southern Oscillation are the main circulation factors affecting precipitation changes,with positive phase transitions associated with reduced precipitation,and vice versa for increased precipitation.展开更多
Lake level,area and volume are sensitive indicators of climate change.At present,many studies have focused on the interannual water balance of lakes,but lake level and area can change remarkably with seasons,especiall...Lake level,area and volume are sensitive indicators of climate change.At present,many studies have focused on the interannual water balance of lakes,but lake level and area can change remarkably with seasons,especially for lakes with seasonal ice cover.Zhari Namco,a seasonal frozen lake,was selected as an example to investigate its seasonal water balance.Multi-source altimetry and Landsat data were used to obtain the seasonal lake level and area from 1992 to 2019,and seasonal lake volume variations were also estimated.The results indicated the average lake level,area and volume in autumn were the largest.The lake level,area,and volume experienced three turning points approximately in 2000,2010,and 2016,and showed an overall increasing trend from 1992 to 2019,with slopes of 0.15 m/year,2.17 km^(2)/year,and 0.14 km^(3)/year,respectively.The lake area expanded significantly in autumn,which was related to the abundant precipitation.Delay time of land surface runoff,increased temperature,and evaporation may be the reason for the low lake level and volume in summer.The precipitation was the dominant factor of water balance,which explained 62.09%,62.43%,and 62.10%of the variations in lake level,area,and volume,respectively.展开更多
Mountain streams act as conveyors of sediments within the river continuum,where the physical transport of sediments between river reaches through the catchment or between individual parts(e.g.,between hillslopes and c...Mountain streams act as conveyors of sediments within the river continuum,where the physical transport of sediments between river reaches through the catchment or between individual parts(e.g.,between hillslopes and channels)of the catchment is assumed.This study focused on sediment connectivity analysis in the SlavíčRiver catchment in the MoravskoslezskéBeskydy Mts in the eastern part of the Czech Republic.The connectivity index and connectivity index target modelling were combined with an analysis of anthropogenic interventions.Additionally,field mapping,grain size of bed sediments and stream power analysis were used to obtain information about connectivity in the catchment.Based on the analysis and obtained results,terrain topography is the current main driving factor affecting the connectivity of sediment movement in the SlavíčRiver catchment.However,the modelling provided valuable information about high sediment connectivity despite different recent land use conditions(highly forested area of the catchment)than those in historical times from the 16th to 19th centuries when the SlavíčRiver catchment was highly deforested and sediment connectivity was probably higher.The analysis of anthropogenic interventions,field mapping,grain size of bed sediments and stream power analysis revealed more deceleration of sediment movement through the catchment,decreased sediment connectivity with bed erosion,and gradual river channel process transformation in some reaches.Field mapping has identified various natural formations and human-induced changes impacting the longitudinal and lateral connectivity in the SlavíčRiver.For instance,embankments along 48%of the river's length,both on the right and left banks,significantly hinder lateral sediment supply to the channel.Stream power index analysis indicates increased energy levels in the flowing water in the river's upper reaches(up to 404.8 W m^(-2)).This high energy is also observed in certain downstream sections(up to 337.6 W m^(-2)),where it is influenced by human activities.These conditions lead to intensified erosion processes,playing a crucial role in sediment connectivity.Similar observations were described in recent studies that pointed out the long-term human interventions on many streams draining European mountains,where a decrease in sediment connectivity in these streams is linked with sediment deficits and the transformation of processes forming channels.展开更多
Forest tree species reproduction is a key factor in maintaining the genetic diversity of future generations and the stability of forest ecosystems.The ongoing ash dieback disease could affect the reproductive ecology ...Forest tree species reproduction is a key factor in maintaining the genetic diversity of future generations and the stability of forest ecosystems.The ongoing ash dieback disease could affect the reproductive ecology of Fraxinus excelsior L.and have a major impact on the quantity and quality of pollen and seeds.In this study,we investigated pollen production and viability of pollen and seeds of ash trees with different health status from 2018 to 2022.Inflorescences were collected from 105 trees(pollen production),pollen from 125 trees(pollen viability),and seeds from 53 trees(seed quality)in two seed orchards and in one floodplain forest in southern Germany.Not all parameters were examined at every site every year.The average pollen production per tree was estimated at 471.2±647.9 billion pollen grains.In addition,we found that a high number of inflorescences did not equate to high pollen production per inflorescence.Pollen production of healthy and diseased trees did not differ significantly,although only 47%of severely diseased male trees(vs.72%for healthy trees)produced flowers.With regards to pollen viability,the TTC test showed an average viability of 73%±17%.Overall,there was a slight tendency for diseased trees to have less viable pollen.However,a significant difference could only be calculated for trees in the floodplain forest.The percentage of germinable seeds in 2018 was 38%in the floodplain forest and 57%in one of the seed orchards.The percentage of viable seeds(TTC test)ranged from 17 to 22%in the orchards in 2020.Non-viable seeds were usually heavily infested by insects.In general,seed quality was not significantly different between healthy and diseased trees.Our results indicate that ash dieback affects flower formation and pollen viability but not pollen production or seed quality.Nevertheless,the fact that hardly any flowering was observed,especially for trees that were seriously affected,suggests a negative effect of ash dieback on reproductive performance.Thus,severely diseased trees will transfer their genes to a smaller extent to the next generation.展开更多
The ice phenology of alpine lakes on the Tibetan Plateau(TP)is a rapid and direct responder to climate changes,and the variations in lake ice exhibit high temporal frequency characteristics.MODIS and passive microwave...The ice phenology of alpine lakes on the Tibetan Plateau(TP)is a rapid and direct responder to climate changes,and the variations in lake ice exhibit high temporal frequency characteristics.MODIS and passive microwave data are widely used to monitor lake ice changes with high temporal resolution.However,the low spatial resolutions make it difficult to effectively quantify the freeze-melt dynamics of lakes.This work used Sentinel-1 synthetic aperture radar(SAR)data to derive high-resolution ice maps(about 6 days),then with the aid of Sentinel-2 optical images to quantify freeze-melt processes in three typical lakes on the TP(e.g.Selin Co,Ayakekumu Lake,and Nam Co).The results showed that three lakes had an average annual ice period of 125-157 days and a complete ice cover period of 72-115 days,from 2018 to 2022.They exhibit different ice phenology patterns.Nam Co is characterized by repeated episodes of freezing,melting,and refreezing,resulting in a prolonged freeze-up period.Meanwhile,the break-up period of Nam Co lasts for a longer duration(about 19 days),and the break-up exhibits a smooth process.Similarly,Ayakekumu Lake showed more significant inter-annual fluctuations in the freeze-up period,with deviations of up to 28 days observed among different years.Compared to the other two lakes,Selin Co experienced a relatively short freeze-up and break-up period.In short,Sentinel-1 SAR data can effectively monitor the weekly and seasonal variations in lake ice on the TP.Particularly,this data facilitates quantification of the freeze-melt dynamics.展开更多
基金supported by the Styrelsen för Internationellt Utvecklingssamarbete.
文摘With the continuous increase of rapid urbanization and population growth,sustainable urban land-use planning is becoming a more complex and challenging task for urban planners and decision-makers.Multi-objective land-use allocation can be regarded as a complex spatial optimization problem that aims to achieve the possible trade-offs among multiple and conflicting objectives.This paper proposes an improved Non-dominated Sorting Biogeography-Based Optimization(NSBBO)algorithm for solving the multi-objective land-use allocation problem,in which maximum accessibility,maximum compactness,and maximum spatial integration were formulated as spatial objectives;and space syntax analysis was used to analyze the potential movement patterns in the new urban planning area of the city of Kigali,Rwanda.Efficient Non-dominated Sorting(ENS)algorithm and crossover operator were integrated into classical NSBBO to improve the quality of non-dominated solutions,and local search ability,and to accelerate the convergence speed of the algorithm.The results showed that the proposed NSBBO exhibited good optimal solutions with a high hypervolume index compared to the classical NSBBO.Furthermore,the proposed algorithm could generate optimal land use scenarios according to the preferred objectives,thus having the potential to support the decision-making of urban planners and stockholders in revising and updating the existing detailed master plan of land use.
基金Iran Water Resources Management Company (IWRMC)the Vice Chancellor for Research and Technology at the University of Isfahan
文摘Long-term droughts,temperature rise,and extreme weather events cause changes in runoff,evaporation,and transpiration in basins.These changes are more severe in arid and semi-arid regions.Since 2007,the discharge of baseflow of the Zagros Mountain has decreased and made the supply of agricultural,industrial,and drinking water a big challenge.In this investigation,utilizing data from weather stations,the output of CORDEX,and the WetSpass model,the impact of climate change on river discharge in the Great Karun Basin(GKB)was examined.The temperature and precipitation projections for the period 2019-2040 were analyzed using the Coupled Model Intercomparison Project Phase Six(CMIP6)under scenarios SSP2-4.5 and SSP5-8.5.The findings reveal that the minimum and maximum temperatures are expected to increase by 0.2℃ to 5.1℃ and 0.1℃ to 3.6℃,respectively.Annual precipitation will decrease between 1.3%and 16.7%in scenario SSP2-4.5 and 23.4%in scenario SSP5-8.5.The results of the WetSpass Model for predicting future scenarios indicate a decrease in direct flow(5%),total discharge(27%),and interception(15%).As evapotranspiration will increase by 15%due to climate change,it will be more difficult to predict the water resources’volume of the Karoun Basin for the next decades.Adapting to climate change is the appropriate solution to solve this problem.Changes in temperature and precipitation in these areas pose major challenges to water resources.
基金supported by an internal grant of the University of Ostrava[SGS03/PŘF/2024-The influence of man on the landscape and the landscape on a man III].
文摘River confluences represent an integral component of the fluvial system,with the potential to disrupt downstream longitudinal trends in the main river through inputs of water,sediments,and other materials,such as woody debris.These various inputs at confluence zones result in a high degree of morphological and,consequently,ecological diversity.This study examines the potential relationship between the spatial characteristics of the catchment and the parameters of the confluence hydrodynamic zones(CHZs).A total of 15 tributaries and their adjacent CHZs were selected for analysis along a 50 km reach of the VsetínskáBečva River in the Javorníky and Hostýn-Vsetín Mountains in the Czech part of the Outer Western Carpathians.The VsetínskáBečva River is highly channelized,with the majority of channelization efforts involving riverbank stabilization,weirs,or grade control structures.The study hypothesized a correlation between the spatial arrangement of the channel,as indicated by the channel width symmetry ratio,and the angle between the tributary and main-stem river,and the increased morphological activity,evidenced by changes in average bed depth at the CHZs.The correlation coefficient(r)and p significance were employed to describe the relationships among the parameters.The results indicated a significant correlation between channel width and the catchment area symmetry ratio(r=0.747,p=0.001),likely influenced by channel regulation works(e.g.,channel shape or size),which are often artificially adjusted to accommodate local hydrological conditions and flood discharges for flood protection.A significant inverse correlation between channel width symmetry ratio and average main-stem channel depth was also found(r=-0.584,p=0.022).
文摘Water scarcity in Khuzestan Province,Iran,has attracted growing concerns despite the region's abundant water resources.The province predominantly relies on surface water,prompting an assessment of groundwater's potential to supplement water supplies during surface water shortages.This study assesses the province's groundwater availability and quality under increased exploitation conditions.Between 2008 and 2018,data on groundwater quantity and quality were collected from 204 exploration wells and 70 piezometric wells across 19 aquifers.The analysis revealed that 53%of aquifers in the eastern and northeastern regions experienced declining groundwater levels.Hydrochemical assessments indicated low concentrations of major ions in the northeastern,while high levels were observed from the central region towards the southeast.These variations were attributed to agricultural and industrial activities,seawater intrusion,and the influences of evaporation and geological factors.The dominant hydrochemical facies identified were of the Ca-Cl type.Water quality classification showed that 48%of groundwater samples fell within the C4S4-C4S1 category,primarily in the western,central,and southern regions,while 27%were classified as C3S2,C3S1,and 25%as C2S1,mainly in the northern and eastern regions.The Irrigation WWater Quality(IWQ)index indicated that many samples were suitable for irrigation.Additionally,the analysis potable groundwater was primarily found in the northern,northeastern,and eastern aquifers,with quality declining toward the south.The study highlights that certain aquifers in the northern and eastern regions offer greater potential for sustainable groundwater exploitation during water shortages.These findings provide valuable insights for on how to implement effective land and water management strategies to mitigate future water crises.
文摘Doline susceptibility mapping(DSM)in karst aquifer is important in terms of estimating the vulnerability of the aquifer to pollutants,estimating the infiltration rate,and infrastructures exposed to the development of dolines.In this research,doline susceptibility map was prepared in Saldaran mountain by generalized linear model(GLM)using 14 affecting parameters extracted from satellite images,digital elevation model,and geology map.Only 8 parameters have been inputted to the model which had correlation with dolines.In this regards,306 dolines were identified by the photogrammetric Unmanned Aerial Vehicles(UAV)method in 600 hectares of Salderan lands and then,these data were divided into the training(70%)and testing(30%)data for modelling.The results of DSM modeling showed that classified probability of doline occurrences in the Saldaran mountain were as follow:16.5%of the area high to very high,72%in the class of low to very low,and 5%in the moderate class.Also,locally,in Saldaran mountain,the Pirghar aquifer has the highest potential for the doline development,followed by Bagh Rostam and Sarab aquifers.Also,the precipitation,digital elevation model,Topographic Position Index,drainage density,slope,TRASP(transformed the circular aspect to a radiation index),Snow-Covered Days and vegetation cover index are of highest importance in the DSM modeling,respectively.Accurate evaluation of the model using the Receiver Operating Characteristics(ROC)curve represents a very good accuracy(AUC=0.953)of the DSM model.
基金funding from of Kien Giang University of MOETV,pay the fee of this article from Authors which by themselves,research funding from Ministry of Education and Training of Vietnam(MOETV)funding Number B2024–KGU 01-2024.
文摘A new renewable material by use reed biochar(Phragmites autralis);a species strong grows and very high biomass,it can be exploit a renewable resources for agriculture and environmental treatment.People often used rice husks as materials for organic fertilizers in agriculture.This study is a new discovere to made of reed biochar to filter N,P,K of chemical mineral fertilizer and pig urine use to provide bio-organic fertilizer for rice plant(ST 25).Methods:(1)Made of biochar by use the local method;(2)analyse the chemical indicators of locations on trunks,leaves,flowers;(3)identify chemical indicators of peatland on locations of experiment;(4)adsorpting chemical fertilizer(nitrogen,phosphorus and potash),pig urine filter by reed biochar,analize its chemical indicators;(5)use fomulas of reed plant biochar mixed peat and mineral inorganic fertilizer.Results:Made of reed biochar and it can adsorpted as ammonium,nitrate,nitrogen,phosphorus and kalium the pig urine and it also adsorpted inorganic fertilizer as nitrogen,phosphorus and Kalium.Thus it used for environmental treatment in the region polluted and planting local rice ST 25 in the experiment area.Conclusion:Biochar of reed can use to environment treatment and agriculture fertilizer;chemical indicators of bichar indentified;the mixed biochar,peat and inorganic in formulas in 5 days and 10 days were not differences;biochar can adsorb some chemical components of pig urine and nitrogen,phosphorus and kalium;biochar can mixed peat and inorganic mineral to planting rice ST 25 in Mekong Delta.
文摘The intertwined challenges of climate change, resource scarcity, and conflict require innovative integrated solutions that address both environmental and societal vulnerabilities. Technological innovation offers a transformative pathway for climate change adaptation and peacebuilding, with emphasis on a holistic approach to managing resource conflicts and environmental challenges. This paper explores the synergies between emerging technologies and strategic framework to mitigate climate-induced tensions and foster resilience. It focuses on the application of renewable energy systems to reduce dependence on contested resources, blockchain technology to ensure transparency in climate finance, equitable resource allocation and Artificial Intelligence (AI) to enhance early warning systems for climate-related disaster and conflicts. Additionally, technologies such as precision agriculture and remote sensing empower communities to optimize resource use, adapt to shifting environmental conditions, and reduce competition over scares resources. These innovations with inclusive governance and local capacity-building are very primordial. Ultimately, the convergence of technology, policy, and local participation offers a scalable and replicable model for addressing the dual challenges of environmental degradation and instability, thereby paving the way for a more sustainable and peaceful future.
基金supported financially by the National Nature Science Foundation of China(No.41901129)the University Natural Sciences Research Project of Anhui Educational committee(2024AH050270)the support from the Joint China–Sweden Mobility Grant funded by NSFC and STINT(CH2019-8250)。
文摘Compared to lake area and water level,lake storage capacity more intuitively reflects regional climate changes.In this study,we first derived lakebed elevation profiles for individual ICESat-2 tracks based on the underwater stratification of laser photons,then integrating all valid elevation tracks within the water body to interpolate the bathymetry.On this basis,we calculated the capacity and its time series directly,with the aid of lake boundaries and water levels obtained from optical imagery and CryoSat-2 data.Next,we also applied an empirical formula to estimate the water volume changes of Bangdag Co by combining the area and water levels from 2010 to 2023.Finally,we compared the results of Bangdag Co's water volume changes obtained from the two different methods and conducted a detailed analysis of their performance and regional applicability.The bathymetric map of Bangdag Co reveals a distinct spatial pattern,with the northeastern part significantly deeper(with a maximum depth of 35.27 m)and the southwestern part shallower.The average depth of the lake is 13.99 m.We further estimated that the lake storage capacity in November 2023 was 2.95 km^(3).Water volume changes estimated using the empirical formula were highly consistent with those derived from the lake storage capacity time series(from 2010 to 2023,the lake storage capacity increased by 1.04 km^(3)).Our comparison revealed that the empirical formula method reflects only changes in water volume.In contrast,while our method can accurately estimate lake storage capacity,it is constrained to shallow,clear,and elongated east-west lakes(e.g.,Ayakkum Lake).In summary,the ICESat-2 laser altimetry data,which do not rely on measured water depths,offer an essential complement to underwater topography detection and provide a novel perspective on lake volume estimation research.
基金supported by the Swedish Research Council(Vetenskapsradet,Grant No.202203129)the Project of Youth Science and Technology Fund of Gansu Province(Grant No.24JRRA439)partially funded by the Swedish Research Council(Vetenskapsradet,Grant No.2022-06725)。
文摘This study investigates the impact of vegetation-climate feedback on the global land monsoon system during the Last Interglacial(LIG,127000 years BP)and the mid-Holocene(MH,6000 years BP)using the earth system model EC-Earth3.Our findings indicate that vegetation changes significantly influence the global monsoon area and precipitation patterns,especially in the North African and Indian monsoon regions.The North African monsoon region experienced the most substantial increase in vegetation during both the LIG and MH,resulting in significant increases in monsoonal precipitation by 9.8%and 6.0%,respectively.The vegetation feedback also intensified the Saharan Heat Low,strengthened monsoonal flows,and enhanced precipitation over the North African monsoon region.In contrast,the Indian monsoon region exhibited divergent responses to vegetation changes.During the LIG,precipitation in the Indian monsoon region decreased by 2.2%,while it increased by 1.6%during the MH.These differences highlight the complex and region-specific impacts of vegetation feedback on monsoon systems.Overall,this study demonstrates that vegetation feedback exerts distinct influences on the global monsoon during the MH and LIG.These findings highlight the importance of considering vegetation-climate feedback in understanding past monsoon variability and in predicting future climate change impacts on monsoon systems.
基金Department of Water Resources of Shaanxi Province of China,No.2023slkj-8National Natural Science Foundation of China,No.51779209。
文摘Studying runoff characteristics and quantifying human activities’impact on northern Shaanxi,a crucial mineral resource area in China,is crucial to alleviate water resource contradictions.In this study,hydrological element trends were analyzed using theβ-z-h three-parameter indication method.The Mann-Kendall,Pettitt,moving T,and Yamamoto methods were used to test the mutation point of hydrological elements.The Budyko framework was used to quantitatively assess the impacts of climate change and multiple human activities on runoff reduction.The results showed that(1):Precipitation(PRE),potential evapotranspiration(E0),and temperature(TEM)showed increasing trends;runoff in the Huangfuchuan,Gushanchuan,Kuye River,Tuwei River,Wuding River,Qingjian River,and Yanhe River catchments showed decreasing trends(HFC,GSC,KYR,TWR,WDR,QJR,YR);whereas runoff in the Jialu River(JLR)catchment showed a“V-shaped”trend from 1980 to2020.(2)Runoff was positively correlated with PRE and negatively correlated with E0and the subsurface index(n),with the elasticity coefficients of PRE,E0,and n showing an increasing trend in the change period.(3)Human activities were a key factor in runoff reduction,although the impact of different human activities showed spatial variations.This study provides a scientific foundation for achieving the sustainable development of water resources in mining areas.
基金supported by the RECARE Project from the European Union Seventh Framework Programme (FP7/2007-2013) (No. 603498)COST actions 1306
文摘Soil capacity to support life and to produce economic goods and services is strongly linked to the maintenance of good soil physical quality(SPQ). In this study, the SPQ of citrus orchards was assessed under three different soil managements, namely no-tillage using herbicides, tillage under chemical farming, and no-tillage under organic farming. Commonly used indicators, such as soil bulk density,organic carbon content, and structural stability index, were considered in conjunction with capacitive indicators estimated by the Beerkan estimation of soil transfer parameter(BEST) method. The measurements taken at the L'Alcoleja Experimental Station in Spain yielded optimal values for soil bulk density and organic carbon content in 100% and 70% of cases for organic farming. The values of structural stability index indicated that the soil was stable in 90% of cases. Differences between the soil management practices were particularly clear in terms of plant-available water capacity and saturated hydraulic conductivity. Under organic farming, the soil had the greatest ability to store and provide water to plant roots, and to quickly drain excess water and facilitate root proliferation.Management practices adopted under organic farming(such as vegetation cover between the trees, chipping after pruning, and spreading the chips on the soil surface) improved the SPQ. Conversely, the conventional management strategies unequivocally led to soil degradation owing to the loss of organic matter, soil compaction, and reduced structural stability. The results in this study show that organic farming has a clear positive impact on the SPQ, suggesting that tillage and herbicide treatments should be avoided.
基金supported by a grant from Shahid Beheshti University。
文摘This study investigated the relationship between climate and biophysical variables in burned areas in Iran.The fire burned area(FBA)product(Fire CCI 5.1.1),land surface temperature(MOD11C3C),vegetation index(MOD13A1),and climate variables such as temperature,wind speed,relative humidity,and volumetric soil moisture from the ERA5 reanalysis dataset were used.Pearson correlation coefficient was used to determine the relationship between biophysical and climate variables and fire occurrence.The results show that FBA increased by 1.7 hectares/decade from 2001 to 2020.The high FBA in 2010(the black summer of Iran)was due to high temperatures and significant heatwaves that led to extensive wildfires.Although anthropogenic activities are considered a significant cause of wildfires,several variables,including increased temperatures,less precipitation,relative humidity,and wind speed and direction,contribute to the extent and occurrence of wildfires.The country’s FBA hotspot is in the Arasbaran region during the summer season.Temperature and relative humidity are the most significant variables influencing the occurrence of wildfires.The results show the vulnerability of Iran s forests and their high potential for fires.Considering the frequency of fire occurrences in Iran and the limited equipment,fire prevention plans should be carried out by applying proper management in high-risk regions.
基金supported by the Joint Research Project Sustainable Deltas co-funded by the National Natural Science Foundation of China(NSFCGrant No.51761135022)+11 种基金the Dutch Research Council(NWOGrant No.ALWSD.2016.026)the Engineering and Physical Sciences Research Council(EPSRCGrant No.EP/R024537/1)the National Natural Science Foundation of China(Grant No.42176202)the Innovation Group Project of the Southern Marine Science and Engineering Guangdong Laboratory,Zhuhai(Grant No.311021004)the Guangdong Provincial Department of Science and Technology(Grant No.2019ZT08G090)the 111 Project(Grant No.B21018)the ERC H2020 ESTUARIES Project(Grant No.647570)the Horizon 2020 Marie Skłodowska-Curie Actions Individual Fellowship(Grant No.896888)the China Scholarship Council(Grant No.201706710005)the NWO“LIVING DIKES e Realising Resilient and Climate-Proof Coastal Protection”Project(Grant No.NWA.1292.19.257)。
文摘Nature-based coastal protection is increasingly recognised as a potentially sustainable and cost-effective solution to reduce coastal flood risk.It uses coastal ecosystems such as mangrove forests to create resilient designs for coastal flood protection.However,to use mangroves effectively as a nature-based measure for flood risk reduction,we must understand the biophysical processes that govern risk reduction capacity through mangrove ecosystem size and structure.In this perspective,we evaluate the current state of knowledge on local physical drivers and ecological processes that determine mangrove functioning as part of a nature-based flood defence.We show that the forest properties that comprise coastal flood protection are well-known,but models cannot yet pinpoint how spatial heterogeneity of the forest structure affects the capacity for wave or surge attenuation.Overall,there is relatively good understanding of the ecological processes that drive forest structure and size,but there is a lack of knowledge on how daily bed-level dynamics link to long-term biogeomorphic forest dynamics,and on the role of combined stressors influencing forest retreat.Integrating simulation models of forest structure under changing physical(e.g.due to sea-level change)and ecological drivers with hydrodynamic attenuation models will allow for better projections of long-term natural coastal protection.
基金National Natural Science Foundation of China,No.U23A2020National Science and Technology Basic Resource Investigation Program,No.2023FY100701。
文摘In the context of global warming,escalating water cycles have led to a surge in drought frequency and severity.Yet,multidecadal fluctuations in drought and their multifaceted influencing factors remain inadequately understood.This study examined the multidecadal changes in drought characteristics(frequency,duration,and severity)and their geographical focal points within China's north-south transitional zone,the Qinling-Daba Mountains(QDM),from 1960 to 2017 using the Standardized Precipitation Evapotranspiration Index(SPEI).In addition,a suite of eight scenarios,correlation analysis,and wavelet coherence were used to identify the meteorological and circulation factors that influenced drought characteristics.The results indicate the following:(1)From 1960 to 2017,the QDM experienced significant interdecadal variations in drought frequency,duration,and severity,the climate was relatively humid before the 1990s,but drought intensified thereafter.Specifically,the 1990s marked the period of the longest drought duration and greatest severity,while the years spanning 2010 to 2017 experienced the highest frequency of drought events.(2)Spatially,the Qinling Mountains,particularly the western Qinling Mountain,exhibited higher drought frequency,duration,and severity than the Daba Mountains.This disparity can be attributed to higher rates of temperature increase and precipitation decrease in the western Qinling Mountain.(3)Interdecadal variations in droughts in the QDM were directly influenced by the synergistic effects of interdecadal fluctuations in air temperature and precipitation.Circulation factors modulate temperature and precipitation through phase transitions,thereby affecting drought dynamics in the QDM.The Atlantic Multidecadal Oscillation emerges as the primary circulation factors influencing temperature changes,with a mid-1990s shift to a positive phase favoring warming.The East Asian Summer Monsoon and El Ni?o-Southern Oscillation are the main circulation factors affecting precipitation changes,with positive phase transitions associated with reduced precipitation,and vice versa for increased precipitation.
基金jointly funded by the National Natural Science Foundation of China(Nos.42011530120,41830105,41901129)the Swedish Foundation for International Cooperation in Research and Higher Education(No.CH2019-8250)。
文摘Lake level,area and volume are sensitive indicators of climate change.At present,many studies have focused on the interannual water balance of lakes,but lake level and area can change remarkably with seasons,especially for lakes with seasonal ice cover.Zhari Namco,a seasonal frozen lake,was selected as an example to investigate its seasonal water balance.Multi-source altimetry and Landsat data were used to obtain the seasonal lake level and area from 1992 to 2019,and seasonal lake volume variations were also estimated.The results indicated the average lake level,area and volume in autumn were the largest.The lake level,area,and volume experienced three turning points approximately in 2000,2010,and 2016,and showed an overall increasing trend from 1992 to 2019,with slopes of 0.15 m/year,2.17 km^(2)/year,and 0.14 km^(3)/year,respectively.The lake area expanded significantly in autumn,which was related to the abundant precipitation.Delay time of land surface runoff,increased temperature,and evaporation may be the reason for the low lake level and volume in summer.The precipitation was the dominant factor of water balance,which explained 62.09%,62.43%,and 62.10%of the variations in lake level,area,and volume,respectively.
基金supported by an internal grant of the University of Ostrava[SGS10/PřF/2021-Specificity of fluvial landscape in the context of historical and future changes].
文摘Mountain streams act as conveyors of sediments within the river continuum,where the physical transport of sediments between river reaches through the catchment or between individual parts(e.g.,between hillslopes and channels)of the catchment is assumed.This study focused on sediment connectivity analysis in the SlavíčRiver catchment in the MoravskoslezskéBeskydy Mts in the eastern part of the Czech Republic.The connectivity index and connectivity index target modelling were combined with an analysis of anthropogenic interventions.Additionally,field mapping,grain size of bed sediments and stream power analysis were used to obtain information about connectivity in the catchment.Based on the analysis and obtained results,terrain topography is the current main driving factor affecting the connectivity of sediment movement in the SlavíčRiver catchment.However,the modelling provided valuable information about high sediment connectivity despite different recent land use conditions(highly forested area of the catchment)than those in historical times from the 16th to 19th centuries when the SlavíčRiver catchment was highly deforested and sediment connectivity was probably higher.The analysis of anthropogenic interventions,field mapping,grain size of bed sediments and stream power analysis revealed more deceleration of sediment movement through the catchment,decreased sediment connectivity with bed erosion,and gradual river channel process transformation in some reaches.Field mapping has identified various natural formations and human-induced changes impacting the longitudinal and lateral connectivity in the SlavíčRiver.For instance,embankments along 48%of the river's length,both on the right and left banks,significantly hinder lateral sediment supply to the channel.Stream power index analysis indicates increased energy levels in the flowing water in the river's upper reaches(up to 404.8 W m^(-2)).This high energy is also observed in certain downstream sections(up to 337.6 W m^(-2)),where it is influenced by human activities.These conditions lead to intensified erosion processes,playing a crucial role in sediment connectivity.Similar observations were described in recent studies that pointed out the long-term human interventions on many streams draining European mountains,where a decrease in sediment connectivity in these streams is linked with sediment deficits and the transformation of processes forming channels.
文摘Forest tree species reproduction is a key factor in maintaining the genetic diversity of future generations and the stability of forest ecosystems.The ongoing ash dieback disease could affect the reproductive ecology of Fraxinus excelsior L.and have a major impact on the quantity and quality of pollen and seeds.In this study,we investigated pollen production and viability of pollen and seeds of ash trees with different health status from 2018 to 2022.Inflorescences were collected from 105 trees(pollen production),pollen from 125 trees(pollen viability),and seeds from 53 trees(seed quality)in two seed orchards and in one floodplain forest in southern Germany.Not all parameters were examined at every site every year.The average pollen production per tree was estimated at 471.2±647.9 billion pollen grains.In addition,we found that a high number of inflorescences did not equate to high pollen production per inflorescence.Pollen production of healthy and diseased trees did not differ significantly,although only 47%of severely diseased male trees(vs.72%for healthy trees)produced flowers.With regards to pollen viability,the TTC test showed an average viability of 73%±17%.Overall,there was a slight tendency for diseased trees to have less viable pollen.However,a significant difference could only be calculated for trees in the floodplain forest.The percentage of germinable seeds in 2018 was 38%in the floodplain forest and 57%in one of the seed orchards.The percentage of viable seeds(TTC test)ranged from 17 to 22%in the orchards in 2020.Non-viable seeds were usually heavily infested by insects.In general,seed quality was not significantly different between healthy and diseased trees.Our results indicate that ash dieback affects flower formation and pollen viability but not pollen production or seed quality.Nevertheless,the fact that hardly any flowering was observed,especially for trees that were seriously affected,suggests a negative effect of ash dieback on reproductive performance.Thus,severely diseased trees will transfer their genes to a smaller extent to the next generation.
基金supported financially by the National Nature Science Foundation of China(No.41901129)the University Natural Sciences Research Project of Anhui Educational committee(KJ2020JD06)DUAN Zheng acknowledges the support from the Joint China-Sweden Mobility Grant funded by NSFC and STINT(CH2019-8250).
文摘The ice phenology of alpine lakes on the Tibetan Plateau(TP)is a rapid and direct responder to climate changes,and the variations in lake ice exhibit high temporal frequency characteristics.MODIS and passive microwave data are widely used to monitor lake ice changes with high temporal resolution.However,the low spatial resolutions make it difficult to effectively quantify the freeze-melt dynamics of lakes.This work used Sentinel-1 synthetic aperture radar(SAR)data to derive high-resolution ice maps(about 6 days),then with the aid of Sentinel-2 optical images to quantify freeze-melt processes in three typical lakes on the TP(e.g.Selin Co,Ayakekumu Lake,and Nam Co).The results showed that three lakes had an average annual ice period of 125-157 days and a complete ice cover period of 72-115 days,from 2018 to 2022.They exhibit different ice phenology patterns.Nam Co is characterized by repeated episodes of freezing,melting,and refreezing,resulting in a prolonged freeze-up period.Meanwhile,the break-up period of Nam Co lasts for a longer duration(about 19 days),and the break-up exhibits a smooth process.Similarly,Ayakekumu Lake showed more significant inter-annual fluctuations in the freeze-up period,with deviations of up to 28 days observed among different years.Compared to the other two lakes,Selin Co experienced a relatively short freeze-up and break-up period.In short,Sentinel-1 SAR data can effectively monitor the weekly and seasonal variations in lake ice on the TP.Particularly,this data facilitates quantification of the freeze-melt dynamics.
