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Détail de l'auteur
Auteur Heide Bruelheide |
Documents disponibles écrits par cet auteur
Affiner la rechercheDiversity of lowland hay meadows and pastures in Western and Central Europe / Maria Pilar Rodriguez-Rojo in Applied Vegetation Science, vol. 20, n°4 (Année 2017)
Titre : Diversity of lowland hay meadows and pastures in Western and Central Europe Type de document : Livre Auteurs : Maria Pilar Rodriguez-Rojo, Auteur ; Borja Jiménez-Alfaro, Auteur ; Ute Jandt, Auteur ; Heide Bruelheide, Auteur ; John Rodwell, Auteur ; Joop H. J. Schaminée, Auteur ; Philip Perrin, Auteur ; Zygmunt Kazcki, Auteur ; Wolfgang Willner, Auteur ; Federico Fernandez-Gonzales, Auteur ; Milan Chytrý, Auteur Année de publication : 2017 Article en page(s) : pp. 702-719 Langues : Anglais Résumé : "This analysis challenges the traditional concept of mesic grassland alliances separating hay meadows from pastures. New classification should be based mainly on the differences in management intensity rather than in management practice. Consequently, nutrient‐poor extensive pastures, which currently are not considered in the European Habitats Directive, should receive the same conservation attention as low‐intensive hay meadows, because both types of vegetation can be equally species‐rich and do not differ substantially in floristic composition from each other." Type de publication : périodique Référence biblio : Rodriguez-Rojo M., Jiménez-Alfaro B., Jandt U., Bruelheide H., Rodwell J., Schaminée J.-J., Perrin P., Kazcki Z., Willner W., Fernandez-Gonzales F., Chytrý M., 2017 - Diversity of lowland hay meadows and pastures in Western and Central Europe. Applied Vegetation Science, 20 (4) : 702-719. DOI : 10.1111/avsc.12326 Permalink : http://www.cbnbrest.fr/catalogue_en_ligne/index.php?lvl=notice_display&id=65948
in Applied Vegetation Science > vol. 20, n°4 (Année 2017) . - pp. 702-719[article]Exemplaires
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Titre : A new measure of fidelity and its application to defining species groups Type de document : Livre Auteurs : Heide Bruelheide, Auteur Année de publication : 2000 Article en page(s) : pp. 167-178 Langues : Anglais Mots-clés : distribution binomiale COCKTAIL unité de végétation espèce différentielle distribution hypergéométrique méthode numérique base de données donnée phytosociologique classification de la végétation Résumé : "The first objective of this paper is to define a new measure of fidelity of a species to a vegetation unit, called u. The value of u is derived from the approximation of the binomial or the hypergeometric distribution by the normal distribution. It is shown that the properties of u meet the requirements for a fidelity measure in vegetation science, i.e. (1) to reflect differences of a species’relative frequency inside a certain vegetation unit and its relative frequency in the remainder of the data set; (2) to increase with increasing size of the data set. Additionally (3), u has the property to be dependent on the proportion of the vegetation unit's size to the size of the whole data set.
The second objective is to present a method of how to use the value of u for finding species groups in large data bases and for defining vegetation units. A species group is defined by possession of species that show the highest value of u among all species in the data set with regard to the vegetation unit defined by this species group. The vegetation unit is defined as comprising all relevés that include a minimum number of the species in the species group. This minimum number is derived statistically in such a way that fewer relevés always belong to a species group than would be expected if the differential species were distributed randomly among the relevés. An iterative algorithm is described for detecting species groups in data bases. Starting with an initial species group, species composition of this group and the vegetation unit defined by this group are mutually optimized. With this algorithm species groups are formed in a data set independently of each other. Subsequently, these species groups can be combined in such a way that they are suited to define commonly known syntaxa a posteriori." (source : auteur)Type de publication : périodique Référence biblio : Bruelheide H., 2000 - A new measure of fidelity and its application to defining species groups. Journal of Vegetation Science, 11 (2) : 167-178. ID PMB : 65719 Permalink : http://www.cbnbrest.fr/catalogue_en_ligne/index.php?lvl=notice_display&id=65719
in Journal of Vegetation Science > vol. 11, n°2 (Année 2000) . - pp. 167-178[article]Exemplaires
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Titre : Towards unification of national vegetation classifications : a comparison of two methods for analysis of large data sets Type de document : Livre Auteurs : Heide Bruelheide, Auteur ; Milan Chytrý, Auteur Année de publication : 2000 Article en page(s) : pp. 295-306 Langues : Anglais Catégories : [ZG] République tchèque Use for events after 1992.Mots-clés : classification de la végétation méthode Résumé : "In European phytosociology, national classifications of corresponding vegetation types show considerable differences even between neighbouring countries. Therefore, the European Vegetation Survey project urgently needs numerical classification methods for large data sets that are able to produce compatible classifications using data sets from different countries. We tested the ability of two methods, TWINSPAN and COCKTAIL, to produce similar classifications of wet meadows (Calthion, incl. Filipendulenion) for Germany (7909 relevés) and the Czech Republic (1287 relevés) in this respect." (source : auteurs) Type de publication : périodique Référence biblio : Bruelheide H., Chytrý M., 2000 - Towards unification of national vegetation classifications : a comparison of two methods for analysis of large data sets. Journal of Vegetation Science, 11 (2) : 295-306. ID PMB : 65718 DOI : 10.2307/3236810 Permalink : http://www.cbnbrest.fr/catalogue_en_ligne/index.php?lvl=notice_display&id=65718
in Journal of Vegetation Science > vol. 11, n°2 (Année 2000) . - pp. 295-306[article]Exemplaires
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