The chances of anything coming from mars are a million to one” he said “The chances of anything coming from Mars, are a million to one ... But still, they come! Jeff Wayne, Eve of the War – part of the musical version of the War of the Worlds.

Red Herring #5 and its Consequences
Upon hearing the word “alien”, most people conjure up an image of something extra-terrestrial – UFOs, ET or perhaps little green men such as Kang and Kodos from the Simpsons (as shown in the above cartoon). Perhaps they will whistle the Jeff Wayne’s ditty précised above. But, unless the person belongs to the small select world of biological invasions specialists, they are unlikely to think of… species introduced into new ecosystems directly or indirectly by people that increase in density and/or spread, to threaten ecosystems, habitats or species with economic, social or environmental harm!!

But even though the chances of anyone thinking of non-native species as aliens are practically a million to one … still they (the cognoscenti) come… to use the ‘A-word’. Unfortunately the term Invasive Alien Species (IAS) is with us now and it is not going away. So why do I feel so strongly about this “A-bomb?”

My first concern is that the use of the word alien causes confusion – a classic red herring. When the word alien is brought up for the first time during meetings I have facilitated, people inevitably talk about little green men; sometimes as a flippant aside, sometimes because they have an interest in extra-terrestrial life, and sometimes because they share my concern about the A-word being a red herring.

To be honest, such discussions are more water bomb than atomic bomb when you have a few minutes available for the bomb disposal process. My approach is to explain that the term 'Invasive Alien Species' is widely used in the discipline so we need to be aware of its existence. I then introduce my preferred alternatives such as 'exotic invasive species', a term I don’t care that much for either - because the word exotic conjures up stereotypically positive images (smiling twenty-somethings sipping piña coladas while lounging in a hammock under the tropical sun, … you get the picture), or 'non-native invasive species' – my personal preference. But ideally I would simply use the term 'invasive species' to which you can add non-native or native whenever pertinent (more on that later).

Job done? Well not quite. The problem is that the A-word is so ubiquitous in the scientific literature that it ends up being passed on unadulterated when communicating with non-experts. Without an explanation of the kind given above, the previously contained red herring can once more rear its ugly head. The narrator Edward Norton uses the term invasive alien species throughout the National Geographic documentary Strange Days on Planet Earth – Invaders, a programme targeted at a lay audience. Postings from those who were clearly confused and distracted by the A-word peppered the comments section of YouTube.  Typical comments included I think they need to be careful when calling plants "aliens" because ... plants aren't aliens....., and I didn’t know termites were from another planets and there invading human civilization using highly complicated military tactics. Oh wait.” And “wtf with the term alien, dude. They evolved within this planet not from outer space...get it?

Things can get even more confusing when the word 'alien' is translated into different languages. Believe me; I have seen invasive alien species translated into les espèces envahissantes extraterrestres in the francophone world!!

My second, related, concern is the way in which the term invasive alien species or IAS has been used as a label for all invasive species, whether they are native or introduced. This is related to Red Herring #4 (Concern about species introductions is essentially racism) and the fact that some invasion biologists appear to pay insufficient attention to native species that can become invasive. In some cases it is necessary to distinguish between native and non-native invaders as this affects management. For instance, prevention at the national level will not be a part of the management toolkit for native invaders!

Some suggestions for addressing Red Herring #5
We are stuck with the A-word in certain quarters but it doesn't mean we should use it when communicating with lay audiences. Let’s try to raise awareness among experts of the fact that the word aliens does not work with the other 99.something percent of people who are not immersed in the world of biological invasions. Most biological invasions awareness-raising products produced nowadays do not use the A-word, which is encouraging. Explicit recognition of Red Herring #5 will help to reinforce this trend so that any references to 'aliens among us' are safely contained!

Below are some excerpts from articles about biological invasions: 

• “The survey is not even halfway done, yet it has already revealed a disturbing trend: immigrants are forcing old-timers out of their homes.” (Stewart 2001)
  
• “U.S. Can’t Handle Today’s Tide of Immigrants” (Yeh 1995)
  
• “Congress Threatens Wild Immigrants” (Weiner 1996)
  

Is it just my imagination or do these quotes sound ever so slightly racist?

The above snippets are carefully selected and devoid of context. As we all know, the devil can quote scripture for his own ends. I am as guilty as anybody when it comes to searching for catchy hooks and headlines to attract an audience… but we have got to be careful!

Critics can and do gleefully seize upon quotes such as these and use them as sticks to bash those who are working to mimimise the impacts of biological invasions. Banu Subramaniam (2001) argues that “the battle against exotic and alien plants is a symptom of a campaign that misplaces and displaces anxieties about economic, social, political, and cultural changes onto outsiders and foreigners.” - A serious accusation indeed, which is particularly ironic as so many of those working in the on biological invasions hold politically liberal views.

Unfortunately there have been well-documented links between the love of indigenous landscapes and extreme right wing views that we cannot bury under the carpet. Daniel Simberloff (2003) outlines this sorry history in detail, but this does not, mean that those who care about indigenous landscapes should be assumed to be racist! As Simberloff states the Nazis opposed introduced species, and that they related this agenda to their campaign to rid Germany (and perhaps the rest of the world) of people they considered foreign and inferior, need not mean that everyone who opposes introduced species does so for xenophobic, racist motives. However, muck has a nasty habit of sticking and any association with racism can only weaken the cause of those who seek to manage species introductions.

Some folks who would like to equate concern about biological invasions with xenophobia have correctly pointed out that introduced species per se are not ‘baddies’. The world’s agriculture is based on a handful of plants such as rice (native to Asia and certain parts of Africa), wheat (native to the Middle East), maize (native to the Americas) and soya (native to East Asia), all of which have been introduced beyond their native range; with massive benefits. And most introduced species do not become invasive. The ‘tens rule’ for non-native plants states that of ten per cent of introduced non-native plant species establish in the wild, and of these, ten per cent become invasive (Williamson 1993, and Williamson & Fitter 1996). This rule is far from cast-iron but the message is clear – the large majority of introduced species will not cause serious damage in their new homes.

Unfortunately, it is very difficult to predict which species will become invasive in what situation. And the stakes are very high as it is much more difficult to control a species once it has established than to keep it out in the first place. Although invasion risks are usually low, the potential impacts are high. Hence invasion biologists tend to advocate a precautionary approach to new species introductions - If in doubt keep it out! I guess this can sound pretty xenophobic if you don’t know the full story!

The flip side of this is that not all native species are ‘goodies’. Native species can become invasive too. You can be sure that a farmer in Senegal who has lost an entire sorghum crop to native desert locusts or a cattle herder in Nigeria whose land has been rendered useless by native bracken fern does not care where these species hail from. Invasion biologists focus on introduced species for very good reasons (see my posting on Red Herring #3 for an explanation). But, in our well-intentioned efforts to keep out suspected baddies we may neglect the “enemy within” and underplay the potential invasiveness of native species under certain circumstances. Thus, once again, we open ourselves to accusations of xenophobia.

Some suggestions for addressing Red Herring #4
It’s more difficult than my suggested response to Red Herring #3 (‘It’s only natural’) because the xenophobia accusation concerns several issues: Concern for introduction equates to racism; introduced species are good; and you are only worried about introduced ‘baddies’ are those I have highlighted here. My suggestions are outlined below, but I am sure that they are not the last word, given the complex nature of this particular red herring:

We need to acknowledge the fact that some individuals and groups have conflated a love of indigenous species and landscapes with racist or extreme nationalistic viewpoints. We should apologise on behalf of these people but this chequered history does not mean we should relinquish our right to care about native species and ecosystems.

We need to carefully choose our words so that they cannot be twisted to makes it appear as if we are acting from racist motives. I know many people recoil at such ‘political correctness’ but, for better or worse, we are judged on our words even if those words are stripped of their original context.

We need to make it clear that most introduced species are not problematic and we do not advocate closing the doors on future introductions. However, the precautionary principle dictates that we cannot simply introduce any species into any area without some form of risk analysis. Advocating a systematic risk analysis process is not xenophobic.

We need to acknowledge that native species can become invasive. Ultimately our concern is the balance between positive and negative impacts and not the place of origin of the species.

Last but by no means least, we must clearly communicate that our major concern is the fact that biological invasions can cause huge and unintended negative social, cultural, economic and environmental impacts. It is all about context; a species can have positive impacts in some situations and negative impacts in others. We need to embrace this complexity which cannot be dumbed down to native good, introduced bad!!

Coming up next: Red Herring #5: Aliens! What’s in A-word? – Alien means extra-terrestrial and those species you talk about evolved on planet earth.

References
Simberloff. D. (2003). Confronting introduced species: a form of xenophobia? Biological Invasions 5, 179–92.

Stewart, B. (2001). The Invasion of the Woodland Soil Snatchers. New York Times, April 24, 2001.

Subramaniam, B. (2001). The Aliens Have Landed! Reflections on the Rhetoric of Biological Invasions. Meridians: Feminism, Race, Transnationalism 2(1), 26-40. Indiana University Press. 

Weiner, H. (1996). Congress threatens wild immigrants. Earth Island Journal 11, no. 4.

Williamson, M. (1993). Invaders, weeds and the risk from genetically modified organisms. Experientia, 49, 219-24.

Williamson, M. H. & A. Fitter (1996). The characters of successful invaders. Biological Conservation 78, 163-170.

Yeh, L. (1995). U.S. can’t handle today’s tide of immigrants. Christian Science Monitor 87, no. 81.

Red Herring #3 and its Consequences
Recipe for a new species ('speciation'): take some individuals of an existing species, move them to an isolated area, leave them to breed for many generations, allow them to adapt to the new environment… Result – new species. There are a few variations on this theme but this in essence is how speciation works. Example: Over many, many, many years a pigeon evolved into a dodo.

Recipe for species movement without evolving into a new species (range expansion): take some individuals of an existing species, move them to a new area that is not isolated, continue to move individuals of an existing species into the new area... Result – same species but with an expanded range. Example: Human beings who have spread throughout the world but we are still just one species.

Recipe for biological equilibrium ('dynamic equilibrium'): take some individuals of an existing species, move them to a new area, the new species increase in numbers and overuse resources, there is some premature death - perhaps from predation or disease or lack of food and/or migration, and new fluctuating (“dynamic”) equilibrium levels are reached. Example: The cyclical movement of wildebeest in the Serengeti and Masai Mara in Tanzania and Kenya.

So if species movement, which has been going on for as long as life itself, leads to new species, range expansion and dynamic equilibrium then what’s the difference between ‘natural’ species movement and human-induced biological invasions. Simply stated, there has been a dramatic change in the numbers of species moving and type of species movement compared to the situation in pre-human times.

Pimentel (2001) estimated that more than 400,000 species have been moved from one region of the Earth to another by human agency over the past 10 000 years – that’s a serious shuffling of the pack! So why does this frequency matter? In a nutshell, ecosystems just don’t have enough time to adapt. Imagine a species introduction as a pebble thrown into a pond. If you throw a single pebble into a pond it will cause ripples but the movement will settle down soon enough. If you continue to throw pebbles…, and rocks…, and boulders into the pond the water will be in a constant state of disturbance. It will never return to an equilibrium because it is never given the time to recover.

Some of these species (the ‘pebbles’ if you will) may have been able to colonise a recipient ecosystem without our help - I call this group the ‘couldhavegottheres’. But there is another group of species (the ‘boulders and rocks’) that would almost never have been introduced to certain places without our help. I call this group the ‘neverwouldhavegottheres’. Human action has enabled this group to overcome barriers that previously prevented them from getting to certain places. More often than not its the neverwouldhavegottheres that are the most  troublesome to the recipient ecosystem.

Couldhavegottheres include seeds and spores, insects and other invertebrates, birds and mammals, and reptiles that originate in places close to the recipient ecosystems. Neverwouldhavegottheres include rats, cats, mongooses and other ground-dwelling mammals that are brought to isolated oceanic islands; freshwater fish from Asia that are introduced to the Americas and vice versa; clams, mussels and crabs that are moved between the Atlantic and the Pacific Oceans in ballast water; and species that have been separated for millions of years who can now colonise previously inaccessible seas through the Suez and Panama Canals.

Recipient ecosystems can take a real hammering when a new kind of species makes its entrance because species adapt to what is and was present and not to what has never been present.

So are biological invasions just a slightly accelerated version of business as usual?

In a single word… NO!

In a few words… NOT EVEN CLOSE!!

Some suggestions for addressing Red Herring #3
Fortunately this red herring is one of the easier ones to address - we need to clearly outline the differences between background (pre-human) and current species movement, both in terms of quantity (frequency) and quality (overcoming nature’s barriers) and the reasons why these changes can result in severe impacts if effective management measures are not taken. These ideas are simple to explain and once outlined often contribute to Ah-Ha moments. So that’s why rats are such a big deal on isolated islands! or Now I understand why you need to manage the movement of ballast water! are common rejoinders. 

All of this is biological invasions 101 for the cognoscenti but we, the so-called experts, forget that we take a great deal of our knowledge for granted. At all times we need to guard against the curse of knowledge when communicating with people from different backgrounds to ourselves.

Coming up next: Red Herring #4: Concern about species introductions is essentially racism - Species introductions, like human immigration is a positive thing and those who advocate managing the process are eco-fascists.

Reference
Pimentel, D. (2001). Agricultural invasions. In Encyclopedia of Biodiversity, vol. 1 (ed. S. A. Levin), pp. 71–83. San Diego, CA: Academic.