Flora of Ireland


is in the Atlantic European Province of the Circumboreal Region, a floristic region within the Holarctic.

Composition of the flora

Ireland has a small flora for a European country because of its small size, lack of geological and ecological variation and its Pleistocene history. There are 3,815 species of plant listed for Ireland:
An additional 2,512 species of fungus occur in Ireland.
Ice-sheets covered most of Ireland until 13,000 years ago when the Holocene began. The majority of Ireland's flora and fauna has only returned as the ice sheets retreated and sea level rose accompanied by post-glacial rebound when 10,000 years ago the climate began to warm. At this time there was a land bridge connecting Wales and the east coast of Ireland since sea levels were over 100 metres lower than they are today. Plants and animals were able to cross this land-bridge until about 7,500 years ago, when it was finally covered by the rising sea level as warming continued.
Mesolithic hunters entered Ireland around 8000 BC beginning human occupation and from the
Neolithic landscape was progressively altered by agriculture, especially in the 19th and 20th centuries. Aside from the
habitat alteration new species were introduced deliberately or accidentally. The archaeologist Emmet Byrnes and botanist Declan Little, Woodlands of Ireland give a history of woodlands in Ireland.

Habitats

There are two major habitats, making up most of the land area:

Grassland

Grassland includes
Lowland meadow and pasture with grasses such as sweet vernal grass, perennial ryegrass, meadow foxtail, false oat-grass, crested dog's-tail, Festuca rubra, red fescue, downy oat-grass, Yorkshire fog, timothy grass and yellow oat-grass.
Lowland meadow and pasture flowers include meadow thistle, creeping thistle, spear thistle, pignut, lesser knapweed, meadow thistle, smooth hawksbeard, eyebright, ragged robin, red bartsia, yellow rattle, marsh lousewort, cowslip, catsear, autumn hawkbit, meadow buttercup, bulbous buttercup and dandelion
Upland pasture. Typical species are: moor matgrass, wavy hair-grass, species of Agrostis, sheep's fescue, green-ribbed sedge, cross-leaved heath, bell heather, bilberry, black crowberry, deergrass and bog asphodel.

Bogs

Importance

Ireland possesses almost of actively growing bogs and fens. This compares with in the United Kingdom, each in Switzerland and Germany and total loss in the Netherlands and Poland. In Ireland in 1998 there were of raised bog at 164 sites, of blanket bog at 233 sites and hectares of fen at 221 sites. These 200,000 hectares of actively growing raised and blanket bogs and fens are of European conservation importance.

Formation

In Ireland two factors led to the formation of such extensive peatlands. High rainfall- there are 175 rain-days each year in the west, southwest and northwest of Ireland and poor drainage The bogs formed at the end of the last ice age, about 10,000 years ago in the central lowlands of Ireland in basins of calcareous boulder clay. These became lakes overgrown with fen vegetation and infilled with fen peat which cut off the surface plants from mineral-rich water below. Nutrient-demanding fen plants were then replaced by bog mosses and plants which could survive on low levels of nutrients. The fen peat below prevented the rainwater draining away and the sponge-like bog moss and plants soaked it up.

Bog flora

The vascular plants characteristic of raised bogs include: common heather, cross-leaved heath, bell heather, bogbean, hare's-tail cottongrass, common cottongrass, bog-rosemary, common cranberry, bog asphodel, bog myrtle, Pedicularis sylvatica, round-leaved sundew, oblong-leaved sundew, great sundew, royal fern, species of Utricularia, Juncus squarrosus, common tormentil, black bogrush, bog orchid, Euphrasia scottica, heath bedstraw, green-ribbed sedge, little green sedge, black crowberry, moor matgrass, soft rush, northern firmoss and wolf's-foot clubmoss.
Cut-out raised bogs are colonised by a wet woodland of birch and alder trees. Characteristic species are downy birch, black alder, grey willow, crack willow, broad buckler fern, narrow buckler fern and remote sedge.
, Killarney, Co. Kerry

Open water

Open water habitats include rivers, canals, lakes, reservoirs, ponds and, uniquely, turloughs). Common species of wet places include common reed, marsh willowherb, common marsh bedstraw, water avens, angelica, brooklime, marsh pennywort, water plantain, marsh cinquefoil, marsh marigold, watermint, yellow water lily, bulrush and the invasive species Canadian pondweed.

Sea shore

A much smaller fraction is occupied by coastal habitats.
Significant or characteristic species of sand dunes and dune slacks are: Ammophila arenaria, seaside sandplant, sea milkwort, pyramidal orchid, sea holly, sea lyme grass, heartsease, houndstongue, common centaury, fairy flax, seashore false bindweed, dovesfoot cranesbill, bee orchid and stone bramble. Saltmarsh species include Salicornia europaea, sea purslane, sea arrowgrass, greater sea-spurry and common scurvygrass.

Karst

, inland cliffs and scarps

The Burren

Over 70% of Ireland's 900 native species occur in The Burren which is less than 0.5% of the area of Ireland. The Burren contains twelve Annex 1 habitats listed in the EU Habitats Directive. A 2001 survey found 28 different species per square meter in upland grasslands, with up to 45 species per square metre in some samples. 22 of Ireland's 27 native orchid species are found in the region. Such high diversity has several explanations. Firstly, several hundred square kilometers of species-rich unimproved limestone grasslands and upland pastures grazed mainly in winter, a practice which removes potentially dominant grass and weed species. Secondly, there is a mixture of Arctic–alpine and Mediterranean species, and calcicole and calcifuge species. The area is dominated by bare rock and rendzina soils.

Woodland

Woodland plants include wood sorrel, blackthorn, bird's nest orchid, wood anemone, bluebell, wood avens, bugle, ramsons, self-heal, dog violet, honeysuckle, holly, lords and ladies, herb robert and woody nightshade. Woods dominated by oak and birch, with lesser amounts of rowan, holly, hazel, yew and aspen are called western oakwoods and occur principally in the uplands of Ireland, Scotland and Wales. They are temperate rainforests.

Artificial habitats

Quarries, gravel and sand pits, roads and railways, field boundaries, walls, waste ground and rubbish tips contain such plant species as common ragwort, pineapple weed, hairy bindweed, creeping buttercup, common daisy, catsear, coltsfoot, fat hen, nettle, redshank, germander speedwell, ivy-leaved toadflax, rosebay willowherb, great willowherb and wall pennywort.
Cultivated ground
Julie A. Fossitt gives a habitat classification.

Conservation

Threats to the flora include agriculture, drainage, housing developments, golf courses, mowing of roadside verges and introduced species. Conservation agencies include the National Parks and Wildlife Service, the Northern Ireland Environment Agency, the and the Royal Society for the Protection of Birds. There is a Threatened Species Programme at the National Botanic Gardens. There was also a range of Non-Governmental Organisations in Ireland dedicated to preserving plant habitats such as the Irish Peatland Conservation Council, the Irish Wildlife Trust and the Native Woodland Trust.

Herbaria

Major herbaria are conserved at the National Botanic Gardens and the Ulster Museum.