South Sakhalin-Kurile mixed forests

Content Cover Image

Kunashir Island, Russia Photograph by Igor Shpilenok


This relatively small ecoregion is comprised of a chain of over fifty islands separating the Sea of Okhotsk from the Pacific Ocean. These islands were formed from volcanic activity from the Miocene-Pliocene and mid-Pleistocene. Biodiveristy is high for this chain of islands comprising of 1,380 species of vascular plants,153 species of birds, and thirty-one species of mammals.

The flora is similar to that of northern Hokkaido while much of the fauna is of Siberian origin. Avian species richness is higher here than in the northern Kuriles and northern Sakhalin and some species have evolved into island endemics. These islands are geographically remote, only six are inhabited by humans.

Location and General Description

caption WWF Stretching 1,200 kilometers (km) between Hokkaido, the northernmost island of Japan, and the Russian peninsula of Kamchatka (from 43? to 51?N latitude), the Kurile Islands divide the Sea of Okhotsk from the Pacific Ocean. The Kurile Islands are a chain of more than 56 islands, some rising to nearly 2,300 meters (m), and contain over 100 volcanoes; 39 of which are currently active (some emitting a constant flow of lava, others producing periodic explosions and violent ejections of toxic gases, ash, and molten rock). Boiling crater lakes, and bubbling fields of sulfur contrast strikingly with deep hidden fjords, glassy crater lakes, dense forests of silver fir, and giant grasses, including wild bamboo. The geology of the area is described as being within the Alpine folding zone of the Pacific Ocean Geosyncline and is largely the result of subduction by the Pacific Plate under the Eurasian Plate. Most of the islands date from the Miocene-Pliocene and mid-Pleistocene. Extending over eight degrees of latitude, the arc is divided into distinct botanical zones. Near-arctic tundra dominates in the northern zone (Shumshu to Shiashkotan islands), with only a scattering of stunted pines, birches, and assorted scrub. The central zone (Lovushki to Simushir islands) has the poorest vegetation, with islands consisting of little more than rocky protuberances that support only lichens, mosses, and a few species of bushes.

Biodiversity Features

caption Kuril Islands, Russia (Photograph by Igor Shpilenok)

The most distinctive feature of the Kurile Islands is its diversity. The flora consists of at least in 556 genera and 135 [family|families]]; at least 14 species are thought to be endemic. About 3,000 species of insects have been recorded, but the true number is probably well in excess of this figure. Among freshwater mollusks, nine bivalves (one endemic) and eight gastropods (two endemic) are known. Numerous shoals of fish congregate here, both from the moderately cold and subtropical waters. Fish from the colder waters include the walleye pollock (Theragra chalcogramma), cod (Gadus morrhua), mackerel (Scomber scomber), flounder, halibut (Hippoglossus hippoglossus), and salmon (Onchorhynchus); subtropical species include the Pacific saury (Cololabis saira), sardines (Sardina), tuna (Thunnus), and Japanese mackerel. Other species such as crab, shrimp, sea urchin, squid, sea slugs, and scallops are also abundant. At least 48 species of freshwater fishes (including anadromous forms) are found in freshwater habitats adjacent to the Kurile Islands, but only 18 species are known to occur on the Archipelago itself.

Seven species of amphibians and reptiles are recorded from the Kurile Islands: one salamander, two frogs the Asiatic Toad (Bufo gargarizans), Siberian Wood Frog (Rana amurensis), and Dybovsky’s Frog (Rana dybowskii), one skink, and three snakes.

Estimates of the numbers of bird species are approximately 153 for this region. Birds with restricted range include the spotted redshank (Tringa erythropus), Jananese Robin (Erithacus akahige), Bull-headed Strike (Lanius bucephalus), and the Forest Wagtail (Motacilla lutea). Other species recorded from the Kurile Islands include: six insectivores, six chiropterans, nine carnivores, nine rodents, and one lagomorph. At least four undescribed species of rodents have been identified. Most of the estimated 5,500 pinnipeds inhabiting the southern Kurile Islands-Hokkaido region are currently concentrated in the waters around Kunashir and the Small Kurile Chain where their main rookeries, habitats, and breeding grounds are found. These animals include Steller's sea lion (Eumetopias jubatus) and a subspecies of the harbor seals (Phoca vitulina Kurilensis) (both listed in the Russian and IUCN Red Data Books), largha seals (Phoca vitulina largha), and a subspecies of sea otter (Enhydra lutris kurilensis).

Current Status

Kurilsky Zapovednik (strict nature reserve), located with the region, was primarily established to protect the breeding grounds of seals and consists of three parts: the northern and southern sites are located on Kunashir Island, the southernmost island of Big Kurile Chain, while the third site lies on Demina and Oskolki Islands, two rocky islands in the Small Kurile Chain. The zapovednik's territory also encompasses the Maliye Kuriley Zakaznik (special purpose preserve), located on Shikotan Island and on several large islands of the Small Kurile Chain. The total area administered by the zapovednik is 151,840 hectares (ha). (The core area is 65,365 ha, the buffer zone 41,475 ha, and the zakaznik 45,000 ha).

Types and Severity of Threats

The convergence of warm and cold sea currents in close proximity to the southern Kurile Islands has made it one of the richest fishing zones in the world. As a result, moderate levels of fishing have escalated to an uncontrolled plundering of the sea with enormous quantities of crab, shrimp, squid, and sea urchin from the southern Kurile Islands region going directly to Japan. In order to help thwart poaching, a marine buffer zone was extended from both sections of Kurilsky Zapovednik on Kunashir Island in 1996.

Justification of Ecoregion Delineation

This ecoregion in the Far East of Russia encompasses the broadleaf forests at the southwest tip of Sakhalin, and the Kurile Islands of Kunashir, Iturup and Shikotan. Ecoregion boundaries correspond to the southern subzone of polydominant-thermophylic forests in the Sakhalin-Kurile province in Kurnaev’s forest map of the USSR.

Additional Information on this Ecoregion

Further Reading

  • Much of the information contained in this ecoregion description comes from the home page for the International Kurile Island Project, administered by the University of Washington, Seattle, USA.



Disclaimer: This article is taken wholly from, or contains information that was originally published by, the World Wildlife Fund. Topic editors and authors for the Encyclopedia of Earth may have edited its content or added new information. The use of information from the World Wildlife Fund should not be construed as support for or endorsement by that organization for any new information added by EoE personnel, or for any editing of the original content.






Fund, W. (2014). South Sakhalin-Kurile mixed forests. Retrieved from


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