the Ushkanii Islands, Lake Baikal (original) (raw)

The Ushkanii Islands, Lake Baikal

by Robert Liebermann

This information is edited from my geography of the Ushkanii and Caribou Islands, which you can find in full here.

Baikal and its climate, animal, and plant worlds -- it's a phenomenon; there's nothing in the world like it. But the Ushkanii Islands with their natural and climatic conditions; this is an exceptional wonder for Baikal. One could say that here is uniqueness within the unique.
—Nikolai Ladeischikov, 1975

ushkanii island maryan

The Islands
The Ushkanii Islands, also known as the Ushkanii Archipelago or the Ushkaniis, are situated at 53°50'N, 108°40'E, near the center of Lake Baikal and approximately 10 kilometers northwest from the east-central lakeshore at Svyatoi Nos Peninsula (ÐÏÌÕÏÓÔÒÏ× ó×ÑÔÏÊ ÎÏÓ). Though not as far from the shore as**Caribou Island** on Lake Superior, they nonetheless represent the most remote islands in Lake Baikal. The shortest land-to-land distance between the eastern most of the Ushkanii Islands (Dolgii and Kruglii) to the mainland at Svyatoi Nos Peninsula is approximately 6 km—the shortest possible migration route between the mainland and the Ushkaniis. The minimum distance to the western shore of Baikal is 27 km between Bolshoi Ushkanii Island and Cape Sharmla (ÍÙÓ ûÁÒÍÌÁ). The Ushkanii Islands are at the northern end of a submerged ridge of small mountains. This is known as the Academic Ridge (áËÁÄÅÍÉÞÅÓËÉÊ ÈÒÅÂÅÔ), and stretches for about 100 kilometers northeast from Olkhon Island to the Ushkaniis. The ridge rises a maximum of 1360 meters from the bottom of Baikal in the area, and the four Ushkanii Islands represent the tops of these submerged mountains.

Toponymy
The largest island of the group is Bolshoi Ushkanii (Ï. âÏÌØÛÏÊ õÛËÁÎÉÊ), which means "Big Ushkanii", and the three smaller islands nearby to the east: Tonkii, Kruglii, andDolgii (ôÏÎËÉÊ, ëÒÕÇÌÙÊ, äÏÌÇÉÊ); which mean "tiny", "round", and "long", respectively. The name Ushkanii comes from a local Siberian word, "ushkan" (ÕÛËÁÎ) for "hare" (ÚÁÑÃ). Ushkan is taken from the Russian word for ears (ÕÛÉ), in reference to the large ears of hares. On a 1701 map of the Baikal region by the historian, geographer, and cartographer S. U. Remezov, the islands were named the "Hares" (úÁÑÞØÉÉ). Adding to the confusion is the fact that this word may refer either to hares (Lepus sp.) or the Baikal nerpa (seal, Phoca sibirica), which has also historically been given the name "ushkan" in local speech. Incidentally, a species of White Sea seal is also sometimes called ushkan. The islands have also occasionally been referred to as the Marble Islands (íÒÁÍÏÒÎÙÅ ÏÓÔÒÏ×Á). A general map of the Ushkanii Islands, showing place names referred to in this study, is given in figure 2 (General map of the Ushkanii Islands with toponyms). You can see this and other pictures of the islands here.

Size and Arrangement
The Ushkanii Islands are comprised of four islands within an archipelago of one large island and three smaller islands arranged in an arc to the east of the main island. The largest island, Bolshoi Ushkanii Island, is approximately 7 km2 in area, and shaped somewhat like an east-west oriented oval. It is in longest dimension approximately 4.9 kilometers wide from east to west, and 2.7 km from north to south. Its longest continuous dimension is about 5 km in a east-northeast direction from the southwest tip near the meteorological station to the northeast tip. The maximum elevation above Lake Baikal is 216 meters, although Galazii (çÁÌÁÚÉÊ 1988) gives a figure of 211 meters.

There are an additional three islands located to the east of Bolshoi Ushkanii Island, which are known collectively as the Small Ushkanii Islands, and all are much smaller than the main island. The largest of the Small Ushkaniis, Dolgii Island, is located about 3.4 km east of the northeast tip of Bolshoi Ushkanii Island. It is oriented SSW-NNE, is approximately 1250 meters long and 500 meters wide at maximum dimension, and its area is approximately 32ha. It rises to an elevation of 21 meters above lake level. Tonkii Island is the smallest to the group, and is located approximately 2.3 km east of the southeast corner of Bolshoi Ushkanii Island. Its area is approximately 14ha, and its maximum height is 17 meters. The island is shaped approximately like a triangle with rounded corners, and is about 400 meters in "diameter". Kruglii Island is the middle-sized island of the small group, and is positioned approximately between Dolgii Island and Tonkii Island, 2.5 km east of the southeast side of Bolshoi Ushkanii Island, 400 meters south of Dolgii Island, and about 300 meters from the east shore of Tonkii Island. It is, like Tonkii, approximately a triangle, and about 500 meters in diameter. Its area is 20ha, and its elevation is 22 meters above the Lake Baikal mean.

Topography
The topography of the Ushkanii Islands is quite rugged, especially for its small surface area, and Bolshoi Ushkanii Island's highest elevations are near the southeast side of the island, as are the steepest slope areas. Former beach ridges, described best by Lamakin (ìÁÍÁËÉÎ 1952), are a dominant topographical feature on many areas of the islands. Figure 3 (View of Bolshoi Ushkanii Island from Tonkii Island) clearly shows several former beach ridges and the difference in slope between the north and south sides of Bolshoi Ushkanii Island. On the north and east sides, for example, there is a steep slope from the higher areas of the island to a wide beach ridge, and then another steep slope to the lake level. On the west side of the island, there is a larger lower elevation than elsewhere on the island, and the steepest slope is further inland than on the east and north sides. Lamakin and others have differentiated approximately 9 or 10 different terrace levels on Bolshoi Ushkanii and three on the Small Ushkaniis. The south-facing slope is perhaps the most dramatic topographic feature of Bolshoi Ushkanii Island. The combination of climatic exposure and edaphic-geological conditions combine to create a landscape suitable for a type of steppe known as a "maryan" (ÍÁÒÑÎ); a Buryat term for a grassy opening amidst forested areas, found on south-facing mountain slopes of the Baikal region.

The Small Ushkaniis have minor differentiation of former shorelines due to their low elevations, although they do have steep enough south slopes to permit some steppe microhabitats. They have landscapes resembling in many ways miniatures of Bolshoi Ushkanii; for example, there are smaller areas with similar proportions of rocky and gravelly shorelines, lower relief, small steppe areas, and small, relatively simple larch forests.

Geology
Much of the landscape of the Ushkanii Islands is dominated by outcrops of metamorphosed sedimentary rock of lower Proterozoic age. There are several alternating layers of marble, but there is also a large area of much more resilient darker, non-carbonitic rock consisting mainly of amphibole, plagioclase, andquartz. Near the southern shore of Bolshoi Ushkanii there is also an outcrop of hornblende-plagiogneissic and crystalline slate, and in areas near the north shore there are also exposures of hornblende and slates. According to Lamakin and Ivanova, the same rock strata are also encountered on the Small Ushkaniis.

Lamakin postulated that Bolshoi Ushkanii rose above the lake level in the early Quaternary (about 2.4 million years old), and the Small Ushkaniis during the middle Quaternary. He estimated the present average rate of rise of the Ushkaniis at 20 centimeters per 100 years. Later, Palshin suggested that the Ushkaniis may be somewhat older. He estimated their origin as closer to the late Tertiary (approximately 2.6 million years old).

The shallow and often outcropping bedrock is strongly expressed in the topography, soils, and vegetation of the islands. Much of the island has a rocky character, and there are many rocky slopes, even cliffs, especially along the south slope and several of the terrace rises. The well-weathered rock in these areas allows continued erosion and accumulation of young talus slopes.

The shorelines of the Ushkaniis are very rocky, and there are no appreciable areas of sand deposition. The total shoreline length of Bolshoi Ushkanii Island is approximately 13 kilometers; approximately 40% of this is gravel beach, and 60% is rocky or bouldery. Many areas of the shoreline are composed of steep rock outcrops, punctuated by gravelly or rocky beaches. This is particularly evident along the west and southwest sides of Bolshoi Ushkanii, and on areas of the Small Ushkaniis. More shallow shoreline topographies are typical of the west and northern shores of Bolshoi Ushkanii, with smaller areas of bedrock punctuated by gravel and rocky beaches. Ivanova states that the beaches were considerably wider before the rise in Baikal's level following the construction of theIrkutsk Hydroelectric Station (GES). Other than the Baikal shoreline, there are no water features of any kind on the Ushkanii Islands. A map of the topography and geology of the Ushkanii Islands is given in figure 4.

Climate
The climate of the Ushkanii Islands is, as on Caribou Island and other large lake islands, strongly influenced by the waters of the lake. The limnoclimate of islands is stronger than most shoreline areas due to the lack of a suitable "buffer" of land climate, such as exists slightly inland at the mainland shore. This phenomenon of limnoclimate, microclimate, and bioclimate has been extensively investigated at the Ushkanii Islands, and Vuikhristyuk (÷ÙÈÒÉÓÔÀË 1969Á, 1969Â, 1980) presented a good synthesis of the conditions present. Since the late 1950s, a meteorological station at the southwest end of Bolshoi Ushkanii has recorded comprehensive climatic data. This enables direct long—term comparison with areas of the mainland and a better delineation of the differences between mainland and lake climate of the area.

Animal Life
Litvinov, Matveichuk, and others have studied and reported the zoogeography of the Ushkanii Islands. The fauna of the Ushkanii Islands is relatively poor, especially in mammals. There are essentially two mammals permanent to the Ushkaniis; the Baikal nerpa and the red polevka, and only a few other wild mammals have been recorded for the islands. Two factors exist at the Ushkanii Islands which greatly enhance the possibility of other mammals; the close proximity to undisturbed wilderness of the Svyatoi Nos Peninsula and the consistent, solid ice cover of Baikal during the period from early January to late May. This sometimes results in transient animals during the winter, and occasionally for longer periods. It also allows a relatively easy natural restocking of several mammals known periodically to the islands, such as hare. In addition, another mammal, which clearly has influenced the vegetation of the Ushkanii Islands, finds easy passage at this time: man, as snowmobile access provides the easiest access of the year to the islands. The following accounts apply to Bolshoi Ushkanii Island only (as the literature and other sources largely did not address the Small Ushkaniis), except where noted for the nerpa and red polevka.

Vegetation of the Ushkanii Islands
By far the most comprehensive vegetation survey of the Ushkanii Islands is that of Ivanova. Though there have been some changes to the vegetation in the last 30 years, the vegetation descriptions and community associations on the Ushkaniis still generally follow those of Ivanova, despite several fires and other impacts.

Bolshoi Ushkanii Island is covered largely with a variation of the low mountain forests similar to those that surround much of Baikal. Larch and pine forests, with admixture of birch, poplar,willow, and mountain ash, are the main forest tree species, with the forests of Ushkanii being differentiated into two main types with either larch or pine dominant. Several common taiga trees of the region, such as spruce (Picea obovata), fir (Abies sibirica), and two other species of pine (Pinus sibirica, P. pumila) are rare on the islands, and are not significant components of the forests. Other areas of the Ushkanii support several unique communities.

Steppe vegetation is a characteristic feature on the southeast and east slopes, as well as a small area of the west side. On areas of the south slope there are rockycliffs and talus slopes which, while having many species in common with the steppe areas, have a suitably distinct flora and microlandscape to be differentiated. Shoreline communities are well developed in various areas along the perimeter of the island, with some small areas ofemergent aquatic vegetation on the northwest and south-central shores. Transition zones are also significant phytogeographical features on the island, particularly the forest edge at steppe and shoreline areas. The broadest transitions are from the pine forest to the steppe areas, while those of the forest-shore are often quite abrupt. Other noteworthy transition zones are the larch forest-pine forest transition (particularly on the southeastern side of the island), and the south slope-pine forest transition. There are no permanent or intermittent wetlands of any kind on the Ushkanii Islands, save for the Baikal shoreline, and hence few species associated with such habitats.

Human activities on the islands have affected the vegetation. In addition to the "natural" communities, the area of the island near the meteorological and ranger station maintains some "weedy" species, and there are also several introduced species close to an old dwelling nearPescherka Bay. Many of these species may have been directly introduced by man, and all have found a suitable habitat among the disturbed and deforested areas.

Vegetation of the island has also been affected byfires, which have burned large areas of the island in the 20th century (and perhaps past centuries). Later in this thesis an overview will be given of the fire history of the Ushkanii Islands in this century, and their possible influences on the islands' flora.

The Small Ushkanii Islands are too small to have vegetation zones as well defined as Bolshoi Ushkanii, though there is a definite steppe-xerophyte association on the southern slopes of the islands, a narrow forest-shore transition, and shoreline vegetation similar to that of Bolshoi Ushkanii Island. The forest areas are dominated by Larix x czekanowskii, as on the lower areas of the west side of Bolshoi Ushkanii Island. The wooded areas of the Small Ushkaniis have a relatively open larch-dominant forest with small additions of Pinus sibirica, Sorbus sibirica, Pinus sylvestris, Picea obovata, Abies sibirica, Betula hippolyti, and Duschekia fruticosa. Notable is the thick ground cover in most forest areas of the Small Ushkaniis of Empetrum sibiricum. Several species are exclusive to the small Ushkaniis and are not known from Bolshoi Ushkanii; including Carex amgunensis, Salix stenolivida, Betula rotundifolia, Betula divaricata, the hybrid Betula divaricata x B. exilis, Astragalus sericeocanus, Conioselinum longifolium, Carex krausei, and Ribes paciflorum.

The Small Ushkaniis have a thinner forest—more closely approximating the shore-larch forest transition on Bolshoi Ushkanii, attesting to a strong limnoclimatic influence on these islands. Ivanova (é×ÁÎÏ×Á 1969) notes this pronounced limnoclimatic influence on the vegetation of the islands, particularly on the northern shores of the islands. There are several arctoalpine species on the Small Ushkaniis, including Pinus pumila, Betula divaricata, B. rotundifolia, Salix divaricata, Sorbaria palassi, and Epilobium latifolium. The arctoalpine flora of the Small Ushkaniis includes all arctoalpine species from Bolshoi Ushkanii Island with the exception of Polemonium boreale and, therefore, shows the suitability of these smaller islands—with their strong limnoclimates—to arctoalpine species.

This information is cut and edited from a more comprehensive report; see photographs, maps, and much more detail here.

2012.03.16. all content © Robert Liebermann