[article]
| Titre : |
World mire classification : an approach based on their origin, development and vegetation |
| Type de document : |
texte imprimé |
| Auteurs : |
Philippe Julve, Auteur |
| Année de publication : |
2004 |
| Article en page(s) : |
pp. 41-54 |
| Langues : |
Anglais (eng) |
| Catégories : |
[habitats/milieux] 5 - Tourbières et marais
|
| Mots-clés : |
classification dynamique des écosystèmes facteur écologique |
| Résumé : |
"A new vision of global mire classification is proposed, taking into acccount the mire origin: When the water balance is positive, two processes of peat formation may occur: terrestrialization and paludification. These two processes give birth to seven kinds of mire origin, in which may be included, as subtypes, all the classical mires types based on regional hydromorphology the water balance is positive, two processes of peat formation may occur: terrestrialization and paludification. These two processes give birth to seven kinds of mire origin, in which may be included, as subtypes, all the classical mires types based on regional hydromorphology
Each ontogenesiac mire type may change dynamically through time, from a geotrophic stage towards an ombrotrophic one. Some mires stay at the geotrophic stage, however, owing to their young age or special, local ecological conditions. These dynamic phenomena may generally be observed at microtope level. The purely ombrotrophic stage (central stage of mire dynamic) may evolve towards a mineralized stage by natural or artificial drainage. The ombrotrophic stage may also be a little bit enriched, owing to surface running water, or the chemical features of rain (oceanic areas). At a finer scale (microform level), the classification may operate at the floristic-ecological perception level . Vegetation can indicate the different ecological gradients occurring on a mire site: water supply type: depending on the water origin (rain, spring, flood, lake, condensation...) and quality (Mineralbodenwasserzeigergrenze of Du Rietz 1954); climatic gradient: latitudinal, altitudinal, longitudinal (oceanic versus continental); hydric gradient: accompanying primary succession, disturbances and regeneration; trophic gradient: oligotrophic - mesotrophic - eutrophic soils (with oligotrophilous - mesotrophilous - eutrophilous vegetation); pH factor: basic or acidic soils (neutrophilous or acidophilous vegetation); mire expanse - mire margin zonation. Vegetation may also show well the small-scale pattern of a mire , with the correlation between vegetation and T-A terminology. To classify mires at a world scale, two different classifications are proposed: - one, which could be named « ontogenesiac classification » is useful to understand the basic global features of mire creation on the earth, allowing comparison of mires complexes at world scale, between very different regions. The primary units produced by this classification could be subdivided into geomorphological types and dynamic stages.
A second, which could be named « floristico-ecological classification » (i.e. phytosociological classification) would be useful to understand, compare and predict the ecological processes and features, at microform level but also at geographical level (vicariance of communities and species)." (source : auteur) |
| Type de publication : |
périodique |
| Référence biblio : |
Julve P., 2004 - World mire classification : an approach based on their origin, development and vegetation. International Peat Journal, 12 : 41-54. |
| ID PMB : |
71039 |
| Permalink : |
http://www.cbnbrest.fr/catalogue_en_ligne/index.php?lvl=notice_display&id=71039 |
in International Peat Journal > n°12 (Année 2004) . - pp. 41-54
[article]
|
World mire classification : an approach based on their origin, development and vegetation in International Peat Journal, n°12 (Année 2004)