Отграничение и районирование Арктики

One thing is the delimitation of the Arctic from more southern areas, and this delimitation has been an object of controversy for a long time. We have avoided much of this controversy by mainly following the arctic tree-line in continental areas but extending the arctic to some more oceanic tree-less areas in the Pacific and Atlantic sectors where the climatic data indicate a similarly restricted growth season. Our arctic delimitation is therefore mainly climatical and ecological.

Quite another thing is how to divide the Arctic into regions to be used for differentiation of the distributional data. We have agreed on two manners of subdivision, one based mainly on bioclimatical criteria and one on topographical and historical criteria. The former - into five zones - runs from the boreal areas to the northernmost and each of the zones roughly corresponds to a 2 degree difference in mean summer temperatures. The latter - into sectors - aims to reflect the different histories of the different parts of the Arctic and is by necessity much more subjective. We have by principle avoided (with one exception) to divide the Arctic politically. The sectors most often run from the south to the far north and include several zones. They reflect the different influences of Beringian and Atlantic glacial survival, of American, European and Siberian influence northwards into the Arctic, and of the influence of mountain ranges (and partly oceans) as ways of migration.

Elvebakk, A. 1999. Bioclimatic delimitation and subdivision of the Arctic. - Det Norske Videnskaps-Akademi. I. Mat. Naturv. Klasse, Skrifter, Ny serie 38: 81-112.
The complicated issue of defining and subdividing the Arctic has been approached by designing topographic sequences of communities along the ridge-snow bed-wetland gradient, partly also including riparian habitats. These data show that many communities serve as criteria for separating zones, although there still is much work to do to have a full overview of communities on a circumarctic scale and with communities arranged in a hierarchic system. The distribution of communities supports the separation of five zones within the Arctic, and also serves to exclude from the Arctic some oceanic areas that have been included by some authors. Easily extracted aspects from the community structure like the growth forms of lignified plants and vegetation physiognomy, is of primary importance, but is not sufficient alone to define all the zones. In the naming of zones, several criteria have been put forward, and primary importance has been given to vegetation physiognomy as it directly characterizes the areas in question in a way that attracts a broad audience. This follows a tradition of using the vegetation physiognomy name instead of the name of the major growth forms that make up the physiognomy. The names arctic polar desert zone, northern, middle and southern arctic tundra zones and arctic shrub-tundra zone are proposed here, including the original definitions of polar desert and arctic tundra as they were developed in the former USSR.
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Keywords: zonation, circumpolar Arctic, toposequence, zonal vegetation.
Arve Elvebakk (e-mail: arve@ibg.uit.no), Dept. of Biology, University of Tromsø, N-9037 Tromsø, Norway

Razzhivin, V.Yu. 1999. Zonation of vegetation in the Russian Arctic. – Det Norske Videnskaps-Akademi. I. Mat. Naturv. Klasse, Skrifter, Ny serie 38: 113-130.
This paper is aimed to discuss peculiarities of Russian botanical tradition in vegetation zonation, especially the “plakor” concept. The last one is widely used in geobotanical subdividing of plant cover (cf. Aleksandrova 1980) in Russia. Its applicability in the areas of permafrost distribution and limitations as compared to the European and North American zonal approach are discussed. The seashore cooling effect of arctic seas differently pronounced in plain and mountain seashore areas usually leading to the seashore zonal inversion is discussed. The new subdividing of Wrangel Island, northeastern Koryak Upland, northernmost Taimyr and Kolguev Island is proposed according to the concept of the seashore effect.
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Keywords: vegetation zonation, Arctic, plakor, seashore effect
V.Yu. Razzhivin (e-mail: volodyar@north.bin.ras.spb.ru), Komarov Botanical Institute, Russian Academy of Sciences, ul. prof. Popova, 2, 197376 St. Petersburg, Russia.

Elvebakk, A.,  Elven, R., &  Razzhivin, V. Yu. 1999. Delimitation, zonal and sectorial subdivision of the Arctic. – Det Norske Videnskaps-Akademi. I. Mat. Naturv. Klasse, Skrifter, Ny serie 38: 375-386.
The paper reflects the decisions made in May 1999 after hard discussions especially on the sectorial subdivision of the Arctic. Subdivision of N American and Beringian area remained unsolved at that time and the discussion has been continued until May 2000 when the new sectorial subdivision of the areas under discussion was accepted (see below).
The May 1999 version of the subdivision remains here as it is published in the Proceedings to allow you to follow the discussion.
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During the period since the publication of the Proceedings there has been some discussion on the taxonomic principles and much discussion on the division into regions. In the latter case, the divisions have been significantly changed in two areas compared with the maps in Proceedings.

In North America, the Canadian areas are now proposed divided into a large central region ('Central Canada') with the mainland west of Hudson Bay and which includes much of the Arctic Archipelago, an eastern region ('Hudson-Labrador') in the coastland around Hudson Bay, in Ungava and Labrador Peninsulas and the southernmost part of Baffin Land south of Cumberland Sound, and a northwestern region ('Northwest Canada') with the lowermost Mackenzie River and Anderson River areas and a short distance further east on the mainland, Banks Island, western Victoria Island, Melville Island, Prince Patrick Island and some smaller islands. In the northeast, the 'Ellesmere Land - North Greenland' region is kept but Devon Island is transferred to 'Central Canada'.

In the Beringian area, the North Beringian Sea islands have with one exception been united with 'West Alaska'. The exception is Big Diomede Island, which goes to East Chukotka. Wrangel Island is separated as its own region from West Chukotka. There is still a problem left in the Beringian area as South Chukotka seems to differ less from West and East Chukotka than the southern part of West Alaska differs from the northern part. An imbalance is therefore left in the Bering Sea area.

Canada.jpg (30401 bytes)Canadian group of sectors

Beringian group of sectorsBering.jpg (24548 bytes)


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