Die Vergesellschaftung von Urtica subinermis (R. Uechtr.) Hand & Buttler an der Mittelelbe zwischen Elster (Sachsen-Anhalt) und Lenzen (Brandenburg)

Abstract

Krumbiegel, A.: The association of Urtica subinermis (R. Uechtr.) Hand & Buttler along the middlecourse of the river Elbe between Elster (Saxony-Anhalt) and Lenzen (Brandenburg). - HercyniaN. F. 45 (2012): 111 – 124.Urtica subinermis is, although it forms large stands, an often overlooked and unrecognised species alongthe middle course of the river Elbe. It is apparent already by light green colour, long and tapering leavesand not or only few branched shoots. Compared with Urtica dioica it is averagely taller. A particularcharacteristic trait is the nearly or fully absence of stinging hairs. Urtica subinermis and Urtica dioicaalso differ concerning their preferred sites. Urtica subinermis prefers transitional zones between Phalarisarundinacea reeds growing close to river bank and the alluvial willow forests and the mixed oakelm-ash forests of great rivers. Based on fifty vegetation relevés it could be demonstrated, that Urticasubinermis has its phytosociological emphasis within nitrophilous river bank and edge tall herb communities(Convolvuletalia sepium / Senecionion fluviatilis). Some of the relevés could become assignedto described associations, e.g. Cuscuto europaeae-Convolvuletum sepium and Urtico-Leonuretum marrubiastri,but most of them can only be assigned as Convolvuletalia sepium- and Senecionion fluviatilisbasal communities. In some relevés Phalaris arundinacea dominates, so they belong to the (Urtico-)Phalaridetum arundinaceae (Magnocaricion elatae). Furthermore Urtica subinermis also occurs in transitionalstands between Phalaris arundinacea reeds and annual river bank communities (Chenopodionglauco-rubri). Alluvial willow forests mostly only occur as residual stands in the investigation area.However, ecologically, they belong to the phytosociological spectrum as well as the mixed oak-elm-ashforests of big rivers and their edges, respectively, which are typically developed especially between thesmall town Aken and the mouth of the river Saale.The hitherto sole relevés of such riverside forest edges which regard Urtica subinermis originate fromPevestorf in Lower Saxony (Brandes 1998).By means of indirect determination of indicator values with the help of the accompanying species itcould be shown the preference of moister stands compared with Urtica dioica. The values of the ecologicalfactors nutrient, oceanity, light, temperature and soil reaction were determined indirectly as well. Themost constant companion species of Urtica subinermis by far is Phalaris arundinacea.Key words: Urtica subinermis, Convolvuletalia sepium, Senecionion fluviatilis, vegetation relevés, indicatorvalues, Elbe river