|Dengler, J; Eisenberg, M; Schröder, J: Die grundwasserfernen Saumgesellschaften Nordostniedersachsens im europäischen Kontext - Teil I: Säume magerer Standorte (Trifolio-Geranietea sanguinei)., Tuexenia, 26, 51-93 (2006)|
|Key words: Melampyro pratensis-Holcenea mollis, nomenclatural revision, Poion nemoralis, phytosocio- logical methodology, syntaxonomy, vegetation classification|
We analysed the anhydromorphic forest edge communities of NE Lower Saxony based on nearly 500 new relevés. Here we deal with communities of the class Trifolio-Geranietea sanguinei (incl. Melam- pyro-Holcetea: 246 relevés). We found 16 associations (or equivalent units) in the study area. We present the diagnostic species composition for each association, characterise them floristically and structurally, and give information on their site conditions, distribution and frequency as well as on their syntaxono- mic treatment by other authors. All relevés are provided in phytosociological tables, and a synoptic table of the associations enables a comparison of their floristic composition. In the classification, we applied a consistent axiom-based method that puts the Braun-Blanquet approach into concrete terms. Parallel to dealing with the regional data, we developed a Europe-wide classification based on 246 constancy columns from 15 countries, comprising altogether more than 5,000 relevés. We present the results as two synoptic tables, one for the higher syntaxa of the Trifolio- Geranietea, the other for the associations of the order Melampyro-Holcetalia mollis. Our results suggest that all European forest edge communities of nutrient-poor sites should be included in a single class Trifolio-Geranietea, as this is floristically better defined than its acidophilous and basiphilous subentities if treated as separate classes, as suggested by other authors. We divide the Trifolio-Geranietea into an acidophytic subclass Melampyro pratensis-Holcenea mollis with the single order Melampyro-Holcetalia and a basiphytic subclass Trifolio-Geranienea sanguinei comprising the two orders Origanetalia vulgaris s. str. (mesophytic) and Antherico ramosi-Geranietalia sanguinei (xerophytic). The Melampyro-Holceta- lia consist of four alliances: Melampyrion pratensis (widely distributed, 3 associations), Teucrion scorodo- niae (with an Atlantic distribution, 1 association), Poion nemoralis all. nov. (steep, shaded sites, 2 asso- ciations: Aulacomnio androgynae-Polypodietum vulgaris ass. nov. and Veronico chamaedryos-Poetum nemoralis ass. nov.) and Violo rivinianae-Stellarion holosteae (slightly acidic, somewhat more nitrogen- rich sites, 2 associations). The Origanetalia vulgaris occur in the study area with the single alliance Trifo- lion medii (6 associations) and the Antherico-Geranietalia only with the Geranion sanguinei (2 associati- ons, fragmentary). We undertook a comprehensive nomenclatural revision including all treated syntaxa and their syno- nyms. We document the nomenclatural types of all valid syntaxon names and give reasons for planned proposals to the Nomenclature Commission. Neotypes are designated for the Agrimonio eupatoriae- Vicietum cassubicae Passarge 1967 nom. invers. propos. and the Geranio-Anemonetum sylvestris T. Mül- ler 1962. In a final section, we highlight the supra-regional relevance of the proposed classification, dis- cuss methodological questions, and give general recommendations for phytosociological studies.