Scientific name Ranunculus penicillatus – Fontinalis antipyretica aquatic community
Common name Stream Water-crowfoot – Greater Water-moss aquatic community
Community code FW2C

 

FW2C map: Ranunculus penicillatus – Fontinalis antipyretica aquatic community

Download full pdf synopsis: FW2C

 

Vegetation

Mid-channel expanses of the floating leaves of Ranunculus penicillatus (subsp. penicillatus) are the key feature of this aquatic community, although rarer vegetation with Ranunculus peltatus is also included here. Fontinalis antipyretica is also a constant species in the channel but is never abundant. Rarely, there may be some sparse floating cover from pondweeds (Potamogeton species) or duckweed (Lemna species). A minor marginal element to the vegetation is frequently provided by Phalaris arundinacea, Apium nodiflorum and Sparganium erectum, with Epilobium hirsutum, Filipendula ulmaria, Mentha aquatica and Juncus effusus occasionally present. The non-native invasive Impatiens glandulifera is also only occasional but can dominate margins of watercourses.

 

Ecology

This vegetation occurs in mildly eutrophic, distinctly base-rich rivers and streams.

 

Sub-communities

No sub-communities are currently described.

 

Similar communities

Ranunculus penicillatus and Fontinalis antipyretica are also constant features in the FW2D Apium nodiflorum – Ranunculus penicillatus aquatic community. That community, however, has a more pronounced emergent and marginal element with Apium nodiflorum a constant species and Berula erecta frequent. Furthermore, Callitriche stagnalis is seldom encountered in FW2C unlike FW2D where it is a constant.

 

Conservation value

Due to the relative abundance of crowfoots (Ranunculus spp. subgenus Batrachion) almost all examples of this community correspond with the EU HD Annex I habitat 3260 Floating river vegetation. Several non-native plants occur in this community and impact on conservation value. Impatiens glandulifera and Crocosmia × crocosmiiflora are aggressive invaders of bankside vegetation. Elodea canadensis is a submergent that is not considered a major ecological threat and has already colonised much of its suitable niche in Ireland.

 

Management

This community has no specific management. Eutrophication from discharges and agriculture run-off is probably the major threat. Other impacts may come from river engineering, spread of invasive species and trampling from livestock with access to the bankside.