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Characteristics of soil seed banks at different geomorphic positions within the longitudinal sand dunes of the Gurbantunggut Desert, China

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Journal of Arid Land 2017年第3期9卷 355-367页

作者： JIA Fengqin Tashpolat TIYIP WU Nan TIAN Changyan ZHANG Yuanming Key Laboratory of Biogeography and Bioresources in Arid Land Xinjiang Institute of Ecology and Geography Chinese Academy of Sciences Key Laboratory of Oasis Ecology/Resources and Environment Department Xinjiang University Tourism College Urumqi Vocational University

Understanding the characteristics of soil seed banks in sand dunes is crucial to stabilize the dune systems and maintain the plant populations in deserts. In this study, we conducted a survey investigation in the field and a seed germination experiment in the laboratory to explore the characteristics of soil seed banks at various geomorphic positions of longitudinal sand dunes in the Gurbantunggut Desert, China. Totally, 17 plant species belonging to 17 genera and 9 families were identified in soil seed banks, and 35 plant species belonging to 34 genera and 17 families were identified in aboveground vegetation. Plant species richness in soil seed banks decreased with increasing soil depth. The highest species richness was presented in the upper slope of the windward slope and the lowest species richness was presented in the base of the windward slope. There was no significant difference in seed density of soil seed banks among the examined seven geomorphic positions. The highest seed density occurred in the lower slope of the leeward slope while the lowest occurred in the crest. Moreover, seed density decreased with increasing soil depth, being the highest in the upper soil layer （0-2 cm）. For both soil seed banks and aboveground vegetation, there was no significant difference in Simpson＇s diversity index among the seven geomorphic positions; however, Shannon-Wiener diversity index and Pielou＇s evenness index showed significant differences among the seven geomorphic positions. Those results showed that although there was no significant difference in seed density of soil seed banks among the seven geomorphic positions, the geomorphic positions significantly affected the species richness, diversity and distribution of soil seed banks. Therefore, understanding the characteristics of soil seed banks at different geomorphic positions of sand dunes is essential to vegetation restoration or reestablishment. Furthermore, the Jaccard＇s similarity coefficients of plant species between soil seed banks and aboveground vegeta

关键词： soil seed banks geomorphic position seed density species diversity sand dunes Gurbantunggut Desert

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Morphological Profiles of sand dunes from ICESat-2 Geolocated Photons

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Journal of Geoscience and Environment Protection 2021年第2期9卷 71-91页

作者： Giribabu Dandabathula Srinivasa Rao Sitiraju Chandra Shekhar Jha Regional Remote Sensing Centre-West NRSC Indian Space Research Organization Jodhpur India National Remote Sensing Centre Indian Space Research Organization Hyderabad India

Aeolian process leads to the transportation and accumulation of sand particles that result in sand dune landforms. The structure and shape of the sand dunes are driven by the parameters of interacting wind force and the material composition of sand within. Cross-section profiles over the sand dunes will essay the geomorphological parameters through which the steady state and rate of sand transport can be computed. National Aeronautics and Space Administration’s novel satellite namely Ice, Cloud and land Elevation Satellite-2 (ICESat-2) hosts a solo sensor namely Advanced Topographic Laser Altimeter System (ATLAS) which is a photon counting instrument that measures the round-trip time of the light pulse being emitted and reflected back from the surface determines the true height of the topographic feature on the Earth. In this article, cross-section profiles generated from the beams of ICESat-2 ground-tracks acquired over sand dunes of the Thar Desert region were analysed for detecting the geomorphological parameters. Observations from the cross-section profiles have resulted in giving unprecedented details about the shapes and morphological settings of various types of sand dunes like barchanoids, parabolic, longitudinal, and transverse dunes. Morphological parameters of sand dunes like the length of the stoss slope, crest height, slip face details, inter-arms spacing, height of the trailing arms, length of the depositional lobes, and sinuosity of the recurring crest lines were retrieved with ease from the Level-2A data product namely ATL03 of ICESat-2/ATLAS.

关键词： Geomorphological Parameters ICESat-2 Geolocated Photons sand dunes 2D Profiles

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Determination of actual evapotranspiration and transpiration in desert sand dunes (Negev Desert) using different approaches

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Forestry Studies in China 2006年第1期8卷 1-9页

作者： Thomas Littmann Maik Veste University of Halle-Wittenberg University of Hohenheim

In an arid environment, especially in sandy areas where surface runoff is of no practical importance in the hydrological budget, it is rainfall, dewfall and evapotranspiration that become the most important variables. To assess actual evapotranspiration, several methods （flux-gradient, BREB, eddy correlation） were applied to data from the Nizzana experimental site in the northwestern Negev Desert. Additionally, a model specifically designed for arid environments is introduced in this paper. This zero plane model shows the most reasonable results compared with the other methods, which overestimate evapotranspiration to a large degree. It is shown that plant transpiration is the dominant process in total evapotranspiration while advective processes do not play a major role in the near-ground boundary layer, although the study area is influenced by a sea breeze. Actual transpiration ofArtemisia monosperma was measured in a field experiment to validate the calculated evapotranspiration. The vegetation contributed 41% of the calculated total evapotranspiration in a single month.

关键词： desert microclimate add environment desert sand dunes Artemisia monosperma Nizzana Negev

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Species composition and diversity,and carbon stock in a dune ecosystem in the Horqin sandy Land of northern China

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Journal of Arid Land 2015年第1期7卷 82-93页

作者： FeiLong HU WenKai SHOU Bo LIU ZhiMin LIU Carlos A BUSSO State Key Laboratory of Forest and Soil Ecology Institute of Applied Ecology Chinese Academy of Sciences University of Chinese Academy of Sciences Agronomy Department National University of the South and CERZOS (CONICET)

In this study, we determined carbon allocation and carbon stocks in the plant-soil system of different dune ecosystems in northeastern China. We quantified the species composition, above and below-ground bio masses, and carbon stocks of three dune types （i.e. active dunes, semi-stabilized dunes and stabilized dunes） and their corresponding inter-dune lowlands （i.e. interdune lowlands of active dunes, interdune lowlands of semi-stabilized dunes and interdune lowlands of stabilized dunes） in the Horqin sandy Land. The results showed that the succession series on interdune lowlands of the Horqin sandy Land confirmed differences in species composition of the various dune types. Aboveground carbon （AGC） on the interdune lowlands of semi-stabilized dunes （33.04 g C/m2） was greater （P〈0.05） than that on the interdune lowlands of active dunes （10.73 g C/m2）. At the same time, the different dune types did not show any significant differences （/：〉〉0.05） in belowground plant carbon （BGC）. However, the percentage of plant BGC in interdune lowlands of active dunes （81.5%） was significantly higher （P〈0.05） than that in the interdune lowlands of semi-stabilized dunes （58.9%）. The predominant carbon pool in the study dune ecosystem was in the soil. It accounted for 95% to 99% of total carbon storage. Soil organic carbon （SOC） was at least 55% greater （P〈0.05） in the interdunes than in the dunes. Stabilized dunes showed at least a 37% greater （P〈0.05） SOC content than active dunes up to a 1-m soil depth. Meanwhile, SOC content of interdune lowlands of semi-stabilized dunes was greater （P〈0.05） than that of interdune lowlands of active dunes only up to a 20-cm soil depth. The dune ecosystem showed a great potential to store carbon when interdune lowlands of active dunes were conversed to interdune lowlands of semi-stabilized dunes, which stored up to twice as much carbon per unit volume as interdune lowlands of active dunes.

关键词： species diversity carbon storage sand dunes interdune lowlands semi-arid areas

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Limitations on the recruitment of the rare sand shrubby legume Eremosparton songoricum(Fabaceae) in Gurbantunggut Desert,China

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Journal of Arid Land 2011年第2期3卷 75-84页

作者： DaoYuan ZHANG HuiLiang LIU Xiang SHI JianCheng WANG YongKuan ZHANG Key Laboratory of Biogeography and Bioresource in Arid Land Xinjiang Institute of Ecology and Geography Chinese Acad- emy of Sciences Urumqi 830011 China Turpan Eremophytes Botanical Gar（t3n Chinese Academy of Sciences Turpan 838008 China Graduate University of Chinese Academy of Sciences Beijing 100049 China College of Agriculture Shihezi University Shihezi 832000 China

Eremosparton songoricum,a rare and endemic sand dune plant,appears to be experiencing recruitment failure.The structure of five populations from the Gurbantunggut Desert,China,was investigated for recruitment patterns,and two of them were examined for flowering,pollination and seed germination limits on regeneration.The results showed that total 150 seedlings only occurred on line transects in riverside Dure population,but they all died half a month later;no seedlings occurred in other four hinterland desert populations indicating recruitment was a failure at all populations although flowers were plentiful.Reproductive success depends on pollinators.Nectar is ＇reward＇ for pollinators,with 0.06 μL-0.12 μL and 0.15 μL-0.35 μL per flower in Dure and Kabu populations,respectively,in continuously two secreting days.Spontaneous self pollination is rare with nearly zero fruit production.Geitonogamous self pollination is predominant with 14.47% fruit set.Seed mass in the riverside Dure population was significantly greater than that in other hinterland desert populations.Consequently,the Dure population exhibited a significantly higher germination rate（about 90%） than those in other populations（about 30%）.Results suggested that recruitment failure of E.songoricum is not due to flower shortage,pollination limitation,or poor seed germination but environmental pressure and/or human disturbance.

关键词： seedling recruitment sand dunes regeneration population structure pollination ecology

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Vertical distribution of soil moisture and surface sandy soil wind erosion for different types of sand dune on the southeastern margin of the Mu Us sandy Land,China

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Research in Cold and Arid Regions 2015年第6期7卷 675-686页

作者： ChaoFeng Fu JingBo Zhao FanMin Mei TianJie Shao Jun Zuo Key Laboratory of Western Mineral Resources and Geological Engineering Ministry of Education of China&Chang'an University College of Tourism and Environment Science Shaanxi Normal University Environmental and Chemical Engineering College Xi'an Polytechnic University

Soil moisture is a critical state affecting a variety of land surface and subsurface processes. We report investigation results of the factors controlling vertical variation of soil moisture and sand transport rate of three types of dunes on the south- eastern margin of the Mu Us sandy Land. Samples were taken from holes drilled to a depth of 4 m at different topographic sites on the dunes, and were analyzed for soil moisture, grain-size distribution and surface sediment discharge. The results show that：（1） The average soil moisture varies in different types of dunes, with the following sequences ordered from highest to lowest： in the shrubs-covered dunes and the trees-covered dunes the sequence is from inter-dunes lowland to windward slope to leeward slope. The average moisture in the bare-migratory sand dunes is sequenced from inter-dunes lowland to leeward slope to windward slope. （2） Vegetation form and surface coverage affect the range of soil moisture of different types of dunes in the same topographic position. The coefficient of variation of soil moisture for shrubs-covered dunes is higher than that of other types of dune. （3） The effect of shrubs on dune soil moisture is explained in terms of the greater ability of shrubs to trap fine-grained atmospheric dust and hold moisture. （4） The estimated sand transport rates over sand dunes with sparse shrubs are less than those over bare-migratory dunes or sand dunes with sparse trees, indicating that shrubs are more effective in inhibiting wind erosion in the sandy land area.

关键词： soil moisture surface sandy soil wind erosion vegetation form micro-geomorphology sand dunes deserti-fication control

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Phytogenic Mounds (Nebkhas): Effect of Tricomaria usillo on sand Entrapment in Central-West of Argentina

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Journal of Geographic Information System 2016年第4期8卷 429-437页

作者： Graciela Pastrán Eduardo Martínez Carretero Geobotánica y Ecología Vegetal Departamento Biología-Museo de Ciencias Naturales Facultad de Ciencias Exactas Físicas y Naturales Universidad Nacional de San Juan San Juan Argentina Geobotánica y Fitogeografía (IADIZA) (CONICET) Mendoza Argentina

Nebkhas, developed by the trapping of sand within the body of a plant, were studied in the Médanos Grandes system, arid central Argentina, during the springs of 2009-2010. The dynamics of nebkhas was studied in three draas (megadunes), and considering both orientations: leeward and windward. The Drift Potential (DP) for the study area was 42, evidencing the inactivity of the sand dunes or the scarce activity only in crests. Dominant sand movement is in south-southeast direction, with deflation processes at the southern side of the nebkhas. All nebkhas showed uniformity in the morphometry. Tricomaria usillo is the dominant plant species in the nebkha formation process;and results showed a significant positive relationship between nebkha and canopy volumes.

关键词： sand dunes Nebkhas Dynamics Vegetation

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