The History of the European Fauna

by R. F. Scharff

If we suppose that an extensive centre of origin existed in the Polar area, or we may say in Greenland, both animals and plants would have been able to spread from it into Northern Europe and North America by means of the land-connections which are generally supposed to have existed in pliocene times, that is to say, just before the commencement of the Glacial period. There must have been at this time a connection too between Scotland and Scandinavia, which will be dealt with more fully presently. The important point is to consider what light the Greenland flora and fauna will throw upon the problem of the continuity of the aforesaid land-connection during the Glacial period. We have seen that the Barren-ground Reindeer, a typically Polar species, penetrated as far south as the Pyrenees, the Arctic Hare went as far, while a number of other species of Polar animals and also of plants occur in the Alps. Of these it remains to be seen how many have come direct by way of Northern Europe or from the Polar Regions by way of Asia. At any rate, as the origin of the Alpine animals and plants will be discussed in another chapter, there is no need to dwell on this subject at present.

From the nature of the distribution in Ireland of Arctic plants and animals, which occur mostly on the north and west coasts, it would seem that a stream of migration entered from Scotland, and I have no doubt that that same migration came into Scotland directly from Scandinavia by a route over which now roll the waves of the North Sea. There is, moreover, as I already mentioned on p. [94], a very interesting so-called American element in the north-western European flora, that is to say, plants now found in North-west Europe and North America without occurring in Greenland or any of the islands which might have formed the former highway between the Old World and the New. These are probably some of the more ancient Polar plants which have become extinct in the Arctic Regions and survive in isolated patches in favourable localities. We find seven species of these American plants in Ireland, almost entirely confined to the north and west coasts. These are Spiranthes Romanzoviana, Sisyrinchium anceps, Naias flexilis, Eriocaulon septangulare, Juncus tenuis, and Polygonum sagittifolium. To them must be added another plant recently discovered by the Rev. Mr. Marshall in the south of Ireland, namely Sisyrinchium californicum. As I have mentioned in former writings, there are three species of North American freshwater-sponges in Ireland which have not hitherto been discovered elsewhere in Europe or in Asia. These, namely Ephydatia crateriformis, Heteromeyenia Ryderi, and Tubella pennsylvanica, all occur in some of the lakes near the western coast of Ireland.

There are in all groups of animals instances of species which are confined to Europe and North America, while unknown from the Asiatic continent, but none, as far as is known, have such a very discontinuous range as that of the animals and plants just referred to. In some cases the species still occur in Greenland, and in this way make it still clearer that their migration in former times took place from one continent to the other by way of that country. As an interesting instance of such distribution may be mentioned the Common Stickleback (Gasterosteus aculeatus), which is found in Greenland, North America, and Europe, but is quite absent from Asia. Then again, the Nine-spined Stickleback (Gasterosteus pungitius) is confined to Western Europe and North America, though an allied species, Gasterosteus sinensis, lives in China and has probably penetrated there from the New World across the old Behring Straits land-connection.

The Coleoptera Diachila arctica, Elaphrus lapponicus, and Blethisa multipunctata are good instances of species which have come to us from North America by way of Greenland. I have already referred to the Lepidoptera, but might add that eleven species of Anarta occur in Scandinavia, eight of which reappear again in Labrador, none of them, however, being met with in Siberia. Then again, take the interesting Crustacean Lepidurus (Apus) glacialis. It is found in Greenland, Spitsbergen, Lapland, and Norway; and formerly, as we know from fossil evidence, it ranged into Scotland. Another Phyllopod, viz., Branchinecta paludosa, inhabits Greenland, Lapland, and Norway. Mr. Kennard suggests that the freshwater Snail Planorbis glaber might also belong to the same migration. And there are no doubt large numbers of others.

Professor Emery mentions that Northern Europe possesses one peculiar genus of Ant, viz., Anergates. This is closely allied to Epoccus, another genus confined to North America. It seems probable, therefore, that both of these have sprung from an Arctic genus which sent two branches southward into the two continents without there being any migration through Asia.

The general range of the Arctic plants and animals gives no reason to suppose that the Greenland fauna and flora of the present day were exterminated by the Glacial period and then reintroduced into that country. Nor have we any evidence that such a fauna and flora migrated across the British Islands northward. The Greenland animals and plants too are altogether much more like the Lapland ones than those of Scotland. It will also become evident to the reader of this work that no very extensive migrations could have taken place during the post-glacial period, and that almost everything points to a survival of both fauna and flora in northern latitudes throughout the Glacial period.

If we take into consideration the palæontological evidence of the two races of Reindeer in Europe, one of which came to us from the north, and that the Arctic Hare and one of the races of the Stoat entered our continent from the same direction—when we, moreover, carefully review the numerous other instances quoted of plants and animals which could only have reached us from the north, the irresistible conclusion is forced upon us that a land-connection existed at no very distant period between Northern Europe and the Arctic Regions of North America. This is not a new hypothesis. Many geologists are of opinion that a land-passage did exist within comparatively recent times, uniting Europe, Greenland, and North America. But the position of this old land-bridge, as I have mentioned, has been generally placed somewhat farther south than I should feel inclined to put it.

The fact that very extensive glaciers formerly covered the mountains of Scandinavia on the eastern side, whilst they scarcely reached the sea on the west (Feilden, a, p. 721), seems to favour the view of a warm current having washed the western shores. As I shall attempt to show later on (p. [179]), the Arctic Ocean extended across Northern Russia at that time from the White Sea to the Baltic—that is to say, to the eastern shores of Scandinavia, which country was then joined to the north of Scotland. The predisposing agents to a copious snowfall existed in Scandinavia, viz., an excessive evaporation of the warm Atlantic waters and unusual precipitation in the form of snow owing to the cold given off by the Arctic waters on the east side of the mountains. It is therefore probable that the land-connection which united Europe and North America was farther north than has been supposed.

If we sail straight across from Northern Scandinavia to Greenland, we traverse an exceedingly deep marine basin; but if we examine the sub-marine bank which runs all along the coast of the former country from south to north, we find that it does not end when the extreme north of the land is reached. The bank extends much farther north, and is continued as far as Spitsbergen. As I have said before, the latter, as well as Bear Island, must be looked upon as the remains of a large mass of sunken land—the ancient Scandinavia stretching far into the Arctic Circle. Professor Nathorst speaks of Spitsbergen as a northern continuation of Europe, not only geographically, but also botanically and geologically. However, this northern land must have stretched even farther—not perhaps farther north, but farther west. Here lay the old land-connection between Scandinavia, Greenland, and North America ([Fig. 13]). One of the highest authorities on the geographical distribution of plants, Professor Engler, maintains that the arguments in favour of this Arctic connection of America with Europe are more weighty than those for a land-bridge between Greenland, Iceland, the Faroes, and Great Britain. Moreover, he is of opinion that a certain number of species of plants belonging to the Alpine flora of Arctic Siberia have travelled from Scandinavia viâ Greenland and North America to Eastern Asia, and not direct from Scandinavia to Siberia (p. 143).