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Unraveling the spatial patterns and driving mechanisms of avian functional assemblages in the agro-pastoral ecosystems of the Tibetan Plateau 认领 引用
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作者 Aodong Wang Zikun Gao +5 位作者 Xingzhe Wang Xing Shi Yuanxing Ye Weidong Bao Kun Shi Qiaoqi Sun 《Avian Research》 SCIE CAS CSCD 2026年第2期259-268,共10页
China's new national park system prioritizes the conservation of large-scale ecosystems to maintain ecological integrity,exemplified by Qilian Mountain National Park(QMNP)in northwestern China.QMNP straddles both ... China's new national park system prioritizes the conservation of large-scale ecosystems to maintain ecological integrity,exemplified by Qilian Mountain National Park(QMNP)in northwestern China.QMNP straddles both pristine and pastoral landscapes and provides critical habitat for diverse migratory and resident birds as key stopover and breeding grounds.In this region,centuries of pastoralism have shaped grassland structure and biodiversity.However,spatial distribution patterns of avian species across the heterogeneous,coupled natural and pastoral landscapes of the Tibetan Plateau remain poorly understood due to persistently low detection rates resulting from high species richness,vast distribution ranges,and extensive landscape heterogeneity.To address this,we combined field surveys with functional guild-based Bayesian hierarchical occupancy modeling to elucidate guild-specific spatial distributions and their environmental drivers.Over the three consecutive summers of 2022–2024,we surveyed 72 line transects and 27 fixed observation points,recording 40 species classified into three functional guilds(small-sized,medium-sized and raptors).Vegetation cover and slope gradient were the primary determinants of guild distributions:small-sized birds strongly preferred patches of dense vegetation and avoided hotspots of medium-sized birds,whereas raptors favored gentle slopes.Furthermore,effects of growing season precipitation,distance to water,and human activity varied substantially among guilds in both magnitude and direction.These findings reveal distinct guild-specific habitat selection patterns driven by environmental filtering.Our findings demonstrate that extensive natural-pastoral landscapes remain crucial for avifauna despite traditional pastoral practices,and that functional trait-based modeling can effectively address the significant low-detection challenge in remote,biodiversity-rich grassland ecosystems of the Tibetan Plateau. 展开更多
关键词 Agro-pastoral ecosystems Avian functional assemblages Conservation prioritization Habitat selection Tibetan Plateau
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Oceanographic significance of planktonic foraminiferal assemblages in the northwest Indian Ocean-Basin-Ridge system under monsoon influence 认领 引用
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作者 Feng WANG Yunhai LI +6 位作者 Xuan DING Mingjiang CAI Zhikun LAI Jian CHEN Pengfei SHEN Liang WANG Xiang YE 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2026年第3期990-1004,共15页
Planktonic foraminifera in ocean sediments serve as unique paleoenvironmental recorders,and their distribution and diversity are affected by environmental factors.The northwest Indian Ocean,influenced by monsoons and ... Planktonic foraminifera in ocean sediments serve as unique paleoenvironmental recorders,and their distribution and diversity are affected by environmental factors.The northwest Indian Ocean,influenced by monsoons and ocean-basin-ridge systems,is a key research area in this regard.However,few studies have focused on the foraminiferal distribution in surface sediments.We analyzed 60 surface sediment samples in April 2023,from which 11 genera and 32 warm-water species were identified.The distribution was primarily controlled by depth-dependent carbonate dissolution,temperature-salinity gradients,and monsoon-driven hydrography.Four distinct assemblages were identified:the Arabian Basin assemblage(dominated by Globorotalia cultrata)demonstrates strong influence from the Arabian Sea high-salinity water and winter monsoon circulation;the Carlsberg Ridge assemblage(dominated by G.cultrata,Globorotalia tumida)exhibits depth-controlled productivity signatures;the Carlsberg Ridge Flanks assemblage(mainly including Globigerinita glutinata,G.cultrata,Globigerinoides ruber)reflects monsoon-induced mixing processes;and the Somali Basin assemblage(including mainly G.cultrata,Pulleniatina obliquiloculata,G.tumida)shows clear imprints of summer monsoon upwelling.Carbonate dissolution in the Somali Basin is strongest,followed by Arabian Basin,the Carlsberg Ridge showed the weakest dissolution.Based on planktonic foraminiferal abundance,fragmentation rate,CaCO3 content,and dissolution susceptibleesistant species,the carbonate lysocline and compensation depth were estimated at~3700 and~4800 m,respectively. 展开更多
关键词 northwest Indian Ocean surface sediment planktonic foraminifera assemblage
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Reservoir types and reservoir-forming differentiation of onlap-type carbonate-evaporite paragenetic assemblages:A case study of the second member of the Ordovician Majiagou Formation in the central-eastern Ordos Basin,NW China 认领 引用
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作者 DU Jiansheng XIONG Ying +7 位作者 REN Junfeng ZHONG Shoukang WEI Liubin YU Zhou CAI Wenjie YONG Jingkang TAN Xiucheng LI Ling 《Petroleum Exploration and Development》 SCIE 2026年第2期444-459,共16页
Based on drilling core,thin section,physical property and logging data,taking the second member of the Ordovician Majiagou Formation(Ma 2 Member) in the Ordos Basin as an example,this paper discusses the reservoir typ... Based on drilling core,thin section,physical property and logging data,taking the second member of the Ordovician Majiagou Formation(Ma 2 Member) in the Ordos Basin as an example,this paper discusses the reservoir types,distribution and forming mechanisms of the carbonate-evaporite paragenetic system.The results are obtained in three aspects.First,the Ma 2 Member was deposited in an onlapping pattern toward the Central Paleouplift and is in unconformable contact with the underlying Cambrian around the paleouplift.From the paleouplift to the eastern depression,sedimentary environments such as tidal flat,grain shoal and lagoon,as well as five types of carbonate-evaporite paragenetic sequences,developed in turn.Second,dolomicrite,silt-crystalline dolomite and grain dolomite reservoirs are developed in the Ma 2 Member.According to sedimentary and diagenetic differences,they are further subdivided into four types of reservoir rocks,including mottled silt-crystalline dolomite,grain dolomite,burrow-bearing micritic(silt-crystalline) dolomite,and gypsum-mold-pore-bearing dolomicrite.Among them,grain dolomite reservoirs have superior physical properties and high development frequency,representing the high-quality reservoirs in the study area.Vertically,the reservoirs are mainly developed in the middle and upper parts of high-frequency cycles;laterally,they show a pattern of distribution along sags and around structural highs("along sags and around highs"),characterized by multi-stage superposition and lateral migration.Third,based on the understanding of the sedimentary geomorphic pattern and onlap sedimentary filling model,combined with the lithology,lithofacies distribution and evolution of reservoir rocks,and considering the penecontemporaneous dissolution and dolomitization under high-frequency periodic sea-level cycles,a four-element reservoir-controlling differentiation model of slope geomorphology,particle shoal,dissolution and dolomitization("slope–shoal–dissolution–dolomitization") has been established..The research results can provide a basis for evaluating the exploration potential of hydrocarbon replacement areas in the deep Ma 2 Member of the basin. 展开更多
关键词 onlap filling carbonate-evaporite paragenetic assemblage reservoir characteristics reservoir-forming regularity Ordovician second member of Majiagou Formation Ordos Basin
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Lithofacies Assemblages,Source-Reservoir Characteristics,and Gas Enrichment Mechanisms of the Permian Longtan Formation Shale in Central Hunan Province,South China 认领 引用
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作者 TAN Jingqiang HUA Shihao +5 位作者 MA Xinyao MA Xiao WANG Yaohua ZHANG Baomin TIAN Wei WANG Bohao 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2025年第3期862-878,共17页
The marine-continental transitional shale of the Upper Permian Longtan Formation is widely distributed in Hunan and shows significant exploration potential.Frequent changes in lithofacies have however notably influenc... The marine-continental transitional shale of the Upper Permian Longtan Formation is widely distributed in Hunan and shows significant exploration potential.Frequent changes in lithofacies have however notably influenced the shale gas enrichment.The strata of the Longtan Formation in the Shaoyang Depression,central Hunan,were taken as the study object for this project.Three lithofacies assemblages were identified:shale interbedded with sandstone layer(SAL),sandstone interbedded with shale layer(ASL)and laminated shale layer(LSL).The SAL shale shows significant variability in hydrocarbon generation potential,which leads to shale gas characterized by'hydrocarbon generation in high total organic carbon(TOC)shale,retention in low TOC shale and accumulation in sandstone'.The ASL shale,influenced by the redox conditions of the depositional environment,shows a lower concentration of organic matter.This results in an enrichment model of'hydrocarbon generation and accumulation in shale,with sealing by sandstone'.The laminar structure of LSL shale causes both quartz and clay minerals to control the reservoir.Shale gas is characterized by'hydrocarbon generation in mud laminae,retention and accumulation in silty laminae,with multiple intra-source migration paths'.In the marine-continental transitional shale gas system,the enrichment intervals of different types of shale gas reservoirs exhibit significant variability. 展开更多
关键词 lithofacies assemblages source-reservoir characteristics migration model shale gas enrichment mechanism Longtan Formation shale
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Deterioration mechanism and dynamic constitutive model of coal-rock assemblages considering chemical corrosion and impact damage 认领 引用 被引量：3
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作者 Jianhang Chen Banquan Zeng +7 位作者 Wuyan Xu Kun Wang Peng Liu Songsong Hu Shiji Wang Zhixiang Song Shaokang Wu Xuyang Bai 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2025年第6期837-861,共25页
To reveal the deterioration mechanism of coal-rock assemblages under chemical corrosion and dynamic loading,chemical corrosion and dynamic impact experiments were conducted.Under different chemical corrosion condition... To reveal the deterioration mechanism of coal-rock assemblages under chemical corrosion and dynamic loading,chemical corrosion and dynamic impact experiments were conducted.Under different chemical corrosion conditions,the weakening characteristics,observable characteristics,softening characteristics of the dynamic parameters,dynamic failure characteristics,dynamic failure forms and dynamic microscopic characteristics were analyzed.Under each corrosion condition,the dynamic elastic modulus,dynamic deformation modulus and dynamic peak intensity tended to decrease with immersing time.The dynamic elastic modulus,dynamic deformation modulus and dynamic peak intensity exhibited an inverted U-shaped trend.Under dynamic impact,the failure process of acidly corroded samples can be divided into the following stages:the initial stage,elastic energy accumulation stage,local failure of coal and secondary rock crack expansion stage,coal fragment ejection stage,rock spalling stage and complete instability stage.Under dynamic impact,failure modes exist:coal crushing failure,rock fragmenting failure,rock splitting failure and full splitting failure.After impact failure,sample fragments are distributed in powder,granular,cone and block forms.Based on Zhu-Wang-Tang nonlinear viscoelastic properties,a model considering chemical corrosion and impact damage was proposed.The combined effects of chemical and impact-induced damage on the dynamic mechanical properties of coal-rock assemblages were systematically analyzed. 展开更多
关键词 Coal-rock assemblage Chemical corrosion Dynamic impact Deterioration characteristics Dynamic constitutive model
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Gold Occurrence and Mineral Assemblages in the BuriticáGold Deposit,Colombia:Implications for Ore-Forming Environment and Deep Exploration 认领 引用
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作者 Wenyuan Liu Xianwei Sun +5 位作者 Bo Xing Xiaohuan Luo Jingwen Chen Liyuan Wang Yongsheng Hu Lingwang Lin 《Journal of Earth Science》 SCIE CAS CSCD 2025年第6期2812-2818,共7页
0 INTRODUCTION The Andean orogenic belt,a globally significant active continental margin(Lamb et al.,1997),extends in a north-south direction along the western coast of South America.The Colombian Andes,located in the... 0 INTRODUCTION The Andean orogenic belt,a globally significant active continental margin(Lamb et al.,1997),extends in a north-south direction along the western coast of South America.The Colombian Andes,located in the northern segment of this orogen,constitute a vital component and host abundant Au-Cu resources.Three principal Au-Cu metallogenic belts(Chocó,Middle Cauca,and Antioquia)are developed from west to east across Colombia(Lesage et al.,2013;Sillitoe,2008;Figure 1a). 展开更多
关键词 deep exploration active continental margin lamb colombian andeslocated colombia mineral assemblages ore forming environment andean orogenic belta gold occurrence
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The genetic environmental transformation mechanism of coal and oil shale deposits in eastern China’s continental fault basins and the developmental characteristics of the area’s symbiotic assemblages——taking Huangxian Basin as an example 认领 引用 被引量：6
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作者 Dong-Dong Wang Zeng-Xue Li +2 位作者 Hai-Yan Liu Da-Wei Lyu Guo-Qi Dong 《Petroleum Science》 SCIE CAS CSCD 2019年第3期469-491,共23页
Coal and oil shale are two common sedimentary energy sources which are often symbiotically developed in M esozoic- Cenozoic continental fault basins. However, the mechanisms and characteristics of the symbiotic develo... Coal and oil shale are two common sedimentary energy sources which are often symbiotically developed in M esozoic- Cenozoic continental fault basins. However, the mechanisms and characteristics of the symbiotic development are not yet clearly known. In this research study, the typical continental fault basins of eastern China were chosen as examples for the purpose of conducting an examination of the coal and oil shale symbiotic assemblage types, genetic environmental differences, and transformation mechanisms, as well as the development and occurrence characteristics o f different assemblage types. Through a large number of investigations, systematic experimental testing, and sequence stratigraphy studies, the following conclusions were obtained:(1) There were five types of coal and oil shale symbiotic assemblages observed in the continental fault basins,(2) The development of coal and oil shale deposits requires a warm and humid climate, stable structure, abundant organic matter supply, a certain water depth, and a lower terrestrial source debris supply. The observed differences were that the water depth conditions were diversified in the study area, as well as the sources, types, and content of the organic matter.(3) The rapid transformations of the coal and oil shale genetic environments were mainly controlled by the tectonic settings and climatic conditions, which were determined to control the changes in the water depths, salinity,redox conditions, and lake productivity of the genetic environments. Also, in the symbiotic assemblages, genetic environment changes had induced the development of oil shale deposits, which gradually evolved into coal genetic environments.(4) In the isochronous sequence stratigraphic framework of the coal and oil shale symbiotic assemblages, the lake expansion system tracts (EST) were determined to be the most beneficial to the growth o f all the types of assemblages and were characterized by more assemblage development phases and smaller bed thicknesses. From the early to the late stages of the EST, and from the lakesides to lake centers, the thicknesses of the coal seams in the symbiotic assemblages showed trends of thinning, while the thicknesses of the oil shale deposits exhibited increasing trends. The early stages of high stand system tracts were found to be beneficial to the development of the symbiotic assemblages of coal seams overlying the oil shale. This tract type generally presented large bed thicknesses and distribution ranges. The low stand system tract and the late high stand system tract were determined to be unconducive to the development of the symbiotic assemblages. 展开更多
关键词 Coal and oil shale symbiotic assemblages Genetic environments Conversion mechanism Sequence stratigraphic framework Occurrence characteristics Continental fault basin
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Modern pollen assemblages of the forest communities and their relationships with vegetation and climate in northern China 认领 引用 被引量：8
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作者 李月丛 许清海 +3 位作者 张丽艳 王学丽 曹现勇 阳小兰 《Journal of Geographical Sciences》 SCIE 2009年第6期643-659,共17页
53 pollen traps and surface samples were collected in order to detect the characteristics of pollen assemblages and their relationships with vegetation and climate in 16 forest communities located in 10 mountains in n... 53 pollen traps and surface samples were collected in order to detect the characteristics of pollen assemblages and their relationships with vegetation and climate in 16 forest communities located in 10 mountains in northern China. The results show that 72% of the pollen taxa (80 taxa) are the same between the traps and the surface samples. The dominant taxa in the plant communities are consistent with the main pollen taxa in the pollen assemblages at the same sites. In Pinus plant communities, both Pinus pollen influx and concentration are higher, indicating the high pollen productivity and good pollen preservation ability of Pinus. In Picea and Abies plant communities, Picea and Abies have lower pollen influxes but higher concentrations, suggesting their low pollen productivities but better pollen preservation abilities. In Betula and Quercus plant communities, Betula and Quercus have higher pollen influxes but lower concentrations, revealing their high pollen productivities but poor pollen preservation abilities. The study of relationships between pollen and vegetation with discriminant analysis shows that pollen assemblages from both trap and surface samples can reflect the characteristics of different communities and distinguish different ecological areas, but surface samples can reflect the dominant components of communities much better than the traps. The study on correlations between pollen assemblages and climate with DCCA reveals that significant correlations exist between pollen assemblages and mean temperature of the coldest month (r = 0.84 for trap samples, r = 0.72 for surface samples), and then annual mean precipitation (r = 0.73 for trap samples, r = 0.71 for surface samples). 展开更多
关键词 forest communities Tauber traps surface samples pollen assemblages pollen influx pollen concentration vegetation climate
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Spatial structure and seasonal changes of nekton assemblages in the Taiwan Strait 认领 引用 被引量：5
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作者 SONG Puqing LIN Longshan +1 位作者 LI Yuan ZHONG Zhihui 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2016年第6期59-67,共9页
The Taiwan Strait is a transition zone between the East China Sea and the South China Sea with unique hydrology and a geographical environment that creates special marine community features.To analyze the spatial stru... The Taiwan Strait is a transition zone between the East China Sea and the South China Sea with unique hydrology and a geographical environment that creates special marine community features.To analyze the spatial structure and seasonal changes of the nekton assemblages in the Taiwan Strait,seasonal experimental trawl surveys were conducted during 2006-2007.The results showed that there were two assemblages in the area with different sets of species,and the average similarity within each group varies between 39.38% and 74.20%.By using multivariate statistical analysis and analyzing the distribution of dominant species,we found that the structures of the assemblages had obvious seasonal variation.The middle region from the Putian transect to the Xiamen transect could be considered a mixing area for the two assemblages.The analysis of the relationship between species assemblages and environmental factors indicated that temperature was the most important factor affecting the community structure in cold seasons,and 22.5°C and 17°C could be considered dividing lines for spring and winter,respectively.In warm seasons,the most important factor was water depth,but the relationship with depth was not as significant,with a correlation between 0.264 and 0.399.The seasonal changes of nekton assemblages basically reflected the dynamic currents in the Taiwan Strait.The south coastal assemblage extended to nearly the entire area of the Taiwan Strait along with a strong and intense warm current that shrinks in spring and winter when the southward intrusion of the cold Zhejiang-Fujian coastal current becomes stronger.The impact of shortterm and long-term environmental changes,such as extreme weather,global warming and human activity on nekton assemblages,had been recognized but need further research.Our study on nekton assemblages could be used as a baseline for measuring future changes. 展开更多
关键词 nekton assemblages species composition spatial structure transition zone Taiwan Strait
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Effects of shrub presence and shrub species on ground beetle assemblages (Carabidae,Curculionidae and Tenebrionidae) in a sandy desert,northwestern China 认领 引用 被引量：9
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作者 JiLiang LIU WenZhi ZHAO FengRui LI 《Journal of Arid Land》 SCIE CSCD 2015年第1期110-121,共12页
Shrub presence has an important effect on the structuring of ground beetles in desert ecosystems. In this study, in order to determine how shrubs and different species influence ground beetle assemblages in a sandy de... Shrub presence has an important effect on the structuring of ground beetles in desert ecosystems. In this study, in order to determine how shrubs and different species influence ground beetle assemblages in a sandy desert scrubland dominated by two different shrub species, namely Calligonum mongolicum and Nitraria sphaerocarpa, we sampled the ground beetles using pitfall traps during spring, summer and autumn in 2012. At the community level, the activity density of the ground beetles was shown to be significantly higher under shrubs than in intershrub bare habitats in spring; but an opposite pattern occurred in autumn, suggesting the presence of sea- son-specific shrub effects on the activity density of the ground beetles. Meanwhile, at the trophic group level, the activity density and species richness of predators were significantly greater under shrubs than in intershrub bare habitats in spring, whereas an opposite trend occurred on the activity density in autumn. N. sphaerocarpa shrubs had a positive effect on the activity density of herbivores in the three seasons, and C. mongolicum shrubs had a positive effect on the activity density of detritivores in spring and autumn. At the species level, more Microdera sp. was captured under shrubs than in intershrub bare habitats in spring. During the same time, we also found that C. mongolicum shrubs had a positive effect on Blaps gobiensis in spring, Carabus sp. in autumn, and Tentyria sp. in spring and autumn, and N. sphaerocarpa shrubs had a positive effect on Cyphogenia chinensis, Sternoplax setosa in spring and summer, and Curculionidae sp. 1 in summer and autumn. The study results suggest that shrub presence, shrub species and season variation are important factors for ground beetle assemblages in this desert ecosystem, but the responses of beetles differed among trophic and taxonomic levels. 展开更多
关键词 Calligonum mongolicum Nitraria sphaerocarpa ground beetle assemblages sandy desert ecosystem Heihe River basin
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Early Cretaceous Palynological Assemblages of the Shuangliao Fault Depression, Songliao Basin and their Geological Implications 认领 引用 被引量：5
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作者 WANG Chenglong ZHANG Meisheng +1 位作者 LI Xiaobo WANG Yini 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2017年第6期1949-1963,共15页
The pollen and spores found in the Early Cretaceous strata of two cores from the Shuangliao Fault Depression were studied systematically, and two palynological assemblages have been recognized. Assemblage I from the Y... The pollen and spores found in the Early Cretaceous strata of two cores from the Shuangliao Fault Depression were studied systematically, and two palynological assemblages have been recognized. Assemblage I from the Yingcheng Formation is named Paleoconiferus-Pinuspollenites; the assemblage is characterized by an extremely high content of Paleoconifer pollen. Assemblage II from Member 1 of the Denglouku Formation is named Cicatricosisporites-Cyathidites-Pinuspollenites; the assemblage is characterized by the abundant presence of Laevigati spores, but less Paleoconifer pollen. According to the palynological data and zircon U-Pb dating, the geological age of the Yingcheng Formation is thought to be Aptian-Albian, and that of the Denglouku Formation is thought to be Early Albian. On the basis of the composition of each assemblage, we can infer that during the depositional period of the Yingcheng Formation, the paleovegetation was mainly conifer forest, the paleoclimate was consistent with the temperate climate of today, and the paleoenvironment was humid feature. During the depositional period of Member 1 of the Denglouku Formation, the paleovegetation was mainly conifer forest and shrubs, the paleoclimate was consistent with the subtropical climate of today, and the paleoenvironment was humid. The results significantly improve our understanding of the stratigraphy in the Shuangliao Fault Depression, provide biostratigraphic evidence for the division and correlation of Early Cretaceous strata in the Shuangliao Fault Depression, and provide new data for analyzing paleovegetation and paleoclimate in the Songliao Basin. 展开更多
关键词 palynologieal assemblages Yingcheng Formation Denglouku Formation Shuangliao Fault Depression Songliao Basin
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Modern pollen assemblages and their relationships with vegetation and climate on the northern slopes of the Tianshan Mountains, Xinjiang, China 认领 引用 被引量：3
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作者 ZHANG Wensheng AN Chengbang +8 位作者 LI Yuecong ZHANG Yong LU Chao LIU Luyu ZHANG Yanzhen ZHENG Liyuan LI Bing FU Yang DING Guoqiang 《Journal of Arid Land》 SCIE CSCD 2023年第3期327-343,共17页
The reconstruction of paleovegetation and paleoclimate requires an understanding of the relationships between surface pollen assemblages and modern vegetation and climate.Here,we analyzed the characteristics of surfac... The reconstruction of paleovegetation and paleoclimate requires an understanding of the relationships between surface pollen assemblages and modern vegetation and climate.Here,we analyzed the characteristics of surface pollen assemblages across different vegetation zones in the Tianshan Mountains.Using surface pollen analysis and vegetation sample surveys at 75 sites on the northern slopes of the Tianshan Mountains,we determined the correlation between the percentage of dominant pollen types and the corresponding vegetation cover.Redundancy analysis was used to investigate the relationships between surface pollen assemblages and environmental factors.Our results show that the Tianshan Mountains contain several distinct ecological regions,which can be divided into five main vegetation zones from low to high altitudes:mountain desert zone(Hutubi County(HTB):500-1300 m;Qitai County(QT):1000-1600 m),mountain steppe zone(HTB:1400-1600 m;QT:1650-1800 m),mountain forest zone(HTB:1650-2525 m;QT:1850-2450 m),subalpine meadow zone(HTB:2550-2600 m;QT:2500-2600 m),and alpine mat vegetation zone(HTB:2625-2700 m;QT:2625-2750 m).The surface pollen assemblages of different vegetation zones can accurately reflect the characteristics of the mountainous vegetation patterns on the northern slopes of the Tianshan Mountains when excluding the widespread occurrence of Chenopodiaceae,Artemisia,and Picea pollen.Both average annual precipitation(Pann)and annual average temperature(Tann)affect the distribution of surface pollen assemblages.Moreover,Pann is the primary environmental factor affecting surface pollen assemblages in this region.A significant correlation exists between the pollen percentage and vegetation cover of Picea,Chenopodiaceae,Artemisia,and Asteraceae.Moreover,Picea,Chenopodiaceae,and Artemisia pollen are over-represented compared with their corresponding vegetation cover.The Asteraceae pollen percentage roughly reflects the distribution of a species within the local vegetation.These results have important implications for enhancing our understanding of the relationship between surface pollen assemblages and modern vegetation and climate. 展开更多
关键词 surface pollen assemblages environmental factors vegetation cover redundancy analysis Tianshan Mountains
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A phylogenetic perspective on the evolutionary processes of floristic assemblages within a biodiversity hotspot in eastern Asia 认领 引用 被引量：10
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作者 Rong Li Juan Yue 《Journal of Systematics and Evolution》 SCIE CAS CSCD 2020年第4期413-422,共10页
How to maximize the conservation of biodiversity is critical for conservation planning,particularly given rapid habitat loss and global climatic change.The importance of preserving phylogenetic diversity has gained re... How to maximize the conservation of biodiversity is critical for conservation planning,particularly given rapid habitat loss and global climatic change.The importance of preserving phylogenetic diversity has gained recognition due to its ability to identify some influences of evolutionary history on contemporary patterns of species assemblages that traditional taxonomic richness measures cannot identify.In this study,we evaluate the relationship between taxonomic richness and phylogenetic diversity of angiosperms at genus and species levels and explore the spatial pattern of the residuals of this relationship.We then incorporate data on historical biogeography to understand the process that shaped contemporary floristic assemblages in a global biodiversity hotspot,Yunnan Province,located in southwestern China.We identified a strong correlation between phylogenetic diversity residuals and the biogeographic affinity of the lineages in the extant Yunnan angiosperm flora.Phylogenetic diversity is well correlated with taxonomic richness at both genus and species levels between floras in Yunnan,where two diversity centers of phylogenetic diversity were identified(the northwestern center and the southern center).The northwestern center,with lower phylogenetic diversity than expected based on taxonomic richness,is rich in temperate-affinity lineages and signifies an area of rapid speciation.The southern center,with higher phylogenetic diversity than predicted by taxonomic richness,contains a higher proportion of lineages with tropical affinity and seems to have experienced high immigration rates.Our results highlight that maximizing phylogenetic diversity with historical interpretation can provide valuable insights into the floristic assemblage of a region and better-informed decisions can be made to ensure different stages of a region's evolutionary history are preserved. 展开更多
关键词 biodiversity conservation evolutionary history floristic assemblages historical biogeography phylogenetic diversity taxonomic richness
Pollen assemblages of cultivated vegetation in central and southern Hebei Province 认领 引用 被引量：2
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作者 PANG Ruiming XU Qinghai +1 位作者 DING Wei ZHANG Shengrui 《Journal of Geographical Sciences》 SCIE CSCD 2011年第3期549-560,共12页
The study on 82 surface soil pollen samples from different types of cultivated vegetations in central and southern parts of Hebei Province indicates that the pollen assem-blages from farmlands in the plain have not on... The study on 82 surface soil pollen samples from different types of cultivated vegetations in central and southern parts of Hebei Province indicates that the pollen assem-blages from farmlands in the plain have not only their own plant types,but also the pollen components from the nearby mountains.Arboreal pollen percentages and concentrations(dominated by Pinus)from farmlands in mountain area are higher than those in the plain,and it reduces gradually with the increasing distance away from the mountains.Taking Pinus pollen in Taihang Mountains as an example,its content is 20%-30%,10%-20%,20%-30%and below 16%respectively for the samples from the area of 0-50,50-100,100-150 and more than 150 km away from the east Taihang Mountains.The increase of Pinus pollen proportion in the central plain is probably related to the fohn effect.The spatial variation of AP from mountains to the plain in Hebei Province may be similar to the forests clearance by human activities in the early historical period.Shrubby pollen proportion is small both in mountains and in the plain,but their major components are different.Elaeagnaceae,Corylus,Ostryopsis and Oleaceae are common in mountain areas,while there are relatively high contents of Rosaceae and Vitaceae in the plain.Herbs content in the plain(about 60%)is 15%higher than that in mountains,among which the Cereals and Cruciferae pollen percentages are 5%and 2%higher respectively.Artemisia pollen percentage in the plain is lower than that in mountains.Since the human activities are weaker in mountains compared with that in the plain,the general trend is that Chenopodiaceae pollen increases from mountains to the plain gradually,reflecting the raising intensity of human activities.The fern spores of Selaginella sinensis in mountains are higher than that in the plain,but it still reaches to about 7%in the plain.The fern spores of Selaginella sinensis are not prone to be spread by wind,indicating that those in the surface soil of the plain may be carried by river water from mountains during the deposition of the plain. 展开更多
关键词 farmlands human activity pollen assemblages Taihang Mountain plain Hebei Province
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Long-term changes in sedimentary diatom assemblages and their environmental implications in the Changjiang(Yangtze) River estuary, China 认领 引用 被引量：3
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作者 程芳晋 俞志明 宋秀贤 《Chinese Journal of Oceanology and Limnology》 CSCD 2014年第1期155-161,共7页
Long-term data on diatom assemblages in a sediment core （60 cm） obtained from the Changjiang （Yangtze） River estuary were analyzed in order to assess the environmental changes that took place in the approximately ... Long-term data on diatom assemblages in a sediment core （60 cm） obtained from the Changjiang （Yangtze） River estuary were analyzed in order to assess the environmental changes that took place in the approximately 38 years （as determined by 210pb measurements）, i.e., between 1974 and 2012, of sediment accumulation. From the sediment core, 62 diatom taxa and genera were identified. The diatom biomass in the core generally increased beginning in the mid-1990s （core depth： 35 cm）, accompanied by a shift in the dominant species from Podosira stelliger and two species of Cyclotella （C. stylorum and C. striata） to Paralia sulcata, three species of Thalassiosira （ T. eccentria, I＂. oestrupii, and T. excentrica）, Actinoptychus undulates, and Thalassionema nitzschioides. The changes in both species diversity and abundance suggested that since the 1980s the estuary has undergone extensive eutrophication. This conclusion was supported by the increased proportion of planktonic species, another indicator of high nutrients inputs, in the Changjiang River estuary. 展开更多
关键词 diatom assemblages Changjiang River estuary East China Sea environmental implications
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The Characteristic Patterns of Macrofaunal Fouling Assemblages in Nearshore Waters of the South China Sea 认领 引用 被引量：1
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作者 CHEN Xin LIU Qiuyu +3 位作者 ZHUO Wen LIU Wenjuan LI Ziwei TANG Min 《Journal of Ocean University of China》 SCIE CAS CSCD 2018年第5期1142-1148,共7页
The spatio-temporal patterns of macrofaunal fouling assemblages were quantitatively investigated in the nearshore waters of the South China Sea.The work was undertaken by deploying seasonal panels at two sites(H-site,... The spatio-temporal patterns of macrofaunal fouling assemblages were quantitatively investigated in the nearshore waters of the South China Sea.The work was undertaken by deploying seasonal panels at two sites(H-site,L-site) for one year,and the fouling communities on the panels were examined and analyzed.The results indicated that species composition of assemblages was obviously different between the two sites.At both sites the assemblages were characteristic with solitary dominant species throughout the year,with Amphibalanus reticulates dominating at H-site and Hydroides elegans at L-site.Shannon index and biomass of the assemblages varied with depth and season at both sites.At H-site the total biomass in summer and autumn were significantly higher than those in spring and winter,while at L-site the assemblage biomass also differed significantly among the four seasons,and the greatest biomass occurred at the depth of 2.0 m in winter.The abundance of all seasonal samples in non-metric multidimensional scaling was clustered as one group at L-site and three groups at H-site.The environmental factors were more likely to be related to the variation of fouling assemblages.Furthermore,it also suggests that in tropical seas the integrated adaptability would qualify a species for dominating a fouling assemblage despite its short life cycle,rather than the usually assumed only species with long life span.This study reveals the complexity and characteristic dynamics of macrofaunal fouling assemblages in the tropical habitats,and the results would provide valuable knowledge for biodiversity and antifouling research. 展开更多
关键词 fouling macrofaunal assemblages dominant species non-metric multidimensional scaling the South China Sea
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Origins of natural gas and the main controlling factors of gas accumulation in the Middle Ordovician assemblages in Jingxi area,Ordos Basin 认领 引用 被引量：1
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作者 Liu Xinshe Jiang Youlu +4 位作者 Hou Yundong Liu Jingdong Wen Caixia Zhu Rongwei Wang Feiyan 《Natural Gas Industry B》 2016年第3期216-225,共10页
During the progressive exploration of the Jingbian Gas Field in the Ordos Basin,multiple gas-bearing regions have been discovered in the dolomite reservoirs in the Middle Ordovician assemblages of Lower Paleozoic in J... During the progressive exploration of the Jingbian Gas Field in the Ordos Basin,multiple gas-bearing regions have been discovered in the dolomite reservoirs in the Middle Ordovician assemblages of Lower Paleozoic in Jingxi area,but these gas-bearing regions and intervals are significantly different in terms of gas enrichment degrees.So far,however,the reasons for the difference have not been figured out.In this paper,the origin and source of natural gas in the Middle Ordovician assemblages in Jingxi area was investigated on the basis of geochemical data(e.g.natural gas composition and carbon isotope),and then the main factors controlling the gas accumulation were analyzed.It is shown that the natural gas in the Middle Ordovician assemblages in the Middle Ordovician assemblages in Jingxi area is similar to that in the Upper Ordovician assemblages and Upper Paleozoic reservoir in terms of genesis and sources,and they are mainly the Upper Paleozoic coaliferous gas with some oil-derived gas.Under the influence of hydrocarbon generation center of coal source rocks and the source-rock-reservoir contact relationship,the proportion of coaliferous gas increases areally from the north to the south and vertically from Ma55 sub-member of the Lower Ordovician Majiagou Fm.It is concluded that the natural gas enrichment degree is controlled by the gas charging capacity at the hydrocarbon-supplying windows.Second,the vertical migration and distribution of natural gas is dominated by the differences of Ma55-Ma510transport pathways.And third,the lateral migration direction of natural gas and the range of gas accumulation are controlled by the superimposition relationship between structures and reservoirs. 展开更多
关键词 Ordos Basin Jingxi area Early Paleozoic Middle Ordovician assemblages Natural gas origin Source rockereservoir contact relationship Charging capacity Gas enrichment difference Gas accumulation controlling factor
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Telluric iron assemblages as a source of prebiotic phosphorus on the early Earth:Insights from Disko Island,Greenland 认领 引用
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作者 Oleg S.Vereshchagin Maya O.Khmelnitskaya +4 位作者 Larisa V.Kamaeva Natalia S.Vlasenko Dmitrii V.Pankin Vladimir N.Bocharov Sergey N.Britvin 《Geoscience Frontiers》 SCIE CAS CSCD 2024年第5期415-429,共15页
Phosphorus is one of the key elements,which determined the emergence of primordial life on our planet.The source of prebiotic phosphorus was most likely to be easily soluble compounds containing phosphorus in the nega... Phosphorus is one of the key elements,which determined the emergence of primordial life on our planet.The source of prebiotic phosphorus was most likely to be easily soluble compounds containing phosphorus in the negative form of oxidation(e.g.,phosphides).The present paper is the first thorough investigation of phosphide-bearing mineral assemblages confined to telluric(terrestrial)native iron from volcanic rocks of Disko Island,Greenland.Phosphorus speciation in given assemblages varies from the solid solution in native iron(up to 0.3 wt.%P),different phosphides–schreibersite Fe3P,nickelphosphide Ni3P,barringerite Fe2P,and phosphates,including fluorapatite,anhydrous Fe-Na phosphates,phosphoran olivine and pyroxene(up to 1 wt.%P).The diversity of observed phosphorus speciation can be explained by the steep changes of redox conditions during subsurface crystallization of iron-phosphide-bearing lavas.Based on the available data on likely redox conditions on the early Earth,we hypothesize that reactive prebiotic phosphorus may have originated from shallow crustal rocks. 展开更多
关键词 Prebiotic phosphorus Native iron Phosphide Reduced mineral assemblages
Relationship between pollen assemblages and organic geochemical proxies and the response to climate change in the Zhuye Lake sediments 认领 引用
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作者 Yu Li XueHua Zhou +3 位作者 ChengQi Zhang ZhuoLun Li Yue Wang NaiAng Wang 《Research in Cold and Arid Regions》 CSCD 2014年第1期37-43,共7页
This paper examines the relationship among organic geochemical proxies （TOC, C/N ratio and ~13C） and pollen assemblages in Zhuye Lake sediments since the Late Glacial. Results show that the reaction extent of organi... This paper examines the relationship among organic geochemical proxies （TOC, C/N ratio and ~13C） and pollen assemblages in Zhuye Lake sediments since the Late Glacial. Results show that the reaction extent of organic geochemical proxies and pollen as- semblages to environment changes are different. Organic geochemical proxies are sensitive to overall environmental change, while pollen assemblages indicate detailed information of environmental change. For the entire sedimentary section （except the sand layer fi＇om the bottom of the section）, when values of TOC, C/N ratio and total pollen concentrations are high, 813C values are low, and vice versa. The different responses of organic geochemical proxies and pollen records in Zhuye Lake are mainly due to their different sensitivity and diverse influencing factors in different environmental conditions. 展开更多
关键词 Zhuye Lake lacustrine sediments pollen assemblages geochemical proxies
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Macroinvertebrate assemblages of surface mine wetlands of Southwest Virginia,USA 认领 引用 被引量：2
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作者 David H.Jones Robert B. Atkinson John Cairns,Jr. 《Journal of Environmental Sciences》 SCIE EI CAS 1996年第1期1-14,共14页
The focus of this study was to investigate the macroinvertebrate community in surface mine wetlands. Nine wetlands were sampled for macroinvertebrates from July 1993 through May 1994.These sites represented a range of... The focus of this study was to investigate the macroinvertebrate community in surface mine wetlands. Nine wetlands were sampled for macroinvertebrates from July 1993 through May 1994.These sites represented a range of physical,chemical, and biological parameters. Macroinvertebrates were found in all sites;a total of 14 orders, 40 families,and 70 genera were identified in the samples. Insects were the most common invertebrates,and most functional feeding groups were represented. Predators dominated with 63% of the taxa, followed by the collector/gathers with 20%,shredders 14%, and scrapers 3%. Sites differed in the number of taxa inhabiting them.Richness ranged from 10 genera to 52.The lowest richness was found in two seasonal wetlands that were dry for the majority of the year. A permanently flooded site with no water quality problems and a dense growth of aquatic plants had the highest richness. 展开更多
关键词 macroinvertebrate assemblages surface mine wetlands wetland faunas.
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