Forth Rivers Trust INNS Control 2020

With the first early morning frost comes the end of the Forth Rivers Trust’s battle with Non-Native Invasive Plant species as plants begin to become dormant for the winter months.

This year despite issues facing the Trust with covid-19 which limited the time and manpower available, the Trust carried out invasive plant species control on many of the Forth district rivers. Through the RiverLife project we have been able to tackle a significant amount of invasive plants along the Avon and Almond. On these two rivers there are large amounts of Japanese knotweed, Giant hogweed and Himalayan Balsam. During the project we have seen great improvements on areas where continuous funding has allowed us to treat these plants year on year.

We have also been working in partnership with the Loch Lomond & The Trossachs National Park. In this partnership we have been controlling the plants mentioned above along with American Skunk Cabbage. We continued to control invasive non-native species on the banks of the River Teith and Forth within the National Park.

We have seen a vast improvement during the control efforts over the past 7 years in the areas that have been consistently treated thanks to funding from the park. A top down approach to invasive species control means if you remove plants at the top of a river the area usually can’t be re-colonised by the invasives.

For Many years, the Forth Rivers Trust have also deployed resources on the Allan water to control giant hogweed. Anyone who has taken a train through the area will have no doubt seen the plant which is prevalent along some parts of the train track that follows the river.

Standing around 3m tall with an umbrella-like white flowering head the plant is very noticeable. We have been treating plants from Greenloaning down to Ashfield and have seen a significant difference within the areas we have been able to treat year on year.

Non native invasive plant species are a substantial threat to our native habitats and it should be man’s responsibility to control these plants as they were imported as ornamental plants in the 20th century. These plants outcompete native species as they have no natural inhibitors meaning they can quickly grow and spread. Some of these invasive plants can also affect humans directly. Giant Hogweed is very dangerous as sap in the plant when in contact with skin can cause third degree burns because of a chemical reaction involving sunlight.

Japanese Knotweed can cause damage to structures and might affect the price of a property as it can grow into cracks in structures and push its way through. Many invasive plants can also have a negative impact on river banks causing erosion leading to a loss of agricultural land and destroying instream habitats.

The Forth Rivers Trust would like to control more invasive plants in the Forth district but can’t because of a lack of year on year funding. The trust is always looking for opportunities to fund Non-Native Species control on more areas within the Forth district. When treating these plants it is important to take a multi year approach because many of the plants create a seed bed that can produce seedlings for many years meaning one year of treatment will not be enough!