FW3N Iris pseudacorus beds
Vegetation
This community comprises species-poor, dense beds of Iris pseudacorus with its tall, broad leaves and large yellow flowers. Beneath there is likely to be some growth of Agrostis stolonifera, but no other species are constants. Occasional plants, characteristic of wet grasslands, are Holcus lanatus, Potentilla anserina, Filipendula ulmaria, Poa trivialis and Ranunculus repens.
Ecology
Iris beds occur in a range of wet, fertile habitats including ditches, lake margins, dune slacks and poorly draining grassland, including soakways through coastal grassland.
Sub-communities
No sub-communities are currently described.
Similar communities
Whilst Iris is a feature of several swamp communities and can also occur scattered across wet grassland, Iris usually does not dominate as strongly elsewhere as it does within the FW3N community.
Conservation value
This community does not correspond to EU HD Annex I habitat 6430 Hydrophilous tall-herb swamp due to the lack of tall-herb diversity, but it can support the Annex II species Desmoulin’s whorl snail (Vertigo moulinsiana). Species diversity is high compared to other swamp types (species/4 m2 = 11.0, n = 33).
Management
The main threat to these beds is likely to be agricultural improvement as Iris is viewed as an undesirable plant of pastures and meadows by some landowners, who may seek to control it using a combination of rolling and spraying.