Invasive non-native species (plants and animals) threaten the survival of native wildlife and our natural ecosystems, cost the economy nearly £2 billion a year, and can even harm our health and interfere with activities we enjoy.
Here at the Malvern Hills Trust, we are working to tackle the spread of invasive non-native species (INNS) that could threaten our native species and habitats. As part of our land management plan, which is reviewed every 5 years, we survey and identify any target species which should be managed and monitored.
Throughout this week, we will be sharing some examples of INNS which we are currently managing on our land, and sharing our best practice methods and key information about these species for wider awareness. For further information, please refer to the great resources at https://www.nonnativespecies.org/NNSS
A well-known example of an INNS is Japanese Knotweed, (Fallopia japonica) a plant which has stems typically about 2m tall and an extensive system of rhizomes. It occurs on disturbed habitats in urban areas, by water courses, canals and on waste ground. It is legally classed as a controlled plant under the Wildlife and Countryside Act 1981 section 114 (2). It is illegal to allow this plant to cross the boundary from your land to your neighbours, or to allow this plant to spread into the wild. Fly-tipping knotweed plant material is a criminal offence.
It was introduced to gardens as an ornamental 'architectural' plant, and it is still widely grown in larger gardens and parks. Plants and fragments of root, if discarded, can become established in the wild, particularly along riverbanks where root pieces are easily dispersed.
The presence of this plant can alter habitat structure and dominate native plant communities, which support greater biodiversity. As well as hindering conservation efforts & the viability for angling, the presence of these plant species pose great management and access concerns if left uncontrolled.
The high economic impact is due to legislation that makes its eradication a legal requirement and the cost of its disposal expensive. Eradicating it from construction sites can cost well over £1,000 per square metre and, as a controlled waste, it can be expensive to dispose of the 'contaminated' topsoil.
When managing INNS it is important to have a management plan in place which outlines the strategy and involves the relevant people. Read more about this here via the Environment Agency's Japanese Knotweed Code of Practice (PDF)
A competent and qualified person carries out herbicide treatment in a localised way at certain times of year to target growth effectively. Rhizomes (beneath soil) can remain dormant for a considerable period after regrowth has apparently stopped, and checks must be carried out to see if rhizomes are still living before disturbing the site. Unconfirmed observations suggest rhizome can stay alive for more than 20 years.
Photo credit; GBNNSS
