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Invasive non-native species

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An invasive species is defined as an organism (plant, animal, fungus, or bacterium) that is not native and has negative effects on our economy, environment, or health.

There are many non-native species in our environment. They may have arrived through natural processes or through deliberate or unintentional release by humans. Most of these species cause no problems but some do. We call these Invasive Non-Native Species (INNS).

Why are INNS a threat

INNS are a substantial environmental and economic threat as they can:

  • prey on native species
  • out-compete native species for food and shelter
  • spread disease
  • interfere with the genetic integrity (DNA) of native species.

Every year, it costs around £125 million to tackle this in Wales.

The combination of increased global movement of people and goods along with climate change will increase the threat of INNS over the next few decades.

Although the impact of new invasive non-native species entering our environment is uncertain, we are working to ensure a biologically diverse and resilient environment, able to adapt to change and pressures.


We are working with partners including Natural Resources Wales (external link), Welsh Local Government Association, voluntary groups and the GB Non-Native Species Secretariat to determine priority actions to control and eradicate INNS.  

The Wales Biodiversity Partnership (external link) INNS Working Group provides advice and support to us and our partners. 

The Great Britain Invasive Non-native Species Strategy (external link) provides a framework on how to minimise the risks posed by invasive non-native species. The strategy sets out key aims and actions for addressing the threats posed by invasive non-native species. It aims to:

  • get people working together better including government, stakeholders, land managers and the general public
  • improve co-ordination and co-operation on issues at a European and international level.

This strategy covers 2015 to 2020.  It replaces the first strategy published in 2008.


Terrestrial and freshwater INNS

Plant Health and Environment Protection Branch
Welsh Government
Rhodfa Padarn
Llanbadarn Fawr
SY23 3UR


Marine INNS


Or telephone:

  • Aberystwyth (General Enquiries, Policy and Quota): 0300 062 2184
  • Swansea (General Enquiries): 0300 025 2454.

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