The Riverbank Flora in Town Centres Exeniplificd by the Oker Riverbanks in Brunswick (Lower Saxony)

The embankments of a river flowing through the centre of an old town are very rich in plant species, as the example of the river Oker in Brunswick (Federal Republic of Germany) shows. 311 different vascular plant species - almost one third of Brunswick's spontaneous flora - are present on the banks of the river Oker. 64 of the species are indigenous, 10 are archaeophytes. 14.1 are naturalized aliens and 11.9 are ephemerophytes. On embankments in the town centre Acer pseudoplatanus, Acer platanoides, Aesculus hippocastanum, Ulmus glabra are the most common trees; the most frequent shrub is Sambucus nigra. Very apparent is a high proportion of climbing plants (Hedera helix, Clematis vitatba, Bryonia dioica). As a rule nitrophilous plants are dominant in the weed layer. The proportion of neophytes is particularly high on embankments adjoining to gardens. The importance of river banks in towns for nature conservation is discussed; for several endangered species such as Parietaria officinalis or Tutipa sylvesiris they are important places of refuge. The investigations about the river bank flora in towns published so far are briefly described and compared to the own findings