Flora und Vegetation der Deiche an der mittleren Elbe zwischen Magdeburg und Darchau

The flora and vegetation of the dikes of the river Elbe have been investigated between Magdeburg and Darchau with special interest to their ecological importance. Using spot-test measures 216 species were counted, the real number is estimated to 230-240 species. In contrary to the opinion given in literature, the recent investigations show no significant differences between the facing the river side of the dike and the corresponding back side. The flora depends first of all on the exposition and the age of the dikes. Ancient dikes are important growing places of species of sand grasslands. The dikes are also secondary habitats for threatened meadow communities of the flood plains, especially for the Eryngium campestre-[Arrhenatherion]-community and the Campanula patula-Leucanthemum vulgare-community. Dikes are able to act as a leading path as well as a barrier for the spreading of plants. So Eryngium campestre, Carduus nutans and Verbascum blattaria (rare!) have been able to migrate along the dikes far to the northwest. For the expensive weeds, which have established themselfes on the riverbanks of the Elbe during the last two decades, the dikes acts as a barrier, which they have not been able to surmount till now.