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Ecological Framework of Canada
Ecoregions of Canada


This ecoregion occurs along the southern coast of Hudson Bay, from the Seal River in Manitoba east to James Bay in Ontario. The ecoregion is marked by short cool summers and very cold winters. The mean annual temperature is approximately -4°C. Temperatures can be colder in the Manitoba part of the ecoregion reaching a mean annual low of -7°C. The mean summer temperature is 10.5°C and the mean winter temperature is -19°C. The mean precipitation ranges from 400 mm in the northwest to 600 mm in the east. The ecoregion has a high subarctic ecoclimate and is part of the broad area of tundra and boreal forest transition where the latitudinal limit of tree growth is reached. The vegetation is characterized by very open stands of stunted black spruce and tamarack with secondary quantities of white spruce. A shrub layer of dwarf birch, willow or ericaceous shrubs, and a ground cover of cottongrass or lichen and moss is predominant. Poorly drained sites usually support tussock vegetation of sedge, cottongrass, and sphagnum moss. Low shrub tundra vegetation consisting of dwarf birch and willow is also common. The ecoregion is part of the Hudson Bay Lowland, a distinct physiographic unit within the Hudson geologic platform, which is a large flat geological structure of Palaeozoic limestone. After deglaciation the ecoregion was inundated by the Tyrrell Sea and covered by marine sediments. This was followed by a continued uplifting of the land surface due to isostatic rebound. Along the Hudson Bay coast east of the Nelson River numerous, parallel, well-drained raised beaches present a striking pattern of successive white spruce-covered ridges, alternating with fens, polygonal peat plateaus, and peat plateaus. North of the Nelson River beaches are more subdued and the terrain is dominated by fens, polygonal peat plateaus, and peat plateaus. Peat plateaus occur often in parallel rows marking the underlying beaches. In the fens, small incipient palsa bogs are common. The coastal areas are dominated by marshes and shallow waters and extensive tidal flats, especially north of the Nelson River. Extensive tidal flats and well developed beach ridges of limestone shingles are found at the junction of Hudson and James bays. Wetlands occupy up to 75% of the ecoregion. Organic Cryosols formed on sedge and fibrous sphagnum peat are dominant; Mesisols formed on moderately decomposed sedge and woody peat are significant; and saline Regosols and Gleysols occur on silty to clayey marine sediments along the coast of the bay. Permafrost with low to high ice content is widespread throughout the ecoregion. Characteristic wildlife includes barren-ground caribou, polar bear, arctic fox, brown lemming, snow and Canada goose, swan, sea ducks, and shorebirds. White whale and seal are found in coastal waters. Human activities are limited to trapping and hunting, marine mammal hunting, fishing, recreation, and tourism. The major communities include Peawanuck, Fort Severn, and Churchill. The population of the ecoregion is approximately 1600.

This ecoregion is part of the Hudson Plains ecozone.