Guidance for landowners and land managers
Landowner responsibilities
It is the responsibility of the landowner or land manager to prevent any non-native species on their land or water from spreading into the wild.
This means that if a non-native species is present on land or water you own or manage, you should take all reasonable steps to avoid it from spreading. In the case of aquatic species, this includes preventing it from spreading out of a pond or loch via any outflowing waters.
For invasive non-native species, you should also take steps to avoid them causing damage, for example by eradication, containment, or control.
Eradication, containment, and control
Where possible, and where it is likely to help prevent spread, the best approach can be to eradicate the INNS. This may not be feasible for some aquatic species, especially where there are native or protected species which could be damaged during an eradication; in this situation the INNS should be contained and/or controlled.
Details of how to develop a management plan for eradication or control of plant INNS, including links to information on potential control approaches for different plant species and how to apply for any permits needed, are given in:
- Application of pesticides near water (WAT-G-052)
- Application of pesticides and adjuvants to water (WAT-G-053)
Containment could take the form of screen or other capture mechanisms at the outlet of standing waters (see Preventing downstream spread section below). Where the affected waters are used for recreation, it is vital to encourage good biosecurity for all water users (see our INNS and biosecurity in water section).
Preventing downstream spread
When carrying out any control that will disturb an aquatic INNS, measures must be taken to prevent propagules (plant fragments, animals, eggs etc.) from drifting downstream in any watercourses or drains.
This usually means that some form of screen should be put in place in the watercourse or at the pond or loch outlet to provide sufficient filtration to capture propagules of non-native species. It should be removed once there is no longer a risk of propagules washing downstream. All material captured by the screen should be disposed of appropriately (see Disposal of plant waste; seek further advice where non-native animals are involved).
The screen may need to be in place for several days or weeks after control is completed. Where there is a long-term risk of downstream spread then installation of a permanent screen should be considered, along with plans for ongoing management of the screen and any waste materials arising.
Any plans to place structures into a pond or loch outlet or downstream watercourse should be discussed with the SEPA Permitting Team at an early stage of the design to ensure it will not create an obstruction to flow or cause other issues.
Disposal of plant waste
When developing a management plan, the disposal of any plant waste removed from the waterbody should be included in the plan.
Most non-native aquatic plant species can be successfully composted, but it should be done in a location where any leakage (including tiny plant fragments) cannot get back into a waterbody or any surface water drain.
For domestic scale volumes of aquatic plant waste, adding it to a well-managed compost bin is sufficient, provided it is positioned away from any waterbodies. Once fully composted the plant material is no longer viable so the compost can be used in garden borders etc. as normal.
For large scale infestations which create a large volume of aquatic plant waste, high temperature composting is recommended, where plant material will reach at least 50°C. A Local Authority composting facility may be suitable, with appropriate waste transfer authorisation.
The ‘compost with care’ information provided by the Be Plant Wise campaign provides additional guidance.
Spraying INNS with herbicide
Before considering the use of herbicide, check SEPA guidance:
- Application of pesticides near water (WAT-G-052)
- Application of pesticides and adjuvants to water (WAT-G-053)
If herbicide is the only available option, the only herbicide licensed for use in or near water is glyphosate.
All plant protection products, such as herbicides, are licensed by the Health and Safety Executive. They can provide more information on appropriate use of licensed products.
To ensure you use a product authorised for aquatic use, check the HSE pesticides register. Note that this list is frequently updated so you should always check before using any herbicide.
What to do if you find an INNS
It is illegal to release, plant or allow to spread any non-native species into the wild. Don’t collect it or move it - leave it where it is!
Non-native species can easily be spread and are not always easy to see therefore good biosecurity practice is essential.
If you find NNS where you are working, check your legal obligations (see our INNS in regulated activities section).
If possible, please report your sighting (see our How to report a sighting of INNS page). Your data helps improve our understanding of how INNS are behaving in Scotland and can help inform management plans or other action to contain or control them.
For more information on which agency to contact regarding as INNS as well as what their responsibilities are, read the Habitat Responsibility section on our INNS homepage.