Weed smothers Thames wildlife

An invasive species from North America is blotting out sunlight and killing wildlife in the River Thames at Sonning, the village in Berkshire where George Clooney, the Hollywood star, and his wife Amal have a home.

Nature experts have warned that floating pennywort wreaks “devastation” because it squeezes the life out of river systems by forming dense “mattresses” of weed that the sun’s rays can’t penetrate. It results in other plants being deprived of light and oxygen, causing them to wither. That has a knock-on effect on insects, fish and creatures that feed on them, such as herons, kingfishers and otters.

Alistair Driver, a river management expert, said: “This highly invasive plant which originates from the Americas can grow incredibly fast, up to 20cm a day, and can completely smother waterways and weir structures, impacting on wildlife, recreation and flood management.”