(91EO* alluvial forests with Alnus glutinosa and Fraxinus excelsior)
Alders form riparian woodland on riverbanks in very wet or waterlogged soils affected by the periodic flooding of rivers. They grow to form habitats of Community interest, generally on upper and middle courses, consisting chiefly of alder (Alnus glutinosa), mountain ash (Fraxinus excelsior), birch (Betula alba or Betula pendula), hazel (Corylus avellana) or black poplar (Populus nigra).
Some of the most characteristic ecological functions of these forests include: regulating the water cycle, halting erosion and maintaining the balance of the river ecosystem, biodiversity and connectivity, since they constitute first-rate ecological corridors which provide animals averse to coming into the open with refuge and protection. This last point is particularly relevant in the IREKIBAI project
Presence
Although alder woodland cover is widespread throughout the territory, the area it occupies is small considering its potential due to the problems it has coexisting with man (urban development, fields and crops, infrastructures, etc.). The situation is worse in mountainous areas such as the Basque Country and Navarre, where most of the areas it grows in are in valleys, near river basins.
The alder forests are highly fragmented and there is not one waterway in the region where this type of habitat exists uninterrupted for kilometres. Some small representations do, however, display a medium-to-high level conservation status, with a significant wealth of species, some of which are endangered and unique in the two Autonomous Communities. The Natura 2000 sites selected for the IREKIBAI project contain significant examples of alder woodland.
Habitat 91E0*, Alluvial forests with Alnus glutinosa and Fraxinus excelsior (Alno-Padion, Alnion incanae, Salicion albae)
| Site | Surface covered (% of site) | Conservation status |
|---|---|---|
| SAC River Leitzaran ES2120013 | 76,9% | A |
| SAC River Bidasoa ES2200014 | 31.15% | B |
| SAC River Baztan and Artesiaga Brook ES2200023 | 11,34 % | B |
| SAC Señorío de Bertiz ES2200017 | 2,33 % | A |
| SCI Artikutza ES2200010 | 0,12 % | A |
| SCI Belate ES2200018 | 0,99 % | B |
A: Excellent representation B: Good representation C: Significant representation. D: Insignificant representation
More information
Publication: Habitats of Navarre Manual (see pages:370 – 371 Cantabrian alder forests)
Basque Country Nature information system – Alder forests
Forests of Temperate Europe (Ministry of Agriculture, Food and the Environment)