Rivers and Lakes
The river system in the region is complex. The commmon pattern is many small rivers originating within the region and discharging into the northeast Atlantic Ocean or the North Sea. They may form small estuaries and lagoons. There are only a few very large rivers, which fall into the Atlantic Ocean or North Sea (British Isles and Ireland): the Rhine, Elbe, Loire, Garonne and (Table 4). Their large catchments originate in the Continental or even Alpine region. Only Ebro originates in the region in Spain. Its main course is, however, eastwards through the Mediterranean region to the Mediterranean Sea (total catchment area more than 50 000 km2). The following habitats occur in this ecosystem: Oligotrophic waters containing very few minerals of sandy plains (Littorelletalia uniflorae), Oligotrophic to mesotrophic standing waters with vegetation of the Littorelletea uniflorae and/or of the Isoëto-Nanojuncetea, Natural eutrophic lakes with Magnopotamion or Hydrocharition - type vegetation, Water courses of plain to montane levels with the Ranunculion fluitantis and Callitricho-Batrachion vegetation, Alluvial forests with Alnus glutinosa and Fraxinus excelsior (Alno-Padion, Alnion incanae, Salicion albae) (European Environment Agency, Europe’s biodiversity, The Atlantic region - ETC/NPB).