The History of the European Fauna

by R. F. Scharff

Only one species of the well-known Polar genus Œneis, viz. Œ. aëllo occurs in the Alps. It has always been taken at very high elevations near the verge of the snow-line on the most lofty parts of the Simplon Pass, and other similar situations. Altogether about a dozen species of this genus of butterfly are known, most of which are confined to the polar regions of the Old World and the New, though some have found their way to the extreme south end of South America, in what manner is still a mystery. Like the preceding genera, this also appears to have emerged from Central Asia. The genus, too, is closely allied to the last, and though its range is not quite so extensive, it resembles it in many respects. The Alpine species of Œneis came to Europe by the Oriental route. But the Lapland species—at any rate Œ. jutta and Œ. bore—have taken a somewhat circuitous route to reach our continent. They first migrated from Asia to North America, and then by the old land-connections by way of Greenland to Lapland. It is noteworthy that Professor Engler felt convinced (cf. p. [171]) that the occurrence of many of the Arctic plants in North Scandinavia and Siberia could be best explained by the assumption of such a migration from Asia viâ North America to Europe rather than by the shorter route.

There are far more Alpine beetles than butterflies, but their geographical distribution is less well known, and it is therefore not at all safe to base important conclusions as to the origin of a fauna on that group alone; however, as far as my limited knowledge of the Coleoptera of the Alps goes, their general range seems to agree perfectly with other orders of insects. Many can also be traced to an Asiatic home, and the route they came by is the Oriental and not what I have called the Siberian.

Take, for instance, the genus Nebria, of which we have one species in England—a black insect with a bright reddish-yellow border and long light legs—known as N. livida. There are about eighty European species, most of which are confined to the Alps, the Caucasus, the Pyrenees, Spain, and Greece. The genus, however, ranges all over the Holarctic Region, that is to say roughly, over Europe, Central and Northern Asia, and North America. The centre of distribution lies in Central Asia. If the genus had poured into Europe by the northern or Siberian route, we should probably now find many species in Northern Russia, Germany, and France; but this is not the case, and we may therefore assume with some justification that the Southern or Oriental route was the only one available at the time when the bulk of the species of Nebria wandered to Europe. Many of the Nebrias occur in Switzerland and in the Alps, generally on the margins of the snow-fields and glaciers, like N. Germari and Brunii. Others, for example, N. atrata, ascend to the highest limit of animal life, having been observed at a height of over 10,000 feet.

Of the remaining orders of insects we know as yet very little. Central Asia and even Siberia are only beginning to be explored, and their invertebrate fauna—except Lepidoptera and Coleoptera—is practically unknown. However, I cannot conclude this short summary of some of the more characteristic Alpine animals without referring to the Grasshoppers which are so conspicuous in the mountains. The mountain air simply rings during a bright summer's day with the loud and cheerful song of millions of these insects. It is one of the most vivid impressions a tourist brings back from Switzerland—this constant shrill sound issuing from an apparently invisible source.

Among these Grasshoppers there are some highly characteristic Alpine genera. Pezotettix—formerly known as Podisma—is one of these. P. alpinus is almost confined to the high Alps; with P. mendax it occurs in lower levels chiefly towards the south-east, that is to say, in the direction of Hungary, Servia, and Dalmatia. P. frigidus occurs not only in the high Alps, but also in Lapland. P. Schmidti and P. salamandra are found in Carinthia, Servia, and Transylvania; and one species also inhabits the Pyrenees and another the Italian Mountains. Finally, the only English species of Pezotettix, viz. P. pedestris, has been taken in Sweden, Denmark, and then again in Austria, Hungary, Servia, etc., as far east as the Volga, and also on the high Alps, in Sardinia and the Abruzzi Mountains in Italy.

Very little, as I remarked, is known of the Asiatic range of this genus, but either the same or a closely allied one has many representatives in North and South America. Whether Pezotettix is therefore of Asiatic origin we cannot positively affirm, but whatever view we take, the general range of the European species indicates that the migration took place from the Alps in a south-easterly direction, or to them in a north-westerly one. That is to say the Oriental route, and not the Siberian, was utilised by the migrants.

Fortunately, we know a little more about another Grasshopper genus, called Chrysochraon. There are only two species, one of which, Chr. dispar, has been found from Northern France to the mountains of Servia, but not in the Alps. The other, Chr. brachypterus, has a somewhat similar range in the plain; but, moreover, it inhabits the Alps up to a considerable height. It is interesting to note that both these Grasshoppers again turn up on the Amur in Eastern Siberia.

In conclusion, I might mention one more Grasshopper, viz. Tettix, because it includes a species—T. bipunctatus—which, though well known in the plain of Middle and North Europe, ascends the Alps to a height of nearly 10,000 feet. It is one of the few instances I know of an animal occurring in the same form in such an enormous range of altitude—from sea-level to the highest regions where animal life is known to exist. It is also known from Asia Minor and Siberia. T. subulatus has a similar distribution, but is more common in Southern Europe than the other. T. fuliginosus occurs in Lapland and Siberia, T. meridionalis and T. depressus all along the shores of the Mediterranean. There can be no doubt that here also we can trace migration to or from Siberia, and again, as on previous occasions, by the Oriental route.

We now possess a fair general idea of the fauna of the Alps. We have learned that a good many of the animals are indigenous, and that others have migrated to the Alps by various routes. The majority of these have come from Central and Southern Asia with what has been described as the Oriental migration. A much smaller number have reached the Alps from the north and the west, but none of the latter are among the high Alpine forms. What will be the most surprising revelation is that the eastern species, which arrived in Europe with the Siberian migration, are practically absent from the Alps proper. No doubt some of them still survive in the lowlands of Switzerland and the Tyrol, but none of the true Alpine fauna owes its origin to the Siberian migration. If we compare the Alpine mammals with the Siberian forms which reached England (vide p. [202]), we at once perceive the difference. We should expect to find in the Alps—if not the Reindeer and the Glutton—the Arctic Fox, the little Pica, the Lemmings, and the pouched Marmots. It might be urged that some of the smaller Siberian carnivores and rodents do inhabit the Alps. So they do. The Stoat and Weasel have found such a congenial home in Europe, both in the plain and mountains, that they have spread rapidly to the latter, and no doubt reached within a comparatively short time the great heights at which they now occur in the Alps. But the Voles (Arvicola) have scarcely spread beyond the region of fields and cultivated ground. A height of 5000 feet at the most marks their maximum altitude in the Alps.

The fauna which reached the Alps in miocene and pliocene times, as well as the indigenous element, must have survived the Glacial period in their mountain home. Though I think that the conditions of the climate at that time and the size of the Scandinavian glaciers have been greatly exaggerated, there can be no doubt at all about the enormous size of many of the Alpine glaciers at this period. The climate was probably much moister but not colder than what it is now, possibly warmer. The snowfall was therefore greater, so that glaciers filled many of the lower valleys of Switzerland which are now quite free from ice, and even invaded the plain. But there is no reason whatsoever why the Alps should not even then have supported a luxuriant fauna and flora as they do now. Possibly many of the miocene plants and animals became extinct then, but extinction of species occurs at the present day. We hear complaints that the Chamois and the Steinbock have nearly vanished; we know that the Marmot is now much scarcer than it used to be, and that the Edelweiss and many other plants are more and more difficult to find, and seem rapidly to disappear. No doubt all this is in a great measure due to the influence of man, but not altogether. There is a constant struggle for existence going on among the animals and plants themselves—the stronger and fitter species driving the less fit and weaker into a corner, where they finally succumb. This happens now just as it did in pliocene and pleistocene times, and need not imply change of climate.