Mayo Ireland

Geomalacus maculosus.-Ireland, extreme south- west. Great Britain, absent. elsewhere, N.W. Spain, Portugal. This is the famous Spotted Slug of Kerry. beetles. Pelophila borealis.- ireland, western half. Great Britain, Orkneys. elsewhere, sub-arctic Europe. A little black ground-beetle found on lake shores.

Otiorrhynchus auropunctatus.-Ireland, coast from Wicklow to Donegal. Great Britain, unknown. elsewhere, Pyrenees and Auvergne. A handsome species.

Spiders. Tegenaria hibernica, the Dublin House Spider.-ireland, Dublin district mainly, also in the west and south. Unknown elsewhere, but nearly related to a Pyrencan species.

Shrimps. Mysis relicta.-ireland, a few lakes in the north. great britain, unknown. elsewhere, Scandinavia, Russia, N. America. This is a small fresh- water shrimp, its relatives being marine. Woodlice. This small group furnishes much interesting evidence. Three species, in Ireland confined to Dublin (Eluma purpurascens, Metapornothus cingemdus, Philoscia Couchii), are elsewhere confined to thy Mediterranean region and the Atlantic islands, except that the first occurs also in Cornwall. In addition Trichoniscus vividus has the distribution S.E. Ireland, France, Spain ; and Metapornothus cingendus, which ranges along the. Irish coast from Cork to Mayo and Dublin, is found also in Devon, and, like the last, in France and Spain.

Sponges. Heteromeyenia Ryderi, a sponge which is abundant in lakes in many parts of Ireland and sparingly in western Scotland, is elsewhere known only in N. America.

Flowering Plants. Saxifraga umbrosa and ,S. Geum. -Ireland, the former widely, the latter more sparingly, along the west coast. Both found elsewhere only in the Spanish peninsula. The former is tlie well-known London Pride.

Arbutus Unedo, the beautiful Strawberry Tree.- ireland, Killarney district. great britain, un- known. elsewhere, from the Bay of Biscay through- out the Mediterranean.

Dabeocia -polifolia, Erica, mediterranea, E. Mackaii.– These three heaths, characteristic of West Mayo and West Galway, are all confined, elsewhere to S.W. France and Spain, the first extending to the Azores. It should be noted that two other heaths, E. varans and E. ciliaris, in the British Isles found only in S.W. England, have- the same distribution on the Continent. Pinguicula. grandiflora, the lovely Great Butterwort.- - Ireland, south-west. great Britain, unknown. elsewhere, Spanish peninsula and Alps. Euphorbia hiberna, the Irish Spurge.-Ireland, along the west coast. great Britain, Devon. else- where, W. France, N. Spain.

Neotinea intacta.-A little Orchid, in Ireland abundant on certain western limestone areas, great Britain, unknown. elsewhere, Mediterranean and Asia Minor.

Spiranthes Romanzoffiana, an interesting and fragrant Orchid.-Ireland, Lough Neagh basin (N.E.), Kerry, Cork (S.W.). great Britain, unknown. elsewhere. northern N. America, Kamtschatka. Sisyrinchium angustfolium, the Blue-eyed grass of Canada.-Ireland, widespread in the west. Great Britain, unknown. elsewhere, northern N. America. Simethis bicolor, a slender Liliaceous plant found in Kerry.-Great Britain, Dorset. elsewhere, S.W. Europe and the western Mediterranean. Eriocaulon septangulare, the Pipewort.-Ireland, west coast. Great Britain, Skye. elsewhere, northern N. America.

Glyceria fcstucaeformis, a maritime grass.-Ireland, Co. Down and Shannon estuary. Great Britain, unknown. elsewhere, Mediterranean.

The facts of distribution detailed in the case of the foregoing species of animals and plants may be sum- marized as follows:-quite a number of species which inhabit western Ireland arc absent from northern Continental Europe, and have their headquarters in the Spanish Peninsula, in some cases spreading thence eastward along the Mediterranean, or westward and southward to tlie Atlantic islands. A few species found on the eastern coasts of Ireland, or on both cast and west coasts, have a similar distribution. Where any of these occur in Great Britain, as happens in only a few cases, they are confined to south-western England. In addition to this southern group, we find in Ireland a number of remarkable northern forms, elsewhere un- known from such low latitudes, a few of them reappearing in western Scotland. They have their headquarters either in sub-arctic Europe, or in the northern parts of North America.

Now, in endeavouring to arrive at a conclusion as to how these animals and plants of far countries reached Ireland, we have to consider whether they possess special means for rapid or distant dispersal over large areas of sea or land, which would account for their having reached Ireland while other members of the same faunas and floras were left behind. We find that they arc not specially favoured in this respect. As regards the animals, it is true that many Beetles have considerable powers of flight, and that Spiders may attain wide dispersal when young by means of gossamer webs. But Mollusks and Woodlice are at all stages of their life-history unprovided with any better means of dispersal than their power of crawling. The Woodlice are particularly sensitive creatures, living half under- ground, many of them unable to endure even a hot sun or a short immersion in water. The Kerry Slug is likewise quite unfitted for adventures by sea or land. Turning to the plants named above, We find that their powers of dispersal are as a whole low. Plants achieve dispersal almost solely in the seed stage ; many plants possess seeds displaying special characters, such as minute size, lightness, or the presence of parachute appendages, which render possible the performance of daring aerial voyages, or prolonged journeys by water. Other seeds, mostly ones which are embedded in juicy fruits, are eaten by birds, and carried by them over stretches of both land and sea. We find among the plants listed above no preponderance of species possessing such seeds. Two Orchids are indeed in the list, and the seeds of all Orchids are very buoyant in air, owing to the loose netted coat in which they arc enclosed ; and one other plant, the Arbutus, has a juicy fruit which is a favourite food of birds. To these we may allow a possibility of fairly distant dispersal, proportionate to the rapid digestion of a bird in the one case, and to the rate of fall of the seeds in the. others. In all the other cases, the seeds are devoid of facilities for air- dispersal, and all of thorn which have been tested (10 out of 13) sink in water–six of them instantly, the remainder after a few days immersion. It is clear, then, that neither these animals nor plants exhibit as a group modifications which would favour the theory that they migrated direct from their distant homes to the isolated regions which they inhabit in Ireland. It seems more reasonable to look on them as very old inhabitants of the country, which arrived here at distant periods when the distribution of sea and land was different, allowing, in the case of the southern species, of migration along an old western coastline. The problem of the American species is more difficult. But the improbability of direct dispersal is here so great as to suggest a former extension of land, connecting north-western Europe with Greenland and North America by way of Iceland.

This question of the northern and southern elements in the Irish fauna and flora has been dealt with at some length, because it is quite the most interesting problem connected with the natural history of the country.

For the rest, the plants and animals occurring in Ireland, and their distribution, accord in general with the position of tlie island and the physical conditions which prevail upon it. Whatever may be tlie history of the peculiar northern aud southern elements of tlie fauna and flora there can be no doubt that the bulk of our animals and plants migrated into the country from the eastward, at a time when Ireland formed part. of the European mainland, and the difference between Ireland and Great Britain, as regards their animal and vegetable inhabitants, is mainly one of reduction in the further and smaller island. As pointed out on a previous page, the insular position of Ireland and the prevalence of westerly winds combine to render the climate unusually mild, equable, and damp. These features are specially noticeable in the west and south, which are also the regions of greatest exposure. Geological causes such as the nature of the rocks and the discontinuity of the glacial deposits, also combine to render the west and south-west tlie barest and least cultivated portion of the country. In Donegal, West Mayo, West Galway, Kerry and West Cork in particular, bog, moorland, and rocky mountains occupy large areas. Woodland is rare, though where shelter is afforded from wind trees grow luxuriantly. Lakelets are very numerous, lying mostly in rock basins. Snow and frost are rare, and of short duration. Cloud and mist are prevalent, and the rain- fall is high (40 to 70 inches). The, summers are cool, and drought occurs but seldom. All of these conditions have their due effect upon life within tlie area.

In the middle part of Ireland striking changes of surface produce corresponding changes in the nature of the fauna and flora. Instead of mountains formed of ancient granites, gneisses, slates and sandstones, we have a far-stretching plain of limestone, mostly overlaid by a sheet of limy boulder-clay. Great peat-bogs occupy much of the surface, with a good deal of wet land and swamp, and small lakes especially towards tlie west. The River Shannon, meandering southward across tlie country, spreads out here and there over the plain in broad lake-like expanses. Rainfall and exposure are less than in the west ; summer is rather warmer, and winter colder. The effects of these conditions are more fully set out in the more detailed account of the country contained in the other volumes of the, scries.

In the east we get conditions which conform more nearly to those found in western England. Lighter soils prevail, and a drier summer than is found else- where in Ireland. Bogland ceases to lie a familiar type, and woodland reaches its maximum. As a result of greater similarity of conditions and of proximity, we find in the east a closer approximation in the fauna and flora to those of Great Britain than is observable elsewhere in Ireland.

As regards the large clement in the vegetation which owes its presence to the activities of man, there can he no doubt that the introduction of certain plants - Rhopalomesites Tardyi and its distribution in the British Isles culinary and medicinal herbs in particular-took place at an early period. In medieval times, the monasteries were the centres of dispersal for this section of the flora. Certain species, such as Inida Hclenium, Petroselinum sativum, etc., are still found, associated with the ruins of ancient abbeys ; and certain non-native plants which are now widespread and established, such as Aegopodium Podagraria, Smyrnium Olustrum, Allium Babingtonii, probably owed their first introduction to the monks. The importation of seeds of cereals and of green crops for the use of tillers of the ground has been from early times, as it still is, a fruitful source of alien plants. But as most of these seeds came from the east and south, and belonged to plants accustomed to lighter soils and a warmer climate than are found in Ireland, the bulk of them have not succeeded in establishing themselves ; and those which, have clone so have their headquarters in eastern Ireland, where climate and soil best suit their requirements. If tlie list of weed seeds detected in samples of agricultural seeds imported into Ireland be compared with the recorded list of aliens found growing in the country, tlie high mortality among these immigrants will be apparent. Nevertheless, as elsewhere, introduced plants form a considerable section of the Irish flora, varying in standing from species fully naturalized in the country, and easily holding their own among the native flora, down to fleeting waifs of tilled land, which are present with us only on account of the continual ousting of the native flora by ploughing, and the frequent introduction of fresh seed. The in- troduction, accidental or deliberate, of new plants still goes on, and occasionally a fresh species obtains a footing in the country, sometimes spreading rapidly. The latest instance of this kind is Matricaria discoidea, an American annual first observed in Ireland in 1894, now found on roadsides and waste ground almost all over the country.

Among our animals, introduction docs not play nearly so important a part, and is seldom successful unless protection is afforded. The Rabbit, Lepits cuniculus, Squirrel, Sciurus vulgaris, and Brown Rat, Mus dccumanus, however, afford instances of successful early introduction-the former two no doubt deliberate, the last accidental. Among the Mollusca, several species, suclh as Helix rufescens and the Testacellas, are considered not indigenous to Ireland ; and among the Beetles, Woodlice, and other groups similar instances occur. But most of the introduced species, such as the Cockroaches and Cricket, only maintain themselves with the aid of the artificial habitat with which man supplies them.

Posted on April 17th, 2008 under Geography. Tags: Atlantic islands, coasts Ireland, Continental Europe, Devon, Donegal, Dublin, Europe, fauna and flora, Flowering Plants, Ireland, Kerry, Kerry Slug, Killarney, Lough Neagh, Matricaria discoidea, Mayo, Orchids, Rhopalomesites Tardyi, River Shannon, seeds, shrimp, soil, species, Spider, tlie island, West Galway, Wicklow. RSS 2.0 feed. Leave a response, or trackback.