Wales Resilient Ecological Network (WaREN)

WaREN Logo


Invasive non-native species

Wales Resilient Ecological Network

Help us tackle invasive species across Wales

What are invasive non-native species?

Invasive non-native species have been introduced by humans, intentionally or unintentionally, beyond their natural range. Their spread threatens native biological diversity and can cause damage to the environment, the economy, our health and the way we live.

Invasive non-native species (INNS) are also referred to as Invasive Alien Species (IAS). Here we refer to them as invasive species.

Find examples of invasive species!  

Wales Resilient Ecological Network

The Wales Resilient Ecological Network (WaREN) will establish a framework for tackling invasive species across Wales. We will develop linkages between stakeholders who are taking action on invasive species, with existing projects such as the Our River Wellbeing project on the river Dee and Local Action Groups in Wales. Local Action Groups focus on reducing the risks and impacts of invasive species in their local area, for example through direct management. WaREN will also increase public engagement to raise awareness of invasive species through effective science communication and sharing best practice.

WaREN is a partnership project being delivered by North Wales Wildlife Trust, find a list of our project partners below.

WaREN Logo


Meet the WaREN team

Tomos Jones - Project Manager

Tomos is responsible for ensuring that this ambitious project is delivered and an invasive species strategy is developed for Wales. Tomos’ particular interest is in identifying ornamental plants that might escape gardens and become invasive in the wild. That is the focus of his PhD at the University of Reading. A native of Anglesey, he is passionate about engaging the public in environmental issues in Wales and in science communication. Tomos sits on the Media and Communication Working Group for INVASIVESNET and the GB NNSS, and the Public Engagement Working Group for the British Ecological Society.


Telephone: 07726358228

Tomos Jones (WaREN Project Manager)

Tomos Jones © University of Reading

Project Officer (South)

Please direct enquiries to the North Wales Project Officer (below).

Gareth Holland-Jones - Project Officer (North)

Gareth is the WaREN Project Officer for North and mid-Wales based at North Wales Wildlife Trust. He is engaging with Local Action Groups and stakeholders dealing with invasive species. Gareth is passionate about bees, particularly bumblebees. He has studied how Agricultural Land Classifications affect bumblebees across the Vale of Clwyd (North Wales). He investigated how both bees and bumblebees are attracted to the flowers of invasive plant species and the potential effects on native floral species.


Telephone: 07508740561

Gareth Holland-Jones

Why is this important?

Invasive species are one of the main threats to biodiversity globally. They have negative impacts on our environment. For example:

  • Competition for resources such as light and water
  • Predation on native species
  • Carrying new diseases
  • Hybridisation - where invasive species breed with closely related native species

Invasive species can also impact on human health and the economy. For example, they were estimated to cost Wales at least £125 million in 2010, a cost which is likely to be increasing. There is information here on current Alert Species and how to report them.

How can you help?

Local Action Group Locations in Wales 2022

Local Action Group (LAG) Locations (2022), main rivers sourced from NRW. 

If you are involved in a Local Action Group (LAG) or want to volunteer to tackle invasive species anywhere in Wales, please get in touch with one of the Project Officers. We are collating a list of Local Action Groups to improve collaboration and to gather experiences across Wales. You can also help by identifying and recording invasive species - see below!

Volunteers 'balsam bouncing'

Volunteers 'balsam bouncing' © Lesley James

Help tackle invasive species

Local Action Groups
American signal crayfish

Invasive non-native species American signal crayfish ©Trevor Renals

Want to identify invasive species?

Download our pocket ID guide
American skunk cabbage stock image

Report sightings of invasive species

Become a citizen scientist

Supporting volunteer action in Wales

Have you ever thought about tackling invasive species in Wales? 

Well look no further, why not try volunteering with your local Wildlife Trust, or check out our Invasive Species Toolkit below to find out more about Local Action Groups and how you can help tackle invasive species in Wales! 

WaREN Invasive Species Toolkit

WaREN invasive species toolkit front cover


The WaREN Invasive Species Toolkit aims to support volunteer action and help you tackle invasive species in Wales. This toolkit is a ‘one-stop-shop’ and should include all of the resources you need, including information on: invasive species in Wales, best practice management, project planning, biosecurity and awareness raising.

There are lots of ways you can help tackle the threats posed by invasive species. This toolkit breaks down this information to help you protect our environment. You can download a pdf of the toolkit or view a summary of each section below.

Download our invasives species toolkit 

ID and Reporting Invasive Species

American signal crayfish (Pacifastacus leniusculus)

American signal crayfish (Pacifastacus leniusculus)

Welsh Priority Species 

The Invasive Priority Species for Action in Wales list can be split into three action categories:

  • Prevention 
  • Management 
  • Long-term Management 

They are chosen based on horizon scanning, risk analysis, and consultation. Species are included on the list as they are a GB priority species, an Invasive Alien Species of Union Concern, or are a species considered a national priority for Wales. 

Here you can find ID guides and information on all current (2018) Invasive Priority Species for Action in Wales. 

Species Alerts 

Species Alerts are a key part of the early warning and rapid response to a new invasion. They are often used to raise awareness of particular species, inform the public on the action that may be required, and encourage reporting of species sightings. Check out the current Alert Species and where to report sightings on the GB NNSS website.


Recording sightings of invasive species is essential in allowing us to coordinate management and strategically tackle invasive species. In Wales there are four Local Environmental Record Centres (LERCs) where you can report invasive species sightings. You can also use a variety of apps and online tools, such as , such as iRecord or the LERC Wales app.  

A partnership project is currently developing a tool called INNS Mapper for recording invasive species across GB. Importantly this will enable you to record your management efforts. Find out more here.

Download the full Toolkit here! 


Balsam bashing

© Jess Minett 

Before managing an invasive species, it's really important to think about the follow three points:

  • Know your species - what are the characteristics, such as life cycle and dispersal methods of your chosen invasive specices?
  • Know your site - what are the characteristics of the habitat or environment – resource availability (e.g., light, water, etc.), level of disturbance, and sources of spread into the area?
  • Know your neighbour - who lives near your site? Who might be interested in what you’re doing? What stakeholders in your community could support your work?

Your management actions can all be affected and altered by the species, site, and your neighbours.

Good practice management 

Here we have linked to good practice management guides for all of the Invasive Priority Species for Action in Wales. You can find good practice management information on species not on the Invasive Priority Species for Action in Wales list from organisations such as: GB NNSS, CABI and Invasive Species Northern Ireland


You may require a licence to carry out certain activities and manage some invasive species. Find out more about what licences may be required and how to obtain them in Management section of the toolkit.  

Download our Invasive Species Toolkit 

Project planning

Balsam bashing

© Wye Valley AONB

Local Action Groups 

Local Action Groups (LAGs) are volunteer-run community groups set up to tackle local issues, such as, invasive species. LAGs play a crucial role, often carrying out work on the ground and getting directly involved in invasive species management in their area. Without LAGs a collective effort to tackle invasive species would not be possible. You can:

Setting up a LAG

Begin by considering your group’s purpose (the reason you want to set up a LAG), aims (broad targets that you want to achieve) and objectives (how your LAG will achieve its aims). Make your objectives:

Make sure your objectives are SMART

© WaREN Invasive Species Toolkit 2023

To ensure your objectives are achievable, we recommend you follow the SMART methodology.

Objectives can be further split into tasks; these tasks can be used as milestones to monitor progress.

Next you’ll need a name! Have you also thought about what members your group requires? At first you may not need many members, but as your group grows you may wish to consider having a member responsible for Health and Safety officer or database management. This allows people with different interests to join in.

Now it’s time to promote your group, find volunteers and keep them engaged! You can do this by: 

    Word cloud to represent how to keep volunteers engaged

    © WaREN-NWWT

    • Creating a Facebook group 
    • Post flyers/posters around community
    • Link to other environmental issues
    • Don’t forget to thank people for their work!

    You can find more information and download helpful templates, e.g. strategic action plan, governing documents and risk assessments from the project planning section of our toolkit. Or contact one of our project officers for advice.

    Now it's time to get tackling invasive species!

    volunteers in Surrey

    Volunteers in Surrey - Jon Hawkins - Surrey Hills Photography

    Monitoring and managing invasive species 

    To effectively and collectively manage invasive species in Wales we need to:

    1. Know where invasive species are, and
    2. Know whether they are being or have have been tackled.


    Surveying is straight forward and used to determine what species are present. Surveys are often the first step towards invasive species control!  Start by trying to identify the upper-most source of the invasive species distribution. Control actions can then be implemented working downstream. 


    You must choose the most appropriate management method to successfully and effectively control invasive species. Management methods can typically be split into four categories:

    • Mechanical
    • Chemical 
    • Biological/natural 
    • Environmental

    Check out or invasive species best practice management section of the Toolkit for species specific advice! 

    Don't forget to report your survey data, invasive species sightings and management actions to INNS Mapper

    WaREN Strimmer Training

    © Andy Morris 


    Check out the project planning section of the Toolkit for more information on what funding opportunities are available or get in touch with one of our project officers for more advice. 

    Download our Invasive Species Toolkit 


    Biosecurity sign

    © NWWT

    What is biosecurity?

    Biosecurity describes any steps taken to reduce the introduction and spread of invasive species. We can all easily and accidently introduce and transport invasive species through leisure activities e.g. gardening, water sports and hiking. But by implementing simple biosecurity practices such as cleaning equipment and clothing, e.g. cleaning footwear after a walk, we can limit their spread and protect our wildlife! You can find out more about biosecurity here or check out our biosecurity best practices below. 

    Demonstration of how seeds can be easily transported by humans e.g. on footwear

    © WaREN - NWWT

    Biosecurity kit 

    Biosecurity is simple! Be sure to clean your kit between sites and make sure to pay attention to any areas that are damp or hard to access.

    You can easily put together your own personal biosecurity kit, all you need is:

    Biosecurity kit - hard brush and hoofpick

    © WaREN - NWWT

    • Plastic storage box/bag
    • Hard brush
    • Hoof pick or boot tread scraper
    • Supply of clean water

    Biosecurity Risk Assessments 

    Before you run any events or activities, it is vital to consider biosecurity and make sure you are not accidently spreading invasive species. You need to assess your activity and sites risk level in order to implement suitable biosecurity best practise measures. To find out more about how to assess you risk level download the biosecurity section of the Toolkit.

    Biosecurity Best Practice 

    We have developed biosecurity best practice advice for low, medium and high-risk activities/sites.

    At low risk sites you need to:

    • Wear footwear and clothing that can be easily cleaned
    • Clean your footwear and ensure it is free of any soil or organic debris after use
    • Only take the required equipment onto site
    • Ensure you have your personal biosecurity kit
    • Only access areas of the site that are required for the activity

    To find out more about medium and high-risk biosecurity best practice procedures download the biosecurity section of the Toolkit.

    Examples of different biosecurity stations

    National campaigns 

    Check out these national campaigns to find out more about biosecurity.

    Check Clean Dry

    Check Clean Dry provides simple advice for recreational water users. However, this advice should be applied to all aspects of biosecurity regardless of whether you have been in contact with the water. 

    Be Plant Wise Logo

    Be Plant Wise ©GBNNSS

    Be Plant Wise was set up to raises awareness of the impacts of invasive plants and encourages people to properly disposal of plant material.

    Keep it clean logo

    © Forestry Commission 

    Keep it clean provides advice for activities and focuses on keeping our green spaces free of plant diseases 

    Find out more about biosecurity visiting our biosecurity webpage, or by checking out the biosecurity section of our Toolkit. 

    Download our Invasive Species Toolkit 

    Raising awareness of invasive species

    People engaging with the Ecosystem Invaders campaign stand at the Eisteddfod, participating in an eDNA activity

    © Tomos Jones - NWWT

    The impacts of invasive species will continue to grow unless they are tackled through a sustainable and collaborative approach. That’s why we need your support! Please help us raise awareness of invasive species and their impacts in Wales to improve public understanding.

    Campaigning and key messages 

    There are a few national campaigns in Wales and GB that aim to raise awareness of invasive species and promote biosecurity. For example, Invasive Species Week, which is held annually in Spring.

    Ymledwyr Ecosystem Invaders 

    Ecosystem Invaders is a campaign run in Wales by WaREN. The campaign aimed to raise awareness of invasive species and their impacts in Wales to improve public understanding. Find out more about Ecosystem Invaders here, you can also access some of our campaign materials in the Toolkit!

    Download our Invasive Species Toolkit 

    WaREN Newsletters

    To improve dialogue between WaREN members, we are formalising our contact with regular newsletters. We hope this will function as a platform to share successes, best practise and also challenges! If you want include content in our newsletter please contact us.

    Our partners

    WaREN is a partnership project being delivered by North Wales Wildlife Trust and Wildlife Trust of South and West Wales. Our Project Board partners are listed below.

    Welsh Government - SMS logo