Biomes - Russie

Biomes en Russie

Treeless tundra is found in the north of Russia, generally above the Arctic Circle. In European Russia, it occupies limited space on Kola Peninsula and in the Arkhangelsk and Komi regions along the coast. In Siberia, the most extensive tundra is found on Yamal, Taymyr, and Chukotka Peninsulas. In North America, tundra covers much of Alaska's North Slope, as well as about one-quarter of Canada. The word “tundra” comes from the Saami people and means “treeless.” North of the tundra, the polar desert has virtually no life. Some hardy blue-green algae, and occasional mosses and lichens, are about all that can be found there. Nevertheless, even the northernmost islands of Russia, in Franz Joseph Land, have a flora of 57 flowering plants, 115 lichens, and 102 mosses. Polar bears, seals, and walruses are important mammals of the surrounding seas and ice. A few species of hardy Arctic birds—murres, puffins, gulls, and terns—live on inaccessible cliffs in “bird bazaars.”

“Taiga” is a Siberian word; it has recently become better known through the efforts of the Taiga Rescue Network, doing important conservation work throughout the Northern Hemisphere. In North America, taiga is known as the “boreal coniferous forest,” which is what covers much of Canada. Note that although the West Coast forests of British Columbia, Oregon, and Washington also have conifers, they have a much higher diversity of plants and much bigger trees, so they are not the true taiga. In Northern Eurasia, the taiga is a huge biome (covering over half of all Russia), but it is rather monotonous. In European Russia the main species are Scotch pine, Norway spruce, and European fir; in western Siberia they are Scotch pine, Siberian cedar pine, and Siberian fir and spruce; and in eastern Siberia they are two species of larch. Coniferous but also deciduous, larch is the only tree that can survive the brutal cold of the Verkhoyansk area, which is the coldest in the Northern Hemisphere. Birch and aspen may be found as secondary-growth species on clearcuts and fire clearings. Low shrubs with berries of the Vaccinium group are very common, as are mosses and lichens. Interspersed with big trees are nutritionally poor bogs with peat mosses (Sphagnum), Labrador tea, cranberries, and carnivorous sundew (Drosera). The boreal forests of Eurasia make up about 21% of the world's total tree cover on 5.3 million km2; this area is twice the size of Argentina!

South of the taiga zone, a narrow wedge of mixed and deciduous forests stretches from the Baltic republics to the Urals and beyond, to Novosibirsk and the Mongolian border. This zone is smaller than the taiga, but it has a warmer and generally wetter climate. Moscow is located in the middle of it, with pine and spruce being more common to the north of Moscow, and oak, maple, and linden being more common to the south. The exact mixtures vary, depending on previous logging, fire history, plantings, and bedrock. The majority of secondary forests in this zone are pure birch stands, very popular among the Russian landscape artists. Deciduous forests can grow faster and utilize resources better than conifers, provided that the weather is not too cold. When autumn comes, they shed their leaves and become dormant for winter to avoid death by desiccation. Broad leaves are efficient water evaporation machines; if they are left on the trees in winter, all the water will escape the trunk. In North America the same zone is found throughout much of the mid-Atlantic region, parts of New England, Ohio, Ontario, and central parts of Wisconsin and Minnesota. Much of Western Europe likewise is in this zone.

Besides the main five biomes of Northern Eurasia, there are some rarer types, of which four merit mention here:

• mountainous ecosystems
• the subtropical vegetation of the Black and Caspian Sea coasts
• the unique forests of the Russian Pacific
• the azonal communities of the floodplains and marine coasts.

All mountain ranges have their own zonation of ecosystems from bottom to top. For example, in the Karachaevo-Cherkessia Republic of Russia in the northern Caucasus, the following ecosystems are found: true steppes (200–500 m above sea level); oak–hornbeam forests (500–1,300 m); beech forests (1,300–1,500 m); fir–spruce forests (1,500–1,700 m); pine forests (1,700–2,100 m); subalpine tall-grass vegetation (2,000–2,500 m); and alpine short-grass vegetation (2,500–3,200 m). Snow and glaciers extend above the highest alpine vegetation. The lower timberline is determined by moisture availability, and the upper by temperature during the vegetative season. The timberline at about 2,100–2,500 m is formed by a krummholz of crooked pines, beeches, birches, aspens, and other trees that grow only as tall as shrubs. In the subalpine belt, rhododendrons, tall forbs from the rose and sunflower families, and some tall grasses play an important role. In the alpine zone, graminoids (grasses, sedges, rushes) and forbs (roses, pinks, primroses, and sunflowers) predominate. The exact sequence and elevation of the vegetation belts are determined by the direction of the slope (north-facing slopes are always colder and have a lower treeline) and by local climatic and biological factors. The treeline, for example, occurs at 300 m in the polar Urals and the Khibins in the Kola Peninsula in the Arctic, but at 2,000 m in the Carpathian mountains, 2,500 m in the Caucasus, and above 3,000 m in much of Central Asia (which is considerably warmer and drier). The main species at the treeline will also differ among mountain ranges. In much of Siberia it is Siberian cedar pine shrub (Pinus pumila), while in the Caucasus it may be birch, beech, or Scotch pine.

Subtropical vegetation can be found at the southern tip of the Crimea Peninsula; in a narrow strip along the Black Sea coast of Russia and Georgia; and in the southeastern corner of Azerbaijan (Lenkoran) along the Caspian Sea coast. These areas all have a subtropical C-type climate, where frosts do not occur even in January. Protected by the mountains from the cold northern wind, these sheltered areas can support Mediterranean-like vegetation. Of the three areas, the Crimean Peninsula is the driest; its native communities consist predominantly of sclerophyllous scrub, but cork oaks, junipers, wild madro?os, pistachio trees, and other unusual plants are well represented. Visually, it bears a striking resemblance to the vegetation of Italy and Greece, much farther south. Much of this native ecosystem has been replaced with fruit orchards, vineyards, and parks full of introduced Mediterranean trees and shrubs (e.g., cypresses, cedars of Lebanon, Italian pines, and palms). Massandra and Livadia Parks, and Nikita Botanical Garden at Gurzuf, have particularly famous arboreta. The Black Sea coast has lush vegetation forming under wetter conditions. Native plants include many evergreen shrubs or small trees (boxwood, laurel, yew, etc.). Many of these are relics of the much warmer Tertiary period, 2–65 million years ago. Lianas and epiphytes are common in the forests. Tea and tangerines can be planted and survive winters here. In Russia, the Great Caucasus Zapovednik near Sochi, including a famous box–yew grove, can be visited for the best representative look at the whole Black Sea coast ecosystem. In Georgia, a few preserves and arboreta existed in the Soviet period (e.g., the Pitsundo-Mussersky Zapovednik south of Gagry and the Sukhumi Botanical Garden); however, many of these are now in the separatist province of Abkhazia, and their status and ease of access are thus uncertain. The Lenkoran region of southeastern Azerbaijan is covered with humid subtropical forests with many Tertiary relics well represented (ironwood, chestnut oak, Hyrcanian box tree, Lenkoran acacia, and others). The Hirkan National Park protects over 150 rare and endemic plant species along with many native bird and mammal species with limited distribution.

The unique mixed and deciduous forests of the Russian Pacific combine northern elements from Siberia with southern elements from Manchuria, and have no analogues in North America or elsewhere. This is the only area of the FSU influenced by summer monsoons; 60% of all rain falls between July and September. The summers are warm (the average temperature of Vladivostok in July is +17?C), but winters are very cold (the mean January temperature is -15?C, colder than Moscow's). These forests have the greatest tree diversity in the FSU, with over 70 species. By comparison, the mixed forest in the Moscow region has at most 15 species. (Parts of New England, on the other hand, have over 70 species of trees, and the Great Smoky Mountains National Park has over 130!) Korean pine, two firs, two spruces, four lindens, and a few oak and maple species are the dominant trees in the north, along the Amur River. In the south near Vladivostok, walnuts, elms, and other southern species with Chinese affinities become more prominent. Actinidia is a common large vine, and Siberian ginseng and lemon-scented Schisandra are common in the understory. On Sakhalin and the Kurils, even bamboo can grow among the fir and spruce trees! The Amur tigers, of course, are the flagship animal species of the Far Eastern forests, numbering in the low 400s. Other interesting mammals include brown and Himalayan black bears, Far Eastern leopards, elk, wolverines, sables, lynxes, and giant shrews. Many rare bird species with limited distribution are found here (Blackiston's fish owls, Mandarin wood ducks, and blue and green magpies). There are 20 species of reptiles and amphibians here; although the state of Virginia (at a comparable location, but farther south) has 67 species of reptiles, these numbers are the highest for Russia. Turkmenistan deserts have over 40 species of reptiles.

The azonal communities of the floodplains, lakeshores, and marine coasts occur everywhere near water, regardless of the natural zone they are in. The river floodplains and lake shores have tall meadows and emergent marshes composed of a few dozen widely distributed species (e.g., cattails, reeds, bullrushes, sedges, grasses, and other wetland plants). Likewise, marine coasts have a rather uniform set of species in the tidal zone (brown and green algae, barnacles, sea urchins, sea anemones, and a few flowering plants), all adapted to saline water and fluctuating tides. In the FSU, the most diverse marine life and the highest productivity of marine life are found along the Barents and White Sea coasts and in the Pacific. The Black Sea, in contrast, is a species-poor basin, because of the extensive anaerobic hydrogen sulfide zone in its depths and a high degree of local water pollution. The Baltic Sea has an intermediate degree of productivity and is the freshest of the major sea basins of Russia.