Bern Convention Resolution No 4 (1998) hierarchical view

The top level is for grouping only

• A : Marine habitats
  
• B : Coastal habitats
  
• C : Inland surface waters
  
• D : Mires, bogs and fens
  
• E : Grasslands and lands dominated by forbs, mosses or lichens
  
• F : Heathland, scrub and tundra
  
• G : Woodland, forest and other wooded land
  
• H : Inland unvegetated or sparsely vegetated habitats
  
• X : Habitat complexes