Tackling invasive non-native plants along the banks of the River Dee – such as Japanese knotweed, giant hogweed, Himalayan balsam and North American skunk cabbage - has become a priority for the River Office because of their potential impact on our river and its existing, native species.
The Trust and Board has had success controlling these species on the Dee in recent years. With the help of volunteers, we have covered a large area from Ballater to Park Bridge near Drumoak. Work has also been carried out on the Rivers Cowie and Carron down to Stonehaven.
The Trust decided to build on the success we had tackling invasive plant species by creating the Dee Invasive Plant Project (DIPP) to target invasive plant species on the lower Dee and its tributaries. The three year DIPP project was launched in May 2015 with the specific aim to eradicate the most significant invasive plant species from the lower River Dee and its tributaries, from the bridge at Drumoak, downriver to Aberdeen Harbour.
So far, this summer, DIPP has made good progress on several fronts:
Giant Hogweed (GH) + North American Skunk Cabbage (SC)
· 4006m2 of GH has been treated (sprayed) so far. In 2015, the total amount of GH on the banks of the river was 2,220m2. Although, all the hogweed was sprayed in 2015, an increase of 1,786m2 was recorded this year which may be attributed to Storm Frank.
· 2,550m2 of SC has been sprayed so far. We have seen a substantial decrease in SC this year.
Himalayan Balsam (HB)
· Surveying the areas treated last year by mechanical means has shown a significant decrease in HB where strimmers were used. Therefore, in 2016, we have used walk behind flail mowers and strimmers covering an area of approximately 4000m2.
· Fourteen volunteers have been trained and have now qualified in Pesticide Application (PA6aw/inj).
· From the middle of July these volunteers will help in controlling Japanese Knotweed along the river.
· So far (April to June) our volunteer workforce have committed a total of 120hrs (past and present volunteers) to the project.
From the middle of July to August the focus will be on treating Japanese Knotweed with the help of volunteers. Specific areas are being surveyed to determine their suitability for sowing of wildflower mixes to encourage bank stabilisation and the reintroduction of native species.
For further information about DIPP and invasive species management and how to volunteer, have a look at our Publicity Poster