Irish butterfly numbers under threat

GIVEN our national penchant for destroying the world, it should not come as a surprise to learn that 18% of our native butterflies are in danger of extinction.

Some people may ask: what matter and why be so concerned about butterflies? Apart altogether from being a thing of beauty in its own right, the butterfly has other important values. It is, for instance, an indicator of the wellbeing of our environment — like a fish kill being the result of polluted water. The diminution of the butterfly in Ireland is caused mainly by the loss of its natural habitat, which has been accelerated by large-scale development in recent decades.

Sometimes, butterflies are confused with moths. Butterflies fly by day and moths generally fly at night. A clearly distinguishing feature is the antennae. Butterflies always have threadlike antennae, but moths can have many types of antennae, some feathery.

The Department of the Environment has issued a Red List of Irish Butterflies 2010 which details species under threat.

All 33 resident and regular migrant species of Irish butterflies are evaluated for their conservation status using the International Union for Conservation of Nature (IUCN) regional criteria. The Red List assessment was compiled using best expert opinion and data from a number of specialist organisations.

Apart from the 18% of butterflies under threat of total wipeout, a further 15% are near threatened. One species, Mountain Ringlet, is extinct, six species are endangered or vulnerable and five species are near threatened.

Insects make up a large proportion of Ireland’s wildlife and are essential to our natural world, but they are an under-studied and under-appreciated component of our wildlife, according to the National Parks and Wildlife Service (NPWS). Butterflies, however, are the exception to this statement, which describes them as a popular, charismatic group of insects that capture the imagination of scientists and the public alike. They are important indicators of biodiversity and they can be used to monitor the health of ecosystems and the impact of land management.

They react quickly, either positively or negatively, to alterations in their environment and so they have great potential for monitoring change. In Europe, many butterflies declined severely in range and population in the 20th century.

This downward trend is still continuing, as shown by the recent European Red List of Butterflies which found that a third had declined during the first decade of this century.

In Britain, the recent regional red list has shown that 39% of British butterflies are classified as regionally extinct or under threat of extinction. Main causes of the decline in butterfly populations throughout Europe are related to changes in land management.

The most significant are the agricultural intensification of productive land and the abandonment of traditional farming practices, especially grazing on marginal land. Such changes in the landscape have reduced the extent and quality of flower-rich habitats that support the most species-rich European butterfly communities.

Ireland is not rich in butterflies, the NPWS points out. We were supposed to halt the loss of biodiversity by 2010, but there is still a great deal of work to do.

The additional pressure on plant and animal species is causing some to disappear at an alarming rate. The Heritage Council has an ongoing campaign to raise awareness of the decline in Ireland’s biodiversity and the loss of natural habitats such as boglands, natural grasslands, hedgerows and sand dunes.

It wants everyone to do their part to help provide food and shelter for a huge number of birds, butterflies and other important wildlife. Growing native trees, shrubs and flowers or planting old-fashioned traditional garden plants, from herbs to scented flowers, provide more food and shelter than the newer hybrid and exotic breeds.

Everyone could play a part by planting native and traditional plants and using less moss peat, insecticide and other garden chemicals in their gardens and public spaces. Changing agricultural practices and the large-scale construction of roads, houses and shopping are major contributors to Ireland’s declining biodiversity.

While climate change and the arrival of invasive species such as the zebra mussel, grey squirrel and hogweed are playing a significant role, the changes to our countryside are having a profound effect, says the Heritage Council.

It has taken EU legislation to force us to do what is necessary, belatedly and often reluctantly. And we still see appalling destruction of the countryside and landscape.


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