Nuttalls waterweed

Overview

Photo credit: © Robert Videki

Habitat:

Elodea nuttallii is most common in calcareous waters and eutrophic waters because it has a high tissue demand for both phosphorus and nitrogen.

Similar Species: Elodea canadensis

Widely Spread Species:

Under Article 19 of Invasive Alien Species Regulation (1143/2014) Nuttall's waterweed has been identified as a Widely Spread Species in Northern Ireland and as such, management measures have been put in place to minimise its impacts.

Description:
E. nuttallii originated from North America. This species is very similar to another invasive specie know as E. canadensis (Canadian waterweed).
Both species grow in still or slow flowing eutrophic waters but E. nuttallii has replaced E. canadensis at many sites possibly due to increased eutrophication.
This is an aquatic weed that grows rapidly towards the surface of eutrophic freshwater systems without branching where they form a densely branched canopy.
E. nuttalli is perennial and over winters in Ireland as horizontal shoots which regenerate new lateral shoots as the temperature reaches 6-8°C.
Download N.I.E.A. ID guide

Origin and Distribution:

This species is native to North America but is now invasive in Britain where it is common.

Impacts:

E. nuttallii tends to dominate native macrophyte communities which may lead to there local extinction. Impacts have also been recorded on invertebrate communities.
This species may also have a significant impact on protected sites.
E. nuttallii is also known to replace other invasive species as the dominant species in an impacted ecosystem.
More recently data from Britain suggests that this species is now becoming replaced by Largarosiphon major.

How did it get here?

Is it found in Ireland or Northern Ireland?

You can help by reporting any sightings:

If it is in Northern Ireland @ the Centre for Environmental Data & Recording (CEDaR) - Or via the iRecord App.
If your sighting is in Ireland please report @ the National Biodiversity Data Centre (NBDC).

Static Distribution Map as of December 2019 - Courtesy of CEDaR

Prevent Spread

Promote native species and biodiversity - use alternative, native plants
Know what you are buying/growing and source native Irish seed and plants
Do not swap plants and cuttings
Clean plants before adding to ponds (dispose of water away from water courses)
Follow control advice and watch out for hitchhikers - inspect new imported purchases for invasive pest and pathogens
Clean equipment before moving between waterbodies
Never collect plants from the wild
Safe disposal of plant material and growing media
Record all sightings.

Current Legislative Position (Listed on 03 August 2017)

This species must not intentionally be brought into the Union; kept; bred; transported to, from or within the United Kingdom, unless for the transportation to facilities in the context of eradication; placed on the market; used or exchanged; permitted to reproduce, grown or cultivated; or released into the environment.

For further queries, you can contact the Non Native Invasive Species Team in the Northern Ireland Environment Agency on 028 9056 9558.