Riparian mixed forests of Quercus robur, Ulmus laevis and Ulmus minor, Fraxinus excelsior or Fraxinus angustifolia, along the great rivers (Ulmenion minoris)
Forests of hardwood trees on the banks of large rivers, liable to flooding during regular rising of water level. Dominant tree species depending on the water regime include ash (Fraxinus excelsior), elm (Ulmus laevis, Ulmus minor) and oak (Quercus robur); forests in nitrogen-rich locations usually with well-developed undergrowth, rich in trailing plants.
Notes on habitat mapping
[A precondition for assignment to this habitat type is a largely intact flooding regime (including inundation by return seepage). This excludes most occurrences of the stated vegetation types enclosed between or separated off by dykes that protect them from natural inundation. These may solely be regarded as development potential if near-natural stands are now lacking. Problems may arise from transitions to oak-hornbeam forest that develop from alluvial hardwood forest when the flooding regime is disturbed or form an adjoining zonation with declining inundation frequency. Small stands occurring mosaic-style on slight rises in the area subject to flooding are included; other such stands may be classified as habitat type 9170.
Comments
Hardwood riparian forests along Europe’s great rivers are under even greater threat than softwood alluvial forests (91E0). They should therefore be given priority classification when Annex I is amended.