This week is Invasive Species Week and an important opportunity to highlight the role that climate change is playing in the spread of invasive and non-native species in the Highlands.

The introduction of invasive non-native species (INNS) is often the result of human activities. However, increased temperatures and habitat disturbance provide opportunities for these invasive species (which are often “generalist,” or quicker to adapt) to establish in the Highland region. Rapid environmental changes can exacerbate the problem by making native species more vulnerable.

Some species of concern have the potential to cause serious economic and environmental damage to the Highland region, as well as impacts on human health.

Generated on NBN Atlas, this map shows four examples of non-native invasive species currently in Highland:

Purple: “Rhododendron ponticum was first introduced into Britain in the 1700s as an ornamental plant… It forms dense thickets and shades out native plants.” Forestry and Land Scotland

Green: “Giant hogweed originates from the Caucasus Mountains and Central Asia. It was first introduced to the UK as an ornamental in the 19th century when it escaped and naturalised in the wild.” The Woodland Trust

Blue: “The American mink (Neovison vison) spread through most of the UK during the second half of the 20th century. Mink were the principal cause of the crash in the British water vole population at this time.” NatureScot

Orange: “[Leathery sea squirt] from the North-West Pacific was first found in Scotland in 1981 (Lutzen, 1999) and has spread up the west coast as far north as the Isle of Skye. Leathery sea squirt is capable of colonising a variety of intertidal and shallow subtidal habitats, taking advantage of gaps in substrata and artificial substrates where it displaces native sea squirts (Ciona intestinalis) (Lutzen, 1999).” Scotland’s Marine Assessment 2020

Under the Scottish Government Non-native species Code of Practice, the following organisations act as habitat leads for managing INNS:

However, it is all of our responsibilities to do our part preventing the introduction and spread of INNS in our region. To learn how you can help combat the spread of invasive non-native species in the Highlands, we suggest you start by checking out The Scottish Invasive Species Initiative. This partnership project works with local organisations and volunteers to control invasive non-native species along riversides in Northern Scotland, for the benefit of our native wildlife and communities.

To learn more about the relationship between climate change and invasive non-native species, check out the following links:

1. IUCN Issues Brief: Invasive Alien Species and Climate Change (2021)

2. NatureScot Climate Change Impacts on Species (2023)

3. Scottish Government Spread of invasive species into Scotland: study (2023)

4. UK, Scottish, and Welsh Governments The Great Britain Invasive Non-Native Species Strategy (2023)

 5. Scottish Environment LINK Invasive Non-native Species in Scotland: A Plan for Effective Action (2024)