Arid regions are vital components of Earth’s land surface.Clarifying the area/boundary of arid region is crucial for comprehending area changes and potential mechanisms.However,the accuracy and applicability of arid ...Arid regions are vital components of Earth’s land surface.Clarifying the area/boundary of arid region is crucial for comprehending area changes and potential mechanisms.However,the accuracy and applicability of arid region boundary delineated by different indices remain unclear.In this study,the annual precipitation(AP),humidity index(H),and aridity index(K)were calculated for delineating arid region of China using 106 meteorological stations during 1990–2019.The results suggest that AP and H can accurately delineate arid region,because they are consistent with the distribution of typical soil and vegetation in arid region,whereas K is not.Moreover,AP is the best index for delineating arid region in regions with limited meteorological data,especially in studying long-term patterns and mechanisms of area changes.The accuracy of delineating arid region using H is enhanced in regions with abundant meteorological data.Over the past 30 years,influenced by the increase of atmospheric moisture influx and precipitation,the area in arid region of northwestern China decreased by 70×10^(3)–90×10^(3)km^(2),resulting in the present area of approximately 1.55×10^(6)km^(2).This study provides appropriate indices for delineating arid region,contributing to improving our knowledge of regional responses difference to climate change.展开更多
In the context of global warming,it is anticipated that both the intensity and the frequency of future global extreme high precipitation(EHP)and extreme high temperature(EHT)events will increase.To evaluate the future...In the context of global warming,it is anticipated that both the intensity and the frequency of future global extreme high precipitation(EHP)and extreme high temperature(EHT)events will increase.To evaluate the future extreme climate changes in the Asian arid region and Tibetan Plateau,this study applied the NASA Earth Exchange Global Daily Downscaled Projections(NEX-GDDP-CMIP6)to assess the changes in EHP(Rx5d and R95pTOT)and EHT(TX90p and TXx)under different emission scenarios in the 21st century.Findings suggest that both the frequency and the intensity of the extreme indices will increase,exhibiting accelerated growth under higher emission scenarios,particularly under the SSP5-8.5 emission scenario.It is suggested that the growth of EHT and EHP in the early subperiod of the 21st century(2026-2045)will be relatively moderate,with small differences between different emission scenarios.However,by the middle subperiod of the 21st century(2041-2060),the differences between different emission scenarios will become larger than the 2035s and the growth will become more intense.In western central Asia,TX90p,TXx,Rx5d,and R95pTOT increase by 9.7%-14.2%(13.3%-24.7%),1.3℃-1.7℃(1.6℃-2.7℃),6.5%-8.9%(8.2%-8.8%),and 18.1%-27.0%(25.6%-30.0%)by the early(middle)subperiod;in eastern central Asia,TX90p,TXx,Rx5d,and R95pTOT increase 8.1%-12.0%(11.3%-21.1%),1.4℃-1.8℃(1.9℃-2.9℃),7.4%-9.7%(10.4%-13.8%),and 20.2%-29.3%(32.0%-40.8%)by the early(middle)subperiod;and over the Tibetan Plateau,TX90p,TXx,Rx5d,and R95pTOT increase 12.5%-17.4%(17.0%-31.0%),1.2℃-1.5℃(1.6℃-2.5℃),7.2%-10.0%(9.9%-15.0%),and 26.6%-33.1%(36.1%-55.3%)by the early(middle)subperiod.展开更多
Soil moisture(SM)is a critical variable in terrestrial ecosystems,especially in arid and semi-arid areas where water sources are limited.Despite its importance,understanding the spatiotemporal variations and influenci...Soil moisture(SM)is a critical variable in terrestrial ecosystems,especially in arid and semi-arid areas where water sources are limited.Despite its importance,understanding the spatiotemporal variations and influencing factors of SM in these areas remains insufficient.This study investigated the spatiotemporal variations and influencing factors of SM in arid and semi-arid areas of China by utilizing the extended triple collation(ETC),Mann-Kendall test,Theil-Sen estimator,ridge regression analysis,and other relevant methods.The following findings were obtained:(1)at the pixel scale,the long-term monthly SM data from the European Space Agency Climate Change Initiative(ESA CCI)exhibited the highest correlation coefficient of 0.794 and the lowest root mean square error(RMSE)of 0.014 m^(3)/m^(3);(2)from 2000 to 2022,the study area experienced significant increase in annual average SM,with a rate of 0.408×10^(-3)m^(3)/(m^(3)•a).Moreover,higher altitudes showed a notable upward trend,with SM increasing rates at 0.210×10^(-3)m^(3)/(m^(3)•a)between 1000 and 2000 m,0.530×10^(-3)m^(3)/(m^(3)•a)between 2000 and 4000 m,and 0.760×10^(-3)m^(3)/(m^(3)•a)at altitudes above 4000 m;(3)land surface temperature(LST),root zone soil moisture(RSM)(10-40 cm depth),and normalized difference vegetation index(NDVI)were identified as the primary factors influencing annual average SM,which accounted for 34.37%,24.16%,and 22.64%relative contributions,respectively;and(4)absolute contribution of LST was more significant in subareas at higher altitudes,with average absolute contributions of 0.800×10^(-3)m^(3)/(m^(3)•a)between 2000 and 4000 m and 0.500×10^(-2) m^(3)/(m^(3)•a)above 4000 m.This study reveals the spatiotemporal variations and main influencing factors of SM in Chinese arid and semi-arid areas,highlighting the more pronounced absolute contribution of LST to SM in high-altitude areas,providing valuable insights for ecological research and water resource management in these areas.展开更多
The author affiliation and the funding information in the Acknowledgement section of the online version of the original article was revised.One affiliation(the 8th affiliation)of the first author is added.The Acknowle...The author affiliation and the funding information in the Acknowledgement section of the online version of the original article was revised.One affiliation(the 8th affiliation)of the first author is added.The Acknowledgement section of the original article has been revised to:Acknowledgments:This research was funded by the National University of Mongolia under grant agreement P2023(grant number P2023-4578)and supported by the Chey Institute for Advanced Studies“International Scholarship Exchange Fellowship for the academic year of 2024-2025”,Republic of Korea,and the National University of Mongolia.We would like to acknowledge the National University of Mongolia and Soumik Das from the Center for the Study of Regional Development,Jawaharlal Nehru University,New Delhi-110067,for his valuable assistance in preparing the geological maps.展开更多
The article examines the impact of increased aridization of the territory due to an increase in air temperature,reduced precipitation,and the formation of moisture deficiency on grain yields in Northern Kazakhstan.The...The article examines the impact of increased aridization of the territory due to an increase in air temperature,reduced precipitation,and the formation of moisture deficiency on grain yields in Northern Kazakhstan.The most important result of the work is the revealed inverse relationship between grain yields and the temperature of the growing season:low-yielding years are associated with high temperatures and droughts,and high-yielding years are associated with lower temperatures and an optimal ratio of heat and moisture.The novelty of this study is the use of the method of hydrological and climatic calculations in identifying the nature of temperature variability and precipitation in the territory of Northern Kazakhstan for the modern period(1991–2020)compared with the base period(1961–1990).At all the studied meteorological stations,there is a tendency for the average annual temperature and the temperature of the growing season to increase:in the forest-steppe zone with an average warming intensity of 0.3–0.33℃ per decade;in the steppe zone by 0.2–0.43℃ per decade;and in the growing season by 0.2–0.7℃ per decade.The air temperature in the steppe zone is rising more intensively than in the forest-steppe zone,and precipitation in the forest-steppe zone has changed more than in the steppe zone.An increase in the average annual air temperature during the growing season(May–August),combined with a shortage of atmospheric moisture or a constant amount of it,led to an increase in the degree of aridization of the territory,an increase in the frequency of droughts in the steppe zone of Northern Kazakhstan.展开更多
[Objectives]Amygdalus tangutica is a new and excellent tree species for afforestation in arid areas of central China for soil and water conservation.It has the characteristics of drought resistance,cold resistance and...[Objectives]Amygdalus tangutica is a new and excellent tree species for afforestation in arid areas of central China for soil and water conservation.It has the characteristics of drought resistance,cold resistance and tolerance to poor soil,and has strong ecological,landscape and economic value.To provide a theoretical basis for the propagation and application of A.tangutica in Minqin and similar arid sandy areas of Northwest China,this paper explored its introduction and cultivation technology through field experiments,considering the natural geographical conditions of the study area.[Methods]High-quality seeds were introduced from forest farms of Chankou Town,Anding District,Dingxi City,and Dian ga Town,Diebu County,Gannan Prefecture,and the introduction and cultivation experiments of A.tangutica were carried out in the greenhouse of Wuwei Oasis Station.[Results](1)Soaking treatment at different temperatures combined with gibberellin treatment and stratification germination could effectively break the dormancy of A.tangutica seeds,thereby accelerating germination and shortening the germination cycle.The germination peak appeared 15-20 d after sowing,and the final germination rate could reach about 50%.(2)In the introduction and cultivation of A.tangutica in arid areas,large fruit seeds with higher thousand-grain weight should be given priority.The emergence rate of large fruit seeds was significantly higher than that of small fruit seeds,with the highest reaching 57%,while the highest of small fruit seeds was only 20%.Soaking treatment at different temperatures had no significant difference in the germination performance and germination potential of A.tangutica seeds,but the germination index of large fruit seeds was higher than that of small fruit seeds.(3)Under the current conditions,seedling propagation is a reliable way to propagate A.tangutica in arid areas.The cutting propagation technology,particularly hardwood cutting which exhibits an extremely low survival rate,is not yet mature and is currently unsuitable for large-scale production.Consequently,future efforts should prioritize more in-depth research on softwood cutting techniques.[Conclusions]This study provides a theoretical foundation for the propagation and broader application of A.tangutica in Minqin and similar arid sandy areas of Northwest China.展开更多
The Monte Desert is characterized by a great diversity of landforms created with fluvial,alluvial which the vegetation patterns are related to.The present work has the following objectives:(1) determine whether topogr...The Monte Desert is characterized by a great diversity of landforms created with fluvial,alluvial which the vegetation patterns are related to.The present work has the following objectives:(1) determine whether topographical attributes,surface characteristics,soil properties and vegetation patterns vary between alluvial landforms,and(2) define whether morphometric,soil and surface properties influence vegetation patterns along alluvial landscape.Morphometric data were obtained by processing a 5 m digital elevation model.The coverage of rock fragments,fine sediments and mulch was quantified.Observations and descriptions of the soil profiles were restricted to the uppermost 50 cm.Vegetation properties were calculated using a Point Quadrat Method.The relationship between variables was evaluated through multivariate statistical analysis.The main results show the presence of 45 plant species distributed in 19 families,where shrubs are dominant.The wind effect,topographic wetness and dissection of the landscape are limiting factors of diversity.The coverage of superficial rock fragments influence vegetation coverage through the distribution and availability of rainwater.Furthermore,the different soil textures reveal that the silt content favors an increase in vegetation coverage.The presence of V horizon could condition the installation and development of vegetation in the early stages of growth.展开更多
Arid West Asia(AWA)is a critical hub of the Silk Road and one of the primary dust source regions in the Northern Hemisphere.Dust storms in AWA emitting substantial dust particles into the atmosphere,significantly infl...Arid West Asia(AWA)is a critical hub of the Silk Road and one of the primary dust source regions in the Northern Hemisphere.Dust storms in AWA emitting substantial dust particles into the atmosphere,significantly influencing air quality,climate change and marine productivity.However,the variability of dust storm activity in this region during the Holocene,particularly its links to vegetation and hydroclimatic changes,remains debated,hindering our understanding of the interconnected dynamics between climate change and surface environments.This study reconstructs dust storm variations in AWA over the past 9000 years using geochemical analyses(trace elements,Sr-Nd isotopes)from a well-dated,high-resolution sediment core from the Almalou Peatland,located on the western Iranian Plateau.Our results reveal a decline in dust storm frequency from the early to mid-Holocene,a minimum occurrence during the mid-Holocene,and a significant increase in the late Holocene.Provenance analysis indicates that the primary dust sources were the arid regions of Mesopotamia,located upwind of the study area.A comparison with proxy records and paleoclimate models suggests an inverse relationship between dust storm activity and regional hydroclimatic and vegetation changes,along with a positive correlation with wind speeds.The concentration of dust storms during the wetter month of May highlights wind speed as a more critical driving factor.Moreover,given the dominant influence of the subtropical high on hydroclimatic conditions and wind speeds in AWA,we propose that this system is the key regulator of regional dust storm dynamics.Our findings provide new insights into the drivers of dust storm activity in AWA and hold implications for developing targeted dust storm management strategies.展开更多
Based on regional paleoclimate sequences,records of human activities,paleoclimate simulations,and detailed environmental historical records,we discuss the impacts of Holocene climate change and human activities on the...Based on regional paleoclimate sequences,records of human activities,paleoclimate simulations,and detailed environmental historical records,we discuss the impacts of Holocene climate change and human activities on the evolution of the Shule River in the western Qilian Mountains,China.The results indicate that during the early to mid-Holocene,the river evolution of the Shule River alluvial fan was closely related to regional climate fluctuations.In the late Holocene,flood agriculture began to emerge along the Shule River.During the historical period,population growth and the expansion of arable land led to increased river water usage,resulting in decreased access to the expected distribution of water resources in other regions,which in turn has caused imbalances in the regional hydrological ecosystem.展开更多
Mountains are important reservoirs of biodiversity and endemism on a global scale, but little is known about the altitudinal configuration of this diversity and its driving factors in arid mountains. We explored varia...Mountains are important reservoirs of biodiversity and endemism on a global scale, but little is known about the altitudinal configuration of this diversity and its driving factors in arid mountains. We explored variations in composition, diversity, cover,and life forms of vascular plants along a complete altitudinal gradient(1300-4000 m a.s.l) in Sierra de Velasco, an arid mountain in northwestern Argentina.We evaluated the influence of environmental variables on plant diversity and cover. Field sampling was conducted in the northern sector of the Sa. de Velasco,on the western slope in eight 50 m wide altitudinal bands at 400 m elevation intervals. We used rectangular plots(20 × 4 m;n:10/altitudinal band) to register the vascular plants of all the growth forms, and linear transects(20 m long.;n:30/altitudinal band) to quantify the vegetation cover using the point intercept method. Diversity was calculated using hill numbers.Data analysis included non-metric multidimensional scaling(NMDS), indicator species analysis,generalized linear models(GLMs), and variance partitioning analysis. A total of 232 species from 51families and 158 genera were registered. Species composition showed greater similarity at intermediate elevations. Plant diversity and cover exhibited a unimodal distribution, peaking at intermediate elevations(2100-2500 m). In contrast, life forms' distribution showed divergent patterns. Therophytes and succulents predominated at low altitudes,phanerophytes and hemicryptophytes at medium altitudes, and chamaephytes and geophytes at high altitudes. The altitudinal patterns of plant diversity and cover were primarily driven by climatic factors.Conservation efforts in the Sierra de Velasco should focus on the middle and upper zones due to their high biodiversity and vulnerability to climate change.展开更多
Livelihood improvement and sustainable natural resource utilization are among the United Nations Sustainable Development Goals;however,most farm households either randomly select or just imitate livelihood strategies ...Livelihood improvement and sustainable natural resource utilization are among the United Nations Sustainable Development Goals;however,most farm households either randomly select or just imitate livelihood strategies being practiced in other areas.As the livelihoods of farm households are vulnerable to several challenges in ecologically fragile areas,identifying the livelihood strategies of farm households in arid and semi-arid areas will help for promoting both livelihood security and environmental conservation.Hence,in this study,we constructed a sustainable evaluation index system for the livelihood of farmers in the Loess Plateau region of China by conducting field research and interviews.We employed the composite index method to measure the livelihood capital and the livelihood strategies chosen by farmers,and then analyzed the resource endowment of farmers under different livelihood strategies using logistic regression and structural equation modeling.The results revealed that under the combined influences of livelihood capital and government policy,farm households in the Loess Plateau region selected agro-dependent,agro-pastoral,agro-industrial,non-agricultural livelihood strategies.The key factors influencing the selection of these household livelihood strategies included the household labor capacity,the farmland owned per household,the number of livestock,and the grassland forage-supply ratio.The grassland forage-supply ratio was a crucial factor influencing the choice between agricultural and non-agricultural livelihood strategies.In this context,the grassland forage-supply ratio increased with the stocking rate.However,once the stocking rate exceeded 56.5 sheep/hm^(2),the grassland forage-supply ratio no longer increased rapidly under the agriculture-based livelihood strategy.The strategy of ecological resource conservation and moderate utilization based on the quality and quantity of natural resources ensures win-win benefits for the environment and human well-being in arid and semi-arid areas.Moderate grazing therefore has the potential to improve farmers’livelihoods without causing grassland degradation.These results contribute to the synergistic co-adaptation of livelihood improvement and ecological conservation in arid and semi-arid areas.展开更多
基金supported by the National Natural Science Foundation of China(Nos.42271003,42301001)the Fundamental Research Funds for the Central Universities(No.lzujbky-2022-ey09)+1 种基金the China Postdoctoral Science Foundation(No.GZB20230275)Supercomputing Center of Lanzhou University。
文摘Arid regions are vital components of Earth’s land surface.Clarifying the area/boundary of arid region is crucial for comprehending area changes and potential mechanisms.However,the accuracy and applicability of arid region boundary delineated by different indices remain unclear.In this study,the annual precipitation(AP),humidity index(H),and aridity index(K)were calculated for delineating arid region of China using 106 meteorological stations during 1990–2019.The results suggest that AP and H can accurately delineate arid region,because they are consistent with the distribution of typical soil and vegetation in arid region,whereas K is not.Moreover,AP is the best index for delineating arid region in regions with limited meteorological data,especially in studying long-term patterns and mechanisms of area changes.The accuracy of delineating arid region using H is enhanced in regions with abundant meteorological data.Over the past 30 years,influenced by the increase of atmospheric moisture influx and precipitation,the area in arid region of northwestern China decreased by 70×10^(3)–90×10^(3)km^(2),resulting in the present area of approximately 1.55×10^(6)km^(2).This study provides appropriate indices for delineating arid region,contributing to improving our knowledge of regional responses difference to climate change.
基金supported by the Second Tibetan Plateau Scientific Expedition and Research Program[grant number 2019QZKK0101]。
文摘In the context of global warming,it is anticipated that both the intensity and the frequency of future global extreme high precipitation(EHP)and extreme high temperature(EHT)events will increase.To evaluate the future extreme climate changes in the Asian arid region and Tibetan Plateau,this study applied the NASA Earth Exchange Global Daily Downscaled Projections(NEX-GDDP-CMIP6)to assess the changes in EHP(Rx5d and R95pTOT)and EHT(TX90p and TXx)under different emission scenarios in the 21st century.Findings suggest that both the frequency and the intensity of the extreme indices will increase,exhibiting accelerated growth under higher emission scenarios,particularly under the SSP5-8.5 emission scenario.It is suggested that the growth of EHT and EHP in the early subperiod of the 21st century(2026-2045)will be relatively moderate,with small differences between different emission scenarios.However,by the middle subperiod of the 21st century(2041-2060),the differences between different emission scenarios will become larger than the 2035s and the growth will become more intense.In western central Asia,TX90p,TXx,Rx5d,and R95pTOT increase by 9.7%-14.2%(13.3%-24.7%),1.3℃-1.7℃(1.6℃-2.7℃),6.5%-8.9%(8.2%-8.8%),and 18.1%-27.0%(25.6%-30.0%)by the early(middle)subperiod;in eastern central Asia,TX90p,TXx,Rx5d,and R95pTOT increase 8.1%-12.0%(11.3%-21.1%),1.4℃-1.8℃(1.9℃-2.9℃),7.4%-9.7%(10.4%-13.8%),and 20.2%-29.3%(32.0%-40.8%)by the early(middle)subperiod;and over the Tibetan Plateau,TX90p,TXx,Rx5d,and R95pTOT increase 12.5%-17.4%(17.0%-31.0%),1.2℃-1.5℃(1.6℃-2.5℃),7.2%-10.0%(9.9%-15.0%),and 26.6%-33.1%(36.1%-55.3%)by the early(middle)subperiod.
基金supported by the Natural Science Foundation of Henan Province(252300421290)the National Natural Science Foundation of China(41771438)+1 种基金the Program for Innovative Research Team(in Science and Technology)of Henan University(22IRTSTHN010)the Postgraduate Education Reform and Quality Improvement Project of Henan Province(HNYJS2020JD14).
文摘Soil moisture(SM)is a critical variable in terrestrial ecosystems,especially in arid and semi-arid areas where water sources are limited.Despite its importance,understanding the spatiotemporal variations and influencing factors of SM in these areas remains insufficient.This study investigated the spatiotemporal variations and influencing factors of SM in arid and semi-arid areas of China by utilizing the extended triple collation(ETC),Mann-Kendall test,Theil-Sen estimator,ridge regression analysis,and other relevant methods.The following findings were obtained:(1)at the pixel scale,the long-term monthly SM data from the European Space Agency Climate Change Initiative(ESA CCI)exhibited the highest correlation coefficient of 0.794 and the lowest root mean square error(RMSE)of 0.014 m^(3)/m^(3);(2)from 2000 to 2022,the study area experienced significant increase in annual average SM,with a rate of 0.408×10^(-3)m^(3)/(m^(3)•a).Moreover,higher altitudes showed a notable upward trend,with SM increasing rates at 0.210×10^(-3)m^(3)/(m^(3)•a)between 1000 and 2000 m,0.530×10^(-3)m^(3)/(m^(3)•a)between 2000 and 4000 m,and 0.760×10^(-3)m^(3)/(m^(3)•a)at altitudes above 4000 m;(3)land surface temperature(LST),root zone soil moisture(RSM)(10-40 cm depth),and normalized difference vegetation index(NDVI)were identified as the primary factors influencing annual average SM,which accounted for 34.37%,24.16%,and 22.64%relative contributions,respectively;and(4)absolute contribution of LST was more significant in subareas at higher altitudes,with average absolute contributions of 0.800×10^(-3)m^(3)/(m^(3)•a)between 2000 and 4000 m and 0.500×10^(-2) m^(3)/(m^(3)•a)above 4000 m.This study reveals the spatiotemporal variations and main influencing factors of SM in Chinese arid and semi-arid areas,highlighting the more pronounced absolute contribution of LST to SM in high-altitude areas,providing valuable insights for ecological research and water resource management in these areas.
文摘The author affiliation and the funding information in the Acknowledgement section of the online version of the original article was revised.One affiliation(the 8th affiliation)of the first author is added.The Acknowledgement section of the original article has been revised to:Acknowledgments:This research was funded by the National University of Mongolia under grant agreement P2023(grant number P2023-4578)and supported by the Chey Institute for Advanced Studies“International Scholarship Exchange Fellowship for the academic year of 2024-2025”,Republic of Korea,and the National University of Mongolia.We would like to acknowledge the National University of Mongolia and Soumik Das from the Center for the Study of Regional Development,Jawaharlal Nehru University,New Delhi-110067,for his valuable assistance in preparing the geological maps.
文摘The article examines the impact of increased aridization of the territory due to an increase in air temperature,reduced precipitation,and the formation of moisture deficiency on grain yields in Northern Kazakhstan.The most important result of the work is the revealed inverse relationship between grain yields and the temperature of the growing season:low-yielding years are associated with high temperatures and droughts,and high-yielding years are associated with lower temperatures and an optimal ratio of heat and moisture.The novelty of this study is the use of the method of hydrological and climatic calculations in identifying the nature of temperature variability and precipitation in the territory of Northern Kazakhstan for the modern period(1991–2020)compared with the base period(1961–1990).At all the studied meteorological stations,there is a tendency for the average annual temperature and the temperature of the growing season to increase:in the forest-steppe zone with an average warming intensity of 0.3–0.33℃ per decade;in the steppe zone by 0.2–0.43℃ per decade;and in the growing season by 0.2–0.7℃ per decade.The air temperature in the steppe zone is rising more intensively than in the forest-steppe zone,and precipitation in the forest-steppe zone has changed more than in the steppe zone.An increase in the average annual air temperature during the growing season(May–August),combined with a shortage of atmospheric moisture or a constant amount of it,led to an increase in the degree of aridization of the territory,an increase in the frequency of droughts in the steppe zone of Northern Kazakhstan.
基金Supported by Gansu Provincial Key Talent Project(GZTZ20240415)The Central Financial Forestry Science and Technology Promotion Demonstration Fund Project(2024ZYTG04)+1 种基金Gansu Provincial Key Research and Development Program(25YFFA073)"Jiebangguashuai"Project for Key Technology Research and Development of the"Three North"Program of National Forestry and Grassland Administration(202401-05).
文摘[Objectives]Amygdalus tangutica is a new and excellent tree species for afforestation in arid areas of central China for soil and water conservation.It has the characteristics of drought resistance,cold resistance and tolerance to poor soil,and has strong ecological,landscape and economic value.To provide a theoretical basis for the propagation and application of A.tangutica in Minqin and similar arid sandy areas of Northwest China,this paper explored its introduction and cultivation technology through field experiments,considering the natural geographical conditions of the study area.[Methods]High-quality seeds were introduced from forest farms of Chankou Town,Anding District,Dingxi City,and Dian ga Town,Diebu County,Gannan Prefecture,and the introduction and cultivation experiments of A.tangutica were carried out in the greenhouse of Wuwei Oasis Station.[Results](1)Soaking treatment at different temperatures combined with gibberellin treatment and stratification germination could effectively break the dormancy of A.tangutica seeds,thereby accelerating germination and shortening the germination cycle.The germination peak appeared 15-20 d after sowing,and the final germination rate could reach about 50%.(2)In the introduction and cultivation of A.tangutica in arid areas,large fruit seeds with higher thousand-grain weight should be given priority.The emergence rate of large fruit seeds was significantly higher than that of small fruit seeds,with the highest reaching 57%,while the highest of small fruit seeds was only 20%.Soaking treatment at different temperatures had no significant difference in the germination performance and germination potential of A.tangutica seeds,but the germination index of large fruit seeds was higher than that of small fruit seeds.(3)Under the current conditions,seedling propagation is a reliable way to propagate A.tangutica in arid areas.The cutting propagation technology,particularly hardwood cutting which exhibits an extremely low survival rate,is not yet mature and is currently unsuitable for large-scale production.Consequently,future efforts should prioritize more in-depth research on softwood cutting techniques.[Conclusions]This study provides a theoretical foundation for the propagation and broader application of A.tangutica in Minqin and similar arid sandy areas of Northwest China.
文摘The Monte Desert is characterized by a great diversity of landforms created with fluvial,alluvial which the vegetation patterns are related to.The present work has the following objectives:(1) determine whether topographical attributes,surface characteristics,soil properties and vegetation patterns vary between alluvial landforms,and(2) define whether morphometric,soil and surface properties influence vegetation patterns along alluvial landscape.Morphometric data were obtained by processing a 5 m digital elevation model.The coverage of rock fragments,fine sediments and mulch was quantified.Observations and descriptions of the soil profiles were restricted to the uppermost 50 cm.Vegetation properties were calculated using a Point Quadrat Method.The relationship between variables was evaluated through multivariate statistical analysis.The main results show the presence of 45 plant species distributed in 19 families,where shrubs are dominant.The wind effect,topographic wetness and dissection of the landscape are limiting factors of diversity.The coverage of superficial rock fragments influence vegetation coverage through the distribution and availability of rainwater.Furthermore,the different soil textures reveal that the silt content favors an increase in vegetation coverage.The presence of V horizon could condition the installation and development of vegetation in the early stages of growth.
基金National Natural Science Foundation of China,No.42201170Young Elite Scientists Sponsorship Program by CAST,No.2022QNRC001。
文摘Arid West Asia(AWA)is a critical hub of the Silk Road and one of the primary dust source regions in the Northern Hemisphere.Dust storms in AWA emitting substantial dust particles into the atmosphere,significantly influencing air quality,climate change and marine productivity.However,the variability of dust storm activity in this region during the Holocene,particularly its links to vegetation and hydroclimatic changes,remains debated,hindering our understanding of the interconnected dynamics between climate change and surface environments.This study reconstructs dust storm variations in AWA over the past 9000 years using geochemical analyses(trace elements,Sr-Nd isotopes)from a well-dated,high-resolution sediment core from the Almalou Peatland,located on the western Iranian Plateau.Our results reveal a decline in dust storm frequency from the early to mid-Holocene,a minimum occurrence during the mid-Holocene,and a significant increase in the late Holocene.Provenance analysis indicates that the primary dust sources were the arid regions of Mesopotamia,located upwind of the study area.A comparison with proxy records and paleoclimate models suggests an inverse relationship between dust storm activity and regional hydroclimatic and vegetation changes,along with a positive correlation with wind speeds.The concentration of dust storms during the wetter month of May highlights wind speed as a more critical driving factor.Moreover,given the dominant influence of the subtropical high on hydroclimatic conditions and wind speeds in AWA,we propose that this system is the key regulator of regional dust storm dynamics.Our findings provide new insights into the drivers of dust storm activity in AWA and hold implications for developing targeted dust storm management strategies.
基金The National Natural Science Foundation of China(Grant 42371159)。
文摘Based on regional paleoclimate sequences,records of human activities,paleoclimate simulations,and detailed environmental historical records,we discuss the impacts of Holocene climate change and human activities on the evolution of the Shule River in the western Qilian Mountains,China.The results indicate that during the early to mid-Holocene,the river evolution of the Shule River alluvial fan was closely related to regional climate fluctuations.In the late Holocene,flood agriculture began to emerge along the Shule River.During the historical period,population growth and the expansion of arable land led to increased river water usage,resulting in decreased access to the expected distribution of water resources in other regions,which in turn has caused imbalances in the regional hydrological ecosystem.
文摘Mountains are important reservoirs of biodiversity and endemism on a global scale, but little is known about the altitudinal configuration of this diversity and its driving factors in arid mountains. We explored variations in composition, diversity, cover,and life forms of vascular plants along a complete altitudinal gradient(1300-4000 m a.s.l) in Sierra de Velasco, an arid mountain in northwestern Argentina.We evaluated the influence of environmental variables on plant diversity and cover. Field sampling was conducted in the northern sector of the Sa. de Velasco,on the western slope in eight 50 m wide altitudinal bands at 400 m elevation intervals. We used rectangular plots(20 × 4 m;n:10/altitudinal band) to register the vascular plants of all the growth forms, and linear transects(20 m long.;n:30/altitudinal band) to quantify the vegetation cover using the point intercept method. Diversity was calculated using hill numbers.Data analysis included non-metric multidimensional scaling(NMDS), indicator species analysis,generalized linear models(GLMs), and variance partitioning analysis. A total of 232 species from 51families and 158 genera were registered. Species composition showed greater similarity at intermediate elevations. Plant diversity and cover exhibited a unimodal distribution, peaking at intermediate elevations(2100-2500 m). In contrast, life forms' distribution showed divergent patterns. Therophytes and succulents predominated at low altitudes,phanerophytes and hemicryptophytes at medium altitudes, and chamaephytes and geophytes at high altitudes. The altitudinal patterns of plant diversity and cover were primarily driven by climatic factors.Conservation efforts in the Sierra de Velasco should focus on the middle and upper zones due to their high biodiversity and vulnerability to climate change.
基金supported by the National Key Research and Development Program of China(2022YFF1300802)the National Natural Science Foundation of China(42130717)the“Light of the West”Cross Team-Key Laboratory Cooperative Research Project(A314021402-1912).
文摘Livelihood improvement and sustainable natural resource utilization are among the United Nations Sustainable Development Goals;however,most farm households either randomly select or just imitate livelihood strategies being practiced in other areas.As the livelihoods of farm households are vulnerable to several challenges in ecologically fragile areas,identifying the livelihood strategies of farm households in arid and semi-arid areas will help for promoting both livelihood security and environmental conservation.Hence,in this study,we constructed a sustainable evaluation index system for the livelihood of farmers in the Loess Plateau region of China by conducting field research and interviews.We employed the composite index method to measure the livelihood capital and the livelihood strategies chosen by farmers,and then analyzed the resource endowment of farmers under different livelihood strategies using logistic regression and structural equation modeling.The results revealed that under the combined influences of livelihood capital and government policy,farm households in the Loess Plateau region selected agro-dependent,agro-pastoral,agro-industrial,non-agricultural livelihood strategies.The key factors influencing the selection of these household livelihood strategies included the household labor capacity,the farmland owned per household,the number of livestock,and the grassland forage-supply ratio.The grassland forage-supply ratio was a crucial factor influencing the choice between agricultural and non-agricultural livelihood strategies.In this context,the grassland forage-supply ratio increased with the stocking rate.However,once the stocking rate exceeded 56.5 sheep/hm^(2),the grassland forage-supply ratio no longer increased rapidly under the agriculture-based livelihood strategy.The strategy of ecological resource conservation and moderate utilization based on the quality and quantity of natural resources ensures win-win benefits for the environment and human well-being in arid and semi-arid areas.Moderate grazing therefore has the potential to improve farmers’livelihoods without causing grassland degradation.These results contribute to the synergistic co-adaptation of livelihood improvement and ecological conservation in arid and semi-arid areas.
