Location and General Description
Most of this ecoregion is within the borders of the Republic of Yakutia (Sakha), situated in northeastern Siberia, between the Lena and Kolyma Rivers, with the Sea of Okhotsk as a southern border. Winter is prolonged and severe, with average January temperatures about
-40°C. Summer is short, but warm with: average July temperatures near 15°C, but as high as 40°C in Yakutsk. In the northeast, the town of Verkhoyansk boasts some of the coldest winter temperatures on Earth, sometimes as low as -70°C. There is little precipitation; from 150-200 mm in Central Yakutia to 500-600 mm in the mountains of eastern and southern Yakutia. The geology of the area is described as being within the Kimmerian folding zone of the Pacific Ocean Geosyncline (Nalivkin 1960). Many of the rocks present are volcanic in origin and date to the Jurassic Period. In western Yakutia, some of the most ancient portions of the Earth's crust can be found and are a source of Yakutia's massive diamond reserves. The region's complex and diverse geological structures are extremely rich in minerals and are well known throughout Russia for gold deposits in the Aldan, Indigirka, and Yana River basins, tin in the northeast.
The Yana, Indigirka, and Kolyma River systems wind northwards through large interior areas of the region before terminating along the northern arctic coast (see ecoregion #142). Much of the area lies within the Arctic Circle and all of it is covered by eternally frozen ground or permafrost, which greatly influences the region's ecology and limits forests to this ecoregion. A vast area of taiga forest makes up the majority of this region. Larch (Larix cajanderi) tree stands accompanied by Betula pendula are found throughout the region. Forests with Ledum palustre, Vaccinium uliginosum, lichens and moses in ground cover dominate in ecoregion. Forests of Populus suaveolens and Chosenia macrolepis occur in the valleys of the rivers (Shcherbakov 1975; Sochava, 1980).
Forests of the Russian taiga play a vital role as one of the largest unaltered boreal forest areas in the world. An enormous carbon sink, the taiga potentially lessens the impact of global climate change. This region contains interior forests as well as coastal areas along the Sea of Okhotsk in the southAbout 40% of ecoregion area is occupied by sparse larch forests with dwarf shrub-lichen ground cover and by brushwoods of Pinus pumila. Sparse larch tree stands with understorey of Betula middendorffii, Pinus pumila, Salix kolymensis and moss-lichen cover are distributed in the western, eastern and southern parts. They also occupy about 40% of the territory. Dense larch and spruce-larch are located in the the cenrtal part of the area (Korrelyatsionnaya ekologo-fitocoenoticheskaya.., 1977). Relict steppe associations are usual for the basins of Yana and Indigirka river. Here they occupy southern, western and sometimes eastern steep slopes of the rock terraces. In Kolyma basin the steppes are more rare associations. They are distributed here on the southern slopes of flood terraces. The dominants of these steppes are as follows: Festuca kolymensis, F. lenensis, Agropyron jacutorum, Poa botryoides, Helictotrichon krylovii, Potentilla tollii, P. asperrima, Orostachys spinosa, Stellaria jacutica, Dracocephalum palmatum, Carex pediformis, C. obtusata, C. supina, Koeleria cristata, Arabidopsis bursifolia, Thellungiella salsuginea. There are 21 endemic species in steppe associations including Agropyron karawaewii, Helictotrichon krylovii, Astragalus vallicola, Oxytropis incana, O. scheludjakoviae, O. adamsiana ssp. janensis, Papaver nudicaule ssp.gracile, Vicia macrantha, Saxifraga multiflora, Thymus indigirkensis, Potentilla tollii, P. asperrima, Poa filiculmis, Artemisia lagopus ssp. jarovoi and some others (Yurtsev, 1981).
Flora of ecoregion contains 680 species of vascular plants (Khohryakov, 1985). In the southern portion of the region, along the north coast of the Sea of Okhotsk, numerous seabird colonies are located along rocky cliffs and islands, some maintaining colonies of nearly 1 million birds and 15 species (Golubova and Pleshenko, 1997). Near the northern border of this region is one of the only breeding areas for the rare little curlew (Numenius minutus) and Siberian white crane (Grus leucogeranus).
Common vertebrates are elk (Alces alces), red squirrel (Scurius vulgaris), Siberian chipmunk (Eutamias sibiricus), arctic hare (Lepus timidus), lynx (Felis lynx), red fox (Vulpes vulpes), Siberian weasel (Mustela sibirica), ermine (Mustela erminea), sable (Martes zibellinus), wolverine (Gulo gulo), and brown bear (Ursus arctos). Common taiga birds are hazel grouse (Getrastes bonasia), capercaillie (Tetrao urogallus and T. parvirostris), the great grey owl (Strix nebulosa), hawk owl (Surnia ulula) and boreal owl (Aegolius funereus), the black woodpecker (Dryocopus martius), northern three-toed woodpecker (Picoides tridactylus), Siberian jay (Perisoreus infaustus) and the nutcracker (Nucifraga caryocatactes). Further north, where the forest become more characteristic of subarctic tundra, waterfowl species are common, such as black scoter (Melanitta nigra), Baikal teal (Anas formosa), and lesser white-fronted goose (Anser fabalis).
Northern portions of the region are relatively pristine due to the lack of human population and little resource extraction. Areas closer to the city of Magadan are facing more severe resource use. Hunting cover all over the territory. Coal mining takes place locally near settlements of Susulak and Zyryanka.
Types and Severity of Threats
Forest fires, mining, reindeer herding, and small-scale logging followed by little to no replanting of harvested trees, has caused much of the area to regenerate into pyrogenic tundra landscapes rather than forests due to the underlying permafrost layers.
Justification of Ecoregion Delineation
The Verkhoyansk Mountains of northeast Russia serve as the western boundary for this sparsely forested ecoregion. Ecoregion boundaries correspond to the sparse forest taiga in the East Siberian province in Kurnaev’s (1990) forest map of the USSR.
Korrelyatsionnaya ekologo-fitocoenoticheskaya karta Asiatskoi Rossii. 1977. Institut geografii Sibiri i Dal’nego Vostoka. Irkutsk. [Correlation ecological-phytocoenotic map of Asian Russia].
Golubova, E. Y., and S. V. Pleshenko. 1997. Colonies of seabirds in the northern Sea of Okhotsk. Pages 141-162 in A. V. Andreev. editor, Species diversity and population status of waterside birds in northeast Asia: A collection of study reports. Institute of Biological Problems of the North, Magadan.
Nalivkin, D. V. 1960. The geology of the U.S.S.R. A short outline. Pergamon Press, Oxford.
Khohryakov, A. P. 1985. Flora Magadanskoi oblasti. [Flora of Magadan district]. "Nauka’, Moscow.
Bakkal, S. N., A. V. Bardin, and I. S. Darevskii. 1989. Redki e zhivotnie nashei strani. Leningrad, "Nauka". 311p.
Shcherbakov, I. P. 1975. Lesnoi pokrov severo-vostoka SSSR. [Forest cover of the north-east of the USSR]. Novosibirsk, "Nauka".
Sochava, V. B. 1980. Geograficheskie aspekti sibirskoi taigi. [Geographic patterns of Siberian taiga]. Novosibirsk, "Nauka".
Yurtsev, B. A. 1972. Phytogeography of northeastern Asia and the problem of trans-Beringian floristic interrelations. Pages 19-54 in Floristics and paleofloristics of Asia and Eastern North America. Elsevier Publ. Co., Amsterdam.
Yurtsev, B. A. 1979. The relicts of the xerophyte vegetation of Beringia in the Northeastern Asia. Gloggnitz.
Yurtsev, B. A. 1981. Relictovie stepnye kompleksy severo-vostochnoy Azii. [Relict steppe associations of Northeastern Asia]. Novosibirsk, "Nauka".
Prepared by: John Pearce
Reviewed by: Olga Alexandrovna Zyryanova