Environment: UK counts cost of invading foreign species

A report, "The Economic Cost of Invasive Non-Native Species to the British Economy" published today, says that the cost to the UK economy of managing invasive non-native species in the UK exceeds GBP1,500 million a year.

The study by CABI for the Scottish Government, DEFRA (Department for the Environment, Food and Rural Affairs) and the Welsh Assembly Government and it breaks down the effect on each country as follows:

* £1,300 million per annum to the English economy,* £251 million to the Scottish economy* £133 million to the Welsh economy.

The effect of the extent of the invasion on control costs was investigated in five case studies (Asian long-horned beetle, carpet sea squirt, water primrose, grey squirrel and coypu). In all examples, early action provided a significant economic benefit compared to the cost of management if the species were to become more widely established.

For example, with water primrose, a group of South American aquatic weeds which grow rapidly and can block waterways it is estimated that the current timely eradication will cost £73, 000 which is significantly less than the estimated £242 million that it would cost if the plant was to become widely established as it has on the continent in countries like France and Belgium.

Roseanna Cunningham, Scottish Government Minister for Environment and Climate Change said "A better understanding of the negative impacts of invasive non-native species can help us raise awareness to help prevent introductions in the first place and to better respond to problems."

Richard Benyon, Minister for the Natural Environment, DEFRA, said:

"Invasive non-native species have a significant impact on the British economy and damage our own wildlife. The costs of controlling these species will rise unless society takes steps to prevent them taking hold and spreading.

"It becomes increasingly difficult and costly to control invasive non-native species as they become more established. Taking early action may seem expensive, but this report shows that it is the most effective approach, saving money in the long run and helping our native wildlife to thrive."

The report comes immediately after WTO found that Australia's ban on the import of apples from New Zealand, imposed to prevent the import of fruit fly, was unlawful.

The top 20 non-native species, with the cost of managing them, are shown in the table below and it contains some surprises - including, as it does, some "pests" that are so established it is difficult to see them as "invasive non-native species." And one group - geese/swans - that few would consider pests.Species Cost £mRabbit 263Japanese knotweed 179Common field-speedwell/ wild oat 100Rat 62Potato cyst nematodes 50Non-native deer 35Varroa mite 27Floating pennywort 25House Mouse 18Grey squirrel 14Rhododendron 9Slipper limpet 6Mink 5Geese/swans 4Green spruce aphid 4Signal crayfish 3Giant hogweed 2Himalayan balsam 1Buddleia 1Edible dormouse 0.4