публикация №1537900242, версия для печати

BISONS RESTORED IN THE CAUCASUS


Дата публикации: 25 сентября 2018
Автор: Andrey BIRYUKOV
Публикатор: Алексей Петров (номер депонирования: BY-1537900242)
Рубрика: ЭКОЛОГИЯ


When we learn of the extinction of some wild animals such news bring most of us no joy. But there are cases when no hope is lost yet. Some representatives of the threatened species survive in remote corners of their habitat and can be saved and multiplied. One such achievement - the restoration of the population of bisons in the mountains of the Western Caucasus-has been described in an article in the PRIRODA {Nature) magazine by Sergei Trepet, Cand. Sc. (Biol.).

At large the last animal of the Belovezhsky sub-species of bisons was killed in 1921 and of the Caucasian (Dombai) one in 1927. By that time only 48 animals of both subspecies were still alive in different zoos. But not all of them were the "forefathers" of the animals we can see today: still alive in the Caucasus, in the Belovezhsky Pushcha and other wild-life preserves, are the descendants of 12 unrelated animals of the Belovezhsky bison and of one male of the Caucasian subspecies. What is more, present in their genomes are genes of three steppe bisons. But thanks to purposeful selection, specialists have been able to achieve a situation in which present-day bisons practically carry no signs of specific similarity with their forefathers.

The Caucasian bisons were taken under special protection in Russia in 1867. Even grand princes who possessed exclusive rights of hunting on the territory of what was called "Kubanskaya hunting range", had to apply personally to the emperor for permission to hunt and kill bisons.

Nevertheless the animals became extinct in the Caucasus. But data about their ecology and behavior had already been accumulated and hunters and forest wardens where the animals survived for the longest time had a very clear idea about the measures required for their reintroduction.

This work was started in the Caucasus in the late 1930s. Five such animals were brought to the Caucasian Preserve from Askaniya-Nova reservation (Kherson Region, Ukraine). They were kept in open-air caged and crossed with thoroughbred males of the Caucasian-Belovezhsky line. In 1960 the animals were released into that wild and the process of multiplication was joined by males of what we call hybridogenic origin.

By the middle of the 1980s a reproductively independent population was produced on the Northern slope of the Main Caucasian Range. It carried features which distinguished it from the predecessor forms and which

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made it possible to name the subspecies Bison bonasius montanus.

Adaptive changes which left the animals' appearance practically unchanged, have influenced their choice of routes of migration. At the turn of the 19th-20th centuries it was noted that in snowy winters the animals move from highlands (their permanent locations) down to middle and low sections of the forest belts. The newly reproduced population behaved in the same way. And with the growing number of animals in the Caucasian Reserve the young animals started moving to lower a mountain areas. The natural habitat of bisons exceeded the boundaries of the reservation and new and stable groups of animals began to be formed.

But later on, in the 1990s, regions of the Western Caucasus favorable for the habitation of bisons became a zone of economic instability. Poaching reached the scale of a natural calamity: in 1989 - 1997 some 184 animals were killed illegally and 40 of them on the reservation's grounds. The numbers of the animals dropped sharply. But their "response" to the mounting anthropogenic pressure was rather peculiar, but effective. In recent years they have been migrating for wintering not down the mountains, but upwards - to the Alpine and sub-Alpine meadows. And although such upward movements along the barren mountain slopes are not something new, but since the end of the 1990s they became something permanent. Even during snowstorms

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of many days the animals do not move down into the forests. And in the second half of the winter they have no such opportunity because the snow cover becomes very deep along the upper border of the forests.

Despite considerable drops of the numbers of animals in the latter half of the 1980s-1990s the population of bisons in the Caucasian Preserve has retained its capacity for selfregulation and development. Their numbers have been steadily growing over the past 5 years and the composition of the "population" is getting better. In other reservations of the Caucasus (Teberdinsky Preserve, etc.) experiments of proliferation of this species have been far less successful. The author of the article attributes this to constant human interference into the processes of accommodation of small populations of animals to natural environment. The biggest and oldest population of mountain bisons owes its stability not only to the maximum genetic diversity, but also to the considerable size and inaccessibility of their habitat.

Trepet S. A., "Mountain Bisons", Priroda (Nature), No. 7, 2005

Prepared by Andrey BIRYUKOV

Опубликовано 25 сентября 2018 года


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