Physical geography
A ring of coastal mountains surrounds low central plains. The highest peak is Carrauntoohil (Irish: Corrán Tuathail) in County Kerry, which is 1,041 m (3,414 ft).[18][19] The River Shannon, at 386 km (240 miles) is the longest river in Ireland.[20][21] The island's lush vegetation, a product of its mild climate and frequent rainfall, earns it the sobriquet "Emerald Isle". The island's area is 84,412 km²[18] (32,591 square miles).
Ireland's least arable land lies in the south-western and western counties.[citation needed] These areas are largely mountainous and rocky, with green panoramic vistas.
Climate
Overall, Ireland has a mild, but changeable, Oceanic climate with few extremes. The warmest recorded air temperature was 33.3 °C (91.94 °F) at Kilkenny Castle, County Kilkenny on 26 June 1887, where as the lowest recorded temperature was −19.1 °C (−2.38 °F) at Markree Castle, County Sligo on 16 January 1881.[22]
Other statistics show that the greatest recorded annual rainfall was 3,964.9 mm (156.1 in) in the Ballaghbeena Gap in 1960. The driest year on record was 1887, with only 356.6 mm (14.0 in) of rain recorded at Glasnevin, while the longest period of absolute drought was in Limerick where there was no recorded rainfall over 38 days during April and May 1938.[23]
The climate is typically insular, and as a result of the moderating moist winds which ordinarily prevail from the South-Western Atlantic, it is temperate, avoiding the extremes in temperature of many other areas in the world at similar latitudes.[24]
Precipitation falls throughout the year, but is light overall, particularly in the east. The west, however, tends to be wetter on average and prone to the full force of Atlantic storms, more especially in the late autumn and winter months, which occasionally bring destructive winds and high rainfall totals to these areas, as well as snow and hail. The regions of North Galway and East Mayo have the highest incidents of recorded lightning annually (5 to 10 days per year).[23] Munster in the south records the least snow with Ulster in the north more prone to snow. Some areas along the south and southwest coasts have not had any lying snow since February 1991.[citation needed]
Inland areas are warmer in summer and colder in winter – there are usually around 40 days of below freezing temperatures (0 °C/32 °F) at inland weather stations, but only 10 days at coastal stations. Ireland is sometimes affected by heat waves, most recently in 1995, 2003, 2006.
Geology
Geologically the island consists of a number of provinces – in the far west around Galway and Donegal is a medium to high grade metamorphic and igneous complex of Caledonide (Scottish Highland) affinity. Across southeast Ulster and extending southwest to Longford and south to Navan is a province of Ordovician and Silurian rocks with more affinities with the Southern Uplands province of Scotland. Further south, there is an area along the Wexford coast of granite intrusives into more Ordovician and Silurian rocks with a more Welsh affinity.[25][26]
In the southwest, around Bantry Bay and the mountains of Macgillicuddy's Reeks, is an area of substantially deformed but only lightly metamorphosed Devonian-aged rocks.[27]
This partial ring of "hard rock" geology is covered by a blanket of Carboniferous limestone over the centre of the country, giving rise to the comparatively fertile and famously "lush" landscape of the country. The west coast district of The Burren around Lisdoonvarna has well developed karst features.[28] Elsewhere, significant stratiform lead-zinc mineralisation is found in the limestones (around Silvermines and Tynagh).
Hydrocarbon exploration is ongoing. The first major find was the Kinsale Head gas field off Cork/Cobh by Marathon Oil in the mid-1970s.[29][30] More recently, in 1999, Enterprise Oil announced the discovery of the Corrib Gas Field. This has increased activity off the west coast in parallel with the "West of Shetland" step-out development from the North Sea hydrocarbon province. The Helvick oil field, estimated to contain over 28 million barrels (4,500,000 m3) of oil, is another recent discovery.[31]
Wildlife
Ireland has fewer animal and plant species than either Britain or mainland Europe because it became an island shortly after the end of the last glacial period, about 10,000 years ago. Many different habitat types are found in Ireland, including farmland, open woodland, temperate broadleaf and mixed forests, conifer plantations, peat bogs, and various coastal habitats. According to the WWF, the territory of Ireland can be subdivided into two ecoregions: the Celtic broadleaf forests and North Atlantic moist mixed forests.
Fauna
Only 26 land mammal species are native to Ireland, because it was isolated from Europe by rising sea levels after the Ice Age. Some species, such as the red fox, hedgehog, and badger are very common, whereas others, like the Irish hare, red deer and pine marten are less so. Aquatic wild-life, such as species of turtle, shark, whale, and dolphin, are common off the coast. About 400 species of birds have been recorded in Ireland. Many of these are migratory, including the Barn Swallow. Most of Ireland's bird species come from Iceland, Greenland, Africa among other territories. There are no snakes in Ireland and only one reptile (the common lizard) is native to the country. Extinct species include the great Irish elk, the wolf, the great auk, and others. Some previously extinct birds, such as the Golden Eagle, have recently been reintroduced after decades of extirpation.
Agriculture drives current land use patterns in Ireland, limiting natural habitat preserves,[32] particularly for larger wild mammals with greater territorial needs. With no top predator in Ireland, populations of animals (such as semi-wild deer) that cannot be controlled by smaller predators (such as the fox) are controlled by annual culling.
Flora
Phytogeographically, Ireland belongs to the Atlantic European province of the Circumboreal Region within the Boreal Kingdom. Until mediæval times Ireland was heavily forested with oak, pine, beech and birch. Forests now cover about 9% (4,450 km² or one million acres) of the land.[33] Because of its mild climate, many species, including sub-tropical species such as palm trees, are grown in Ireland. Much of the land is now covered with pasture, and there are many species of wild-flower. Gorse (Ulex europaeus), a wild furze, is commonly found growing in the uplands, and ferns are plentiful in the more moist regions, especially in the western parts of Ireland. It is home to hundreds of plant species, some of them unique to the island. The country has been "invaded" by some grasses, such as Spartina anglica.[34]
The algal and seaweed flora is that of the cold-temperate. The total number of species is: 264 Rhodophyta; 152 Heterokontophyta; 114 Chloropyta; and 31 Cyanophyta, giving a total of 574. Rarer species include: Itonoa marginifera (J.Ag.) Masuda & Guiry); Schmitzia hiscockiana Maggs and Guiry; Gelidiella calcicola Maggs & Guiry; Gelidium maggsiae Rico & Guiry and Halymenia latifolia P.Crouan & H.Crouan ex Kützing.[35] The country has been invaded by some algae, some of which are now well established: Asparagopsis armara Harvey – which originated in Australia and was first recorded by M. De Valera in 1939; Colpomenia peregrina Sauvageau – now locally abundant and first recorded in the 1930s; Sargassum muticum (Yendo) Fensholt – now well established in a number of localities on the south, west, and north-east coasts; Codium fragile ssp. fragile (formerly reported as ssp. tomentosum) – now well established.[36] Codium fragile ssp. atlanticum has recently been established to be native, although for many years it was regarded as an alien species.
The impact of agriculture
The long history of agricultural production coupled with modern intensive agricultural methods (such as pesticide and fertiliser use) has placed pressure on biodiversity in Ireland.[citation needed] "Runoff" of contaminants into streams, rivers and lakes impact the natural fresh-water ecosystems. A land of green fields for crop cultivation and cattle rearing limits the space available for the establishment of native wild species. Hedgerows however, traditionally used for maintaining and demarcating land boundaries, act as a refuge for native wild flora. Their ecosystems stretch across the countryside and act as a network of connections to preserve remnants of the ecosystem that once covered the island. Subsidies under the Common Agricultural Policy which supported these agricultural practices are undergoing reforms.[37] The CAP still subsidises some potentially destructive agricultural practices, however, the recent reforms have gradually decoupled subsidies from production levels and introduced environmental and other requirements.[37]
Forest covers about 10% of the country, with most designated for commercial production.[32] Forested areas typically consist of monoculture plantations of non-native species which may result in habitats that are not suitable for supporting a broad range of native species of invertebrates. Remnants of native forest can be found scattered around the country, in particular in the Killarney National Park. Natural areas require fencing to prevent over-grazing by deer and sheep that roam over uncultivated areas. This is one of the main factors preventing the natural regeneration of forests across many regions of the country.[38
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