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Launch of a new national campaign to control the highly invasive Floating Pennywort

British Canoeing have joined water-based recreational groups, along with environment organisations and the Government, to help halt the spread of a highly invasive non-native plant that is choking rivers and lakes across the UK.

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The dense rafts can cause problems for wildlife by forming dense mats which block out life, stifle native plants and make the rivers and lakes unsuitable for insects, fish and other wildlife. It also make waters inaccessible to paddlers, anglers, swimmers and other water users and present significant flood risks, creating plant dams which back up around weirs and clog up sluices, drains and whole sections of our fantastic waterways.

Now a new GB wide national strategy to remove floating pennywort from our waterways has been launched which will combine the resources of the government, water companies and volunteers to co-ordinate catchment based action through local partnerships.

Floating pennywort has been spreading across the UK since the 1980s. It is notoriously difficult to control and despite many small-scale management efforts, removal has been unsuccessful as projects have not been undertaken on a large enough scale, or for a long enough duration. As a result, small fragments of the plant were not removed and the plant regrows (up to a rate of 20cms/day), or populations reinvade from upstream.

In recent years, however, more strategic partnerships and collaborative projects have begun to form. On the River Medway, British Canoeing are working in partnership with the Medway Valley Countryside Partnership and the Environment Agency (EA) and local contractors to remove floating pennywort. 

Learning from the success of smaller scale strategic partnerships, in September 2020 the Thames basin project was launched, with the Angling Trust, Environment Agency and British Canoeing working together to coordinate management of floating pennywort in the region.

Based on this project, alongside other successful strategic collaborations that have been formed in other parts of the country, a national Great Britain Floating Pennywort Strategy is being launched, uniting recreational users, water companies and government to tackle this invasive plant. Through closer, coordinated action the aim of the strategy is to share best practice and facilitate further partnerships being formed to control this species and prevent the further spread into other areas.

Lord Richard Benyon, Minister for Rural Affairs and Biosecurity said:

I commend this initiative, which will help inform how we manage this highly damaging invasive species. Invasive non-native species not only challenge the survival of some of our rarest species but cost the economy more than £1.7 billion per year Floating pennywort profoundly disrupts aquatic habitats for insects, fish and other wildlife, and disrupts how people interact with Great Britain’s rivers and lakes. Today’s move is a step in the right direction for improving our cherished waterways.

– Lord Richard Benyon, Minister for Rural Affairs and Biosecurity

Trevor Renals, Invasive Species Technical Lead, Environment Agency said:

“Floating pennywort is a highly-damaging non-native weed, which damages the flora and fauna of our rivers and our ability to enjoy recreation such as angling and boating. It also has the potential to increase flood risk and block flood defence assets. No single organisation has a duty to manage floating pennywort, so it is only by working together that we can control this plant. We encourage people to support local partnerships to manage invasive species and use it as an opportunity to enjoy nature and meet people in a socially-distanced environment."

Later this year, a weevil native to South America will be released into the wild to provide another management tool to halt the spread of this species. This follows extensive research that has been undertaken by the Centre for Agriculture and Bioscience International (CABI) to determine the suitability of the species for release and presents one of a number of biological controls that are being used to assist in invasive species management.

Richard Atkinson, Policy Officer, British Canoeing said:

We welcome the launch of this national strategy to tackle Floating Pennywort and a movement towards a more coordinated approach to invasive species management. Many paddlers are already helping to control invasive species, as highlighted by the fantastic ongoing efforts by Maidstone Canoe Club on the River Medway and The Sharks Canoe Club in the Colne Valley. Through this strategy we hope to be able to facilitate further partnerships such as these, and make strides towards tackling this problematic plant, and protecting the environment and wildlife that we all enjoy.

– Richard Atkinson, Policy Officer, British Canoeing

Djami Djeddour, Senior Scientific Officer, CABI said:

“CABI-UK has already released biocontrol agents against Japanese knotweed, Himalayan balsam and Australian swamp stonecrop (Crassula) in the UK.

"Weevils have a long history of success in the biocontrol of aquatics. Research into the biocontrol of floating pennywort using the Argentine weevil, Listronotus elongatus has been funded by Defra since 2011.  The weevil has undergone comprehensive screening for safety and efficacy and is now in the last stage of approval for permission to release in the UK. 

"CABI are hopeful that this agent will reduce floating pennywort’s dominance on our waterways, providing long-term and sustainable control. A national strategic approach to floating pennywort management provides an excellent opportunity to maximise impact, working closely with partners and stakeholders to integrate this natural solution into conventional management plans.”

How to get involved

The partnership is encouraging everyone to get involved in tackling Floating Pennywort. More information on how to get involved can be found under the Local Action Group pages on the GB NNSS website http://www.nonnativespecies.org//index.cfm?sectionid=144.