The alien invaders threatening Scotland’s wildlife

By Steven McKenzie
BBC Scotland Highlands and Islands reporter

picture copyrightGetty Images

picture captionThere are fears muntjac deer may seem in Scotland

Scotland’s wildlife is more and more in danger from non-native species, based on the nation’s nature company.

NatureScot says there are greater than 180 species – 122 vegetation and about 60 animals – which pose threats equivalent to killing wildlife or damaging habitats.

But how have these species arrived right here – and that are seen as the subsequent massive risk?

Where have they arrive from?

picture copyrightNess Salmon Fishery Board
picture captionPink salmon, that are native to Pacific Ocean waters, have been present in Scottish rivers

Some reached Scotland on the hulls or within the ballast of ships, whereas others have escaped from gardens, non-public animal collections or zoos.

Other species have unfold from elsewhere in Great Britain and continental Europe.

Pink salmon, a fish native to Pacific Ocean waters, have been showing in Scottish rivers in recent times. It unfold to components of northern Europe after being launched into rivers in Russia within the 1960s.

“Unprecedented numbers” have been present in Scottish rivers in 2017

and have been filmed spawning within the River Ness within the Highlands. Anglers reported seeing the fish once more final 12 months.

Abandoned unique pets additionally pose a possible risk.

Last week, a number of tropical fish have been discovered within the River Ness at Inverness. The heat water fish, which didn’t survive lengthy within the chilly river, could have had illnesses dangerous to native species.

The worst offenders

picture copyrightGetty Images
picture captionCrayfish pose a risk to native freshwater species

NatureScot mentioned the worst invasive species included carpet sea-squirt, a marine animal originating from Japan that “smothers” seabed habitats. It has been discovered within the Clyde and components of Argyll.

Brownish with a leathery texture, carpet sea-squirt grows rapidly and covers over areas of seabed, together with fish spawning and feeding grounds.

North America sign crayfish have been discovered at greater than 20 places in Scotland, together with lochs in Dumfries and Galloway and a quarry pond within the Highlands.

The crayfish have been described as an “aggressive” predator that kills native freshwater animals and burrows into riverbanks, inflicting erosion. They feed on fish eggs, in addition to younger salmon, trout and vegetation.

The risk they pose to wildlife is taken into account so critical that it’s unlawful to place even accidentally-caught crayfish again into water. The recommendation is to kill them as an alternative.

Plant strife

picture captionGiant hogweed could be discovered on riverbanks

Some of the vegetation posing dangers to native species have been dropped at Scotland by non-public collectors within the 19th and 20th Centuries.

They have unfold into the wild and in some locations have taken over. In these areas native species have grow to be scarce or died out.

Dense growths of Japanese knotweeds, big hogweed and Himalayan balsam have been discovered on riverbanks.

They help fewer species of bugs than native vegetation, and once they die again in winter they depart river banks naked and vulnerable to flood erosion.

Efforts to deal with their unfold embrace work in North Harris to regulate big rhubarb and efforts led by Forestry and Land Scotland to take away rhododendron. In Argyll, NatureScot has funded a neighborhood challenge to eradicate rhododendron in Glen Creran.

What are the subsequent threats?

picture copyrightNNSS/Environment Agecy
picture captionKiller shrimp might be one of many subsequent invasive species to look in Scotland

NatureScot – previously often known as Scottish Natural Heritage – is asking folks to look out for species it expects may quickly arrive within the nation.

They embrace 3cm (1in) lengthy freshwater killer shrimp, which have been first recorded within the UK in 2010 however haven’t but been seen in Scotland. The shrimp can outcompete rivals for meals.

It preys on an array of species, together with different shrimp, damsel flies and aquatic bugs like water boatmen.

Killer shrimp have been linked to native extinctions in different nations, and analysis has recommended that it might be altering the behaviour of different species via concern alone. Scientists discovered the creatures it preyed on expended extra vitality making an attempt to evade the shrimp than on regular behaviours.

There are additionally fears in regards to the introduction of muntjac, a deer that originates from China and is described as “probably the most harmful non-native animals in Britain”.

Dubbed the “Asbo Bambi” as a result of it’s thought-about such a nuisance, the deer can injury woodlands, crops and gardens. They have been current in England for the reason that late 19th Century.

In Scotland, it’s unlawful to the maintain the deer with no licence and it’s an offence to launch them into the wild.

What’s the size of the issue?

picture copyrightNess Fishery Board
picture captionExotic fish have been discovered dumped within the River Ness

NatureScot mentioned there had been a “dramatic improve” within the variety of non-native species arriving and changing into established for the reason that begin of the 19th Century.

The State of Nature Scotland 2019 report recommended there was no signal of this development slowing down.

The UK’s Department for Environment Food and Rural Affairs (Defra) believes about 25 invasive species have grow to be established in Great Britain within the final 20 years.

It estimates that between 36 and 48 new species may grow to be established within the subsequent twenty years.

NatureScot mentioned non-native species have been one of many greatest threats to Scotland’s wildlife, and price industries like agriculture and forestry tons of of hundreds of thousands of kilos annually.

The company goals to forestall their introduction and unfold within the first place.

“Everyone has a accountability to assist cease the unfold of invasive non-native species,” mentioned a spokeswoman.

“Pets ought to by no means be launched into to the wild – it is merciless in addition to harmful for wildlife.”

How do you deal with a voracious predator?

picture copyrightGetty Images
picture captionMink have nearly been eradicated from components of the Western Isles

NatureScot says the American mink is a “voracious predator” which preys on ground-nesting birds and water voles.

Those present in Scotland and different components of Great Britain are descended from mink that escaped or have been intentionally launched from fur commerce farms within the 1950s and 60s.

There has been an effort to regulate their numbers and even eradicate them from some areas.

Trapping by the Hebridean Mink Project within the Western Isles has diminished their numbers to “very low” in Lewis and Harris, the place no younger mink have been caught since 2015. The animals have additionally been “largely eliminated” from Uist.

Mink are additionally a goal species for the Scottish Invasive Species Initiative.

The challenge has been working with 10 fisheries trusts and the University of Aberdeen to regulate mink together with different invasive species at websites in a big space of northern Scotland.

Related Topics

  • Inverness

  • Animals

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