THEY are the foreign invaders threatening to decimate some of our best-loved wildlife.

But although non-native species such as the American mink and Japanese knotweed continue to spread, a ray of hope has emerged following the announcement of a cash injection aimed at clearing them from one of Scotland’s most important waterways.

Loch Lomond Fisheries Trust has been awarded nearly £100,000 to undertake control measures in the catchment of the Endrick Water, which flows into the eastern end of Loch Lomond.

As well as knotweed and mink, incomers including giant hogweed, the American skunk cabbage and the signal crayfish will be targeted as part of moves to tackle a major threat to the country’s eco-systems.

Vulnerable native species such as the water vole and powan – a type of fish – are the primary victims, with populations exposed to predation, disease and competition.

But human beings are also at risk, as anyone who has experienced the agonising blisters caused by hogweed sap will confirm. Malcolm MacCormick, operations manager at the trust, welcomed the new money, which has been made available through the Scottish Government’s Biodiversity Challenge Fund.

However, he also warned that the strategy for tackling invasive plants was far too fragmented.

“There’s no consistent approach across Scotland by councils or national government,” he said.

“Some councils are very good, others not so good. There needs to be a national policy and consistency across Scotland in terms of how we deal with this.”

MacCormick said a wide range of work would be carried out thanks to funding given to the trust’s Endrick Legacy Project.

“This year we’ve been seeing the American mink again so we will be putting out traps,” he said.

“We’ll be killing them, and while this may sound extreme they should not be here. They cause havoc to fish life, bird life – they decimate native species such as the water vole. We’ll never eradicate them but we will be working to keep them in check.

“In terms of the American signal crayfish, you’re talking about an issue of biosecurity. So anglers might go walking along or in the Clyde and spawn attaches to them, then they go to somewhere like Loch Lomond, the spawn detach and the crayfish are able to spread. So people need to be aware of the need to disinfect their kit, for example.

“We haven’t had reports of crayfish in the Endrick but part of the Endrick Legacy Project will be looking to see if we have any here in the Endrick catchment.”

MacCormick said clearing invasive plants was not just about protecting native flora.

“It means we will have a safer riverside – everyone benefits,” he added. “One of the effects a species such as Japanese knotweed and giant hogweed is that in winter, when the plant dies back, the roots are exposed, increasing the risk of erosion of the riverbank.

“This in turn increases water width and reduces depth, which is really bad for the fish you find in the Endrick Water, such as salmonids. Basically, in a warm summer, your fish come under extreme pressure due to to a lack of water cover.”

Scottish Natural Heritage said protecting biodiversity would be critically important.

“As lockdown conditions lift, green recovery projects like the Biodiversity Challenge Fund put nature, and nature-based solutions, at the heart of rebuilding our economy,” said chief executive Francesca Osowska.

“But it’s not just about conservation – enriching our nature is also part of the solution to the climate emergency too.

“People know that climate change is a big issue but not as many know that biodiversity loss is also a global and generational threat to human wellbeing.

“Nature is at the heart of what we do, and we will continue to deliver the transformational change needed to bring a nature-rich, sustainable and more economically secure future for Scotland.”

A spokeswoman for the Scottish Government said it was taking the control of invasive non-native species “extremely seriously”.

She added: “The Scottish Biodiversity Strategy provides a strategic focus, setting out the major steps we need to take in order to halt the loss of biodiversity and improve the state of nature in Scotland. This strategy includes priorities on preventing the release and spread of non-native species, particularly in areas where they can cause damage to native species and habitats and to economic interests.

“We are also focused on ensuring there is a rapid response to new populations of non-native species before they become established and to apply effective control and eradication measures where needed.”