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Changing Our Attitudes Towards Invasive “Alien” Species

Above, zebra mussels on a native mussel; it has been estimated that invasive zebra mussels have cost Canada and the United States over 5 billion USD. Image courtesy Wikimedia Commons.


A guest post from Susanna Lidström of KTH Royal Institute of Technology in Stockholm and Simon West of Stockholm University


We often hear that complex environmental problems need to be communicated better – that scientists need to tell ‘arresting stories’ before governments and the public will act. But arresting stories can also be profoundly damaging – they are often arresting because they tie-in with taken-for-granted fears, prejudices, and premature judgments. To address and manage environmental change, we need to pay close attention not only to how we act, but also to how we think about nature, and the stories we use to understand it.


Invasive alien species are widely perceived to be a serious threat to global biodiversity. Local “vigilante” volunteer groups enthusiastically take matters into their own hands, ripping up hated invaders such as Japanese Knotweed and smashing cane toads with baseball bats . The media frequently broadcasts eye-catching headlines about ‘alien invaders’ that are ‘coming to get us.’ Why, when attempts to address so many other environmental threats are making little headway, does everyone seem to agree about – and be willing to act against – invasive alien species?


Introduced to Australia in 1935 as a means to combat pestilent beetles as an alternative to rampant pesticide use, the cane toad adapted rapidly to its new home wreaking havoc and devastation in its wake.
Introduced to Australia in 1935 as a means to combat pestilent beetles as an alternative to rampant pesticide use, the cane toad adapted rapidly to its new home wreaking havoc and devastation in its wake.


In a recent research article we (an international team of environmental management and humanities scholars) suggest that at least part of the answer lies in the term ‘invasive aliens.’ The way the question is phrased makes few answers possible. Who would not choose to fight against an invading alien? But far from being a ‘success story,’ the notion of invasive alien species fuels dangerous ideas about the natural world, and is in fact symbolic of our failure to respond appropriately and thoughtfully to complex environmental change.


Why? The concept of invasive alien species steer our thoughts towards countless science fiction films about space invaders – where characters are easily identified in terms of “good versus evil”, “native versus foreign”, “belonging and not-belonging”. The concept also builds on out-dated, idealised views of the natural world, evoking images of harmonious and balanced native ecosystems that are suddenly interrupted and threatened by ‘un-natural’ intruders – scenarios far from the complex and interconnected workings of actual ecosystems.


Removal of inasive species can be costly and labor-intensive. Photo courtesy US Fish and Wildlife.
Removal of invasive species can be costly and labor-intensive. Photo courtesy US Fish and Wildlife Service.


Contemporary science tells us that ecosystems are not characterised by balance or harmony, but rather by change and randomness There is no objective criterion that makes a species ‘good’ or ‘evil,’ ‘alien’ or ‘native.’ Describing a species as one or the other requires drawing arbitrary boundaries in space and time. But biodiversity does not recognise national borders. In the USA, South Africa, Australia and other colonised territories, the desired ‘natural’ state tends to be equated with the time of discovery by Europeans. But these ‘pristine’ landscapes were often intensively managed by indigenous peoples over thousands of years. There is no clear-cut way to separate ‘natural’ from ‘un-natural’ ecosystems, even if human impact is taken as the sole indicator. Many cherished ‘natural’ ecosystems have been shaped by human activities for centuries or more. Neither is there conclusive evidence showing that introduced species routinely impact existing ecosystems in a negative way. In fact, a recent study suggests that where new species thrive, so do natives.


Nevertheless these ideas are extremely powerful. The binary thought that native = beneficial and foreign = harmful produces a story where the desire to eradicate invasive species appears self-explanatory and unquestionable, as well as achievable. It forms a story that, as geographer Charles Warren notes, “. . . .make[s] intuitive sense in our heads.” The ecologist Brendon Larson points out that the concept is an “exemplary performative metaphor,” supporting clear responses that are automatically centred on resistance and eradication. It makes us feel empowered and in control: the sense that we are ‘doing something.’ But this is a fallacy. In South Africa, after twenty years of alien eradication through the flagship Working for Water programme, there are likely more alien species today than when the attempt to eradicate them began. And that is not necessarily a bad thing.


The German Wasp is just one of many invasive species in South Africa that are competing with endemic species.


The story about invasive alien species makes sense to us because it is based on persistent, simplistic ways of framing complex processes of change – whether in ecosystems or in human societies. The way the alien species metaphor describes ecosystem change in terms of static, inherent identities corresponds to how human migration is often discussed. Indeed, research suggests that the invasive alien concept is especially widespread in South Africa because it plays into a post-apartheid desire to forge a sense of national identity – a desire that has produced occasional waves of xenophobic violence against migrants from other southern African states. In Europe, calls for stronger border controls and heightened security employ similar terms whether referring to fears of terrorists, refugees from the Middle East, or ‘invasive’ plants or animals.


We are not arguing that the phrase invasive alien species is an inherently racist concept – but the elements that make the concept effective emerge from the same impulse to deal with complexity through xenophobia: bounding the world in strict, categorical identities, and portraying the relationship between people, species and places in essentialist terms. Some invasion biologists may argue that this is just semantics, and ask whether unique biodiversity should be allowed to be destroyed in favour of ‘alien’ monocultures. That would be beside the point. The point is that the concept of invasive alien species simply does not help us understand how nature works, but instead promotes aggressive ways of relating to our environment, and siphons resources that might be better spent elsewhere.


We make sense of the world through stories. The story of invasive alien species is powerful because it plays to pre-existing cultural fears, persistent but out-dated ideas about nature, and a desire for order and control. But it does not help us navigate the rapid biodiversity changes the world is experiencing. To do this we need to transform and update the stories and metaphors we use to understand nature. All stories frame the world in particular ways, opening up some possibilities and closing down others. We need to closely interrogate the work that they do.


Addition references:

Susanna Lidström, Simon West, Tania Katzschner, M. Isabel Pérez-Ramos, Hedley Twidle. “Invasive Narratives and the Inverse of Slow Violence: Alien Species in Science and Society.” Environmental Humanities 7 (2015): 1–40.

Jacques Tassin and Christian A. Kull. “Facing the Broader Dimensions of Biological Invasions.” Land Use Policy 42 (2015): 165–169.

Charles Warren. “Perspectives on the ‘Alien’ versus ‘Native’ Species Debate: A Critique of Concepts, Language and Practice.” Progress in Human Geography 31, no. 4 (2007): 427–446, 437.

Brendan Larson. Metaphors for Environmental Sustainability: Redefining our Relationship with Nature. New Haven: Yale University Press, 2011: 163.

Brian W. van Wilgen, Greg G. Forsyth, David C. Le Maitre, Andrew Wannenburgh, Johann D.F. Kotze, Elna van den Berg and Lesley Henderson. “An Assessment of the Effectiveness of a Large, National-Scale, Invasive Alien Plant Control Strategy in South Africa.” Biological Conservation 148 (2012): 28–38.

Sally-Ann Murray. “Working for Water’s ‘AlienBusters’: Material and Metaphoric Campaigns Against ‘Alien Invaders’.” Critical Arts: South-North Cultural and Media Studies 19, no. 1–2 (2005): 127–149.

  1. Thank you for this thoughtful article about the xenophobic implications of nativism in the natural world. Those implications have always been there, most notably in the native plant movement in 1930s Germany.

    Stephen Jay Gould wrote eloquently about this historical origin of the modern native plant movement shortly before he died. As a world-renown evolutionary biologist, he was in a unique position to express his opinion that the native plant ideology is inconsistent with evolutionary theory and has dangerous social implications:

    We are presently experiencing a period of political upheaval that has unmistakable parallels with 1930s German fascism and xenophobia. It is therefore wise and appropriate to acknowledge that nativism in the natural world has equally destructive consequences for the environment.

  2. I think that there are vast differences in approach and understanding of the impacts of non-native species upon local ecosystems between the popular press/the public and researchers actually involved in management. Those of us involved in the daily response to these issues are fairly clear-eyed about the subject and realize that we have limited resources to focus on the “problem” of non-native taxa, so we had best identify which ones are going to be difficult for ecosystems that we prefer to adapt to, and which are less likely to become a major issue. A bark-boring beetle that can spread rapidly across the whole mid-Western United States and which may cause a large proportion of residential, commercial, and woodland canopy to go extinct is significant – but a mycetophilic beetle that aids in the decomposition of fallen trees is less likely to be targeted for immediate response. The spore-feeding habits of the latter beetle may prove significant and alter the fungal communities involved in decomposition, but we have to choose where to place our limited research and management efforts.

    Yet as you suggest in your article, the public as a whole remains convinced that all these species are universally problematic or reviled by the research and management communities. I suppose that some of our agencies may be responsible for this disconnect; we rely on charismatic and problematic organisms such as pythons and warn of death, disease, and ecological apocalypse when advertising our issues to policymakers and the public. I believe that we do so at our peril when the established species fails to result in the sometimes hysterical impact we advertise, but it remains true that without some of this excitement around particular taxa, it is exceptionally difficult to attract funding. As any professional advertiser will sell you, by and by large, policymakers and the public respond to emotionally sensational stories. Much nuance can be lost when you are trying to engage the public with the single, simple messages that are so effective. We save the details for journals and splitting hairs for meetings with peers who will appreciate the nuance.

    I would agree that we lose something in not providing the public with all of the details – but frankly, they have a short attention span and otherwise might not be concerned about the snails or mussels or beetles underfoot when compared to the ongoing travails of the latest celebrity.

  3. I agree with the article in that complex environmental problems need to be communicated better. However this blog simplifies the issues surrounding invasive alien species to a very ‘binary’ decision making process – which it most definitely isn’t. There have been many articles and blogs written along similar lines to this one (albeit on slightly different topics) – so rather than repeat them in full, I will refer you (at the bottom of my comment) to a few of these articles in defence of why we must step up action to prevent and manage biological invasions, provided by those who have spent their lives working in conservation.

    In summary – conservation biologists do not oppose non-native species — only those that have negative impacts upon biodiversity, ecosystem services, economies, or human well-being. The evidence base of their negative impacts these overlapping spheres is significant and is constantly growing. While some non-native species do have some benefits (which no one would deny), these benefits are often limited to one, or a limited number, of ecosystem services, and often these benefits flow to a limited group of people (where as the costs can often be widely distributed).

    However you cannot brush aside the evidence for the huge negative impacts that invasive alien species also have – they are the second biggest driver of species extinctions (Bellard et al. 2016., second biggest pressure to World Heritage Sites (IUCN World Heritage Outlook 2014, have huge economic impacts (e.g. Bradshaw et al. 2016. DOI: 10.1038/ncomms12986 & Hoffmann & Broadhurst. 2016. DOI: 10.3897/neobiota.31.6960) and have serious human health impacts (Mazza et al. 2013. DOI: 10.1080/03949370.2013.863225). Decision makers when prioritising which non-native species to prevent the introduction of, or eradicate or manage need to look at all the impacts.

    Importantly the introductions of non-native species are rapidly increasing due to increasing movement of people and goods around the world, and most countries do not have the capacity or policies in place to prevent their introductions (Early et al. 2015 DOI: 10.1038/ncomms12485), in fact progress in addressing biological invasions is lagging far behind internationally agreed targets – the ‘Aichi Targets’ (see CBD 2014, and RSPB 2016

    Prevention is key to addressing invasive alien species and preventing their impacts – it has been shown that by investing in biosecurity measures with early warning and rapid response – the returns (avoidance of environmental and socio-economic losses) can be huge. Also the conservation benefits of invasive alien species eradications has also been proven to be significant (

    So rather seeing the work that addresses invasive alien species as something that ‘siphons resources that might be better spent elsewhere’ – i would make the counter argument that the prevention, eradication and management of invasive alien species desperately needs more resources and action.

    If we don’t address biological invasions we risk undermining many of the goals set out in the UN 2030 Agenda for Sustainable Development (, the Convention on Biological Diversity’s Strategic Plan for Biodiversity 2020 (, and climate mitigation and adaptation work.

    In fact it is exactly for these reasons that at the last IUCN World Conservation Congress, 34 organisation from around the world launched the Honolulu Challenge on Invasive Alien Species – urging countries, NGOs and the private sector to commit to taking urgent measures to address biological invasions in order to protect biodiversity and human wellbeing from their impacts (see:


    – Russell & Blackburn, 2016. The rise of invasive species denialism. TREE 32, 1:3-6

    Blogs on Russell & Blackburn, 2016 (as its not open access)
    Why Doubt Invasive Species Impacts?

    Those who believe invasive species aren’t a problem are jumping on the post-truth bandwagon

    – Simberloff & Genovesi, 2013. Anthropocene: action makes sense. Nature 502, 624:

    – Simberloff, 2011. Non-natives: 141 scientists object. Nature 475, 36

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