Learning to love aliens in the Irish countryside

THERE is a strange and extremely unscientific prejudice embedded in the heart of the environmental movement. It is the prejudice against what are usually described, in distinctly emotive terms, as ‘alien invasive species’, writes Dick Warner

The truth of the matter is that the vast majority of the foreign species of plants and animals that settle in Ireland eventually integrate quite well and end up making a positive contribution to the naturally impoverished bio-diversity of an isolated island.

The xenophobic prejudices against them are based on an outdated and incorrect view of ecology. It used to be thought that every habitat eventually reaches a perfect state of ecological climax and that this state is stable and therefore any changes to it are detrimental. Nowadays we know that ecological reality is much more complex and dynamic. The natural order of things is that new species arrive and old ones depart. The prejudice is enshrined in a new EU regulation that came into force last January which gives officials the power to draw up a list of invader species which will not be allowed to be imported into any member state. The species list has yet to be finalised but the whole thing looks like a disaster about to happen.

To give one minor example, I grow water hyacinths in my pond. They are attractive floating plants with blue flowers from South America. In cold Irish waters they die every winter, unless you bring them indoors, so the threat they pose of becoming invasive is zero. But they have become established in one river in Spain so they are likely to end up on the EU list of banned species and I will no longer be able to buy them in my local garden centre.

The Irish countryside has a tradition of absorbing aliens and benefiting from their presence. The Normans brought in rabbits, much to the delight of our native foxes. The arrival of the brown rat around 1720 may not have appeared to confer much benefit but they did exterminate the black rat and the black rat was the vector for the plague. A century after their introduction the explosive population growth of the grey squirrel reversed and they appear to be contributing to a revival in the population of native pine martens. Sycamores grow where no native broad-leaf will and the zebra mussel helped control the growth of poisonous algae in our waterways.

The prejudice against new species becomes more entrenched every year. Some people profit from this, in particular field biologists, and sometimes expensive and usually futile campaigns are mounted to eradicate some plant or animal that is deemed to be an invasive alien. I find it hard to understand how intelligent people trained in evidence-based science can be duped by what amounts to racist propaganda.


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