Scientific name Juncus bulbosus aquatic community
Common name Bulbous Rush aquatic community
Community code FW1C

 

FW1C map: Juncus bulbosus aquatic community

Download full pdf synopsis: FW1C

 

Vegetation

This community brings together a variety of vegetation assemblages for which Juncus bulbosus is a key indicator. Juncus bulbosus is a constant here, but no other species are more than occasional in the community as a whole, therefore further details on the vegetation are described under sub-communities.

 

Ecology

Juncus bulbosus vegetation is typically associated with nutrient-poor and acidic, aquatic or sub-aquatic conditions. It may be found on the shores of oligotrophic lakes and the margins of peaty dystrophic pools. It also occurs in drainage ditches and erosion channels in degraded bog.

 

Sub-communities

Two distinct sub-communities are described. The Ranunculus flammula – Mentha aquatica sub-community (FW1Ci) unites the examples from lakeshores and pool margins. Here, Juncus bulbosus is omnipresent and Ranunculus flammula is fairly frequent. They are occasional accompanied by Mentha aquatica, Potamogeton natans, Hypericum elodes, Eleocharis multicaulis, Potamogeton polygonifolius, Menyanthes trifoliata, Hydrocotyle vulgaris or Eriocaulon aquaticum. In the Juncus effusus – Polytrichum commune sub-community (FW1Cii) of degraded bogs, Juncus bulbosus, Campylopus introflexus, Juncus effusus and Polytrichum commune are constant species, with the bryophytes Lophocolea bidentata, Kindbergia praelonga, Sphagnum subsecundum agg. and Aulacomnium palustre all frequent.

 

Similar communities

Sub-community FW1Ci occurs in similar situations to the FW1A Littorella uniflora – Ranunculus flammula community but Littorella uniflora is seldom present in the sub-community and never abundant. Sub-community FW1Cii differs from the degraded bog represented by BG1 Eriophorum angustifolium – Campylopus introflexus bog by the greater frequency of Juncus bulbosus and the absence of bog species such as Eriophorum angustifolium, Calluna vulgaris or Molinia caerulea.

 

Conservation value

Examples of sub-community FW1Ci are likely to correspond to EU HD Annex I habitats 3160 Dystrophic lakes or 3110 Oligotrophic soft water lakes. Examples of sub-community FW1Cii are likely to correspond to the inactive variant of EU HD Annex I habitat 7130 Blanket bog.

 

Management

This vegetation is typically unmanaged. Lakeshore and pool margin stands may be impacted upon by drainage and eutrophication. Stands of FW1Cii are typically a result of turf-cutting, either by machine or by hand, or erosion, which may be linked to extensive sheep grazing.