Acclimatization

Acclimatization, the process of adaptation of plants, animals, and humans to life in geographical areas remote from their original homeland and differing from it in climatic and other living conditions. Each species of plants and animals has a more or less definite area of distribution over the earth's surface, and each zoogeographical area is characterized by its climatic and other conditions of existence. Often, with the participation of humans, animals, sea and river currents, wind, or other factors, an animal or plant may be introduced into a geographical area foreign to it. If in the new area the organism manages to change its organization and way of life to such an extent that it is able to survive in the new conditions, and if in the new area it continues to produce offspring capable of further reproduction, then in such a case it becomes possible to speak of the acclimatization of this species. However, the concept of acclimatization suffers from a certain indefiniteness due to the complexity of the concept of climate itself, encompassing the entire set of atmospheric (temperature, humidity, air currents), hydrological, and geographical-geological conditions of a given area. Therefore, elucidating the elementary biological mechanism of acclimatization is often an almost insoluble task. Ultimately, the acclimatization of living beings relies on their ability to adapt (see), which in many cases can be reduced to the action of elementary physicochemical factors of the environment. However, equating these two concepts would be incorrect, although in the literature, for example, the survival of freshwater organisms in salt water and vice versa is often designated precisely as acclimatization. In other cases, the mechanism of acclimatization represents such a complex interweaving of climatic-geographical factors that determining the role of each of them separately may prove completely impossible. The process of acclimatization is accelerated even more in cases where the action of purely climatic factors is joined by biological relationships between various living organisms inhabiting a given geographical area and forming part of its biocenosis (see). Hence it is understandable why in some cases the acclimatization of one species or another stubbornly fails, despite the fact that there seem to be no climatic obstacles to this. For example, for a long time the acclimatization of vanilla on the island of Java failed, despite favorable climatic conditions. The actual obstacle to acclimatization turned out to be that there were no insects on Java that, on the homeland of vanilla, in South America, contribute to its pollination. Finally, there are also cases when acclimatization is impossible not due to climatic obstacles, but because in the new place the organism cannot freely follow its natural instincts. For example, the acclimatization of bison in Europe proved impossible, because they did not encounter here the conditions for those long migrations (wanderings) that are characteristic of them in their natural environment. This same reason (along with unreasonable extermination) also led to the extinction of bison in their homeland, in America, in connection with the construction of railroads across the continent, which blocked the path of their usual migrations. Regarding the term 'survival' of an organism in new climatic or, generally speaking, new conditions, it must first be said that survival (adaptation) can possess different degrees and characters. An organism, for example, can live in new conditions but not reproduce: in the Askaniya-Nova (see) zoo, large flocks of flamingos and red-breasted shelducks lived for more than ten years, but neither of them began nesting and laying eggs. An organism may retain the instinct to reproduce in new conditions and yet not produce viable offspring: in the same Askaniya-Nova, African ostriches lay fertilized eggs but do not incubate them to completion. An organism can finally both live and reproduce and produce viable and fertile offspring; an example of this is the various antelopes, llamas, yaks, American ostriches and other animals in Askaniya-Nova. Such are the different degrees of adaptation. Along with this, the character of adaptation can also be different: an organism is able to live and reproduce in new conditions, sometimes retaining old forms of its life, sometimes acquiring, in adaptation to new conditions, new forms of manifestations of life. In other cases, significant changes are observed in periodic processes, which is most clearly manifested when moving from the southern hemisphere to the northern or vice versa. Thus, the Australian black swan, the rhea ostrich, and the South American black-necked swan, when acclimatized in southern Ukraine, begin nesting and raising chicks in March-April (i.e., our spring), while in their old homeland they nest in November-December (spring of the southern hemisphere). In some cases, changes in organization are also observed: the wildebeest (Connochaetes gnu), when transferred from its old homeland (Central Africa) to Askaniya-Nova, acquires a warm woolly coat by winter, which it does not have in its old homeland. However, not all animals are equally malleable: the Australian goose and emu on the northern coast of the Black Sea still retain the period of their homeland and attempt to nest in the frost of our Ukrainian winter (in November-December, corresponding to summer in the southern hemisphere). Interestingly, in the Moscow Zoo, emus nest not in December but in February—which is obviously connected with the greater sharpness in the climate change Australia-Moscow than Australia-Askaniya. In phenomena of acclimatization, the composition of plant and animal communities (biocenosis) in which the acclimatized organism has to live also plays a major role. A new form entering the biocenosis of a given place most often perishes or spreads only very weakly; in case of successful acclimatization, it leads to a change in the biocenosis itself. Thus, a sparrow acclimatized on the Sandwich Islands displaced almost all native birds; conversely, the Chinese carnation, which in our country is found only in old parks and immediately dies when it goes into the open field, where it is displaced by wild-growing grasses, serves as an example of the limitation of life by the biocenosis. The conditions created by the biocenosis are the main reason why most acclimatized animals and plants can exist only in the conditions of domestication. The difference between acclimatization and domestication consists mainly in that the latter assumes the protection of the acclimatizing species by humans, while the former consists in adaptation to new natural conditions for the organism, mainly through independent and free struggle for existence. It is extremely difficult to draw a distinction between true acclimatization and domestication for each individual species. However, some examples are very striking. Thus, Agassiz already pointed out that all 130 species of weed grasses in the northwestern states of North America are of European origin, and that local grasses have been pushed westward; in New Zealand there are no less than 250 species of acclimatized plants, of which 100 species have spread far throughout the country, displacing the local flora; cases of displacement of representatives of the local fauna by alien animals are also no less well known. A large number of our tree species, which are now considered common trees of the European part of the USSR, acclimatized here, starting from the 16th-17th centuries, first under the direct protection of man, and then in the literal sense of the word acclimatization. Siberian cedar, larch, fir, yellow acacia, willow (a species of willow that has received particularly wide distribution and importance in sand fixation and basketry), laurel-leaved and fragrant poplar, Caucasian cherry and a number of others, most of which have great importance in the forest and woodworking industries—all these tree species have fully acclimatized with us and grow freely alongside native species. The number of useful plants requiring special care but feeling excellent in the conditions of new climatic conditions for them is extremely large. Thus, a striking example of a high ability to acclimatize is the potato, which from its homeland—America—was brought to Europe, in the 18th century received wide distribution in France, from the beginning of the 19th century began to take root in Russia and is now widely distributed throughout the globe, growing under the most unfavorable conditions of soil and climate; corn, which spread from America throughout the globe (up to 52° N latitude); further, hemp, whose homeland is considered to be the coast of the Black Sea, is now distributed not only throughout Europe but also grows well in Asia, Africa and North America; rice from Asia has spread to all continents of the globe; wheat, rye, barley, apparently, even in prehistoric times were spread from northern Persia and the Caucasus throughout the world.

Some plants of industrial importance have been acclimatized in the USSR very recently: in the 1860s, ramie, or textile nettle, began to be cultivated in the Caucasus; in the 1870s, bamboo; in the 1880s, oranges, lemons, tea, and Japanese persimmon; American cotton, which has such exceptional industrial importance, began to be grown in Turkestan only from the 1870s. A splendid example of successful acclimatization are the decorative plants of the southern coast of the Crimea—laurel, cypresses, magnolia, and others. Classic examples of true animal acclimatization are the complete feralization and exceptional spread of horses and cattle in the South American pampas, noted by Darwin and Wallace, where they were introduced by the Spaniards after the discovery of America; the same applies to donkeys in Quito (Central America), pigs in America, and rabbits in Australia. The most striking examples of animal acclimatization, having economic importance and therefore spreading mainly through the agency and under the protection of man, are: the widespread acclimatization of the chicken, domesticated within India in the 12th century B.C., which apparently reached Europe in the era of the Roman Empire and was introduced to America by Columbus; from America in 1530, the turkey was introduced to Europe. In the middle of the 19th century, the first scientific society for studying the ability of animals and plants to acclimatize was organized in Paris (Societe d'acclimatation); similar societies were subsequently organized in other countries. In 1857, the 'Russian Society for the Acclimatization of Animals and Plants' was formed in Moscow, which functions to the present day. Within the USSR, systematic experiments in acclimatization are conducted in the Nikitsky Garden on the southern coast of the Crimea, in the Sukhumi Botanical Garden, in the Ukrainian zoo 'Askania Nova,' and in the Moscow zoo; at present, a Department for the Naturalization of Tree Species is being organized at the Institute of Applied Botany of the Lenin Academy of Agricultural Sciences.