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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

A comparative study of Corynephorus canescens (L.) P.Beauv. communities of inland sand dunes in England and Poland

Blunt, Arthur Godfrey January 2008 (has links)
Inland sand dunes supporting Grey Hair-grass Corynephorus canescens are a declining European habitat designated for conservation under the EU’s Habitats Directive. In Britain they are confined to a handful of sites in East Anglia and the West Midlands. This study investigated the relationships of the British populations to each other and to populations on five sites in Poland, where C. canescens is still widespread. It also conducted exploratory investigations into factors relevant to the conservation of this ecosystem, particularly in the West Midlands. Data were collected chiefly from 1m2 quadrat samples and direct sampling, which recorded the plants and animals present together with parameters such as vigour and fecundity in C. canescens, amounts of bare sand and litter, and measures of erosion and grazing. These data were variously analysed including by CANOCO multivariate analysis and, for the vegetation, TWINSPAN analysis. 153 taxa of plants and 251 of invertebrates were identified. Though strongly distributed on a regional basis, both flora and invertebrate fauna showed relationships particularly between Polish and West Midlands sites. Analysis of the vegetation suggested that West Midlands vegetation had some associations with C. canescens habitats in Europe and that East Anglian vegetation had links with British coastal C. canescens habitats. The invertebrate fauna showed some complex community relationships in Poland and the West Midlands but less so in East Anglia, while assemblages of invertebrates were associated with various vegetational and abiotic factors. Rabbits and hares were the only vertebrates regularly exploiting C. canescens habitats, which they grazed and, in the former case, produced sand disturbances for colonisation by C. canescens. Ants and to a lesser degree some other invertebrates also produced sand disturbances. Observations made in a preliminary cultivation study in the West Midlands suggested that C. canescens may have a biennial phenology, high fecundity, low germination rates and limited dispersal powers in that region. A trampling investigation suggested that C. canescens may be very sensitive to heavy uncontrolled trampling and to vegetational succession under protection. Stages in succession of the C. canescens community were identified, and suggestions for further study and the conservation of C. canescens were drawn up.
2

Äolische Prozesse und Landschaftsformen im mittleren Baruther Urstromtal seit dem Hochglazial der Weichselkaltzeit

Boer, Wierd Mathijs de 16 November 2012 (has links)
Das mittlere Baruther Urstromtal und Umgebung zwischen Luckenwalde und Golßen (Brandenburg, Deutschland) ist reich an äolischen Bildungen (DE BOER, 1990). Aus einer Kombination der bekannten Dünentypen (Parabel-, Längs-, Quer- und Kupstendünen) wird eine Reihe von 6 Dünenkomplexen abgeleitet. Sie sind aus einem oder mehreren Dünentypen aufgebaut und haben eine unterschiedliche Genese, Unterschiede im Alter und der Alterssfolge sowie eine bestimmte topographische Lage. Die (oberflächig anstehenden) Talsande/Flug(deck)sande, die Alt- und die Jungdünensande werden von Fein- bis Mittelsanden gebildet. In den jeweiligen Vertikalprofilen ist nach dem Körnungsbild eine Dreiteilung zu erkennen: die "liegenden" (Urstromtalterrassen-)Sande, die Altdünensande und die "hangenden" Jungdünensande. Das Liegende der ältesten Binnendünen ähnelt den Terrassensanden sehr. Daher darf angenommen werden, daß die oberen Urstromtalsande eine starke äolische Komponente besitzen. Altersbestimmungen wurden durch relative Positionierung, Feststellungen zur Art der Bodenbildungen, archäologische Funde, Pollenanalysen sowie Karten- und Literaturstudien vorgenommen, ergänzt durch Radiokarbon- (14C-) und Thermolumineszenzdatierungen. Eine methodische Neuerung ist die automatisierte Bearbeitung der Dünnschliffbilder. Mit dem Quantimet-970-Bildverarbeitungssystem wurde die Einregelung der Längsachsen von Quarzkörnern ermittelt. Die Messungen ergaben, dass die (N)NO-(S)SW-, die ONO-WSW- und die SSO-NNW-Richtungen vorherrschen. Es ist zu vermuten, dass die wichtigsten dünenbildenden Winde im Weichselspätglazial und im Holozän aus den westlichen und südlichen Quadranten wehten, wobei Südwestwinde vorgeherrscht haben dürften. Auf Grund der Forschungsergebnisse werden 12 Phasen der Dünenbildung unterschieden. Sie vermitteln ein Bild der äolischen Prozesse und Landschaftsformen, welches mit Daten aus Niedersachsen und West-Polen größtenteils übereinstimmt. / The Central Baruth Ice-Marginal Valley and surroundings between Luckenwalde and Golßen (Brandenburg, Germany) is rich in aeolian deposits and aeolian landscape forms DE BOER (1990). From a combination of the well-known dune forms (longitudinal, transverse, parabolic and hummocky dunes) a series of 6 dune complexes can be identified. These dune complexes are built by one or several dune types and differ in genesis or building sequence, in age or age sequence as well as in topographic position. The (surficial) valley/aeolian sands, the cover sands and the drift sands are mainly composed of fine- to medium-grained fractions. Based on grain-size analysis three units can be distinguished in the studied vertical profiles: the underlying (valley terrace) sands, the cover sands ("Altdünensande") and the overlying drift sands ("Jungdünensande"). The sands of the substratum of the oldest inland dunes are very similar to these dune sands. Therefore it is accepted that the upper parts of the valley sands contain a strong aeolian component. A modernization is the automated method of long axes orientation measurements on elongated quartz grains in thin sections with the Quantimet-970 Image Analyzer. The results showed that the (N)NE-(S)SW-, the ENE-WSW- and the SSE-NNW-directions dominated. It is to be expected that the most important dune building winds during the Weichselian Late Glacial and during the Holocene were winds from the western and southern quadrants, with southwest winds most likely being the most important. Dating was done by means of relative positioning, palaeosols, archaeological finds, pollen analysis, cartographic and literature research as well as by means of the 14C- and thermoluminescence dating methods. Based on the results of this research 12 dune-forming phases have been distinguished. They give an impression of aeolian processes and landscape forms that are in accordance with dates obtained from dunes in Niedersachsen and west Poland.

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