Many years ago, while working for Plantlife, I spent a lot of time trying to highlight the threats posed by invasive non-native species (INNS) both to wildlife but also to the economy.   To be honest, I made little progress but long after I had gone Plantlife kept arguing for reform and it was great that this year they were able to celebrate some progress when five INNS were banned from sale (for an excellent critique of the UK Govenment's proposals, see Nicola Hutchinson's blog here).

Now, the European Commission has taken a view.   This week it published the long-awaited draft EU legislation on INNS.  As this is likely to generate quite a lot of debate over the coming months, I thought it would be worth delving in to this issue in a bit of detail.  And, the RSPB, of course, has had a long history of involvement INNS for example tackling problems on our own land, advocating action to control ruddy ducks to protect the white-headed duck and eradicating introduced rats to conserve seabird colonies (for example on Lundy or on Henderson island).

It's fair to say that INNS can be a fraught issue mixing economics, ecology and ethics.  I'll try to unpack it a bit for you.

A cursory look at global assessments of the natural world, and the human impact on it, highlights an uncomfortable reality: the action of people moving animals and plants around the world, and letting them escape into areas where they don’t occur naturally, is a major driver of biodiversity loss, ecosystem degradation and economic pressure. Europe is no exception, with at least 1094 INNS causing significant ecological harm, and the economic impact of INNS estimated to be at least €12,000 million per year - almost certainly an underestimate.

There is a rule of thumb that says 1 in 10 species that are introduced become established and only 1 in 10 of these go on to cause problems.  And then there is the often vexed question about what to do when a problem incurs.  The guiding principle is of course that preventing introductions is better (and probably cheaper) than dealing with an established problem, but sometimes, species have become so widespread that it no longer becomes realistic (or desirable) to eradicate.

  More often that not, grey squirrels become the focus of debate.  To some grey squirrels are ‘American tree-rats’ serving no apparent purpose other than to engender feelings of malice towards these animals. To others, they offer a connection to wildlife in parks, gardens and woodlands.  Yet, the ecological reality is that the grey squirrel is one of those many damaging non-native species established and expanding in Europe - impacting woodland habitats and inadvertently transferring a novel and deadly virus to native red squirrels that lack natural resistance. Planned, coordinated action needs to be taken on grey squirrels to protect biodiversity and habitats preferably in and around key red squirrel hotspots. We have supported some of these efforts in parts of the UK.

But, it's worth remembering that this is not because grey squirrel is intrinsically a 'bad species': the INNS issue is one entirely of human making.

At the other extreme, there are those who insist that there is, in fact, no problem in the first place, that action to tackle non-native species issues is purely a form of ‘xenophobia’, an irrational hatred of ‘outsiders’. They argue that we should learn to love these human introductions to our flora and fauna. Introduced species really do include some amazing organisms - who cannot admire the incredible vigour of Buddleia in city waste grounds (and my garden), or the astounding annual growth of a giant hogweed? This ‘let in the invaders’ view, however, misses a fundamental ecological point. Geographical barriers around the world - oceans, mountains, deserts, currents - the essential ‘roughness’ of the planet - prevent the wildlife of different regions from mixing. Evolution proceeds independently in different regions and this, in turn, generates and maintains a high proportion of global biodiversity. Different living forms fulfil similar ecological functions in different continents – tigers as the big jungle cat in Asia, jaguars in America; kangaroos as the large herbivore in Australia, ungulates in Africa, and so on throughout the living world. When people use our modern trade and transport networks to move animals and plants across these barriers and, deliberately or accidentally, release them, we break down the barriers, and thus we inevitably drive down biodiversity.

As an aside, it's worth noting that botanists have come up with an interesting hybrid solution (no pun intended) where species introduced before 1600 (such as many of our arable flowers) are deemed 'archaeophytes' and therefore accepted as part of our cultural heritage, while those introduced later are neophytes.    

Evidence is now showing that INNS problems are worsening. The number of INNS establishing, in Europe and the world, is rapidly increasing, and their impact on biodiversity and ecosystem services is sharply intensifying. The rate of new invasions is expected to increase yet faster as climate change proceeds and world trade – the single biggest source of INNS - continues to expand. Some EU member states have taken significant positive steps to prevent and combat INNS impacts, and this includes the UK countries. There are active GB (and all-Ireland) INNS programmes, strong INNS legislation passed recently by the Scottish Parliament and some excellent public awareness campaigns, like ‘Check Clean Dry’. However, the INNS issue is, by definition, an international problem that no single member state can solve on its own. In the European Union, if one member is insufficiently vigilant, the whole community is put at risk. As I wrote last year (see here), the recent spread in Europe of ‘ash dieback’ disease, and the damage to our woodlands predicted, is a wake-up call to us all about the risks of incautiously moving organisms between countries.

So, the European Commission’s publication of draft legislation is to be warmly welcomed. No one should have any illusions about the scale and difficulty of the task at hand. The European Union is a global hub, physically contiguous with the Earth’s biggest land-masses, and has the promotion of trade, movement and communication between member states, and with the world beyond, as its core political function. It is probably the single most challenging area on the planet for establishing effective mechanisms to tackle the INNS issue.

EU member states and stakeholders must, over the coming months of debate, develop this draft into a genuinely effective instrument. The good new is that there is much in the draft that promises real progress. However, many of the measures will be based upon a key list of species – Species of European Union Concern – which has been, in the draft, strictly limited to a maximum of 50 species, just 3% of the INNS known to be already present in the EU. Moreover, the list would only come up for review 5 years after adoption of the legislation (realistically not before 2020). These restrictions could, unless they are revised, severely hamstring the core measures in the draft. The INNS problem is burgeoning, unpredictable and dynamic – an over-restricted, unresponsive legislative system will not be adequate.

So what are we going to do about it?  

We'll obviously continue to the debate and seek to influence  the final draft being laid before the European Parliament. With a growing problem, this is a matter of real urgency. For now, however, let’s congratulate the European Commission for making a bold start to tackling this issue. The solutions will not be straightforward, and finding that delicate line that keeps our collective response proportionate, yet effective, will challenge everyone. But if we cannot arrive at that effective approach, we surely will fail to halt biodiversity loss by 2020.

But what do you think?  Where do you stand on the non-native species debate?

It would be great to hear your views.

  • Martin,

    Good to hear that the EU behemoth is finally waking up to the future threat of INNS.  However, in the meantime, we need to deal much more effectively with those INNS that are already present in the British Isles, some of whom as you rightly point are already wreaking havoc with native species.

    But where to start and what to do given limited resources?  As a Scotsman, I believe protection of our native wildcat would be a good place.  The Scottish wildcat, our rarest native mammal (and now rarer than the Siberian tiger), is teetering on the verge of extinction after centuries of persecution and hybridisation with domestic cats  The former threat has been addressed, but the latter not.  Why not?  We need to get a grip on the proliferation of free-roaming, non-native, domestic and feral cats and somehow or other foster a better sense of responsibility in cat owners, land managers and the authorities.   The RSPB could give an excellent lead in this by trapping and removing cats from all its reserves ('trap-neuter-return') and particularly where wildcats and other threatened species still survive.  Such action would of course benefit native birds and other small mammals as well.          

    Similarly, bearing down on non-native grey squirrels is essential if we are not to lose the native red squirrel.  Again, a robust eradication/control regime is essential at the boundaries between the bulk of the red and grey squirrel populations.  Good examples of what can be achieved can be seen in Anglesey and in some parts of the north of England, Tayside etc. where the line is being held, albeit with difficulty.  Equally, Aberdeen city and county councils' policies are models for all local authorities to follow.  The RSPB could again give a good lead here by instituting such a policy on its reserves, and joining in partnership with 'Saving Scotland's Red Squirrels' the Red Squirrel Survival Trust  and others.  Once again, this action would benefit native birds.  Further, it should also be a requirement for forest managers and local authorities in their woods and parkland.

    And so on – ring-necked and monk parakeet, muntjac deer, American mink and signal crayfish, Japanese knotweed, Himalayan balsam, rhododendron, Asian hornets and non-native ants etc. etc.  As red kite recommends, we need prioritised (and legally binding or incentivised) action plans for current INNS, let alone mitigation plans for potential future threats.  Access to public funds for agencies, NGOs, arms-length bodies and others should be conditional upon compliance with, and participation in, such action plans.

    Other countries such as the Australia, NZ and the USA take a more robust approach to protecting their native wildlife from INNS – perhaps it is time we followed suit?

  • I think there is no doubt that INNS have to be tackled, especially where they are threatening native species. The grey squirrel that is severely threatening our native red squirrel is a classic example. The shame is that it is the fault of man that INNS are a problem and not the species themselves which, in their native habitats, live in harmony with other species, but one does need to be "hard headed" on this subject.

    Like all good accountants that take on a loss making business it is the biggest loss making lines that that need to be tackled first and which if corrected will show the biggest improvements in the business.

    So it is with INNS, we cannot hope to eradicate every non native species (and indeed may not want to)but we do need to address the INNS causing the most major problems. So some sort of prioritisation list will be needed.

    I am sure there will be arguments regarding these prioritisations and methods but the biggest disaster would be to get too bogged down on these issues and so effectively do nothing. Time is not on our side in addressing INNS.