Rational Agriculture

Several UK news sources have carried a story about the threat to native ladybird populations by the harlequin ladybird (see, for example Survey to track "alien" ladybird on the BBC news website).

This species was introduced into parts of northern Europe in order to reduce aphid infestation. However, they were spotted in the UK last autumn - some having arrived on Tesco flowers from the Netherlands - and there is now some concern about their ecological impact. Apparently, once they've polished off the aphids - which they do avidly and thus out- compete native ladybirds for food - they start to feed on the native species themselves.

Of course, if we look at this over a longer timescale, the current ecological balance is not a static one. Climate changes (yes, climate changed even before we started to become alarmed about it in recent years) and different land use patterns will have contributed to significant changes to the balance of species. Going back far enough, many of our current "native" farmland specialist birds would not have been present, and the UK would have been dominated by woodland species.

All of which leads to the conclusion that any changes to farming practice - including sensible moves towards biological pest control - will have consequences, and it is unrealistic to expect that we should engineer the landscape to take us back to some mythical golden age of biodiversity, (which normally coincides with our childhood years). Species of birds, animals, insects and plants, whether already present or introduced, will exploit whatever ecological niches they are best suited to, often to the detriment of other species. What is then "good" or "bad" is purely in the eye of the beholder.