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Patterns and drivers of avian taxonomic and phylogenetic beta diversity in China vary across geographical backgrounds and dispersal abilities
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作者 Jian-Chao Liang Zhi-Feng Ding +7 位作者 Chun-Lin Li Yi-Ming Hu Zhi-Xin Zhou Gan-Wen Lie Xiao-Nan Niu Wen-Bin Huang Hui-Jian Hu Xing-Feng Si 《Zoological Research》 SCIE CSCD 2024年第1期125-135,共11页
Geographical background and dispersal ability may strongly influence assemblage dissimilarity;however,these aspects have generally been overlooked in previous large-scale beta diversity studies.Here,we examined whethe... Geographical background and dispersal ability may strongly influence assemblage dissimilarity;however,these aspects have generally been overlooked in previous large-scale beta diversity studies.Here,we examined whether the patterns and drivers of taxonomic beta diversity(TBD)and phylogenetic beta diversity(PBD)of breeding birds in China vary across(1)regions on both sides of the Hu Line,which demarcates China’s topographical,climatic,economic,and social patterns,and(2)species with different dispersal ability.TBD and PBD were calculated and partitioned into turnover and nestedness components using a moving window approach.Variables representing climate,habitat heterogeneity,and habitat quality were employed to evaluate the effects of environmental filtering.Spatial distance was considered to assess the impact of dispersal limitation.Variance partitioning analysis was applied to assess the relative roles of these variables.In general,the values of TBD and PBD were high in mountainous areas and were largely determined by environmental filtering.However,different dominant environmental filters on either side of the Hu Line led to divergent beta diversity patterns.Specifically,climate-driven species turnover and habitat heterogeneity-related species nestedness dominated the regions east and west of the line,respectively.Additionally,bird species with stronger dispersal ability were more susceptible to environmental filtering,resulting in more homogeneous assemblages.Our results indicated that regions with distinctive geographical backgrounds may present different ecological factors that lead to divergent assemblage dissimilarity patterns,and dispersal ability determines the response of assemblages to these ecological factors.Identifying a single universal explanation for the observed pattern without considering these aspects may lead to simplistic or incomplete conclusions.Consequently,a comprehensive understanding of large-scale beta diversity patterns and effective planning of conservation strategies necessitate the consideration of both geographical background and species dispersal ability. 展开更多
关键词 Beta diversity Environmental filtering dispersal limitation Hu Line Species dispersal ability Breeding birds
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Study on concentration distribution and detonation characteristics for non-axisymmetric fuel dispersal
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作者 Linghui Zeng Zhongqi Wang +1 位作者 Xing Chen Jianping Li 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第1期484-495,共12页
The study of non-axisymmetric fuel dispersal and detonation can provide reference for the prevention of industrial cloud explosion accidents and the design of fuel air explosive(FAE).The concentration and detonation f... The study of non-axisymmetric fuel dispersal and detonation can provide reference for the prevention of industrial cloud explosion accidents and the design of fuel air explosive(FAE).The concentration and detonation fields of 85 kg cylindrical and fan-shaped fuel are investigated by experiments and numerical simulations.A dynamic model of the whole process for fuel dispersal and detonation is built.The concentration distribution of fuel is used as the initial condition to calculate the detonation stage,thus solving the initial value problem of detonation field.The phase and component changes of fuel cloud at different locations are compared.The fuel cloud is divided into directions of 0°,90°,135°and 180°.The results show that the maximum cloud radius is 20.94 m in 135°and the minimum is 12.04 m in 0°.The diameter of the detonation fireball is 53.6 m,and the peak temperature is 3455 K.The highest peak overpressure is 3.44 MPa in 0°and the lowest is 2.97 MPa in 135°.The proportion of liquid phase in 0°is22.90%,and the fuel loss is 11.8% and 9% higher than that in 135°and cylindrical charge,respectively.The stable propagation distance of blast wave in 135°is 42.50% longer than 0°and 28.37% longer than cylindrical charge. 展开更多
关键词 Fuel dispersal Concentration distribution Detonation characteristic Fuel loss Numerical simulation
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Effects of wind speed,underlying surface,and seed morphological traits on the secondary seed dispersal in the Tengger Desert,China
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作者 QU Wenjie ZHAO Wenzhi +3 位作者 YANG Xinguo WANG Lei ZHANG Xue QU Jianjun 《Journal of Arid Land》 SCIE CSCD 2024年第4期531-549,共19页
The maintenance of sand-fixing vegetation is important for the stability of artificial sand-fixing systems in which seed dispersal plays a key role.Based on field wind tunnel experiments using 11 common plant species ... The maintenance of sand-fixing vegetation is important for the stability of artificial sand-fixing systems in which seed dispersal plays a key role.Based on field wind tunnel experiments using 11 common plant species on the southeastern edge of the Tengger Desert,China,we studied the secondary seed dispersal in the fixed and semi-fixed sand dunes as well as in the mobile dunes in order to understand the limitations of vegetation regeneration and the maintenance of its stability.Our results indicated that there were significant variations among the selected 11 plant species in the threshold of wind speed(TWS).The TWS of Caragana korshinskii was the highest among the 11 plant species,whereas that of Echinops gmelinii was the lowest.Seed morphological traits and underlying surface could generally explain the TWS.During the secondary seed dispersal processes,the proportions of seeds that did not disperse(no dispersal)and only dispersed over short distance(short-distance dispersal within the wind tunnel test section)were significantly higher than those of seeds that were buried(including lost seeds)and dispersed over long distance(long-distance dispersal beyond the wind tunnel test section).Compared with other habitats,the mobile dunes were the most difficult places for secondary seed dispersal.Buried seeds were the easiest to be found in the semi-fixed sand dunes,whereas fixed sand dunes were the best sites for seeds that dispersed over long distance.The results of linear mixed models showed that after controlling the dispersal distance,smaller and rounder seeds dispersed farther.Shape index and wind speed were the two significant influencing factors on the burial of seeds.The explanatory power of wind speed,underlying surface,and seed morphological traits on the seeds that did not disperse and dispersed over short distance was far greater than that on the seeds that were buried and dispersed over long distance,implying that the processes and mechanisms of burial and long-distance dispersal are more complex.In summary,most seeds in the study area either did not move,were buried,or dispersed over short distance,promoting local vegetation regeneration. 展开更多
关键词 seed dispersal seed morphological traits wind speed vegetation regeneration wind tunnel Tengger Desert
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Modeling Analysis of Factors Influencing Wind-Borne Seed Dispersal: A Case Study on Dandelion
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作者 Kemeng Xue 《American Journal of Plant Sciences》 CAS 2024年第4期252-267,共16页
A weed is a plant that thrives in areas of human disturbance, such as gardens, fields, pastures, waysides, and waste places where it is not intentionally cultivated. Dispersal affects community dynamics and vegetation... A weed is a plant that thrives in areas of human disturbance, such as gardens, fields, pastures, waysides, and waste places where it is not intentionally cultivated. Dispersal affects community dynamics and vegetation response to global change. The process of seed disposal is influenced by wind, which plays a crucial role in determining the distance and probability of seed dispersal. Existing models of seed dispersal consider wind direction but fail to incorporate wind intensity. In this paper, a novel seed disposal model was proposed in this paper, incorporating wind intensity based on relevant references. According to various climatic conditions, including temperate, arid, and tropical regions, three specific regions were selected to establish a wind dispersal model that accurately reflects the density function distribution of dispersal distance. Additionally, dandelions growth is influenced by a multitude of factors, encompassing temperature, humidity, climate, and various environmental variables that necessitate meticulous consideration. Based on Factor Analysis model, which completely considers temperature, precipitation, solar radiation, wind, and land carrying capacity, a conclusion is presented, indicating that the growth of seeds is primarily influenced by plant attributes and climate conditions, with the former exerting a relatively stronger impact. Subsequently, the remaining two plants were chosen based on seed weight, yielding consistent conclusion. 展开更多
关键词 Seed dispersal Wind Intensity Climatic Effect Factor Analysis Model
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Spatio-Temporal Change of Dispersal Areas of Greater Kudu (Tragelaphus strepsiceros) in Lake Bogoria Landscape, Kenya
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作者 Beatrice Chepkoech Cheserek George Morara Ogendi Paul Mutua Makenzi 《Open Journal of Ecology》 2024年第3期183-198,共16页
Decline in wildlife populations is manifest globally, regionally and locally. A wildlife decline of 68% has been reported in Kenya’s rangelands with Baringo County experiencing more than 85% wildlife loss in the last... Decline in wildlife populations is manifest globally, regionally and locally. A wildlife decline of 68% has been reported in Kenya’s rangelands with Baringo County experiencing more than 85% wildlife loss in the last four decades. Greater Kudu (Tragelaphus strepsiceros) is endemic to Lake Bogoria landscape in Baringo County and constitutes a major tourist attraction for the region necessitating use of its photo on the County’s logo and thus a flagship species. Tourism plays a central role in Baringo County’s economy and is a major source of potential growth and employment creation. The study was carried out to assess spatio-temporal change of dispersal areas of Greater Kudu (GK) in Lake Bogoria landscape in the last four years for enhanced adaptive management and improved livelihoods. GK population distribution primary data collected in December 2022 and secondary data acquired from Lake Bogoria National Game Reserve (LBNGR) for 2019 and 2020 were digitized using in a Geographic Information System (GIS). Measures of dispersion and point pattern analysis (PPA) were used to analyze dispersal of GK population using GIS. Spatio-temporal change of GK dispersal in LBNR was evident thus the null hypothesis was rejected. It is recommended that anthropogenic activities contributing to GK’s habitat degradation be curbed by providing alternative livelihood sources and promoting community adoption of sustainable technologies for improved livelihoods. 展开更多
关键词 Spatio-Temporal Change dispersal Greater Kudu (Tragelaphus Strepsiceros) Point Pattern Analysis (PPA) GIS
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Trees species’ dispersal mode and habitat heterogeneity shape negative density dependence in a temperate forest
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作者 Lishunan Yang Daniel J.Johnson +5 位作者 Zhichun Yang Xiaochao Yang Qiulong Yin Ying Luo Zhanqing Hao Shihong Jia 《Forest Ecosystems》 SCIE CSCD 2023年第5期589-596,共8页
Conspecific negative density dependence(CNDD)is a potentially important mechanism in maintaining species diversity.While previous evidence showed habitat heterogeneity and species’dispersal modes affect the strength ... Conspecific negative density dependence(CNDD)is a potentially important mechanism in maintaining species diversity.While previous evidence showed habitat heterogeneity and species’dispersal modes affect the strength of CNDD at early life stages of trees(e.g.,seedlings),it remains unclear how they affect the strength of CNDD at later life stages.We examined the degree of spatial aggregation between saplings and trees for species dispersed by wind and gravity in four topographic habitats within a 25-ha temperate forest dynamic plot in the Qinling Mountains of central China.We used the replicated spatial point pattern(RSPP)analysis and bivariate paircorrelation function(PCF)to detect the spatial distribution of saplings around trees at two scales,15 and 50 m,respectively.Although the signal was not apparent across the whole study region(or 25-ha),it is distinct on isolated areas with specific characteristics,suggesting that these characteristics could be important factors in CNDD.Further,we found that the gravity-dispersed tree species experienced CNDD across habitats,while for wind-dispersed species CNDD was found in gully,terrace and low-ridge habitats.Our study suggests that neglecting the habitat heterogeneity and dispersal mode can distort the signal of CNDD and community assembly in temperate forests. 展开更多
关键词 BIODIVERSITY Conspecific negative density dependence dispersal Replicated point patterns Temperate forest Topographic habitat
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ENTIRE SOLUTIONS OF LOTKA-VOLTERRA COMPETITION SYSTEMS WITH NONLOCAL DISPERSAL
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作者 郝玉霞 李万同 +1 位作者 王佳兵 许文兵 《Acta Mathematica Scientia》 SCIE CSCD 2023年第6期2347-2376,共30页
This paper is mainly concerned with entire solutions of the following two-species Lotka-Volterra competition system with nonlocal(convolution)dispersals:{u_(t)=k*u-u+u(1-u-av),x∈R,t∈R,vt=d(k*v-v)+rv(1-v-bu),c∈R,t∈... This paper is mainly concerned with entire solutions of the following two-species Lotka-Volterra competition system with nonlocal(convolution)dispersals:{u_(t)=k*u-u+u(1-u-av),x∈R,t∈R,vt=d(k*v-v)+rv(1-v-bu),c∈R,t∈R.(0.1)Here a≠1,b≠1,d,and r are positive constants.By studying the eigenvalue problem of(0.1)linearized at(ϕc(ξ),0),we construct a pair of super-and sub-solutions for(0.1),and then establish the existence of entire solutions originating from(ϕc(ξ),0)as t→−∞,whereϕc denotes the traveling wave solution of the nonlocal Fisher-KPP equation ut=k*u−u+u(1−u).Moreover,we give a detailed description on the long-time behavior of such entire solutions as t→∞.Compared to the known works on the Lotka-Volterra competition system with classical diffusions,this paper overcomes many difficulties due to the appearance of nonlocal dispersal operators. 展开更多
关键词 entire solutions Lotka-Volterra competition systems nonlocal dispersal traveling waves
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Seed Dispersal of Citharexylum tetramerum and Ziziphus penduculata by Carnivorous in a Xerophilous Scrub at Tehuacan, Puebla, Mexico
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作者 González-Pérez Adrián Miguel A. Armella +2 位作者 Maria de Lourdes Yáñez-López María de Lourdes Martinez-Cárdenas José Alejandro Zavala-Hurtado 《American Journal of Plant Sciences》 2023年第9期977-987,共11页
Seed dispersion reduces the depredation rate and increases genetic flow. Some species of Carnivora consume fruits as a standard component of their diet, so they become potential seed dispersers. In Mexico, a few studi... Seed dispersion reduces the depredation rate and increases genetic flow. Some species of Carnivora consume fruits as a standard component of their diet, so they become potential seed dispersers. In Mexico, a few studies evaluated carnivorous as seed dispersers, especially in dry ecosystems. Citharexylum tetramerum and Ziziphus pedunculata are endemic plants from the Tehuacán-Cuicatlán’s Biosphere Reserve (TCBR);however, there are very little data about dispersal seeds for both species. We assessed the germination of seeds ingested by carnivores obtained from feces. We compared them with seeds from fruits as a control group. At the Metropolitan University laboratory, we germinated seeds, from: plants, scats, and fruits, and we used Kruskall Wallis Test to compare percentage and germination rate. C. tetramerum seeds ingested by a carnivorous decreased in germination percentage and rate. In contrast, the percentage and rate of germination of Z. pedunculata seeds from carnivorous feces were higher than the control group. However, Z. pedunculata control seeds did not germinate during tests, but at the end of the tests, we found that 90% of control seeds were not dead, so they were dormant seeds. Carnivores interact as legitime dispersers for both plants because they are keeping the viability of seeds. Still, we only showed that Z. pedunculata gut carnivores broke with the dormancy of seeds. We consider that in future research, it could be essential to identify other animals that consume fruits of those plants and if it is possible to follow seeds after they have been removed. Those points could help to get better understanding of those endemic plants from Tehuacán. 展开更多
关键词 Seed dispersal
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Bulbuls and crows provide complementary seed dispersal for China's endangered trees 被引量:1
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作者 Bing Bai Ning Li +1 位作者 Xinhai Li Changhu Lu 《Avian Research》 CSCD 2017年第4期226-231,共6页
Background: Different functional frugivores generally exhibit unequal contributions,both in terms of quantity(seed removal) and quality(seedling recruitment),to effective seed dispersal of plant species.However,variat... Background: Different functional frugivores generally exhibit unequal contributions,both in terms of quantity(seed removal) and quality(seedling recruitment),to effective seed dispersal of plant species.However,variations in this dispersal pattern generated by frugivores across different regions are still unknown.Methods: In our study,we evaluated the contributions of two functional frugivore bird groups,the bulbuls(Pycnon?otidae) and crows(Corvidae),in both the seed removal and seedling recruitment of the endangered Chinese yew tree(Taxus chinensis) across three different geographical regions in eastern China.Results: The dominant crow species,Urocissa erythrorhyncha,was the most common disperser crow species at all sites,while the dominant bulbul species varied across the three sites.Furthermore,the two functional groups of dispersers diverged in the aspects of seed removal(quantity) and seedling recruitment pattern(quality).While bulbuls outperformed crows in seed removal(quantity),crows took more seeds to a safer site for seedlings(quality).Conclusions: Our results highlight the importance of variations in the effective seed dispersal patterns of different functional disperser groups across different regions in the conservation and management of endangered tree species. 展开更多
关键词 Complementary seed dispersal Effective seed dispersal Seed removal Seedling recruitment Taxus chinensis
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成熟的种子到哪里去了?——评述“Seed Fates:Seed predation,Seed Dispersal and Seedling Establishment”一书
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作者 肖治术 《植物生态学报》 CAS CSCD 北大核心 2005年第3期519-519,共1页
关键词 《Seed Fates: SEED predation Seed dispersal and SEEDLING Establishment》 书评 食果动物 种子扩散 CAB International Publishing出版社
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Delayed seed dispersal species and related traits in the desert of the United Arab Emirates
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作者 Teresa NAVARRO Hatem A SHABANA +1 位作者 Ali EL-KEBLAWY Noelia HIDALGO-TRIANA 《Journal of Arid Land》 SCIE CSCD 2021年第9期962-976,共15页
The ability of plants to safely retain seeds in the mother plant is an adaptive mechanism described in many desert plants.However,research about delayed seed dispersal species in the desert of the United Arab Emirates... The ability of plants to safely retain seeds in the mother plant is an adaptive mechanism described in many desert plants.However,research about delayed seed dispersal species in the desert of the United Arab Emirates(UAE)is lacking.This study aims to identify these delayed seed dispersal species and assess the relationships of the presence of delayed seed dispersal with plant growth form,habit,spatial dispersal,antitelechoric mechanism,and seed release time.The relationships between the presence of delayed seed dispersal and the above studied traits were assessed by using the Pearson Chi-square test and Nonlinear Principal Components Analysis(NLPCA).Results showed that a total of 46 delayed seed dispersal species were recorded(15.0%of 307 studied species)and the highest incidence occurred in the Fabaceae family(17.4%).Delayed seed dispersal species were predominantly perennial plants(73.9%)with spatial restricted dispersal(67.4%),which released seed in the dry season(45.7%).The dominant groups of delayed seed dispersal species were persistent fruits species and synaptospermy(28.3%).All graminoids showed persistent lignified fruits,while prostrate annuals were basicarpic species with myxospermy.Sandy habitats had the highest number of delayed seed dispersal species(54.3%),whereas salt flats had the lowest(23.9%).In the desert of the UAE,delayed seed dispersal species spread seeds until the end of the dry and windy season,thus breaking seed dormancy at this time and ensuring seed germination in the next arrival of the rainy season.This morphological and ecological adaptation of delayed dispersal species is essential to the survival and sustainable development of vegetation in desert environments. 展开更多
关键词 Arabian desert delayed dispersal restricted dispersal persistent fruits seed release time myxospermy synaptospermy
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Pollination and seed dispersal of Aquilaria sinensis(Lour.)Gilg(Thymelaeaceae):An economic plant species with extremely small populations in China 被引量:5
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作者 Gao Chen Changqiu Liu Weibang Sun 《Plant Diversity》 SCIE CAS CSCD 北大核心 2016年第5期227-232,共6页
Pollination and seed dispersal in angiosperms have long been investigated in order to understand the coevolution of plants and animals.However,the signals from flowers and/or seeds to attract pollinators and/or seed d... Pollination and seed dispersal in angiosperms have long been investigated in order to understand the coevolution of plants and animals.However,the signals from flowers and/or seeds to attract pollinators and/or seed dispersers have received comparatively little attention.In this study,the pollination biology and seed dispersal of the vulnerable agarwood plant Aquilaria sinensis(Lour.) Gilg,a traditional medicinal plant in China,was studied in its natural distribution range.The reproductive tactics of A.sinensis were studied in detail by employing various tests dealing with fruit set and also seed dispersal.Dynamic headspace extraction followed by GC-MS analysis was also performed in order to reveal the composition of floral scent.The results showed that noctuids and pyralids are the most effective pollinators of pollinator-dependent A.sinensis.The main compounds of the floral scent were(E,E)-α-Farnesene(61.9 ± 3.2%),trans-Ocimene(16.6 ± 1.2%),and Benzyl salicylate(4.6 ± 1.1%).The results obtained from seed dispersal experiments indicate that hornets are effective seed dispersers and they may play an important role in long-distance seed dispersal of A.sinensis.Based on our findings,we recommend several protection methods for this threatened agarwood plant in China. 展开更多
关键词 Aquilaria GC-MS POLLINATION PYRALIDAE Seed dispersal VESPA
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Post-fledging dispersal and habitat use of a reintroduced population of the Crested Ibis (Nipponia nippon) 被引量:4
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作者 Zhiping Huo Junfeng Guo +1 位作者 Xia Li Xiaoping Yu 《Chinese Birds》 CSCD 2014年第1期49-57,共9页
Background: Knowledge of dispersal movement of birds and their habitat preference during the post-fledging period is fundamental to the understanding of their ecological and evolutionary processes. The Crested Ibis is... Background: Knowledge of dispersal movement of birds and their habitat preference during the post-fledging period is fundamental to the understanding of their ecological and evolutionary processes. The Crested Ibis is now being reintroduced to protected sites within its historical range, with the goal of establishing a self-sustaining population that may eventually qualify the species for delisting.Methods: We carried out an ecological study of post-fledging dispersal and habitat use of a reintroduced population of the Crested Ibis(Nipponia nippon) from 2008 to 2012 in Ningshan County, China, by using banding and radio-telemetry methods.Results: In about two weeks(an average of 14.3 days) after fledging, the activities of the fledglings were concentrated in a range of about 100 m around their natal sites, such as the oak-pine forest patches at the edge of open habitats.During this period, fledglings were still partially dependent upon parental care and fed typically on a daily basis.Siblings increasingly became independent by mid-August and then gradually moved away from their natal sites to post-fledging dispersal locations. During the period of the post-fledging dispersal process, most juveniles moving southwest were concentrated at the mean direction(μ = 254.6°, ? = 70.5°) with a mean dispersal distance of 5.1 km.It took an average of 56.4 days to disperse from the natal territory to the first wintering area. Also, forging habitats for juvenile ibis varied with time and local conditions. For example, paddy fields were used most frequently among all habitat types, while shallow rivers just from August to October. Masson pine(Pinus massoniana) was often regarded as the roosting tree species preferred by the Crested Ibis, with the highest utilization rate among all the roosting habitat types. The juveniles of the wild population dispersed four times as far as that of the reintroduced population, but the overall pattern of post-fledging dispersal is similar for the reintroduced and wild populations.Conclusions: Our results are very useful for us to predict the distance and direction of dispersal under various landscape conditions in other released sites. The project is a good example for reintroducing endangered species to their former ranges, and will be valuable for the protection of reintroduced populations of this critically and other endangered species. 展开更多
关键词 Crested IBIS Ningshan County Post-fledging dispersal HABITAT use Reintroduced POPULATION
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Variation and dispersal of PM_(10) and PM_(2.5) during COVID-19 lockdown over Kolkata metropolitan city,India investigated through HYSPLIT model 被引量:2
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作者 Biswajit Bera Sumana Bhattacharjee +1 位作者 Nairita Sengupta Soumik Saha 《Geoscience Frontiers》 SCIE CAS CSCD 2022年第1期285-296,共12页
The higher concentration of PM_(10) and PM_(2.5) in the lower atmosphere is severely harmful for human health and it also makes visibility diminution along with weather and climate modifications.The main objective is ... The higher concentration of PM_(10) and PM_(2.5) in the lower atmosphere is severely harmful for human health and it also makes visibility diminution along with weather and climate modifications.The main objective is to find out the spatiotemporal variation and dispersal of PM_(10) and PM_(2.5) along with COVID-19 infection in the dusty city Kolkata.The consecutive two years PM_(10) and PM_(2.5) data of different stations have been obtained from State Pollution Control Board,Govt.of West Bengal.Forward trajectory analysis has been done through HYSPLIT(Hybrid Single Particle Lagrangian Integrated Trajectory)model to find the path and direction of air particles.The result showed that the various meteorological or environmental factors(such as temperature,relative humidity,wind,wind speed,pressure and gusty wind)and geographical location regulate the spatiotemporal variation of PM_(10) and PM_(2.5).These factors like high temperature with relative humidity and strong wind influence to disperse the particulate matters from north to south direction from city to outside during summer in Kolkata metropolitan city.During summer(both pre and lockdown years),the height of particles is extended up to 1000 m owing to active atmospheric ventilation whereas in winter it is confined within 100 m.The HYSPLIT model clearly specified that the particles dispersed from south,south-west to north and north east direction due to strong wind.The constant magnification of PM_(10) and PM_(2.5) in the lower atmosphere leads to greater frequency of COVID-19 infections and deaths.In Kolkata,the one of the crucial reasons of high infection and deaths(COVID-19)is co-morbidity of people. 展开更多
关键词 COVID-19 Lockdown VARIATION dispersal HYSPLIT model
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Effects of breeding success,age and sex on breeding dispersal of a reintroduced population of the Crested Ibis(Nipponia nippon)in Ningshan County,China 被引量:2
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作者 Rong Dong Xinping Ye +4 位作者 Lin Zhong Xia Li Min Li Huaqiang Wang Xiaoping Yu 《Avian Research》 CSCD 2018年第4期314-320,共7页
Background: Breeding dispersal is an important ecological process that affects species' population dynamics and colonization of new suitable areas. Knowledge of the causes and consequences of breeding dispersal is... Background: Breeding dispersal is an important ecological process that affects species' population dynamics and colonization of new suitable areas. Knowledge of the causes and consequences of breeding dispersal is fundamental to our understanding of avian ecology and evolution. Although breeding success for a wild and reintroduced population of the Crested Ibis(Nipponia nippon) has been reported, the relationships between individuals' breeding dispersal and their breeding success, age and sex remain unclear.Methods: Ibises' breeding dispersal distance, which is the distance moved by adults between sites of reproduction, was estimated based on the observations of consecutive breeding sites of marked ibis individuals. From observational and capture-recapture data(n as = 102) over 9 years, individuals' breeding dispersal probability in relation to age, sex, and reproductive success wanalyzed via a generalized linear mixed effect modeling approach.Results: Our results show that 55% males and 51% females keep their previous territories following nesting success. Failed breeding attempts increased dispersal probabilities. Both females and males failed in breeding were more likely to disperse with greater distances than successful birds(females: 825 ± 216 m vs 196 ± 101 m, males: 372 Crested Ibis exhibited a female-biased dispersal pattern that the mean dispersal distance± 164 m vs 210 ± 127 m). of females(435 ± 234 m) was much larger than that of males(294 ± 172 m).Conclusion: Our results are fundamental to predict the patterns of breeding dispersal related to reproductive success under different release sites. From the conservation point of view, landscape connectivity between the reintroduced populations should be taken into account in accordance with the distance of breeding dispersal. 展开更多
关键词 BREEDING dispersal BREEDING SUCCESS Generalized linear mixed effect model Crested IBIS Reintroduced POPULATION
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The Impact of Stream Landscape on Genetic Structure and Dispersal Patterns in Stream Salamander(Pachyhynobius shangchengensis) 被引量:1
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作者 Tao PAN Hui WANG +4 位作者 Peng YAN Chenling ZHANG Wenliang ZHOU Xiaobing WU Baowei ZHANG 《Asian Herpetological Research》 SCIE CSCD 2020年第3期205-218,共14页
Compared with other terrestrial environments,the stream environment generally presents a linear spatial structure and relatively simple environment.In a stream landscape,the dispersal direction of stream-type organism... Compared with other terrestrial environments,the stream environment generally presents a linear spatial structure and relatively simple environment.In a stream landscape,the dispersal direction of stream-type organisms usually presents a linear structure along the stream,which results in the limited dispersal and the genetic differentiation of stream-type organisms across different stream sections.The Shangcheng Stout Salamander(Pachyhynobius shangchengensis)is a narrowly distributed stream salamander in Dabie Mountains of East China.In the present study,we tested for the impact of stream landscape(i.e.waterfalls and underground river)on genetic structure and dispersal pattern in P.shangchengensis based on 12 nuclear microsatellite loci from 195 individuals in 3 populations(A,B and C)from three closely connected sections within one stream.Genetic diversity results suggested that Population B contains relatively high genetic diversity for P.shangchengensis when compared to the other populations(A and C).Detectable genetic differentiation was found(FST=0.008,P=0.007)among three populations,which was also supported by the Structure,FCA analysis and relatedness estimates of each pair of individuals among populations.The assignment test suggested that P.shangchengensis has philopatric males and female-biased dispersal(mean female Alc=.0.031,SE=0.225;mean male Alc=0.026,SE=0.198).Female-biased dispersal was also supported by analyses for each sex(i.e.Spatial autocorrelation,Genetic distance,Relatedness analysis).Our study indicated that small and isolated populations(A and C)had relatively low genetic diversity due to the limited population size.For stream salamanders,landscape features(i.e.waterfalls and underground river)can influence the ability of an individual to disperse through the landscape,and consequently influence the formation of strong genetic differentiation of P.shangchengensis. 展开更多
关键词 Dabie Mounta ins genetic structure landscape features Pachyhynobius shangchengensis sexbiased dispersal
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TRAVELING WAVES IN A SIRH MODEL WITH SPATIO-TEMPORAL DELAY AND NONLOCAL DISPERSAL 被引量:1
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作者 杨璐 杨赟瑞 宋雪 《Acta Mathematica Scientia》 SCIE CSCD 2022年第2期715-736,共22页
This paper deals mainly with the existence and asymptotic behavior of traveling waves in a SIRH model with spatio-temporal delay and nonlocal dispersal based on Schauder’s fixed-point theorem and analysis techniques,... This paper deals mainly with the existence and asymptotic behavior of traveling waves in a SIRH model with spatio-temporal delay and nonlocal dispersal based on Schauder’s fixed-point theorem and analysis techniques,which generalize the results of nonlocal SIRH models without relapse and delay.In particular,the difficulty of obtaining the asymptotic behavior of traveling waves for the appearance of spatio-temporal delay is overcome by the use of integral techniques and analysis techniques.Finally,the more general nonexistence result of traveling waves is also included. 展开更多
关键词 Nonlocal dispersal spatio-temporal delay traveling waves
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A Single Species Model with Symmetric Bidirectional Impulsive Diffusion and Dispersal Delay 被引量:1
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作者 Haiyun Wan Long Zhang Hongli Li 《Applied Mathematics》 2012年第9期1079-1088,共10页
In the natural ecosystem, impulsive diffusion provides a more natural description for population dynamics. In addition, dispersal processes often involve with time delay. In view of these facts, a single species model... In the natural ecosystem, impulsive diffusion provides a more natural description for population dynamics. In addition, dispersal processes often involve with time delay. In view of these facts, a single species model with impulsive diffusion and dispersal delay is formulated. By the stroboscopic map of the discrete dynamical system and other analysis methods, the permanence of the system is investigated. Moreover, sufficient conditions on the existence and uniqueness of a positive periodic solution for the system are derived from the intermediate value theorem. We also demonstrate the global stability of the positive periodic solution by the theory of discrete dynamical system. Finally, numerical simulations and discussion are presented to validate our theoretical results. 展开更多
关键词 dispersal DELAY IMPULSIVE Diffusion PERMANENCE Global Stability PERIODIC Solution
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Characteristics of Sediment Supply and Sediment Dispersal in Binhai District of Qikou Sag,Central Huanghua Depression
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作者 Yuantao Liao~1,Hua Wang~1,Jiahao Wang~1,Dunqing Xiao~2,Chuanyan Huang~1,Shu’e Zhao~1 1.Faculty of Earth Resources,China University of Geosciences(Wuhan) Key Laboratory of Tectonics and Petroleum Resources Ministry of Education,Wuhan 430074,China. 2.Research Institute of Dagang Oilfield Company,PetroChina,Tianjin 300280,China 《地学前缘》 EI CAS CSCD 北大核心 2009年第S1期148-148,共1页
The Qikou sag is the largest hydrocarbon-rich sag in the central Huanghua depression of Bohaiwan basin.It formed as a result of Tertiary rifting and was mainly filled with Cenozoic siliciclastic sediments about 8000-1... The Qikou sag is the largest hydrocarbon-rich sag in the central Huanghua depression of Bohaiwan basin.It formed as a result of Tertiary rifting and was mainly filled with Cenozoic siliciclastic sediments about 8000-10000 m thick.The petroleum exploration of Binhai district in Qikou sag hardly gained breakthrough all through because of previous ambiguous understanding of spatial and temporal patterns 展开更多
关键词 Bohaiwan BASIN Qikou SAG Binhai DISTRICT SEDIMENT supply SEDIMENT dispersal lithologic TRAPS lithostratigraphic TRAPS
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HOARDING BEHAVIOR OF EURASIAN NUTCRACKER ANDITS ROLE IN THE DISPERSAL OF KOREAN PINE
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作者 鲁长虎 孙跃岐 《Journal of Northeast Forestry University》 SCIE CAS CSCD 1996年第3期37-39,共3页
The studiy was carried out in Autunm from 1993 to 1995 in Liangshui Natural Reserve in NE China. After eating some seeds, Nuterackers fly over 1 km or more to some area with seeds in its sublingual pouch and cache the... The studiy was carried out in Autunm from 1993 to 1995 in Liangshui Natural Reserve in NE China. After eating some seeds, Nuterackers fly over 1 km or more to some area with seeds in its sublingual pouch and cache the seeds in the ground for future use. Each cache contains 1-7 seeds commonly. Caching habitats are in accord with seedlings sites. The quantities of caching seeds are very large. Caching depth is adaptable for seed germination. The Eurasian Nutcrackers have an important effect on seeds dispersal of Korean pine. 展开更多
关键词 Eurasian Nuteracker HOARDING BEHAVIOR dispersal KOREAN PINE
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