We are told by Sir Archibald Geikie
that “from the Pyrenees eastwards,
through the Alps and Apennines into Greece, and the
southern side of the Mediterranean basin, through
the Carpathian Mountains and the Balkan into Asia
Minor, and thence through Persia and the heart of
Asia to the shores of China and Japan, a series of
massive limestones has been traced, which, from the
abundance of their characteristic foraminifera, have
been called the Nummulitic Limestone. Unlike the
thin, soft, modern-looking, undisturbed beds of the
Anglo-Parisian area, these limestones attain a depth
of sometimes several thousand feet of hard, compact,
sometimes crystalline rock, passing even into marble,
and they have been folded and fractured on such a
colossal scale that their strata have been heaved
up into lofty mountain crests sometimes 10,000, and
in the Himalaya range more than 16,000 feet above the
sea.” “Nowhere in Europe,”
continues the same author, “do
oligocene strata play so important a part in
the scenery of the land, or present on the whole so
interesting and full a picture of the state of Europe
when they were deposited, as in Switzerland.
Rising into massive mountains, as in the well-known
Rigi and Rossberg, they attain a thickness of more
than 6000 feet.” “By far the larger
portion of these strata is of lacustrine origin.
They must have been formed in a large lake, the area
of which probably underwent gradual subsidence during
the period of deposition, until in Miocene times the
sea once more overflowed the area.”
From these remarks by our most eminent
British geologist, we gather that in early Tertiary
times much of the present area of Switzerland was
either a sea or a large freshwater lake. The Alps
were then appearing in this sea, probably as a chain
of islands, and in the beginning of the Miocene Epoch
one large elongated island had made its appearance the
future European Alps. I have already mentioned
that the Miocene Sea skirted the Alps from the Mediterranean
up the valley of the Rhone and along its northern
and eastern margin. Miocene marine deposits are
also known from the Southern Alps and the east side
of the Apennines, from Corsica, Sardinia, and Malta.
No trace, however, of them has been noticed anywhere
along the AEgean Sea or on the Balkan peninsula.
The Alps were therefore connected to the east with
the outliers of the Balkan Mountains, and in this
way with Asia, from which they received so large a
proportion of their fauna and flora. In pliocene
times the sea still washed the southern shore of the
Alps, but to the north dry land gradually supplemented
the sea, and the Alpine fauna and flora were able
to pour into the plain. It was then that the Arctic
species which we have learned had migrated
into Northern Europe from the north found
their way to the Alps. In a similar way Lusitanian
forms in fact, species from almost all
parts of Europe were now free to wander
to the newly opened up peninsula which had become
part of the mainland of Europe. The typical Siberian
species had not entered our continent at that time,
it was not till much later not until the
middle of the Pleistocene Epoch that they
made their appearance at the foot of the Alps, but,
as we shall see later on, it is doubtful whether many
of these species ever reached the mountains.
The fauna of the Alps, and also the
flora, is therefore made up of a number of component
elements. In the first place we have the Oriental
element the migrants from Central and Southern
Asia. When the nature and origin of the Oriental
fauna in Europe was discussed, reference was made
to the fact that we can distinguish an older
from a newer Oriental migration. Both of these
have entered the Alps. As we might anticipate,
many of the older Oriental migrants have developed
into new species, laying the foundation of an indigenous
Alpine element. From the fact that they set foot
on the Alpine peninsula, it might be expected that
there could have existed no mountains to speak of.
The climate was mild and damp. Now as the country
rose, and a formidable mountain range took the place
of a hilly island, the whole fauna was lifted up and
transferred to entirely different conditions.
A modification of their structure to suit the new
surroundings was therefore to be anticipated, and
that is exactly what occurred, though not in all cases.
Take, for example, the goats which
are of Asiatic origin. Every one has heard of
the “Steinbock,” the Alpine
mountain goat (Capra ibex) though
very few have seen it in its native haunts, where it
is now on the verge of extinction. A closely
allied species (Capra sibirica) inhabits the
Altai and Himalayan Mountains; a third species (Capra
sinaitica) lives in Palestine, and has entered
Egypt by way of the Sinaitic peninsula. Another
(C. aegagrus) occurs in Asia Minor, Persia,
the island of Crete, and some of the Cyclades.
This exemplifies what I remarked in the last chapter
about the former land-connection between Greece and
the Asiatic continent. Finally, we have the Pyrenean
Goat (Capra pyrenaica), which is found in the
Pyrenees, the higher ranges of Central Spain, in Andalusia,
and Portugal, thus indicating that it probably reached
the Spanish peninsula from the south by means of the
old Sicilo-Algerian highway, especially as remains
of the species occur in the cave deposits of Gibraltar.
The ancestors of the goat-like Antelope known
as the Chamois (Rupicapra tragus) no
doubt also came from Asia. The genus is not represented
there, but Nemorhoedus and Budorcas
are allied Asiatic genera, while the Rocky Mountain
Goat (Haploceros montanus) also has certain
affinities with the Chamois. Besides the Alps,
the latter occurs in the Caucasus and the Pyrenees.
The Alpine Marmot (Arctomys marmotta) is sometimes
quoted as owing its origin to the Siberian pleistocene
migration, but it does not occur in Siberia now, nor
is there any palaeontological evidence that it was
ever found there. The genus Arctomys is
an ancient Asiatic genus, to judge from its general
range. Only two species occur in Europe, one of
which, the true Siberian Marmot (A. bobac),
just enters our continent in the east or
rather, it is one of those species which came to us
in pleistocene times and are now gradually retreating
towards their native land. The genus, however,
is probably not of Siberian origin. No less than
seven other species occur in Asia, six of which are
confined to Central Asia and the Himalayan Mountains,
while four have wandered to North America. The
sequence of events, therefore, was that the ancestor
of Arctomys marmotta probably came to the Alps
direct from Central Asia by way of Asia Minor in miocene
or pliocene times. It has since become modified
into a distinct species, and has spread to the European
plain, where it occurs fossil in pleistocene strata,
and to the Carpathian Mountains and the Pyrenees.
The great majority of species of the
large genus Microtus (Arvicola) are
Asiatic, and there can be little doubt that it has
originated in that continent. There is one species
of Vole (Microtus nivalis) which occurs in
the high Alps, and which has been supposed to be a
typical Alpine form. It is known, however, to
occur also in North Italy and in Bohemia, while Microtus
leucurus of the Pyrenees is identical with this
species. But its range is by no means confined
to Europe, for it has also been discovered in Syria
and Palestine, while a closely allied form exists
in the Himalayan Mountains. This shows clearly
that the species has migrated to the Alps from Asia
Minor. That this migration may have taken place
at an early period at a time when Sardinia
and Corsica were still connected with Southern Europe is
indicated by the occurrence of an extinct Vole (Microtus
brecciensis) in Sardinian and Corsican pleistocene deposits.
All the Alpine species mentioned except
the Chamois can be easily traced to their former Asiatic
home. But even it has its nearest relations in
Asia. I might also refer to another Vole (Evotomys
Nageri) which is practically confined to the Alps
and Northern Italy, and which has probably originated
there, though most of its nearest relations are either
Asiatic or North American species.
But besides these Asiatic immigrants
and their modified descendants we have a small truly
native Alpine mammalian fauna. Sorex alpinus the
Alpine Shrew occurs only in the Alps, the
Harz Mountains, Pyrenees, and Carpathians. The
genus has been found in European eocene strata, in
vastly older deposits in our own continent than elsewhere, so
that it is extremely probable that it has originated
there. It may then have developed a new centre
of distribution in the newly-formed Alps where both
Sorex alpinus and S. minutus (pygmaeus)
have their home. From there they again spread perhaps
already in miocene times to Asia and
North America, where a large number of new species
originated. It seems to me even probable that
one of these Asiatic species of Sorex, viz.
S. araneus (vulgaris), subsequently migrated
towards the old home of its forefathers, since we
find it more or less confined to Central and Northern
Asia and Northern Europe.
The Alpine Hare
(Lepus variabilis) is of Arctic origin.
It spread southward into Europe, North America, and
Asia in early glacial times, and reached our continent
from Spitsbergen by means of a direct land-connection
with Lapland. The Scandinavian peninsula was
then separated from Russia, but connected with Scotland
and Ireland. Since England was
then united to France, the Alpine Hare was able to
invade western continental Europe and all the mountain
ranges. Its range is very discontinuous, small
colonies being scattered all over the mountainous
parts of the Northern Hemisphere, while the European
Hare a closely allied species occurs
in the plain, and now occupies to some extent the
former haunts of the Alpine Hare. Might not the European Hare, as suggested,
possess some advantages which enabled it to drive the
other into more inaccessible parts, thus producing
the peculiarity of range? The present distribution
of the Alpine and the European Hare (L. Europaeus)
appears to me to strongly support such an assumption.
It is not the cold which has driven the Alpine Hare
to the Alps; and its presence there is not, as is
often supposed, a “standing testimony of a
former arctic climate” in Europe, but merely
the necessary consequence of the weaker species being
thrust into less accessible regions by a stronger
rival.
Muscardinus avellanarius, the
common Dormouse, though by no means confined
to the Alps, has probably originated there. It
is found up to a height of nearly 5000 feet in these
mountains, and is spread over Europe at nearly equal
distances from the Alps in all directions. Being
absent from Ireland, Scotland, Norway, and Northern
Russia, it seems as if it had only diffused northward
in more recent times.
The closely allied genus Myoxus
is likewise of European extraction, some species being
known from French eocene deposits.
There are only a few typically Alpine
Birds. One of these is the Alpine Accentor (Accentor
collaris), which on rare occasions visits England,
and Northern Europe generally. It is, however,
by no means peculiar to the European Alps; a variety
of this species occurs in Central Asia, Eastern Siberia,
and Japan. The only other Accentor inhabiting
our continent is the Hedge Accentor (A. modularis),
which is resident over the greater part of it, and
also in North Africa and the Mediterranean Islands.
It also extends its range across the AEgean Sea to
Asia Minor, so that really not a single Accentor is
peculiar to Europe.
Both the European species are evidently
old forms, and the genus, as might be expected, is
certainly Asiatic. No less than ten other species
of Accentor are known, all of which are confined to
Central Asia and the Himalayan Mountains, and are
therefore all Holarctic. I may mention that much
difference of opinion still exists as to the true zoological
position of this anomalous genus. It has been
located in several different families by various ornithologists,
but has not yet found a permanent resting-place.
Another bird generally considered to be peculiar to
Switzerland is the Alpine Chough (Pyrrhocorax alpinus),
but its range extends across Asia Minor to the Himalayas.
Whether the European Chough should not form a distinct
genus is a matter of opinion. Some of our leading
ornithologists, like Dr. B. Sharpe, are inclined to
separate it from Pyrrhocorax; however, there
is no doubt that it is closely related to the Alpine
Chough, whatever view we may take of the generic distinctness.
It inhabits principally Western and Southern Europe,
also North Africa; and its range extends eastward to
the Himalayas, China, and Eastern Siberia. If
any doubt still existed as to the Asiatic origin of
the Choughs, it may be noted that the only two other
closely allied genera, viz., Corcorax and
Podoces, live in Australia and Central Asia
respectively.
There are two other birds to which
I should like to refer. These are the Rock Sparrow
and the Alpine Snow Finch. The first of these
(Petronia stulta) is by no means peculiar to
the Alps. It is the only species of the genus
inhabiting Europe; and besides the Alps it occurs in
Southern Europe generally, and ranges as far west
as the Canaries and Madeira. Eastward it is not
found beyond Central Asia. Of the remaining five
species of Petronia, two occur in Asia (including
India) and three in Africa. Whether the genus
is African or Asiatic is immaterial for our purpose,
since, in any case, the only European species came
to us from the east with the Oriental migration.
The distribution of the Alpine Snow Finch (Montifringilla
nivalis) is very similar to that of the birds
we have just been considering. It inhabits the
Alps up to a great height, but occurs also on the
Pyrenees and other South European mountain ranges
as far east as Palestine, where again it is found in
the Lebanon. The genus Montifringilla
has seventeen other species. Twelve of these
live in Central Asia and Japan, extending as far north
as Kamtchatka, while five inhabit Western North America
right down to Mexico. There is every probability
that in this case also we have to deal with an Asiatic
genus which spread eastward to America, and westward
to Europe.
As regards the Reptiles, there are
no peculiar Alpine forms, but among the Amphibia
some species deserve to be mentioned. Up to an
elevation of 10,000 feet we find in the Alps the Black
Salamander (Salamandra atra); and it is apparently
quite peculiar to them, never having been observed
in the plains. The handsome black and yellow Salamander
(Salamandra maculosa) so well known
as a terrarium specimen likewise occurs
in the Alps, and it has besides a fairly wide distribution
in Europe. It is known from Southern Germany,
the Pyrenees, Spain, Portugal, Sardinia, Corsica,
Greece, Syria, and Algiers. A third species (S.
caucasica) inhabits the Caucasus. The evidence
of distribution here points emphatically to an Alpine
origin of the genus Salamandra. We cannot
tell where the ancestors of Salamandra may have
come from, but several other genera of Salamandridae
are certainly Asiatic. Our common Newt (Molge
vulgaris) belongs to a genus with nineteen species,
several of which are peculiar to Europe. The general
range of the genus, however, extends to North America,
and it is more probable therefore that it originated
in Asia. If so, it certainly must have passed
into Europe at a very early date. Let us assume
the first Molges to have traversed the AEgean
Sea on terra firma to Greece in miocene
times, they might thus have been able to travel straight
on to the old Tyrrhenian continent of which Corsica
and Sardinia now form the remains, and also on to
North-west Africa. Indeed, we find high up in
the Corsican mountains an interesting large brownish-grey
Newt (Molge montana), and another in Sardinia
(Molge Rusconii). Again, in Algiers there
are two species, viz., Molge Poireti and
M. Hagenmuelleri, while the Moroccan M.
Waltlii passes into the south of Spain. Here
Molge boscae, M. aspera, and M. marmorata
originated, the latter passing into France.
Another branch of the Molge
tribe turned northward from Greece towards the newly
forming Alps; and there originated Molge alpestris
and M. palmata, which more recently have spread
into England (one at least), Germany, France, Austria,
and Southern Italy. Molge vulgaris is an Asiatic
species which wandered northward after entering Europe,
covering a large area, but never reached the extreme
south or south-west. M. cristata the
large Water Newt has a similar but not quite
so extended a range, while M. vittata never
managed to cross the borders of Asia Minor. Some
of the other species occur in China, Japan, and North
America.
None of the tailless Batrachians the
Frogs and Toads are peculiar to the Alps,
but one, viz. Rana temporaria, ascends
to the height of no less than 10,000 feet. It
is our common British Frog. No other Frog probably
ranges so far north or to such heights.
Let us now inquire what the invertebrate
fauna of the Alps teaches us. We are told by
Dr. Kobelt, the great authority on European land shells,
that a uniformity of character marks the Alpine Molluscan fauna. One of the characteristic
genera Campylaea often looked upon
as a sub-genus of Helix is a group
containing somewhat flattened conspicuous snails of
large size. These are found everywhere in the
Alps, and wherever they occur beyond the confines of
these mountains, remarks Dr. Kobelt, their origin
from the main stock is easily traced. They have
been gathered in the Apennines in Sicily, and even
beyond the Mediterranean in Algeria. On the Balkan
peninsula they occur right down to the most southern
point of Greece, but are not met with either in Crete
or Asia Minor. One species has been found sub-fossil
in Thuringia in Northern Germany.
Another truly Alpine genus, says Dr.
Kobelt, is the operculate Pomatias, which in
its geographical distribution offers some interesting
modifications from that of Campylaea. Less
limited to high elevations, it has spread over a greater
part of the plains. This has happened especially
in France, while in Germany one species advances almost
as far north as Heidelberg. In other directions
also the genus has travelled beyond the limits of
range of Campylaea. Pomatias occurs
in the Pyrenees and Northern Spain, in Sardinia and
Crete, and may, according to the same author, be expected
in Asia Minor, although no species has as yet been
met with there. In Greece, again, it has been
observed, and numerous species inhabit Tunis and Algeria.
Dr. Kobelt connects the wider range of Pomatias with the geological
history of the genus. He tells us that species of Pomatias
have been found in eocene deposits differing
but little from our present forms, while undoubted
Campylaeae are not met with till we reach the
upper Miocene.
Zonites is, according to Dr.
Kobelt, a third Alpine genus, whose range scarcely differs from the other two.
The centre of distribution lies at present in one
of the branches of the most southern Alpine chain
which help to form a large portion of the Balkan peninsula.
The bulk of the species inhabit that peninsula, the
Greek Islands (except Crete) and Asia Minor.
Neither in the Tyrol nor in Switzerland do we find
any Zonites, and the few species that do occur
in the south-eastern Alps only just cross the outliers
of these mountains. Between the south-western
Alps and the Rhone we again find a Zonites a
remarkable case of discontinuous distribution, since
the nearest other habitat of the genus is Monte Gargano
in South-eastern Italy, which is known to harbour
a good many interesting geographical puzzles.
We still have a good deal to learn
as regards the molluscan fauna of Sicily, Sardinia,
and Corsica. These islands have scarcely been
more than skimmed by conchologists, and Zonites
may inhabit one or all of these, which might indicate
to us the manner in which this genus travelled from
Southern Italy to Provence in the south of France.
The distribution of Zonites certainly does
not seem to imply an Alpine origin, because it is
almost completely absent from the Alps proper.
But I do not think my views differ materially from
those of Dr. Kobelt, since the Alps, in the wide sense,
include the mountains of the Balkan peninsula, where
I should feel inclined to locate the ancestral home
of the genus.
The small operculate genus Acme
is a similar case. Dr. Kobelt places the centre
of distribution on the southern slope of the Alps,
but scarcely any of the species inhabit the Alps proper.
Some occur in France, others in North Africa, Sicily,
Southern Italy, and the Caucasus. It is evidently
a very ancient genus. The species live in moss
or underground, and are not likely to be transported
across the sea by accidental or occasional means of
distribution.
Still another genus, which resembles
Acme in its geographical distribution, is Daudebardia a
small slug-like mollusc with a tiny shell. It
does not, however, range nearly so far north or west
as Acme, for it occurs neither in the British
Islands nor in Spain or the Pyrenees.
I shall not be able to refer to more
than a few of the most typical Alpine species of Lepidoptera,
but they may be taken as fair examples of the geographical
distribution of the rest of the group.
Even those visitors to Switzerland
who do not claim to be naturalists have heard of the
remarkably handsome and stately Butterfly known as
Apollo. To the ardent entomologist, the first
sight of this typical Alpine species is a never-to-be-forgotten
delight, and he generally brings home with him a rich
harvest of specimens. The more experienced Butterfly
hunter knows that there are no less than three different
kinds of Apollo or, as we should say more
correctly, of Parnassius in Switzerland.
There is first the common Apollo (Parnassius Apollo),
then the rarer and more local P. delius, which
inhabits more elevated regions, and finally the still
scarcer P. mnemosyne, which is only known from
the highest mountain ranges. It may be a surprise
to those who have accustomed themselves to connect
Apollo with the Alps, and who think the two belong
together and cannot do without one another, to hear
that it is by no means confined to them. It is
also found in Scandinavia, France, Spain, Russia,
and in Siberia. Parnassius delius is confined
to the European Alps and the mountains of Central Asia,
while P. mnemosyne is known from the Pyrenees,
Sweden, Hungary, Sicily, Russia, and Western Asia.
One other Parnassius inhabits Europe, viz., P.
Nordmanni of the Caucasus, but all the remaining
species of the genus and there are nearly
thirty more are confined to Central Asia.
A few, as we have seen, have reached Europe, some have
travelled to the Himalayan Mountains, and others to
Western North America. The centre of distribution
is certainly in Central Asia, and we have no reason
to suppose that the original home in this case does
not agree with that centre.
Melitaea, a genus to which
some of our British Fritillaries belong, has also
some typically Alpine members. Two of these, viz.
M. cynthia and M. asteria, are peculiar
to the Alps, the latter being only found at considerable
elevations. Most of the remaining fourteen European
species are also found in Central Asia. Thus
the isolated M. maturna, which in Europe is
confined to Lapland, is also known from the Altai Mountains,
which again are near the centre of distribution, since
some species of Melitaea range across the Northern
Pacific to Western North America.
The small British Mountain Ringlet,
and also the Scotch Argus, belong to a genus of butterflies
which is very characteristic of the European Alps.
But owing to its enormous geographical distribution,
its probable home is somewhat difficult to ascertain.
Nevertheless it is a noteworthy genus, especially
so from the fact that the two British species Erebia
epiphron and E. aethiops are taken at first
sight for true Arctic migrants. As neither of
them, however, occurs in Scandinavia, Greenland, or
Arctic America, this supposition must be abandoned.
They must be looked upon as species which once had
a wider range in the southern parts of the British
Islands, and which have survived in a few isolated
localities, where they are apparently on the verge
of extinction.
About sixty species of Erebia
are known to science, half of which are found in Europe,
the remainder in Siberia, the Himalayas, Arctic America,
Chili, Patagonia, South Africa, and Madagascar.
Though a few do range into these outlying regions
of the earth, Central Asia seems to lie near the centre
of distribution of the genus, and the probability is
that it also was its original home. Most of the
European species are high Alpine forms E.
glacialis being met with at a height of 10,000
feet and these are generally quite peculiar
to the Alps, showing that their ancestors came from
Asia at an early date, probably by way of Asia Minor
and Greece. A few, as for instance E. lappona,
range right across to the Altai Mountains from the
Alps, and at least one E. melas is
found in Greece. Erebia migrations seem therefore
to have taken place by the Southern or Oriental route
at different geological periods. But some of
the European species which are more or less confined
to the plain, and are either absent from Switzerland
or do not reach the higher elevations, appear to me
to have come by the more direct northern or Siberian
highway, at a still more recent period. These
are Erebia aethiops, medusa, ligea,
and ambla.
Only one species of the well-known
Polar genus Oeneis, viz. Oe. aello
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 Oeneis came to Europe by the Oriental
route. But the Lapland species at any
rate Oe. jutta and Oe. 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 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 via 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
, 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.
As soon as the Miocene sea to the
north of the mountains had retreated, a portion of
the Alpine fauna poured into the plain, and many species
have found their way to the British Islands, a few
to Scandinavia and Russia. Westward too, the
sea soon after retired and opened a way for those
Alpine species which were vigorous enough to extend
their range in that direction. South-eastward,
of course, a highway had long ago been open, and Alpine
forms which were able to migrate towards the incoming
Oriental stream, had no difficulty in doing so.
When they arrived in Greece, some turned westward
again and populated Sicily, Southern Italy, Sardinia,
Corsica, and Northern Africa, while others crossed
over to Asia Minor, which was then connected with
Greece, and wandered towards the Central Asiatic or
the Himalayan Mountains.
But, as I remarked, few of the typical
Alpine species reached Scandinavia and Lapland.
I have already referred to the similarity between
the Northern Scandinavian and the Alpine faunas
in a previous chapter, and I have shown that this
resemblance cannot altogether be explained by the
supposition of an interchange in the faunas of
the two regions. That this has taken place to
some extent is probable, but the resemblance appears
more especially due to the fact that the Alps and
Scandinavia have been peopled from the same centres
of distribution.
In order to make this matter quite
clear, I will give a familiar example as an instance
of the manner in which the present distribution can
be explained without taking recourse to direct migration
from the Alps to Scandinavia or vice versa.
The example I will take is that of a family of birds,
not only of extreme interest from the fact of its northern
range, but also from the pleasure it gives to those
addicted to sport. This is the grouse family,
the Tetraonidae.
Let us commence with our British Grouse
(Lagopus scoticus), which is peculiar to the
British Islands. In Norway we find a Grouse (L.
albus) which differs in habit, and in the fact
of its turning white in winter; otherwise it is so
closely allied to our Grouse that many ornithologists
do not separate them specifically. No doubt the
British Grouse is a descendant of this Scandinavian
Willow-grouse. The latter is known also to inhabit
Greenland and Arctic North America, and it is even
found beyond Behring Straits in Northern Siberia.
En route between Scandinavia and Asia, travelling
in a westward direction, we meet with two other very
local species of Grouse, which may be looked upon as
offshoots of L. rupestris viz., L.
hyperboreus of Spitsbergen, and leucurus
of Western North America. In Asia we then again
find two kinds of Grouse, very closely related, and
by some indeed regarded as belonging to the same species.
These are L. rupestris and L. mutus.
Mr. Ogilvie-Grant tells us of the former, that
it is merely a more northern rufous form of L.
mutus, and that it goes through similar changes
of plumage. In summer the males are readily distinguishable,
but in winter it is impossible to tell one from the
other. “L. rupestris taken as a whole,”
says Mr. Ogilvie-Grant, “appears to us barely
specifically distinct from L. mutus.”
L. rupestris occurs not only in Northern Asia,
but crosses the Behring Straits to Arctic America,
being still found on the Aleutian Islands, which represent
the last remains of the former land-bridge between
Asia and North America, then eastward to Greenland
and Iceland. However, while this form does not
cross the confines of Asia in a westerly direction,
its near relative L. mutus better
known as the Ptarmigan does; and may perhaps
have entered Europe as a Siberian and also as an Arctic
migrant. It is still found in the Ural Mountains,
in Finland, and the highlands of Scandinavia.
It is gradually being driven out of the Alpine lowlands,
while it has long ago disappeared from Germany, France,
and Austria in fact, from all the lowlands
of Europe. It has also been met with in the Pyrenees
and in some of the Spanish mountains. Similarly,
the bird has become extinct in England and Ireland,
while it is becoming more and more scarce in Scotland.
The centre of distribution of the genus lies in Arctic
America, and from there the genus has spread to Europe
and Asia. L. albus and L. mutus appear
in our continent chiefly as Arctic migrants.
The Black Grouse (Lyrurus tetrix)
belongs to a closely allied genus, which has only
two species. One of these is very local in distribution,
being confined to the Caucasus, but the smallness of
range is to some extent compensated for by the peculiarity
of its name, which is L. mlokosiewiczi.
The Black Grouse, on the contrary, is widely distributed.
It inhabits Northern Asia from the Pacific to the Ural
Mountains, and extends as far south as Pekin and the
Tian Shan range. In Europe it is found from the
extreme east to the Pyrenees, the Apennines on the
south, and to Great Britain and Scandinavia in the
north. It is important to note its absence from
Spain, the Mediterranean islands, and Ireland; and
we have learned that it is one of those Siberian migrants
which have succeeded in establishing themselves in
the Alps.
The Capercaillie (Tetrao urogallus) another
great favourite with sportsmen is now generally
separated generically from the Black Grouse, though
they are of course near relations. Its range greatly
resembles that of the Black Grouse, except that it
does not go quite as far east in Siberia, not having
been met with beyond Lake Baikal. From there it
is found westward as far as the Pyrenees. It occurs
also in the Carpathians and the Alps. In England,
where it used to be known by the name Cock of the
Wood, it became extinct at some remote period in history,
while it lingered on in Scotland and Ireland until
the end of the last century. In Scotland it has
been reintroduced into several counties, and being
protected, it appears to spread from these artificial
centres of distribution.
Like the Black Cock, the Capercaillie
is a Siberian migrant, and it is one of the few Siberian
species which have reached Ireland, as I have had
occasion to mention in dealing with the origin of the
British fauna. Two other species of Capercaillie
and an allied genus (Falcipennis) are met with
in the extreme north-east of Siberia, and six other
genera, all belonging to the grouse family, are confined
to North America. We have therefore a very intimate
relationship between the grouse of Asia and those
of North America, some species even ranging right across
the two continents.
The last genus of this very interesting
family is Tetrastes. This grouse is not
familiar to British ornithologists, since it is entirely
absent from the British Islands. But sportsmen
who have tramped over Scandinavia know it well by
the name of Hazel Grouse. It is ashy grey in
colour, barred and vermiculated with black. The
Common Hazel Grouse (Tetrastes bonasia) is
found from Northern Spain in the west right through
the mountainous parts of Central and Northern Europe
and Northern Asia to Kamtchatka and the Russian convict
island of Saghalien in the Pacific. Besides the
Common Hazel Grouse, two other species are known,
one from Eastern Russia and the other from China.
Having now shortly reviewed the whole
grouse family, we have seen that, although some species
live within the Polar Circle, the majority are more
or less confined to the more temperate or rather the
less arctic parts of the Northern Hemisphere.
They are quite absent from Southern Asia and even
the southern parts of North America, and almost so
from the Mediterranean basin. The whole range
of the family is therefore suggestive of a northern
origin, and this view agrees perfectly with all the
details of distribution. The centre of distribution
lies in Northern Asia, or in Arctic North America.
From there the great genus Lagopus spread east
and west, reaching Europe by these vastly divergent
routes at a time when the physical geography was very
different from what it is to-day. Several of
the species common to the Alps and Scandinavia have
migrated from Siberia direct to Eastern Europe.
But we can now imagine how from a similar centre in
Asia perhaps at a rather more remote time a
species spread eastward across North America and Greenland
to Scandinavia, and westward along the mountain ranges
of the Tian Shan and the mountains of Asia Minor to
Greece, and finally to the Alps. We should then
have the same species in the Alps and in Scandinavia,
not far removed from one another; but how different
were their paths of migration! This, however,
is not an imaginary instance. Such a migration
must have actually taken place in a good number of
instances among the terrestrial invertebrates and
also among plants.
The view still current among many
zoologists and botanists, that animals and plants
were driven down into the plain from the mountains
of Europe during the height of the Glacial period
and there lived together till the return of a more
genial temperature, when they retreated to their mountain
homes, is a very plausible one. During their sojourn
in the plain, the plants and animals say
from Scandinavia intermingled with those
from the Alps; and when the time of separation came,
many Alpine forms retired northward with the Scandinavians,
while many Scandinavians would go with the Alpines
to their home. In this way the similarity between
the Alpine and Scandinavian faunas and floras
is assumed to have been brought about. These
theories, first promulgated by Edward Forbes, were
hailed with general satisfaction by the scientific
world. Even Darwin says of them, that
grounded as they are on the perfectly well-ascertained
occurrence of a former Glacial period, they seemed
to him to explain in a satisfactory manner the present
distribution of the Alpine and Arctic productions
of Europe. To the present day this view meets
with much favour among naturalists. It is somewhat
similar to one which has recently been strongly supported
by Professor Nehring and accepted by Professor Th.
Studer and many others. They have never made
it quite clear whether the pre-glacial fauna and flora
are supposed to have been absolutely destroyed by
the glacial climate, or whether part of them have
been able to take refuge somewhere in the south; but
the great mass of our Alpine plants and animals are
believed to have been derived from the Siberian invasion,
which I have fully described in the fifth chapter.
This invasion spread over the European plain, and when
the climate ameliorated, both animals and plants migrated
north and south to the mountains. This view agrees
with the earlier theory, except that the adaptation
to Alpine conditions would, according to the former,
have taken place since the close of the Glacial period,
during which time no such modification or change of
species seems to have been produced in other parts
of the world. The characteristic fauna of the
Alps, as has been gathered from the preceding pages,
is mainly of Central Asiatic rather than of Siberian
origin. Migration to the Alps took place by the
Oriental route long before the Siberian invasion.
Some of the species of the latter have penetrated
to the Alps, but these Siberian species have not given
to the fauna of the highest European mountain range
the striking character with which we all associate
it.
Before concluding this chapter, a
few remarks on the botanical aspect of the Alpine
problem might not be out of place. It will enable
us to judge which of the views indicated is the more
probable, and will add to the interest which may have
been aroused by the perusal of this sketch of the
fauna of the Alps. Very much the same train of
argument was applied as to the course of events in
the formation of the Alpine flora as in the case of
the fauna. The plants were all supposed to have
been killed or driven away by the arctic temperature
of the Glacial period, and their place taken by new
migrants from the north or east when the climate ameliorated.
Professor Engler, one of the highest
living authorities on the geographical distribution
of plants, is of opinion that a large number
of the indigenous Alpine species did not originate
till after the close of the Glacial period, because
so many of them are absent from the Sierra Nevada
in Spain, where the condition for their well-being
exists, while many have evidently spread from the
Alps to the Carpathian Mountains and to the Pyrenees.
He does not believe that a glacial flora could have
existed in the plain between the Sierra Nevada and
the Pyrenees during the Glacial period.
In speaking of the Caucasus, Professor Engler informs
us that a good many species which do not
occur in the Alps reached these mountains from Siberia.
Apart from the northern glacial plants, the Caucasus
has only few species in common with the Alps, more
with the Balkan mountains and Northern Persia.
Turning to Afghanistan, our author mentions
a few Alpine plants as occurring in that country,
and likewise in the Caucasus and the Himalayas.
He considers it probable that the route of migration
of some glacial plants from the east to the west, and
vice versa, lay across the Afghan mountains.
Many of our Alpine plants occur in the Siberian mountains,
but in the Altai and Eastern Siberia generally a considerable
number of these are by no means confined to the mountains. They are also met with in the lower
regions, and the rare Alpine Edelweiss (Leontopodium
alpinum) frequently covers wide tracts in the
plain, and is passed by almost unnoticed by the Siberian
botanist.
Special attention is drawn by Professor
Engler to the fact that several of the Siberian
plants inhabit the Alps and the Caucasus, but are
not found in Scandinavia. And from this he deduces
the conclusion that part of the Siberian flora migrated
in a south-westerly direction towards the Caucasus
and the mountains of the Mediterranean area, exactly
in the manner indicated in respect to the fauna of
the Alps. We learned that the migration to the
Alps from Central and perhaps also parts of Northern
Asia took a south-westerly course first, and was then
followed by one in an easterly direction. I called
the former the Oriental migration and the latter the
Siberian. Later on Professor Engler states that the main mass of the Siberian forms of plants
certainly wandered westward to the south of the Ural.
This is proved by the numerous glacial plants found
in the Caucasus, while the glacial flora of the Ural
Mountains is poor. Finally, he expresses the
opinion that the probability of most of the Alpine
plants occurring in Arctic Siberia, having wandered
from the Alps, by way of Scandinavia, Greenland, and
North America, to North-eastern Siberia, is greater
than the direct migration from Europe to Siberia.
Another continental writer on the
Alpine flora who deserves special mention is Dr. Christ.
His observation that Alpine plants by no means suffer
from a high temperature, but solely from a
drying up of the soil, seems to me to point to the
correctness of the view I have expressed on several
occasions, that these plants have originated long
before the Glacial period at a time when the climate
was warmer and moister than it is now. It seems
quite natural to Dr. Christ that the Arcto-Alpine
flora should have originated in Asia, but he excepts
thirty species which are absent from Northern Asia,
though occurring in America. These he
thinks have penetrated direct from America to the
Alps by way of Scandinavia, since no less than twenty-three
still occur in the latter country. In the human
population of the Alps, he continues, one
can distinguish an indigenous Celtic race, a Germanic
colder and more apathetic race, and a more lively Roman
one. The flora is composed of quite a similar
mixture. We find also an indigenous element an
Arctic and a Mediterranean one. The last element
is a survival of the Tertiary flora of the Central
European plateau. The plants were driven
down to the shores of the Mediterranean, and it is
only after the retreat of the glaciers that a few of
them have been able to regain their ancient territory.
The incoming Asiatic and North American flora likewise
retired at the end of the Glacial period to the Alps
and the Arctic countries, and left isolated traces
of its former abundance on the North European plain.
The bulk of the Arctic or Alpine flora is held to
be of Asiatic origin. Since Siberia shows little
trace of having been glaciated, owing to the dryness
of the climate, a rich flora was able to develop there,
which spread into Europe as soon as the vanishing
glaciers made room for it.
These are the views of Professor Engler
and Dr. Christ. They agree in so far as both
of them maintain that the bulk of the Alpine flora
is post-glacial that is to say, that it
has developed quite recently, or migrated to the Alps
after the glaciers had retreated from the plain to
the mountain recesses. It is assumed by Dr. Christ
that while Europe was practically uninhabitable, a
rich flora survived in Northern Asia, because the
climate there was too dry for the development of glaciers.
Due consideration in this interesting speculation,
however, is not given to the fact which he himself
emphasised, that Alpine plants are particularly prone
to suffer from a dry climate. Even a moderately
dry cold kills most of them. How can we then
reconcile this fact with the theory of their origin
in a dry and intensely cold climate? I quite
agree with the views as to the Asiatic origin of the
bulk of the Alpine flora, while the dry state of the
Siberian climate is certainly indicated by the extremely
feeble development of the glaciers during a large
part of the Glacial period. We know, however,
that in Pliocene and even in early Glacial times the
atmospheric conditions must have been very different
in Siberia. A great slice of Central Asia was
under water, and numerous freshwater lakes covered
the lowlands in the north, so that the climate must
have been damp though not cold enough for the formation
of extensive glaciers. Everything, in fact, seems
to indicate that the migration of the Asiatic Alpine
flora took place at a very early date probably
long before the Glacial period either by
the Oriental or by the Arctic route via North
America, Greenland, and Scandinavia. But would
this not necessitate a survival of the Alpine plants
in the Alps themselves? That is the view which
has already been expressed with regard to the fauna,
and the flora probably followed a very similar course.
This is by no means a novel theory, however, and though
unfortunately an untimely death has removed one of
our very best authorities on the Alpine flora before
he had completed his life’s work, we have some
indications in the earlier writings of John Ball that
his opinions on the origin of that flora did not coincide
with those held by the leading continental authors.
To quote the words of this distinguished botanist: “Is it credible that in the short
interval since the close of the Glacial period hundreds
of very distinct species and several genera have been
developed in the Alps, and what is no less
hard to conceive that several of these non-Arctic
species and genera should still more recently have
been distributed at wide intervals throughout a discontinuous
chain some 1500 miles in length, from the Pyrenees
to the Eastern Carpathians? Nor would the difficulties
cease there. You would have left unexplained the
fact that many of the non-Arctic types which are present
in the Alps are represented in the mountains of distant
regions, not by the same, but by allied species, which
must have descended from a common ancestor; that one
species of Wulfenia, for example, inhabits
one small corner of the Alps, that another is found
in Northern Syria, while a third allied species has
its home in the Himalaya.” Mr. Ball is
of opinion that the effects of the Glacial
period have been greatly overrated. “Even
during the period of maximum cold the highest ridges
of the Alps were not completely covered with snow
and ice; for we still see by the appearance of the
surface, the limit above which the ancient ice did
not reach, and in the middle zone the slopes that
rose above the ancient glaciers had a summer climate
not very different from that which now prevails.
In my opinion the effect of the Glacial period on
the growth of plants in the Alps was to lower the
vertical height of the zones of vegetation by from
one to two thousand feet.” He acknowledges
that there was probably a moderate diminution of the
mean temperature of Europe with an increased snowfall,
so as to cause a great extension of glaciers on all
the mountains of Northern Europe. “But that
the climate of Middle Europe was such that the plants
of the high Alps could spread across the plains seems
to me an improbable supposition”.
On the Continent, also, some botanists
seem to feel that Forbes’s theories of the origin
of the Alpine flora, which were at first hailed with
such delight, and accepted by almost every naturalist
as the final verdict, must be modified in the light
of recent researches. Professor Krasan believes
that many plants which now live in the high Alps flourished
in pliocene times at sea-level. “Especially
the evergreen species exhibit the impression of an
originally mild climate of a climate without
winter frosts for otherwise the plants
would have developed into species with deciduous leaves.”
To the favourable conditions, consisting in periodic
snowfalls and high summer temperature, must be attributed
the fact that in the highlands so many more species
from Tertiary times have survived than in the plains.
The temperature was probably much higher during the
Glacial period than is generally believed. The
climate was more moist, thus contributing to an abundant
snowfall, while the survivors of ancient Tertiary times
were able to repeople the parts which were temporarily
devastated by the advancing glaciers.
In so short a chapter it is impossible
to deal with the Alpine fauna in a manner more deserving
of this theme. I have merely sought to give a
sketch of the general outlines of the subject and to
suggest another possible mode of origin of Alpine
animals than that currently believed in by naturalists.
It is to be hoped these suggestions will be useful
to those intending to reinvestigate the problems raised
in this chapter. When our knowledge of the fauna
of Asia is more complete, it will be possible to give
a more thorough and in many respects a more satisfactory
history of the European fauna than at present.
SUMMARY OF CHAPTER VIII.
In early Tertiary times the area now
covered by the European Alps was covered by the sea.
Islands slowly rose above the surface of the waters,
which finally coalesced to form a peninsula connected
with the mainland in the east. Animals now began
to invade the new territory which continued to rise,
while the sea retired farther and farther to the north
and south. During the Pliocene Epoch the sea ceased
to wash the northern shores of the Alps, and both
emigration and immigration became possible in that
direction, and also from and to the west.
The Alpine fauna and also the flora
are made up of a number of elements, the eastern one
being the oldest. The latter is represented in
the Alps by the older and newer Oriental migration.
The general range of the Alpine Steinbock, Chamois,
Marmot, Vole, Shrew, and Hare are specially referred
to. The Alpine birds are few in number, and all
of them are readily traceable to an Asiatic ancestry.
Among the Amphibia, the Salamanders are considered
of Alpine origin.
Dr. Kobelt tells us that a uniformity
of character marks the Alpine molluscan fauna. Campylaea, often
considered a sub-genus of Helix, Pomatias,
Zonites, are looked upon as truly Alpine genera.
For very long periods the Alps seem to have received
no addition to their molluscan fauna from other areas.
The case is very different with the Lepidoptera,
some of the most striking species being evidently
Asiatic immigrants. Some examples of Coleoptera
and Orthoptera are mentioned, and their origin
discussed.
We find as the result of these considerations
that the majority of the Alpine species are either
indigenous or have come from Asia with the Oriental
migration. None of the northern or western immigrants
appear to be among the characteristic Alpine species,
and it seems that the Siberian migrants have not retired
to the Alps, as some naturalists have been led to
suppose. It is evident that the fauna must have
survived the Glacial period on the Alps, though according
to geological evidence glaciers of enormous size originated
on these mountains.
The identity of many Alpine species
with Scandinavian ones appears at first sight due
to a direct migration from the Alps to Scandinavia
or vice versa. Perhaps such a migration
has taken place to some extent, but it is probable
that from a Central Asiatic centre some species spread
across Arctic America into Northern Europe, and also
westward to the Alps. The Grouse family forms
an interesting example.
There are two older theories which
explain the similarity between the Scandinavian and
Alpine faunas. Forbes’s view, which
gained most adherents among naturalists, was that
the Scandinavian and Alpine animals were driven into
the plain by the cold during the Glacial period, and
when they ultimately regained their homes, some individuals
of the northern species moved southward, and a few
of the southern ones northward. By the more recent
theory of Nehring, the Siberian animals which invaded
our continent from the east, and then spread northward
to Scandinavia and southward to the Alps, formed the
nucleus of the faunas of these two areas.
The objections to both of these views are fully set
forth in this chapter.
A few remarks on the botanical aspect
of the Alpine problem conclude the chapter. The
origin of the flora has been explained in a very similar
manner to that of the fauna. But already Ball
and Krasan have raised their voices against the current
theories, as the facts of distribution appear to them
more satisfactorily explained on lines more consonant
with those which I have used in discussing the origin
of the Alpine fauna. One of the most important
conclusions obtained by this study of the flora in
conjunction with the fauna, is that I have emphasised
in most of the preceding chapters viz.,
that the Glacial period in Europe was not a time of
extreme cold, and that its destructive effect on the
animals and plants was by no means such as is currently
believed.