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Differential response of radial growth and δ^(13)C in Qinghai spruce(Picea crassifolia) to climate change on the southern and northern slopes of the Qilian Mountains in Northwest China

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Journal of Forestry Research 2024年第3期35卷 205-218页

作者： Li Qin Huaming Shang Weiping Liu Yuting Fan Kexiang Liu Tongwen Zhang Ruibo Zhang Key laboratory of Tree-Ring Physical and Chemical Research(CMA)/Xinjiang Key laboratory of Tree-Ring Ecology Institute of Desert MeteorologyChina Meteorological AdministrationUrimqi 830002People's Republicof China Xinjiang Meteorological Information Center Urimqi 830002People's Republic of China

Tree radial growth can have significantly differ-ent responses to climate change depending on the *** elucidate the effects of climate on radial growth and stable carbon isotope(δ^(13)C)fractionation of Qing-hai spruce(Picea crassifolia),a widely distributed native conifer in northwestern China in different environments,we developed chronologies for tree-ring widths and δ^(13)C in trees on the southern and northern slopes of the Qilian Mountains,and analysed the relationship between these tree-ring variables and major climatic ***-ring widths were strongly influenced by climatic factors early in the growing season,and the radial growth in trees on the northern slopes was more sensitive to climate than in trees on the ***-ring δ^(13)C was more sensitive to climate than radial growth.δ^(13)C fractionation was mainly influenced by summer temperature and precipitation early in the growing *** conductance more strongly limited stable carbon isotope fractionation in tree rings than photosynthetic rate *** response between tree rings and climate in mountains gradually weakened as climate *** in radial growth and stable carbon isotope fractionation of *** in response to climate in the Qilian Mountains may be further complicated by continued climate change.

关键词： Tree rings Qinghai spruce(Picea crassifolia Kom.) Stable carbon isotope(δ^(13)C) Qilian Mountains:Climate change

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Thriving green havens in baking deserts:Plant diversity and species composition of urban plantations in the Sahara desert

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Journal of Arid Land 2024年第9期16卷 1270-1287页

作者： Mohammed SOUDDI Haroun CHENCHOUNI M'hammed BOUALLALA laboratory of Saharan Natural Resources Faculty of Nature and Life SciencesUniversity of Ahmed Draia-AdrarAdrar 01000Algeria laboratory of Algerian Forests and Climate Change Higher National School of ForestsKhenchela 40000Algeria laboratory of Natural Resources and Management of Sensitive environments University of Oum El BouaghiOum El Bouaghi 04000Algeria Higher School of Saharan Agriculture Adrar 01000Algeria

Hot arid zones represent vital reservoirs of unique species and ecosystems,holding significant importance for *** study aimed to explore the plant diversity associated with tree plantations in urban ecosystems under hyper-arid climatic conditions in the Sahara desert of *** May 2022,30 quadrats measuring 1 m^(2) each were established at the base of Phoenix dactylifera,Leucaena leucocephala,and Tamarix aphylla,corresponding to the dominant tree species in each of three *** each quadrat,the plant quantitative inventory was conducted to measure plant diversity and similarity among the studied *** on this,we assessed the plant functional traits and rarity/abundance status of the *** findings revealed a diverse flora associated with the studied plantations,comprising 29 plant species grouped into 27 genera and 12 ***,Poaceae(accounting for 30.8% of the flora),Asteraceae(25.0%),and Zygophyllaceae(21.6%)were *** an overall density of approximately 555 individuals/m^(2),Zygophyllum album(120 individuals/m^(2))and Polypogon monspeliensis(87 individuals/m^(2))emerged as the most abundant *** trait analysis underscored the pivotal role of therophytes(constituting over 50.0% of the flora)and anemochorous species(33.0%-62.5%).Phytogeographic analysis emphasized the prevalence of the Saharo-Arabic element(constituting over 31.0% of the flora)and the Mediterranean Saharo-Arabic element(9.5%-21.5%).The Cosmopolitan element thrived under disturbance factors,recording percentages from 13.0% to 20.0% of the plant *** rarity/abundance status of the flora emphasized the significance of rare,common,and very common species in the studied *** findings could provide fundamental data for the effective control and management of biodiversity in hot hyper-arid urban ecosystems.

关键词： urban plantations plant diversity plant functional traits rarity/abundance status Sahara desert Algeria

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中国新疆生态变迁——揭示气候变化对植被动态的影响

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Journal of Geographical Sciences 2024年第6期34卷 1039-1064页

作者：郝海超姚俊强陈亚宁徐建华李稚段伟利萨达夫-伊斯梅尔王桂玲 Key laboratory of Geographic Information Science(Ministry of Education) School of Geographic SciencesEast China Normal UniversityShanghai200241China Graduate School of Advanced Integrated Studies in Human Survivability Kyoto UniversityYoshida-Nakaadachi 1Sakyo-kuKyoto 606-8306Japan Field Scientific Experiment Base of Akdala Atmospheric Background Institute of Desert MeteorologyChina Meteorological AdministrationUrumqi 830011China State Key laboratory of desert and Oasis Ecology Key Laboratory of Ecological Safety and Sustainable Development in Arid LandsXinjiang Institute of Ecology and GeographyCASUrumqi 830011China School of Geographic Science Nantong UniversityNantong 226007JiangsuChina

For the past several decades, climate change has been driving vegetation dynamics in arid regions worldwide. This study investigates vegetation dynamics and their links to climate from 1990 to 2020 in Xinjiang, China, using data from 30-m resolution land use and cover change, remote sensing, and climate reanalysis. Our approach encompasses a range of analytical techniques, including transfer matrix analysis, modeling, correlation, regression,and trend analysis. During the study period, there were major vegetation conversions from grassland to forestland in the mountains, and from cropland to grassland in the plains. Climate change emerged as an important trigger of these changes, as evidenced by the increase in net primary productivity in most vegetation types, except for cropland-grassland and grassland-cropland conversions. Precipitation and soil moisture were the most influential climatic factors, contributing 15.1% and 15.2%, respectively, to natural vegetation *** study also found that evapotranspiration serves as a key mechanism for moisture dissipation in the hydrological cycle of vegetation dynamics. The interplay between precipitation,soil moisture, and evapotranspiration is a critical pattern of climatic influence that shapes vegetation dynamics across zones of intersection, increase, decrease, and change. These insights are invaluable for informing vegetation conservation and development strategies in Xinjiang and other similar environments facing climate-driven ecological transitions.

关键词： climate change ecological transitions LUCC NPP efficiency vegetation dynamics Xinjiang

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Antioxidant antileishmanial cytotoxic and antimicrobial activities of a local plant Myrtus nivellei from Algeria Sahara

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Asian Pacific Journal of Tropical Biomedicine 2017年第8期7卷 702-707页

作者： Farah Ramdane Rym Essid Nadia Fares Dahmane El Ouassis Sana Aziz Mahfoud Hadj Mahammed Mohamed Didi Ould Hadj Ferid Limam biogeochemistry laboratory in desert environments Kasdi Merbah University Faculty of Natural and Life Sciences El Oued University laboratory of Bioactive Substances Biotechnology Center of Borj-Cedria Technopole National Institute of Forest Research Protection laboratory of Ecosystem in Arid and Semi Arid Zone Kasdi Merbah University

To study the phytochemical constituents and in vitro biological activities of hydromethanolic extract and fractions from Algerian Sahara Myrtus nivellei (M. nivellei) collected in Hoggar region and to identify the active fraction that can act as an alternative of commonly used antibiotics and as antileishmanial or antioxidant *** screening of M. nivellei aerial parts was realised according to the literature. Extract was firstly prepared by using aqueous methanol then fractionated with ethyl acetate and butanol solvents. Total phenolics, tannis and flavonoids, of the hydromethanolic extract and their fractions were determined by Folin-Ciocalteu method as gallic acid equivalents and by aluminium chloride as rutin equivalent respectively. Extract and fractions were tested for their antimicrobial and antiparasital activities against standard bacteria using agar diffusion method and two kinds of leishmania visceral and cutaneous. The antioxidant activities were realized using phosphomolybdenum, FRAP and DPPH *** phytochemical screening exhibited the presence of flavonoids, tannins, saponins, and alkaloids. The experimental results showed that plant extract and fractions were high in phenolic compounds and exhibited an important role as antioxidant, antimicrobial and had a moderate antileishmanial *** observations lead us toward more studies in this field, so that we can get more benefits from our local Algerian medicinal plants.

关键词： Phenolic compounds Flavonoids Antioxidant activity Antimicrobial activity Antileishmanial activity Myrtus nivellei

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Bioinspired Double-stranded Yarn with Alternating Hydrophobic/Hydrophilic Patterns for High-efficiency Fog Collection

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Chinese Journal of Polymer Science 2024年第7期42卷 968-975,I0008页

作者： Lan-Lan Hou Meng-Na Qiu Ya-Qiong Wang Tong-Hua Bai Zhi-Min Cui Jing-Chong Liu Ying-Qun Qi Nü Wang Yong Li Yong Zhao Beijing Institute of Graphic Communication Beijing102600China Key laboratory of Bioinspired Smart Interfacial Science and Technology of Ministry of Education Beijing Key Laboratory of Bioinspired Energy Materials and DevicesSchool of ChemistryBeijing Advanced Innovation Center for Biomedical EngineeringBeihang UniversityBeijing100191China Key laboratory of Cryogenics Technical Institute of Physics and ChemistryChinese Academy of SciencesBeijing100190China Beijing Key laboratory for Bioengineering and Sensing TechnologyDaxing Research InstituteSchool of Chemistry and Biological EngineeringUniversity of Science and Technology BeijingBeijing100083China

Efforts to develop innovative water harvesting strategies offer powerful solutions to alleviate the water crisis,especially in remote and arid *** by the hydrophobic/hydrophilic pattern of desert beetles and water self-propulsion property of spider silks,a double-strand hydrophobic PVDF-HFP/hydrophilic PAN nanofibers yarn is proposed by electrospinning and twisting *** double-strand cooperation approach allows for water deposition on hydrophobic PVDF-HFP segment and transport under the asymmetric capillary driving force of hydrophilic PAN segment,thus speeded up the aggregation and growth of *** effects of the composition and the diameter ratio of the two primary yarns were studied and optimized for boosting fog collection *** double-strand anisotropic yarn not only provide an effective method for water harvesting,but also hold the potential to inspire innovative design concepts for fog collection materials in challenging environments.

关键词： Fog collection Wettability Electrospinning Nanofibers Spider silk

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Experimental analysis of sand particles' lift-off and incident velocities in wind-blown sand flux

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Acta Mechanica Sinica 2005年第6期21卷 564-573页

作者： Li Xie Zhibao Dong Xiaojing Zheng Key laboratory of Mechanics on Western Disaster and Environment Ministry of EducationDepartment of Mechanics Lanzhou UniversityLanzhou Gansu 730000 China laboratory of Blown Sand Physics and desert environments Cold and Arid Regions Environment and EngineeringResearch Institute Chinese Academy of SciencesLanzhou Gansu 730000 China

The probability distributions of sand particles＇ lift-off and incident velocities in a wind-blown sand flux play very important roles in the simulation of the wind-blown sand movement. In this paper, the vertical and the horizontal speeds of sand particles located at 1.0 mm above a sand-bed in a wind-blown sand flux are observed with the aid of Phase Doppler Anemometry （PDA） in a wind tunnel. Based on the experimental data, the probability distributions of not only the vertical lift-off speed but also the lift-off velocity as well as its horizontal component and the incident velocity as well as its vertical and horizontal components can be obtained by the equal distance histogram method. It is found, according to the results of the X^2-test for these probability distributions, that the probability density functions （pdf＇s） of the sand particles＇ lift-off and incident velocities as well as their vertical com- ponents are described by the Gamma density function with different peak values and shapes and the downwind incident and lift-off horizontal speeds, respectively, can be described by the lognormal and the Gamma density functions, These pdf＇s depend on not only the sand particle diameter but also the wind speed.

关键词： Wind-blown sand movement - Tunnel experiment- Incident velocity. Lift-off velocity Probability density

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Changes in global land surface frozen ground and freeze-thaw processes during 1950-2020 based on ERA5-Land data

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Advances in Climate Change Research 2024年第2期15卷 265-274页

作者： Yong YANG Ren-Sheng CHEN Yong-Jian DING Hong-Yuan LI Zhang-Wen LIU Qilian Alpine Ecology and Hydrology Research Station Key Laboratory of Ecological Safety and Sustainable Development in Arid LandsNorthwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 73000China State Key laboratory of Cryospheric Sciences Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 73000China Shandong Provincial Key laboratory of Water and Soil Conservation and Environmental Protection College of Resources and EnvironmentLinyi UniversityLinyi 276000China

Frozen ground(FG)plays an important role in global and regional climates and environments through changes in land freeze-thaw processes,which have been conducted mainly in different ***,the changes in land surface freeze-thaw processes under climate change on a global scale are still *** on ERA5-Land hourly land skin temperature data,this study evaluated changes in the global FG area,global land surface first freeze date(FFD),last freeze date(LFD)and frost-free period(FFP)from 1950 to *** results show that the current FG areas(1991-2020 mean)in the Northern Hemisphere(NH),Southern Hemisphere(SH),and globe are 68.50×10^(6),9.03×10^(6),and 77.53×10^(6)km^(2),which account for 72.4%,26.8%,and 60.4%of the exposed land(excluding glaciers,ice sheets,and water bodies)in the NH,SH and the globe,respectively;further,relative to 1951-1980,the FG area decreased by 1.9%,8.8%,and 2.8%,*** FG at lower latitudes degrades to intermittently FG,and intermittently FG degrades to non-frozen ground,which caused the global FG boundary to retreat to higher latitudes from 1950 to *** annual FG areas in the NH,SH,and globe all show significant decreasing trends(p<0.05)from 1950 to 2020 at-0.32×10^(6),-0.22×10^(6),and-0.54×10^(6)km^(2)per decade,*** FFP prolongation in the NH is mainly influenced by LFD advance,while in the SH it is mainly controlled by FFD *** prolongation trend of FFP in the NH(1.34 d per decade)is larger than that in the SH(1.15 d per decade).

关键词： Frozen ground Freeze-thaw processes Frost-free period First freeze date Global warming

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Variations of calcareous nannofossils of cobalt-rich crusts and geological records at the Eocene-OIigocene transition in western Pacific seamounts

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Science China Earth Sciences 2015年第4期58卷 784-794页

作者： ZHANG HaiSheng HU Ji ZHAO Jun HAN ZhengBing YU PeiSong WU GuangHai LEI Ji Jiang LU Bing Irina A PULYAEVA Second Institute of Oceanography State Oceanic Administration Key laboratory of Marine Ecosystem and biogeochemistry State Oceanic Administration State Scientific Centre Yuzhmorgeologia

Two records of the crust laminae from the Marcus-Wake Seamounts and the Magellan Seamount were biostratigraphically studied. Based on biological imprints of the calcareous nannofossils, the geological ages of the two records were determined, with CM1D03 from the Marcus-Wake Seamounts being of late Paleocene to Pleistocene and CM3D06 from the Magellan Seamount of Late Cretaceous （more than 70.0 Ma）. There are the obvious temporal-spatial differences in the initial formation period and enrichment characteristics of the cobalt-rich crusts of the two seamount chains and differences in the combination and distribution of microfossils in the inner crust layers between the seamounts. These differences are due to the adaptabilities of oceanic species in different environments. Ecological research was carried out in terms of population size of the calcareous nannofossi｜s preserved in the crustal layers to discern the relation of the geological events at the Eocene-Oligocene （E/O） tran- sition. The results show the transitions and recombination of species in the biotic community during the E/O transition obvi- ously corresponded to 25 mm depth in the CM1D03 crust and 58 mm depth in the CM3D06 crust. The changes in biological species and the formation of particular ecological structures indicate the adaptive response of the paleo-biological community in the western Pacific Ocean to the global cold-climate events and the close correlation between the formation of the crust and the global climate change.

关键词： Marcus-Wake Seamounts Magellan Seamount cobalt-rich crust nannofossil E/O geological event

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Magnetic property of loess strata recorded by Kansu profile in Tianshan Mountains

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Journal of Arid Land 2011年第3期3卷 191-198页

作者： Jia JIA XianBin LIU DunSheng XIA HaiTao WEI Bo WANG Key laboratory of West China＇s Environmental Systems （Ministry of Education） College of Earth Sciences and Environments Lanzhou University Lanzhou 730000 China Key laboratory of desert and desertification Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou 730000 China

Kansu （KS） profile is located in the east of Yili basin, western Xinjiang, where typical loess sediments are distributed. The magnetic parameters （such as IRM, SIRM SOFT, and M） and grain size in the KS profile were analyzed in the study. The results showed that the magnetic property of KS loess is dominated by ferrimagnetic minerals, such as magnetite and maghemite. Antiferromagnetic and superparamagnetic minerals also exist in the profile, but had less impact on magnetic susceptibility. Compared with the typical loess sediments of the central Loess Plateau in China, the strata of Kansu profile contained more magnetic minerals and hard magnetic minerals. The analysis of grain size for magnetic minerals indicated that the properties of loess and paleosol were respectively dominated by PSD/MD and coarse SSD magnetite. The research found that the contents of magnetic minerals in loess and paleosol sequences in Kansu profile were similar, but the proportion of fine grained magnetite and soft magnetic minerals were varying, which implies a positive relationship between the value of magnetic susceptibility and intensity of pedogenesis.

关键词： loess sediment magnetic properties pedogenesis Kansu profile Tianshan Mountains

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What makes Haloxylon persicum grow on sand dunes while H. ammodendron grow on interdune lowlands: a proof from reciprocal transplant experiments

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Journal of Arid Land 2014年第5期6卷 581-591页

作者： GuiQing XU DanDan YU JiangBo XIE LiSong TANG Yan LI State Key laboratory of desert and Oasis Ecology Xinjiang Institute of Ecology and GeographyChinese Academy of Sciences

Determining the mechanisms underlying the spatial distribution of plant species is one of the central themes in biogeography and ecology. However, we are still far from gaining a full understanding of the autecological processes needed to unravel species distribution patterns. In the current study, by comparing seedling recruitment, seedling morphological performance and biomass allocation of two Haloxylon species, we try to identify the causes of the dune/interdune distribution pattern of these two species. Our results show the soil on the dune had less nutrients but was less saline than that of the interdune; with prolonged summer drought, soil water availability was lower on the dune than on the interdune. Both species had higher densities of seedlings at every stage of recruitment in their native habitat than the adjacent habitat. The contrasting different adaptation to nutrients, salinity and soil water conditions in the seedling recruitment stage strongly determined the distribution patterns of the two species on the dune/interdune. Haloxylon persicum on the dunes had lower total dry biomass, shoot and root dry biomass, but allocated a higher percentage of its biomass to roots and possessed a higher specific root length and specific root area by phenotypic traits specialization than that of Haloxylon ammodendron on the interdune. All of these allowed H. persicum to be more adapted to water stress and nutrient shortage. The differences in morphology and allocation facilitated the ability of these two species to persist in their own environments.

关键词： Haloxylon seedling recruitment root distribution biomass allocation species distribution

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