The Natural History of Northern Ireland

An introduction to the natural history of Northern Ireland

Northern Ireland covers an area of 13,580km², about the size of Yorkshire. Of this area, three quarters are below 150m and only 6% rises above 300m. The climate is temperate and humid. The landscape is dramatically varied for such a restricted area and there are distinct regional variations between such areas as the Antrim Plateau, the Fermanagh Lakelands, the valleys of the rivers Lagan and Bann, the Lough Neagh basin, the Foyle estuary and the Mourne and Sperrin mountains.

The geological story, glacial and volcanic activity
Like the landscape, the variety of underlying geology is unsurpassed in any other area of similar size in Great Britain. Northern Ireland is geologically a south western extension of Scotland, with the Highland structures repeated in north Antrim and the Sperrins and the southern uplands of Scotland continuing into the regions south of the Lagan Valley.

The dominant feature of the north east is the Antrim Plateau, an extensive outpouring of tertiary basalt lava, whose scarped coastal rim from Belfast northwards, lends the Antrim coast its drama. On the northern coast, the same basalt formed the striking hexagonal columns of the world famous Giant’s Causeway.

The Mourne mountains, in south Co Down, are relatively recent formations of hard wearing tertiary granite. The Sperrins, west of the Bann, are formed from older metamorphic rocks and are now much weathered.

The Pleistocene glaciation, some ten thousand years ago, was responsible for many of the characteristic features of the Northern Irish landscape. Drumlins, from the Irish words meaning ‘little hill’, are low oval hills of boulder clay shaped by the passage of ice over the landscape. While they are especially prominent in Co Down, a ‘swarm’ of drumlins run from north Down through to Co Fermanagh.

Wildlife in Northern Ireland
Due to its isolation at the end of the last Ice Age, Northern Ireland, like the rest of the island of Ireland, has a lower biodiversity, that is a smaller range of living plants and animals, than the rest of Europe. However, its rivers and lakes contain a wide variety of fish life. Salmon, brown trout, char, pollan and eel all occur naturally and other varieties such as pike, roach and rainbow trout have been introduced from outside.

Natural mammal inhabitants of Northern Ireland include insectivores, such as the hedgehog and pygmy shrew and rodent species, including the red and grey squirrel, the field mouse, the house mouse and the black and brown rat. Other common small mammals are the brown hare, the Irish hare and the rabbit, with carnivores such as the red fox, otter, pine marten, badger and stoat.

The largest mammals, the red fallow and sika deer, are descendents of the extinct ‘Great Irish Elk’ (Megaceros giganteus), who ranged over a large part of central Europe and Asia, but whose remains are found in largest concentrations in Ireland. The Great Irish Elk stood an impressive 1.8m high, weighed about 400 kg and boasted enormous antlers, spanning perhaps 3.5m.

Northern Ireland also hosts eight species of bat, including Daubenton’s bat, Natterer’s bat and the common pipistrelle. Offshore, the grey and common seal are common, with whales, dolphins and porpoise occasionally observed at sea and in harbours. The only native amphibians are a single species each of frog, toad and newt. There are no snakes and the only reptile is the common lizard.

Birdlife of Northern Ireland
Northern Ireland’s location off the western fringe of the European continent, coupled with its temperate winters, attract large numbers of migrant birds, south from Arctic Canada and Greenland and east from America. Strangford Lough, Lough Foyle and Lough Neagh are all major habitats. Strangford Lough, a wetland of international importance attracts huge numbers of brent geese in autumn and offers breeding grounds to arctic, common and Sandwich terns. Elsewhere in Co Down the Copeland Islands, offshore at Donaghadee, host Northern Ireland’s largest Manx shearwater colony and attract storm petrels in summer and autumn.

Lough Neagh, the largest freshwater lake in the British Isles, provides habitation for up to 100,000 waterfowl, including whooper swan, bewick’s swan, tufted duck and great crested grebe. The mudflats, salt marshes and polder of the wide, shallow Lough Foyle attract pale-bellied brent geese, whooper swan, wigeon and bar-tailed godwit in internationally significant numbers, while inshore populations of finches and larks attract raptors such as buzzard, kestrel, marlin, peregrin and sparrowhawk. To the south the Sperrin uplands attract the same species, as well as golden plover and red grouse.

Human impact on the landscape, deforestation and farming
Afforestation began in Ireland with the withdrawal of the ice sheets 10,000 years ago, but by the Bronze Age, human inhabitants had begun the process of deforestation, clearing ground for farming, for fuel and for building timber. The island of Ireland is second only to Iceland as the least forested country in Europe.

In terms of land use, human farming practices have altered significantly over the last century and a half. In the 1850s much of the land was given over to the cultivation of arable crops, flax and potatoes.

Further reading:
Learning About Your Countryside: Field Studies in Northern Ireland (1973) by Grace Drennan; The Dynamic Landscape (1984) by Ulster Television; Nature Diary of an Ulster School-Boy, 1956-63 (1991) by Basil J Gilroy; Irish Nocturnes (1999) by C J Arthur.