Non-native, invasive plant species such as Japanese Knotweed can often be found along stream banks, roadsides, railway embankments and brownfield sites where they can pose a significant constraint and extra cost to development. Therefore, it is important that such species are identified and an effective plan for their management implemented early in the development process.
Non-native plant species are those which have been introduced either deliberately or unintentionally to an area outside their natural range. Some are highly invasive and in some situations pose a significant threat to our native biodiversity. Often there is no natural form of control such as herbivorous animals, insects or pathogens, further enabling their rapid spread and colonisation of new areas.
Legislation
In the UK it is an offence under the Wildlife and Countryside Act 1981 (as amended) / Wildlife (Northern Ireland) Order 1985 (as amended) to “plant or otherwise cause to grow in the wild” any plant species listed in Schedule 9 of the Act/Order.
Any contaminated soil and plant material from two of the most noxious invasive species, Japanese Knotweed and Giant Hogweed, is classified as ‘controlled waste’ under the Environmental Protection Act 1990 (England, Wales & Scotland) and as such must be disposed of safely at a licensed landfill site.
Penalties for anyone convicted of an offence under the Wildlife and Countryside Act 1981 (as amended) include heavy fines and/or imprisonment, whilst an infringement under the Environmental Protection Act 1990 can result in an unlimited fine and liabilities for the costs of spread of those species covered by this legislation onto other areas.
Until recently there were only two terrestrial species and no freshwater plants listed in Schedule 9 in England and Wales (thirteen species were added to Schedule 9 in Scotland in 2005). However, following an amendment to the Wildlife and Countryside Act 1981 which came into force in April 2010 there are now about 40 terrestrial and freshwater plant species listed in Schedule 9 (England & Wales).
Terrestrial species
Many of the terrestrial species on Schedule 9 were originally introduced as ornamental plants but have since become naturalised in many places. These include Japanese Knotweed, Giant Hogweed and Himalayan Balsam, the latter of which was only added to Schedule 9 in April 2010. Rhododendron, now also listed in Schedule 9, was commonly planted as game cover in woodlands, and together with other invasive species, such as Japanese Rose and Cotoneasters, has been widely used in amenity plantings.
Aquatic species
Among those species added to Schedule 9 were a number of highly invasive aquatic plants such as Water Fern, Parrot’s-feather, Floating Pennywort, Water Primrose, Australian Swamp Stonecrop or New Zealand Pygmyweed and Waterweeds. These can often form very dense monocultures, shading out and excluding native plants and creating unfavourable conditions for many aquatic animals. In some situations their growth can hinder recreational activities such as boating and angling and even pose a flood risk by blocking channels, weirs and other structures. Without help from an expert most are difficult to identify from similar looking native species.
Factors causing spread
It is not an offence to have Schedule 9 plant species growing on your land and there is no legal requirement to control them. However, activities associated with development and other works can cause their spread and potentially result in an offence being committed. These include fragments and propagules (e.g. seeds) being transferred on boots, cars and machinery, movement of contaminated soil and/or material from affected sites, movement of contaminated machinery and equipment between aquatic systems, inappropriate disposal of cut material and activities that disturb the vegetation and underlying soil.
Management
Early involvement by suitably qualified and experienced ADAS Consultants can avoid excessive cost, potential prosecution, liabilities and harm to the environment.
ADAS can identify the presence of non-native invasive plant species on development and work sites and prepare, implement and oversee management plans for their control. In many cases methodologies can be devised to allow the presence of these species to be worked around or for their control to be achieved using non-chemical methods.
Where necessary, site-specific advice on their safe control and eradication using chemicals can be provided and implemented by ADAS Consultants holding NPTC Pesticide Certificates of Competence and BASIS Certificates (Amenity).
ADAS has prepared method statements and briefing material for the control of invasive species in a variety of situations and has undertaken control of Japanese Knotweed for a range of clients. We can also provide tailored advice on the most appropriate landscape and amenity planting for your scheme to include only benign species.
For further information, or if you have any other ecology query please contact William Little by e-mail william.little@adas.co.uk or telephone on 01823 289245.