THE WARRINGTON-based Environment Agency is urging owners to steer clear of alien plants which are damaging the environment.

Species including Australian Swamp Stonecrop and Fairy Fern, also known as fairy moss and water fern, are clogging the town's still waters.

The imported plants form dense floating carpets on the water's surface which deoxygenates the pond, killing fish and aquatic invertebrates and smothering other plants.

The foreign plants also pose a risk to life as they often appear solid enough for people to walk on. Once someone has fallen through the mat, it closes above them making rescue difficult.

There are no natural controls to stop the spread of the plants and clearing invaded sites is expensive. Often herbicides are required, a practice which the Environment Agency is keen to minimise.

Scientist Dr Elaine Fisher said: "We are urging pond owners to be careful in their selections and avoid the alien species.

"The spread of the species is a real problem and one which is hard to tackle, particularly as the use of herbicides is restricted.

"It is wise to avoid buying plants from communal troughs which contain invasive species as there is a risk of transferring fragments of these into your ponds."

Garden centres are being advised to withdraw the species from sale and the Agency is currently investigating the extent of the problem in the region.

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