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Invasive non-native species (INNS), or invasive alien species, are those that are introduced, intentionally or unintentionally, outside of their natural geographic range, causing environmental, social and/or economic impacts. In 2010, the impacts of INNS were estimated to cost the UK more than £1.8 billion per year. INNS can drive losses of native species through impacts such as predation, competition, introducing diseases and altering habitats, and the Convention on Biological Diversity (CBD) has identified INNS as one of the biggest drivers of native biodiversity loss worldwide.

As part of the Government’s Environmental Improvement Plan, and under the Bern Convention, and the CBD, the Government has both international and national commitments to tackle INNS. However, the 2019 Environmental Audit Committee’s INNS report concluded that the Government had missed its INNS targets and that the issue was not receiving appropriate priority or funding.

Funding for INNS management in the UK tends to be short lived, and available for individual projects rather than directed towards routine actions that would avoid future costs. Stakeholders have highlighted INNS biosecurity underfunding, with most resources spent on established species as opposed to preventing new INNS arriving and establishing. NGO’s and academics have highlighted potential savings that could be made taking proactive measures to prevent the arrival of INNS before they become a problem.

Key points: 

  • Non-native species (NNS) can be introduced to a new area beyond their natural range by human activity. A minority of these are described as invasive non-native species (INNS) because of their negative impacts on the environment and economy.
  • The impacts of INNS were estimated to cost the UK more than £1.8 billion per year in 2010. INNS drive losses of native species through impacts such as predation, competition, introducing diseases and altering habitats.
  • The UK Government has international and national commitments to tackle INNS.
  • The UK’s 2019 report to the CBD found that despite some action, the impact, and risks from INNS in the UK remains significant.
  • Most stakeholders say that more needs to be done to prevent the introduction and establishment of INNS. More action could avoid future costs.


POSTnotes are based on literature reviews and interviews with a range of stakeholders and are externally peer reviewed. POST would like to thank interviewees and peer reviewers for kindly giving up their time during the preparation of this briefing, including: 


Members of the POST Board*

Steph Bradbeer, Yorkshire Water*

Emily Smith, The Angling Trust

Kate Mathers, Loughborough University*

Alison Dunn, University of Leeds*

Finn Barlow-Duncan, University of Leeds*

Matthew Bond, Ornamental Aquatic Trade Association

Katharina Dehnen-Schmutz, Coventry University*

Ross Cuthbert, Queens University Belfast*

Kate Dey, University of Portsmouth*

Helen Roy, UK Centre for Ecology and Hydrology*

Chris Thomas, University of York*

Lucy Cornwall, GB Non-native species Secretariat*

Niall Moore, GB Non-native species Secretariat*

Olaf Booy, GB Non-native species Secretariat*

Robert Black*

Alisha Anstee, The Woodland Trust*

Gordon Copp, CEFAS*

Hannah Tidbury, CEFAS*

Debbie Murphy, CEFAS*

Peter Barry, CEFAS*

Phil Davison, CEFAS*

Alex Green, Yorkshire Wildlife Trust

Anthony Ricciardi, McGill University*

Ellie Ward, Wildlife and Countryside Link*

Rachel Williams, RSPCA

Ros Clubb, RSPCA*

Ava Waine, Newcastle University*

Zarah Pattison, Newcastle University

Pete Robertson, Newcastle University*

Aileen Mill, Newcastle University

Wayne Dawson, Durham University

Max Wade, Chartered institute of Ecology and Environmental Management

Trevor Renals, Environment Agency

Silviu Petrovan, University of Cambridge

David Aldridge, University of Cambridge*

Kate Hills, South West Water*

Dick Shaw, CABI

Jane Catford, Kings College London*

Jonathan Hall, RSPB

*denotes people and organisations who acted as external reviewers of the briefing. 

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