Boundaries

This ecoregion includes much of southeastern Saskatchewan, southern Manitoba, southern Ontario, northeastern North Dakota, and northern Minnesota. The major drainages of Lake Winnipeg, including the Saskatchewan River in the northwest, the Red and Assiniboine rivers in the southwest, and the Winnipeg and English rivers in the southeast, are found in this ecoregion.

Topography

Flat-lying Paleozoic limestone bedrock covered with glacial till, silts and clays, and extensive peat deposits characterizes the northern and western portions of the ecoregion. Here, cretaceous shale with shallow depressions has caused a large number of small, shallow lakes, ponds, and sloughs to form. To the east, wetlands are extensive in the regions of the Lac Seul Upland, and undulating lacustrine deposits with occasional bedrock ridges are prevalent. To the southeast where glaciers once covered the region, the area now has thick deposits of glacial drift. Rock outcrops and glacial moraines are common features, providing a gentle rolling landscape.

Freshwater habitats

This ecoregion is on the Canadian Shield and has been covered by glaciers as recently as 10,000 to 15,000 years ago. The combination of glaciation, its landscape, and its geology provide a unique set of habitats, including many oligotrophic lakes and clear, cold streams. Lakes Winnipeg, Winnipegosis, and Manitoba are very large, shallow glacial lakes (once connected as glacial Lake Agassiz, the largest single lake ever to exist in North America).

Terrestrial habitats

Much of the ecoregion is mixed coniferous and deciduous forest, characterized by stands of quaking aspen (Populus tremuloides), balsam poplar (Populus balsamifera), black spruce (Picea mariana), and jack pine (Pinus banksiana). Cold and poorly drained fens and bogs are covered with tamarack (Larix laricina), and may also include an understory of sedges (Carex spp.), ericaceous shrubs (Ericaceae), and mosses. Toward the south-central portion of the ecoregion, the dominant grass species include big bluestem (Andropogon gerardii), switchgrass (Panicum virgatum), and Indian grass (Sorghastrum nutans).

Description of endemic fishes

The area has no endemic fish, mussels, crayfish, or aquatic herpetofauna.

Other noteworthy fishes

The lake sturgeon (Acipenser fulvescens) and the goldeye (Hiodon alosoides) have been severely over-fished and are currently very rare in this ecoregion.

Ecological phenomena

Historically, the lake sturgeon likely undertook long spawning migrations, and the cisco (Coregonus artedi) and lake whitefish (Coregonus clupeaformis) likely formed large spawning schools in the larger lakes.

Justification for delineation

The ecoregions of Canada were identified based on the faunal similarity of 166 major watersheds based on a cluster analysis of freshwater fish occurrences in these watersheds. The extent of the English-Winnipeg Lakes ecoregion was determined by including fish occurrence data for watersheds in contiguous watersheds in the north-central United States. The English-Winnipeg Lakes ecoregion is comprised of watersheds that receive waters from the west and drain towards southern Hudson Bay. As a result of extensive coverage by glacial Lake Agassiz 11,000-8,000 years ago, the fish fauna of this ecoregion consists of freshwater species originating from Mississippian and Beringian refugia. The low productivity of the Canadian Shield and harsh climate currently limit the fish diversity of this ecoregion.

Level of taxonomic exploration

Good / Fair