Beaufort Sea – continental coast and shelf (M27)The Beaufort Sea Ecoregion (M27, on WWF’s RACER ecoregion map [jpg, 4.62 MB]) stretching along the northwestern Canadian and northern Alaska coast is biologically rich.
The ecoregion’s few major rivers, including the Mackenzie River in Canada and the Colville River in Alaska, as well as many smaller watercourses deliver vast amounts of ecologically important nutrients, sediments, and freshwater to the shelf.
The Mackenzie River, for example, is responsible for a large estuarine system over the Canadian portions of this shelf and ranks fourth among circum-Arctic marine systems for freshwater input and first for sediment.
The Beaufort Sea ecoregion is featured in the RACER handbook [pdf, 2.65 MB] as an example case study.
Laptev Sea, Russia (M41)The Laptev Sea Ecoregion (M41, on WWF’s RACER ecoregion map [jpg, 4.62 MB]) on the central Russian arctic coast is made up to a large degree of the Siberian shelf with an average depth of around 53m.
The coastline is characterised by several estuaries and there are many islands in the Laptev Sea, especially in its western part. The Laptev Sea ecoregion is home to many arctic marine mammals, including the Laptev walrus, a population of walrus proposed but not commonly accepted as a distinctive subspecies (Odobenus rosmarus laptevi) that winters in the area where they can feed in the open water of the Great Siberian Polynya.
Central Canada, Canada (T4)The Central Canada Ecoregion (T4, on WWF’s RACER ecoregion map [jpg, 4.62 MB]) is a tundra ecosystem, characterised by lowland plains covered with glacial moraine, which stretches from the Canadian mainland in the South across the islands of the central and western parts of the high arctic archipelago.
Herbs and lichens dominate the ground cover, but on the mainland tundra shrubs also occur (including dwarf birch, heaths, willows). Largely polar desert conditions are common in the high arctic islands. Short summer period and cool conditions likely reduces predation pressure and insect harassment for concentrations of breeding birds and mammals.
East Chukotka, Russia (T5)The Eastern Chukotka Ecoregion (T5, on WWF’s RACER ecoregion map [jpg, 4.62 MB]) is home to a unique combination of vegetation types and plant communities, and its overall geographical features, zoogeography and landscapes bear witness of its history as a land bridge between Eurasia and America.
This history has resulted in a biogeographic exchange between the continents with relic biota (for example cryophilic steppe) still found within the ecoregion.