Distribution of macrophytes in different water-bodies (habitats) influenced by the Gabčíkovo hydropower station (Slovakia) - present status

Abstract

The distribution of macrophytes in the Slovak reach of the Danube is presented in three types of water bodies with different environments and management regimes: i) The Old Danube River (1839-1811 km), ii) the anabranch system, iii) the seepage canal. The succession and content of aquatic plants changed depending on the hydrological regime. The succession of macrophytes started in the Old Danube. Zannichellia palustris is the first hydrophyte that overgrows the river bed, which is covered by a thin layer of fine sediment. Temporary denuded pools on flat littoral zone provided favourable conditions for succession. The semi-natural anabranch system supported high biodiversity, where 24 species in three backwaters were recorded. Also the new artificial habitat of the seepage canal is species-rich. Some of the rare and endangered species, such as Groenlandia densa, Hippuris vulgaris, Apium repens and Characeae found suitable habitats here. The distribution of the neophyte Elodea nuttallii increased rapidly in the Slovak part of the Danube flood plain.