Draw up a list of reasons for wildlife extinction and you’ll surprise no-one by naming poachers, pollution or global warming.
Careless fishpond maintenance, on the other hand, could raise some eyebrows, yet that very problem is behind a campaign to encourage Britain's gardeners to help in the war against invasive water plants which threaten Britain's waterways.
Floating pennywort, New Zealand pigmyweed, water primrose, parrot's feather and water fern are all found in garden ponds. They also feature on a Britain’s Most Unwanted list drawn up by the Be Plant Wise campaign, as the five plants with the worst effect on UK rivers and their wildlife.
Now gardeners are being encouraged to mitigate this threat by properly composting unwanted pond plants and disposing of unwanted fish tank or pond water.
If they get out into the wild, the Infamous Five on the Be Plant Wise list can over-run waterways, block up river banks and damage habitat. Some plants grow so extensively, they form dense mats which appear as dry land, posing a drowning risk for livestock and people. Just one fragment of plant escaping from a pond or fish tank could affect a whole river, insist campaign organisers, who envisage a multi-million pound clearance bill should the problem continue to intensify at current rates.
RSPB reserves are being affected by the problem and the Society’s Dr Paul Walton has named invasive non-native species in new areas as a primary cause of wildlife extinctions worldwide.
Natural Environment Minister Huw Irranca-Davies launched the Be Plant Wise campaign with TV gardener Charlie Dimmock on south London’s River Wandle, itself overrun by floating pennywort.
“From the River Severn to the smallest stream, our waterways are being invaded,” the minister explained. 'We all know about grey squirrels and Japanese knotweed but how many people know that invasive aquatic plants can out-compete native species, choke waterways, harm native wildlife, disrupt the navigation of boats, interfere with recreational activities such as fishing and boating and exacerbate flooding?
“Gardeners can do their bit to help stop the spread by knowing what they grow in their ponds and disposing of unwanted plants with the utmost care.”