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  • 1995-1999  (4)
  • 1945-1949
  • conservation  (2)
  • eutrophication  (2)
  • 1
    ISSN: 1573-5117
    Schlagwort(e): acidic water ; alkaline water ; autoecology ; bioindication ; macrophyte community ; eutrophication
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Two bioindication scales of the degree of eutrophication based on aquatic macrophyte communities were established in two types of running waters free of organic matter, the one in acidic “soft” waters (pH 5.5–7.0, conductivity 40–110 μS.cm−1), the other in alkaline hard waters (pH 7–8, conductivity 500–900 μS.cm−1). We show that the main determining factor of the macrophyte distribution is the nutrient level (trophy), especially the level of phosphate and ammonia. The acidic scale, with increasing pH, includes four stages ranging from oligotrophic to eutrophic level (traces to 300 μg.l−1 N-NHinf4p+ and P-PO4 3−), while the alkaline scale at constant pH comprises six stages of a trophic gradient. For the most part, the floristic composition found in the two sequences is different and depends on conductivity and alkalinity variation. However, some species occur in the two scales and may reflect differences in the trophic level, depending on whether the waters are alkaline or acidic. This change of trophic level for these species is discussed.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    ISSN: 1573-5117
    Schlagwort(e): eutrophication ; acidification ; macrophyte communities ; weakly mineralized streams ; France
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The Northern Vosges streams are subjected to acidification upstream and to eutrophication downstream. A bio-indicator scale of the degree of eutrophication and of the level of acidification, based on four aquatic macrophyte communities, was established in these weakly mineralized streams. Aquatic plant communities therefore begin as Group A, develop into Group B and become Group C or D downstream. The A community was characterized by bryophytes (Scapania undulata, Sphagnum sp.) and Potamogeton polygonifolius in oligotrophic, acidified to weakly acidified, and poorly buffered streams. The B community, defined by P. polygonifolius and the appearance of Ranunculus peltatus and Callitriche species (C. platycarpa, C. hamulata) was found in oligotrophic waters with a higher buffer capacity than the A community. The C community was determined by the disappearance of P. polygonifolius and the appearance of Elodea species (E. canadensis, E. nuttallii) and rare species in mesotrophic and neutral streams. The D community, with very high nutrient loading, was characterized by the abundance of Callitriche obtusangula, by the presence of Amblystegium riparium, Fissidens crassipes and the development of filamentous algae. This macrophyte sequence corresponded to an upstream to downstream zonation, which was characterized by an increase in buffer capacity and in nutrient levels and a decrease in protons and aluminium load.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Biodiversity and conservation 8 (1999), S. 1519-1532 
    ISSN: 1572-9710
    Schlagwort(e): Botrychium ; Pteridophyte ; grassland ; conservation ; plant community
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Two species of Botrychium are present in the Bitcherland grasslands, B. lunaria and B. matricariifolium, and both are protected in this territory. They occur in five different continental grassland communities, (i) a dune grassland (Diantho-Armerietum), (ii) a mesotrophic sandy grassland (Viscario-Avenetum), composed of three sub-units, therophitic ( V.A. airetosum), meso-eutrophic (V.A. saxifragetosum) and acidic (V.A. violetosum caninae), and (iii) an oligotrophic sandy grassland (Aveno-Genistetum). Both species of Botrychium appear in the three sub-units of Viscario-Avenetum, but only one in Diantho-Armerietum (B. matricariifolium) and in Aveno-Genistetum (B. lunaria). These Botrychium species are present in quite similar habitats in other lowland areas in Central Europe. The conservation of these threatened species, sensitive to plant competition, requires the maintenance or restoration of extensive agricultural management with late cutting and no fertilization.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Biodiversity and conservation 8 (1999), S. 1435-1445 
    ISSN: 1572-9710
    Schlagwort(e): clay ; conservation ; pasture ; phytosociology ; ruderal plant ; trampling
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Carex hordeistichos is a peri-Mediterranean species, which is rare over all its distribution range. In Lorraine (France), where the field investigations were conducted, as in other Western European areas, it is present only in secondary habitats, constituted of heavily trampled wet pastures and vehicle tracks on clayed soils. All plant communities with Carex hordeistichos described from Western European areas can be linked to the Carici hordeistichi-Trifolietum fragiferi association, classified in the Agropyro-Rumicion wet pasture alliance. The conservation of this threatened ruderal plant requires the maintenance of a high disturbance level through grazing, trampling and soil packing.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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