Trees blooming earlier than in 1970

Global warming is causing leaves to appear on beech trees nearly three weeks earlier than they were in 1970, research has found.

Studies carried out at Valentia Observatory in Co Kerry have shown that the leaf unfolding date for the trees has, on average, moved from 125 days into the year (May 5/6th) to 105 days (April 10/11th).

The bud burst projections for the birch tree are expected to increase by between 15 and 20 days in Dublin in the period between 1950 and 2100 and between 4 and 17 days in other locations, according to projections.

Dr Alison Donnelly, a phenologist (studying the timing of natural events) at Trinity College Dublin, told a conference on climate change that while the 0.7c rise in temperatures in the last century in Ireland did not seem high it was already having a significant effect on the budding and leafing of trees and the number of bird species that are making Ireland their home.

Common birds including cuckoos, swifts, sand martins and swallows were all arriving in Ireland earlier, she told the UCD Earth Sciences Institute series of lectures on climate change.

In addition, the little egret, a rare visitor to Ireland up to 1989, was now an resident Irish species and the blackcaps, which used to be summer migrants, were now over-wintering in Ireland.

Dr Jane Stout of Trinity College Dublin said climate change was likely to lead to an increase in invasive species in Ireland.

She cited the example of the Asian clam which was recently found in the River Barrow in Co Carlow as an example of an invasive species which might become more common in coming years.

Researchers believe the clam is able to thrive in northern Europe because of increasing water temperatures.

It can be a major nuisance in waterway systems and also a threat to natural species.

Dr Stout said the introduction of invasive species into areas where they previous did not exist can have an economic impact because of our dependence on biodiversity.