|Scientific name||Schoenoplectus lacustris – Sparganium erectum swamp|
|Common name||Common Club-rush – Branched Bur-reed swamp|
Download full pdf synopsis: FW2G
Schoenoplectus lacustris and Sparganium erectum are constants within this river community, forming an emergent element in which Phalaris arundinacea and Apium inundatum are frequently encountered while Berula erecta and Myosotis scorpioides are occasionally found. An accompanying element of floating-leaf and free-floating plants is characterised by Nuphar lutea, which can be abundant, with Potamogeton natans, Potamogeton crispus and Lemna minor occasional. Sparganium emersum is a frequent plant which may contribute to either or both of these elements. Submerged plants may also occur but are infrequent, the chief species are likely to be the non-native Elodea canadensis, submerged forms of Veronica anagallis-aquatica, the bryophyte Fontinalis antipyretica and Myriophyllum spicatum.
This is a community of lowland freshwater river systems with fairly base-rich and eutrophic waters.
Three tentative sub-communities are proposed to help differentiate between areas of vegetation in which different community constants are dominant. These are the Schoenoplectus lacustris sub-community (FW2Gi), the Sparganium erectum sub-community (FW2Gii) and the Nuphar lutea sub-community (FW2Giii). Recording of homogeneous vegetation stands within this community would elucidate these sub-communities.
Schoenoplectus lacustris is also a constant in community FW3D Schoenoplectus lacustris – Phragmites australis swamp. In that less diverse assemblage, Sparganium erectum and Nuphar lutea are much less frequent, however, and S. lacustris tends to dominate.
Elodea canadensis is an invasive non-native species found in this community but it is not considered a major ecological threat and has already colonised much of its suitable niche in Ireland.
This community may be affected by eutrophication, river engineering including dredging and canalisation, clearance works for navigation and trampling from livestock with access to the bankside.