The Environment Agency is winning the battle against an invasive non-native weed on a Northamptonshire river.
Annual works by Environment Agency contractors to tackle floating pennywort on the River Nene found no trace of the plant on the river last year.
The floating pennywort (Hydrocotyle ranunculoides) control programme, which is managed by Environment Agency fisheries and biodiversity staff, has taken place on the river every year since 2007. In 2010 the plant was at 14 sites on the river.
Fisheries and biodiversity technical officer Robert Pitkin said: “We’ve seen a steady reduction in the number of sites and overall extent of the plant along the River Nene since 2010.
“I’m pleased to say we didn’t find any trace of the plant on the river last year.
“However, we will be monitoring the river again this summer as we cannot afford to be complacent.
“We will have to continue monitoring and find none for a further five years before we can declare that floating pennywort has been eradicated from the Nene.
“For this reason, I would ask boaters and other river users to be vigilant. It is vital they report any potential sightings of the plant to us to prevent it regaining a hold on the river.”
Floating pennywort is native to South America and can quickly establish dense mats of vegetation, out-competing native species and dominating watercourses.
The plant chokes waterways making it difficult for boats to navigate and increases the risk of flooding by blocking channels.
In large quantities, it also poses a threat to fish and other aquatic life by starving the water of light, oxygen and nutrients.
Floating pennywort was first spotted on a pond near the River Nene in 2004 but was later found in the river itself, prompting the Environment Agency to begin its eradication programme in 2007.
If people do see floating pennywort, which can grow up to 20cm a day, it is vital they don’t contribute to its spread.
Boats should not be driven directly through clumps of the plant as it can break off pieces which will then re-grow elsewhere.
Avoid picking and discarding pieces of the plant as these can grow and colonise new areas.
Anyone who sees floating pennywort should contact the Environment Agency on 08708 506 506 or email email@example.com.