نتایج جستجو برای: dune
تعداد نتایج: 2774 فیلتر نتایج به سال:
16 In this work we present measurements of vegetation cover over parabolic dunes with 17 different degree of activation along the north-eastern Brazilian coast. We extend 18 the local values of the vegetation cover density to the whole dune by correlating 19 measurements with the relative brightness index C of high resolution QuickBird 20 panchromatic satellite image of the dune field. Next, we...
Coastal dunes worldwide harbor threatened habitats characterized by high diversity in terms of plant communities. In Italy, recent assessments have highlighted the insufficient state of conservation of these habitats as defined by the EU Habitats Directive. The effects of predicted climate change could have dramatic consequences for coastal environments in the near future. An assessment of the ...
Coastal sandy ecosystems are increasingly being threatened by human pressure, causing loss of biodiversity, habitat degradation and landscape modifications. However, there are still very few detailed studies focussing on compositional changes in coastal dune plant communities over time. In this work, we investigated how coastal dune European Union (EU) habitats (from pioneer annual beach commun...
1. Mobility and emigration were investigated for the wolf spider Pardosa monticola in grey dune fragments from two high-density and one low-density population, where population density was related to patch quality. Pitfall trapping was applied in combination with absolute density estimates by means of quadrat sampling. Orientation behaviour was additionally observed in the highand low-density p...
Deserts are one of the major landforms on the Earth. While deserts occupy about one-fifth of Earth’s land surface, they have been studied to a much lesser extent. All over the world, desert landforms are expanding ever rapidly and more and more human settlements are finding place in desert regions for habitation. Thus, quantifying and monitoring dunes becomes more relevant from a managerial per...
Introduction: The number of currently available images of the surface of Mars is in the order of the hundreds of thousands. These have been captured over the years by many different instruments on board automatic probes. They have diverse spectral characteristics, varying spatial resolutions and cover areas of different dimensions, providing global, regional and sometimes local views. To manual...
Coastal sand dunes are extremely dynamic ecosystems, characterized by stark ecological succession gradients. Dune stabilization is mainly attributed to plant growth, but the establishment and survival of dune-inhabiting vegetation is closely linked to soil microorganisms and to the ecological functions they fulfill. Fungi are particularly important in this context, as some interact intimately w...
ion, afforestation, urbanisation (Grootjans et al. 1998; Martinez et al., 2004; Provoost 106 et al., 2011), nitrogen deposition (Jones et al., 2004; Plassmann et al., 2008; Sival and 107 Strijkstra-Kalk, 1999) and from grass and scrub encroachment or exotic species invasion 108 (Martinez et al., 2004). In addition, changes in evapotranspiration due to vegetation change or 109 management will af...
Apollo-Soyuz photographs of the Monte Desert in southeastern San Juan, Argentina, were used for a reconnaissance survey of large-scale desert landforms. The Apollo-Soyuz color photographs were helpful in distinguishing lineaments and probable faults, drainage patterns, rock types, and soil-tonal variations. These photographs were especially useful in studying the distribution of sand deposits a...
Transverse dunes, which form under unidirectional winds and have fixed profile in the direction perpendicular to the wind, occur on all celestial objects of our solar system where dunes have been detected. Here we perform a numerical study of the average turbulent wind flow over a transverse dune by means of computational fluid dynamics simulations. We find that the length of the zone of recirc...
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