Battle plans drawn up to repel alien plants and animals

Published on Thursday 21 May 2009 19:22

SCOTLAND'S fisheries trusts are to spearhead a major offensive against an invasion of "alien" plants and animals threatening our native species.

The Rivers and Fisheries Trusts of Scotland (Rafts) has chosen International Biodiversity Day to announce plans to lead the fightback against the increasing risks being posed by so-called "Invasive non-Native Species" (INNS).

Angling organisations have already warned that one alien invader, the American signal crayfish, could wipe out salmon stocks unless concerted action is taken.

And environmentalists claim that other invasive species, such as the grey squirrel and Japanese knotweed, have already spread out of control.

Dr Chris Horrill, biosecurity planning project officer for Rafts, said yesterday that alien species, which have been colonising a wide range of habitats where they were excluding native flora and fauna, were costing the Scottish economy 500 million each year.

He added: "INNS are a massive and growing threat to our native plants, animals and habitats. To control their populations or mitigate their impacts costs our economy – and therefore us – millions each year.

"Prevention of the introduction and spread of these species is the most cost-effective means to address this threat."

According to Rafts' bio-security plan, Japanese knotweed alone is thought to affect an area the size of London and the total cost of its removal using current techniques is estimated at 2 billion.

The cost of the introduction of the salmon parasite, gyrodactylus salaris, is estimated at 633 million in lost revenue to fragile rural communities, and it could cost as much as 25 million to clear the invasive Rhododendron ponticum from the Loch Lomond and Trossachs National Park.