FW1C Juncus bulbosus aquatic community
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 few 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, the margins of peaty dystrophic pools and in shallow rivers. It also occurs in drainage ditches and erosion channels in degraded bog.
Sub-communities
Two distinct sub-communities are described. The Potamogeton natans – Mentha aquatica sub-community (FW1Ci) unites the examples from rivers, lakeshores and pool margins. Here, Juncus bulbosus is omnipresent and Potamogeton natans is fairly common. They are occasionally accompanied by Mentha aquatica and Ranunculus flammula. 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 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 BG1D 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
Some examples of sub-community FW1Ci are may correspond to EU HD Annex I habitat 3160 Dystrophic lakes. Examples of sub-community FW1Cii are likely to correspond to the inactive variant of EU HD Annex I habitat 7130 Blanket bog. For an aquatic community, it is quite species-rich (species/4 m2 = 9.8, n = 10).
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.