Non-native species

What is the issue?

Non-native species are plants or animals which adversely affect the habitats they invade economically, environmentally and/or ecologically. They can cause significant problems to our native animals and plants and annually cost millions of pounds to manage. Hundreds of freshwater species have been moved outside their native ranges, by deliberate introductions, within ballast waters of international shipping, canals, and releases from aquaria, gardens and bait buckets. This has resulted in many waterbodies now containing several non-native species each.

Introduced fish and invertebrate species are a great threat to our native populations. They predate, outcompete and displace native species from their preferred habitats. They can also spread parasites and introduce novel diseases, to which native populations have no natural immunity. Non native species can cause far-reaching ecological imbalances within watercourses, therefore controlling their spread is vital if we are to protect native species and their habitats.

The top ten ‘high impact’ alien species, according to the Water Framework Directive Risk Assessment, affecting water bodies in England and Wales have been identified as;

Australian swamp stonecrop (Crassula helmsii)
Floating pennywort (Hydrocotyle ranunculoides)
Water Fern (Azolla filiculoides)
Parrot’s feather (Myriophyllum aquaticum)
Common cord-grass (Spartina anglica)
Japanese weed (Sarassum muticum)
North American signal crayfish (Pacifastacus leniusculus)
Zebra mussel (Dreissena polymorpha)
Chinese mitten crab (Eriocheir sinensis)
Slipper limpet (Crepidula fornicata)

What S&TCUK has achieved so far

  • S&TCUK has worked closely with the Environment Agency and NGO colleagues to publicise the arrival of the killer shrimp (Dikerogammarus villosus), which was found for the first time in the UK in Grafham Water, in September 2010 (click to current information of killer shrimp found on website). Communications via our website, e-news, GameFisher etc, have raised awareness of the potential impacts of the killer shrimp and inform water-users how to prevent further spread of the shrimp.

What still needs to be done?

  • Currently, under the Water Framework Directive, alien species cannot, on their own, be a reason for a waterbody to fail ‘good ecological status’. S&TCUK views this as ridiculous, as the presence of dominant alien species may indicate a stressed ecosystem. We will continue to campaign for this to be changed.
  • We believe future focus should be on prevention, rather than cure. Education of the implications and damage to native ecosystems caused by non-native species must be translated to the general public to help prevent accidental introductions.


Other information


Powers to make species control orders to tackle invasive non-native species were announced in Wednesday’s Queens Speech and form part of the Infrastructure Bill that has been published today. It is proposed that these powers may be exercised by the Secretary of State, Welsh Ministers, Natural England, Environment Agency, the Forestry Commissioners and the Natural Resources Body for Wales. The Scottish Government took similar powers in 2011.

Invasive non-native species pose serious threats to biodiversity, the water environment, economic prosperity, human health and welfare. The economic impact in the UK alone has recently been estimated as a minimum of £1.8 billion per annum which includes £1 billion to the agriculture and horticulture sectors and over £200m to the construction, development and infrastructure sectors. Early eradication is critical to tackling invasive non-native species.

At present, Defra, Welsh Government and our network bodies have to rely on reaching voluntary agreements with landowners to undertake work or to gain access to their land to eradicate or control invasive non-native species found there. Whilst most landowners are willing to enter into voluntary agreements, experience has shown that a small minority (around 5%) are not. In contrast to powers available under animal and plant health legislation to combat disease and pests, we have no powers to compel landowners to act, or powers of entry for surveillance or to carry out work ourselves in respect of invasive non-native species. The lack of these powers has already impacted on programmes to eradicate ruddy duck, American bullfrog and monk parakeets.

A key component of the EU regulation on invasive non-native species that will come into force on 1 January 2015 is that Member States should take measures to eradicate newly arrived species of European Union concern within three months of their detection. The lack of these powers places us in a vulnerable position in terms of biosecurity and our ability to meet our future obligations under the EU regulation, and was highlighted in the Environmental Audit Committee’s report published in April following its inquiry into invasive non-native species.

Consequently, Ministers have agreed that we should have powers to compel landowners to take action on invasive non-native species or permit others to enter the land and carry out those operations. The intention is that these powers should be used in exceptional circumstances where a voluntary approach cannot be agreed and there is a clear and significant threat from inaction. We intend that they will be used primarily to support national eradication programmes; the routine use of these powers for widespread species, such as Japanese knotweed, would be considered disproportionate.

The costs of the operations will fall to government to meet, unless the landowner is responsible for the release of the species. The powers will enable action to be taken at an early stage and hence are designed to reduce the spiralling costs to the economy associated with on-going control of these species as well as protecting our native biodiversity. Based on the evidence of recent eradication programmes, we estimate that only around one species control order will be required each year. A ministerial code of guidance will provide more information on how and when these powers should be used. The powers will be supported by new powers of entry and criminal offences.

A PDF of the Infrastructure Bill is available from this link.