River banks face foreign invasion

RIVER ecosystems are at risk of being over-run by invasive foreign plants thriving because of climate change.

Giant hogweed, Japanese knotweed and Himalayan balsam have colonised our river banks, suffocating native plants because of the more favourable weather conditions.

Dr Dylan Bright, director of the Launceston-based Westcountry River Trust, said climate change had led to longer seedling seasons and higher temperatures.

He said invasive plants had been thriving in the region because they were out of their natural habitat and did not have any predators or pests.

Dr Bright said: “These plants may look good in your garden but many are pernicious and pose a real problem to the native vegetation and ecosystem.

“They can badly affect the ecology of our rivers and because many of them die down in winter, they leave the banks bare and exposed to greater erosion.”

Dr Bright said plants like the giant hogweed were also dangerous to people because its sap is caustic and can leave nasty skin blisters and rashes.

He said badly affected areas included the lower end of the River Tamar, the River Camel and the River Dart.

He said: “Along with climate change, invasive non-indigenous plants are a major challenge to biodiversity.

“It doesn't just affect native plants but the fauna as well. It's all linked.”

Between 50 and 60 volunteers have been enrolled by the trust to help pull out foreign weeds this summer.

Hazel Kendall, who is in charge of the project on the River Camel, said: “Himalayan balsam can spread up to 10 metres every year. We go in July and August before they have chance to seed so hopefully there will be fewer next year.”

Mrs Kendall said prevention and information work with local farmers, canoe clubs, landowners, schools and walkers had helped spread the message.