Invasive aliens can pose a risk to our biodiversity
The story goes that in 1911, a guest at a wedding at Castle Forbes, Co Longford, brought a present of a box of live American Grey Squirrels. No doubt the foreign animals imported from England were a great talking point and conversation piece among the wedding guests.
The squirrels were duly released. They survived, bred and multiplied and are now, 106 years later, believed to be the founding stock of those found throughout the length and breadth of the eastern half of Ireland. While the squirrels are pushing west in Cork and Donegal, they are not making headway in the Midlands. The River Shannon is a major natural barrier impeding their spread westward. Those that do cross the river are further hampered by the absence of large hedgerows and the presence of blanket bog.
Though some people regard them as 'cute' when they see them licking ice cream or chocolate from a discarded wrapper in an urban park, others disdainfully view these squirrels as 'big rats with fluffy tails'. Their official legal status is 'invasive alien', that is, unwelcome non-natives likely to damage our environment and/or our human economy.
The Siberian Chipmunk is another invasive alien. They have been reported living wild in counties Dublin, Fermanagh, Limerick, Tipperary, Waterford and Wicklow. They are believed to be people's pets that either escaped or were intentionally released. Expert opinion at the moment is that, if they do survive, they are unlikely to pose a serious risk to our biodiversity.
All of these matters, and much more, is explored in the recently published 'Atlas of Mammals in Ireland 2010-2015' launched last Wednesday in Kilkenny. The 207-page, A4-size hard cover book contains specially written species accounts by 42 leading authorities on mammals. More than 2,000 recorders submitted records to the atlas and almost a quarter of a million sighting from 57 different datasets were used to produce distribution maps of 72 species found on land, in the air and in our marine waters.
The new mammal atlas is edited by Liam Lysaght, Director of the National Biodiversity Data Centre in Waterford and Ferdia Marnell, a zoologist with the National Parks and Wildlife Service in Dublin.
The attractive book is a mine of information and is a publication that everyone with an interest in nature will find rewarding to dip into again and again. The excellent atlas can be ordered online from the Waterford-based National Biodiversity Data Centre for €30 (€25 plus €5 postage) at http://www.biodiversityireland.ie/product/atlas-of-mammals-in-ireland-2010-2015/.