Unwelcome visitors - Alien species a threat to native fauna

MANY of us were lucky enough to have spent some time in the countryside over the bank holiday weekend.

If you were really lucky you’ll have seen uplifting sights: mountains, lakes, shorelines or rivers in all their glory. If you got as far as Killarney national park you would have seen the native oak forest in its autumnal majesty, a warming, reassuring blanket of russet, ochre and gold, constants in an ever-changing world. You might have been really lucky and caught the tail end of the rut and heard a stag calling for a mate, one of the unforgettable sounds of our countryside.

This time of the year such places can be so beautiful they stop you in your tracks; you have to stand still to absorb the humbling beauty, the full gift, of the place.

Leo Tolstoy said hunting acted on the soul as a poultice on a sore. Time spent in one of the very many beautiful places around this country has the same effect. It calms and cures.

Yet, so much of what you might have seen this weekend should not have been there. The Killarney stag might just as well have been a sika as a native red deer. The interlopers descendants of three Japanese deer introduced to Wicklow by Lord Powerscourt in 1860.

We can thank a 1911 wedding at Castle Forbes in Longford for the grey squirrels supplanting native reds – they were released as part of the celebrations.

The Killarney oaks would have been fighting to hold their own against that most destructive introduction – rhododendrons. Killarney’s rhododendron infestation has been described as “the biggest conservation challenge facing the national park” as nothing else can grow where it takes hold.

The lakes of Killarney are being choked too, by Canadian waterweed. Canadian waterweed and Nuttall’s waterweed pose a huge threat to the future of one of our national jewels – Lough Corrib – as well.

Today we report that pike have been illegally introduced to Connemara. The Western Regional Fisheries Board are working to removed pike from loughs Boffin and Agraffard just as they are working to remove Canadian waterweed from Lough Corrib.

In the last while chub, a non-native and aggressive omnivore, has been introduced, again illegally, into the upper Shannon system. Roe and muntjac deer have been introduced too. We are all familiar with the threats posed by mink, zebra mussels and the bullhead catfish introduced to the Erne system. The list is almost endless and poses a huge threat to Irish biodiversity.

Not all introductions represent threats – think potatoes – but others have had a profound impact, probably none more so than the friesian cow.

These are not frontline issues yet but we cannot afford to turn a blind eye either. Some introductions pose a threat to our drinking water so they should be eradicated. Others threaten native species under pressure because of habitat destruction.

We have not been exemplary custodians of natural beauty. We indulged poor planning, destroyed waterways and lakes. We have drained bogs and planted softwoods with an enthusiasm that borders on criminality.

In our heart of hearts we all know this to be true but there is good news. Even the slightest change in attitude can pay dividends; every time an individual decides to protect and encourage the world that sustains us it has an impact. We cannot remove all of the introduced species, nor do we need to, but we can be alert to the introduction of others and do all we can to prevent them gaining a foothold.