Vegetation
Najas flexilis is the key species of this simple aquatic community. Frequently there will some presence of Potamogeton berchtoldii, with its narrow linear leaves, and occasionally some Potamogeton perfoliatus. Stoneworts are frequent companions to Najas and species may include Chara aspera, Chara globularis, Chara virgata, Nitella confervacea, Nitella flexilis or Nitella translucens.
Ecology
This is a submerged community of shallow to deep lake beds in the far west of Ireland. Water conditions are typically circumneutral with low nutrient levels.
Sub-communities
No sub-communities are currently described.
Similar communities
Surveying for Najas usually requires snorkelling or scuba-diving. Once the presence of the species has been confirmed, however, identifying this assemblage is straightforward as the species is not typically present in any other community.
Conservation value
Examples of this community represent the recently redefined EU HD Annex I habitat 3130 Mixed Najas habitat. Najas flexilis is also listed in EU HD Annex II and is listed on the Flora (Protection) Order, 2015. Species diversity is low ( species/1 m2 = 3.0, n = 34).
Management
The main threats to this habitat come from impacts on water quality from forestry, agriculture, peat extraction and effluent.