|Dengler, J; Koska, I; Timmermann, T; Berg, C; Clausnitzer, U; Isermann, M; Linke, C; Päzolt, J; Polte, T; Spangenberg, A: New descriptions and typifications of syntaxa within the project ‘Plant communities of Mecklenburg-Vorpommern and their vulnerability’ - Part II., Feddes Repertorium, 115, 343-392 (2004), doi:10.1002/fedr.200411043|
Within the project ‘Plant communities of Mecklen- burg-Vorpommern and their vulnerability’, a current synopsis of all vegetation types (excluding one- layered cryptogam vegetation) from this federal state in NE Germany has been worked out and published in a two-volume monograph (BERG et al. 2001, 2004 a ). An extensive data base of vegetation relevés and a consistent methodology provided the basis for the classification. On the one hand, this classification differs in various features from well-known syntaxo- nomic concepts. On the other hand, the careful ap- plication of the Code of Phytosociological Nomen- clature has led on several occasions to the conclusion that certain syntaxa lack valid names or that correct names can only be determined after a typification. Consequently all new descriptions, typifications and other nomenclatural decisions which are relevant to our project are being published in separate papers. Most are included in a two-part publication of which this contribution represents the second one. In an introductory section, we describe some of the special features of our project, discuss the pos- sible contribution of this regional study to the gene- ral system of plant communities, and point out the significance of the ICPN. We then briefly explain the nomenclatural evaluations and abbreviations used in the special section, as a supplement to the corresponding paragraphs in Part I (DENGLER et al. 2003). The main substance of the paper deals with the nomenclatural revision of 18 vegetation classes belonging predominantly to the aquatic, semiaquatic or woody vegetation. The following classes are dealt with: Lemnetea, Ruppietea maritimae, Potamogeto- netea, Littorelletea, Thero-Salicornietea strictae, Montio-Cardaminetea, Oxycocco-Sphagnetea, Par- vo-Caricetea, Phragmito-Magno-Caricetea, Juncetea maritimi, Cakiletea maritimae, Salicetea purpureae, Vaccinio uliginosi-Pinetea, Molinio-Betuletea pubes- centis, Alnetea glutinosae, Vaccinio-Piceetea, Quer- cetea robori-petraeae and Carpino-Fagetea. Within these classes we describe 15 new syntaxa. One ille- gitimate name is replaced by a nomen novum, and in four cases we correct syntaxon names based on taxomomic errors. Finally, lecto- and neotypes of a further 134 syntaxa are designated. In the context of the syntaxa treated, we discuss some nomenclatural problems involved and give reasons for the schedu- led proposals to the Nomenclature Commission for nomina ambigua, conservanda, inversa and mutata. The majority of the presented syntaxonomic modifications concern the vegetation of wetlands: In addition to the floristic differentiation of the syntaxa, special emphasis has been put on their clear ecological definition, particularly in terms of nutrient supply, hydrology and alkalinity of their habitats. In the classification of forest and shrub vegetation from hydromorphic sites, we have therefore placed em- phasis on the ground vegetation instead of the few predominantly euryecious tree species. Compared to other classifications, the most important differences are as follows: The drawing up of a central order Sphagno fallacis-Eriophoretalia vaginati ord. nov. beside the Sphagno-Ericetalia and the Sphagnetalia magellanici within the Oxycocco-Sphagnetea – Subdivision of the Parvo-Caricetea (mesotraphent mire vegetation) into an acidophilous and a basiphi- lous subclass (Sphagno fallacis-Caricenea canes- centis subcl. nov. and Drepanoclado revolventis- Caricenea diandrae subcl. nov. respectively) – Sub- division of the Phragmito-Magno-Caricetea into the four orders Phragmitetalia australis, Nasturtio offici- nalis-Glycerietalia fluitantis, Scrophulario umbrosae- Caricetalia paniculatae ord. nov. and Calystegietalia sepium – Subdivision of the Molinio-Betuletea pubescentis (woody vegetation of mesotrophic wet- lands) into the orders Salici pentandrae-Betuletalia pubescentis ord. nov. and Calamagrostio canes- centis-Salicetalia cinereae – Subdivision of the Alnetea glutinosae (woody vegetation of eutrophic wetlands) into the orders Cardamino amarae- Alnetalia glutinosae ord. nov., Alnetalia glutinosae and Alno-Fraxinetalia excelsioris.