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Invasives Project in the River Nith Catchment Area


Non-native plants from around the world have historically been brought into Scotland for botanical garden collections and accidentally imported with other goods.  Although many introduced plants don’t cope well with the Scottish climate there are a few, namely Japanese Knotweed, Himalayan Balsam and Giant Hogweed, which have aggressively colonised many areas of Dumfries and Galloway.  Due to their ecology, these species often spread along watercourses, roadsides and hedgerows and have proved very difficult to control.  The River Nith Catchment Management Plan has highlighted non-native invasives as an issue in the Nith catchment.  The Nith Catchment Management Steering Group has collectively agreed that appropriate action should be taken to control their spread further.



The main aim of this scheme is not to ‘eradicate’ invasive species within the River Nith Catchment but rather to instigate a sustainable land management project to control them in the future, with the biggest contribution and commitment being from the community/landowners themselves.
This will be achieved by:
  1. Raising the profile of invasive species generally with landowners and to encourage them to want to ‘sign up’ to long-term sustainable land management of invasives.
  2. Promoting the benefits of ‘landscape scale’ land management with involvement by all relevant parties.
  3. Encouraging a partnership approach to catchment work, utilising the Nith District Salmon Fishery Board’s good will to get landowners on-board.

Phase 1

The first phase of this project aims to map the extent of the Japanese Knotweed, Fallopia japonica; Himalayan Balsam, Impatiens glandulifera and Giant Hogweed, Heracleum mantegazzianum within the River Nith Catchment Area and to raise awareness and support on the need for control of these species to local farmers, landowners, riparian interest groups and other stakeholders. The successful Tweed Invasives Project will be used as a model for this project and the Tweed Invasives Project Officer has offered to come and speak about their experience at a seminar for landowners.  Phase 1 will be carried out in 2007.  The results of Phase 1 will determine the extent of control of invasives that can be tackled in Phase 2 of the project.

Phase 2

The second phase of the project aims to co-ordinate appropriate control of the target species in partnership with local farmers, landowners, riparian interest groups and statutory authorities within the River Nith catchment.  Previous experience in Scotland, such as in the River Tweed catchment, has already shown that only a systematic, co-ordinated ‘catchment’ approach is effective at controlling invasive species.
It is hoped to start Phase 2 in spring 2008 and to run the programme for 3 years.  It is anticipated that at this stage of the project the landowners will be fully on board and play an active role in controlling the invasive species on their land.



This is a partnership project, to be coordinated by SEPA’s Catchment Management Planning Officer (CMPO).  The CMPO post is a permanent position, co-ordinating catchment management issues in Dumfries and Galloway.  This will ensure that the project can be monitored over a longer period of time than the four year duration of the feasibility study and practical control planned for Phases 1 and 2. The project would be run in partnership with Solway Heritage and the Nith District Salmon Fisheries Board (NDSFB).  The NDSFB has offered ‘in-kind’ support for the project in the form of physical GPS mapping, administrative input, knowledge of local landowners and assistance to 'sell' the idea of sustainable invasive control to landowners across the Nith Catchment.  NDSFB support on the ground will save a huge amount of time and money for the project.  This would otherwise require a new and likely unknown person to contact landowners to develop a working relationship with them.  These relationships already exist through the NDSFB.


The two most serious and widely distributed invasive plant species in the River Nith catchment area are Japanese Knotweed and Himalayan Balsam, although Giant Hogweed is also locally common.  It is not know whether there is a particular problem with Rhododendron, Rhododendron ponticum in the River Nith Catchment but it is envisaged that Rhododendron will be mapped on the river and stream banks.  These species are a particular problem due to:

  • Lack of awareness of problems/threats if not controlled
  • Dense growth which shades out native plants
  • Poor habitat for native insects and other fauna
  • Increased risk of bank erosion
  • Potential flood risk if dead stems block watercourses
  • Damage to infrastructure e.g. Japanese Knotweed can grow through walls, pipes etc
  • Health and safety hazard (poisonous stems) of Giant Hogweed.
The River Nith and its catchment have been identified as an area where these invasive species have become aggressively common.  The River Nith Catchment Management Steering Group have agreed that a co-ordinated catchment approach is needed to investigate the extent of the invasive problem in the catchment, followed by co-ordinated, sustainable catchment based control.
There is evidence of success in controlling invasive species from the Tweed Invasives Project, which is co-ordinated by the Tweed Forum.  The Tweed Project’s aims are long-term, sustainable control of Giant Hogweed and Japanese Knotweed within the Tweed catchment.  Co-ordinated treatment of the target species, in partnership with local farmers, landowners, riparian interest groups and statutory authorities within the Tweed catchment, has been successfully carried out with 107 out of 108 landowners participating.

The project has been run using funds from the Heritage Lottery Fund, various statutory authorities and other partners, to provide technical knowledge, materials and training support for the targeted control of Giant Hogweed and Japanese Knotweed.  Three years after starting the project both Giant Hogweed and Japanese Knotweed have been significantly reduced in area, size and location. The project has also successfully raised the profile of all invasive plants in the catchment, which will help achieve sustainable long-term control for the future.

Project Outcomes


Phase 1 will investigate the feasibility of carrying out practical treatment of the invasive plant species identified.  The following outcomes will be achieved during the first phase of the project:
  • GPS recording of invasive species by the Nith District Salmon Fisheries Board staff. 
  • Digital mapping of the plant locations and production of a distribution map by Dumfries and Galloway Environmental Resources Centre.
  • Production of an invasives information leaflet for landowners, to encourage support for the project, which will include a tear off slip to report locations of invasive plant species.  Distribution of the leaflet to riparian landowners by Nith District Salmon Fisheries Board, FWAG and other relevant organisations. 
  • Organisation of an invasives workshop for landowners to raise awareness of the problem and encourage involvement in a long-term sustainable control project for Phase 2. 
  • Production of a short report on the extent of the invasives problem within the Nith Catchment Area. 
Funding for Phase 1 has been received from Scottish Natural Heritage, Dumfries and Galloway Council’s Nith Area Committee and Scottish Environment Protection Agency with in-kind support coming from the partner organisation, Nith District Salmon Fisheries Board.  Solway Heritage will carry out the majority of the organisation and production of interpretive materials.
Phase 2 will co-ordinate the control of the target species mapped, with the costs involved dependant on the results of Phase 1.  It is anticipated that funding for Phase 2 will be sought from the Heritage Lottery Fund, Landfill Tax Credit Scheme and local spraying companies (for materials).

Follow the link below to view the leaflet:

River Nith Catchment Invasives Leaflet