Invasive Non-Native Species: why we are concerned, what we are doing and how you can help

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Martin Harper's blog

I’ve been the RSPB’s Conservation Director since May 2011. As I settle into the job, I’ll be blogging on all the big conservation topics and providing an inside view of our conservation projects. I hope you enjoy reading it and feel inspired to join in t

Invasive Non-Native Species: why we are concerned, what we are doing and how you can help

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The annual Invasive Species Week is launched today.  

Why we are concerned

Invasive non-native species are known as one of the four horsemen of the ecological apocalypse (alongside habitat destruction, overexploitation and pollution - the worst example being greenhouse gases resulting in climate change) which are responsible for the major drivers of biodiversity loss across the world  This week the RSPB is joining organisations to raise awareness, understanding and vigilance of this key issue.

I’ve written before about the impacts of invasive species before (here, here, here, here).  Whether intentionally (e.g. plants for horticulture, exotic pets) or accidentally (e.g. stowaways with transported goods) humans are moving species around the world and allowing them to escape into new areas at unprecedented rates. This movement of species breaks down the natural barriers – the mountain ranges, oceans, and deserts – which prevent wildlife in different regions from mixing. These natural barriers have allowed evolution to proceed independently in different parts of the world, and have generated and maintained the vast range of species that exist on our planet. When we introduce species into an area where they are not naturally found, some of them will seriously threaten the native wildlife, in a wide range of different ways. This can be through increased predation or competition for food and habitats, the introduction of novel diseases to which native species have no immunity, or even through hybridisation. Non-native species have negatively affected all major taxonomic groups, with birds being a notable case – around half of global bird extinctions since 1500 have been caused or assisted by invasive species.

The intensity of invasive non-native species problems is intensifying and expected to worsen over time - particularly as climate change makes it easier for species to establish in new areas, and as increasing global trade provides a major pathway for transfer of species across the globe. It’s more important now than ever, given the political imperatives for developing international trade, that everyone – government, businesses, conservation organisations, and individuals – is aware of steps they can take to stop the spread.  Prevention is more effective, more feasible, and far more cost effective, than cure. We call behaviour that aims to prevent the spread of invasive species “biosecurity” - and everyone can do their bit.

What we are doing

The RSPB has a long history of engagement with invasive species matters, contributing to the development of government and organisational policies intended to tackle the issue, and promoting best practice on our own nature reserves and across all of our work.

Montage of seabird recovery projects (clockwise front top left: St Agnes and Gugh, Shiants, Henderson Island, mice eating albatross chicks on Gough)

Invasive species impacts are particularly severe on islands. As RSPB reserves include some of the most important and well-known seabird colonies in the UK, we are working to position ourselves as one of the international leaders in seabird island management and restoration. By protecting these sites against future invasions we will maintain safe breeding grounds for native species, maximising their breeding productivity and their resilience against other challenges, in particular climate change.

As a general rule, once a non-native species has established somewhere new it can be difficult and costly to remove it. However sometimes there is a clear conservation imperative to do so. Such work can be dramatically successful, such as on offshore islands where introduced mammals such as rats and house mice prey on seabird eggs, chicks and adult birds. Having evolved in isolation from mammal predators, often these seabirds have few defences against them. The RSPB has developed best practice guidance for advancing this island restoration work, and worked with partners to undertake invasive species eradication projects on seabird islands including the ScilliesLundy, and the Shiants. Plans for major new projects on Gough Island and the Turks and Caicos Islands, UK Overseas Territories in the Atlantic, are well under way, with the latter project launching next week.

Each of these projects are major undertakings, and the job is not complete once the initial eradication has taken place: an invasive mammal eradication on an island cannot officially be declared a success until two years after the last sign of the target species is detected. For example, following an intensive programme of baiting and poisoning to remove brown rats from St Agnes and Gugh in the Isles of Scilly over the winter of 2013-14, last year the islands were officially declared rat-free. Rats are thought to have first colonised the islands in the 18th century following several shipwrecks. As a result the breeding seabird population declined by nearly a quarter in 25 years, including declines in globally important populations of European storm-petrel and Manx shearwater. This was the largest rodent eradication project on inhabited islands to date, and saw the RSPB working with four project partners, and a large number of island residents who volunteered to help. The success of the project has been reflected in the news that both Manx shearwater and European storm-petrel have since been recorded successfully fledging chicks from the islands.

In addition to the practical aspect of invasive species action, RSPB works to develop and advocate policy approaches to tackling invasive species issues at national, EU, and international levels.  This is why we support  the IUCN's Honolulu Challenge on Invasive Non Native Species.  We were recently active in the development of a new EU regulation on invasive species which entered into force in 2015. Before this, action to combat invasive species had been inconsistent and patchy across member states, whereas this new regulation aims to being everyone up to the same minimum standard. As a result, 37 invasive species are now banned from sale, breeding, transport, captivity or release across the EU, and the European Commission has committed to updating this list regularly.  In the context of the UK’s exit from the European Union, it is vital that future UK invasive species legislation continues to apply at the very least equivalent, and ideally stricter, control of species movements and release.

Governments in the UK Countries have produced a strategy to guide and coordinate approaches to invasive non-native species across Great Britain. In England and Wales it is currently illegal to release (or allow to escape) any animal not normally resident in, or a regular visitor to, GB, or any plant or animal listed on Schedule 9 of the Wildlife & Countryside Act. Five invasive non-native aquatic plant species are also completely banned from sale. In Scotland it is illegal to release (or allow to escape) any animal or plant in any place that is outside of its native range, which could include movement of native species to parts of the country where they do not naturally occur.

How you can help

From March 27 – April 2 organisations across Britain are coming together to support Invasive Species Week - and you can take part too. From disposing of garden waste responsibly, recording and reporting invasive non-native species, to volunteering with an invasive species local action group, there are plenty of ways of ensuring that you do your bit to help tackle this key wildlife issue. You can find more information about events being held this week, and ways in which individuals can take part, on the GB Non-native Species Secretariat website:, or by following  Invasive Species Week on social media – just keep an eye on @CheckCleanDryGB and #InvasivesWeek.

  • Martin. Some tough conservation science out there that requires a little more nuanced framing for the social science aspect! Some great new research here

    Moral of the story: be more frank and then society can better handle the tradeoffs of having to cull to save.


  • Well done RSPB, leading the way as usual.