The Canadian High Arctic Tundra ecoregion is the northernmost ecoregion in Canada and in North America, except for those on Greenland. It encompasses most of the northern Arctic archipelago, from much of Baffin Island, Somerset, and Prince of Wales Islands in the south, through all islands northward to the most northern island in Canada, Ellesmere Island.
This large ecoregion borders the Canadian Middle Arctic Tundra ecoregion to the south and the Davis Highlands Tundra ecoregion on the eastern edge of Baffin Island. The western portion of the Canadian High Arctic Tundra is mostly flat and underlain by sedimentary rocks of the Paleozoic and Mesozoic ages. Rugged mountains up to 2,500 m in elevation occur on the north and west coasts of Ellesmere and Axel Heiberg Islands. Eastward and southward, most of the ecoregion consists of lowland plains covered by glacial deposits, but major ridges occur on the Parry Island Plateau. East of Prince of Wales and Somerset Islands, the terrain consists of plateaus and rocky hills of Precambrian granitic bedrock.
The ocean in the northern half of the ecoregion is ice-covered most or all of the year, although, with global warming, the area and duration of open-water conditions are increasing and moving northward. Surprisingly, only 8% of this ecoregion is protected, with an additional 69% of habitat intact outside protected areas. Important protected areas include Qausuittuq National Park on Bathurst Island and Quttinirpaaq National Park on the northeastern corner of Ellesmere Island (in Inuktitut, Quttinirpaaq means “top of the world”).
The climate of this ecoregion is high Arctic, characterized by very cold and dry conditions. Mean summer temperatures in the northern portion of the ecoregion are only -1.5ºC but reach up to 2ºC in the south. Average winter temperatures range from -32ºC in the north to -23ºC in the south. Permafrost is continuous and extends up to several hundred meters in depth. Average annual precipitation is only 100–200 mm over most of the region but increases to 400 mm in higher areas of Baffin Island. The northern portions of this ecoregion have the lowest precipitation in Canada, down to 50 mm annually.
Given the extreme cold and limited moisture, the northern portion of this ecoregion has sparse vegetation of cold-hardy lichens, mosses, and a few vascular plants, mostly sedges such as cottongrass. Arctic willow and species of mountain avens are present at lower elevations, along with low-growing herbs such as purple saxifrage, Arctic poppy, and bog sedges. In the milder southeastern part of the ecoregion, the vegetation is similar but is often more continuous, with wet areas containing relatively dense growth of wood rush, wire rush, and saxifrages.
Characteristic mammals found in this ecoregion include polar bears (in coastal areas), the Arctic wolf subspecies, musk ox, barren-ground caribou, and Arctic hare. The caribou is the endangered Peary caribou, the smallest subspecies of caribou in North America (violating the generalization known as Bergmann’s Rule, where body size within species of mammals and birds increases with increasing latitude).
The Peary caribou population dropped from more than 40,000 in 1961 to about 700 in 2009. This dramatic decline is linked to an increased number of days with temperatures above freezing, which results in ice layers in the snowpack that hinder foraging.
Marine mammals include walrus, several species of seals and whales, and the narwhal in southern areas. Characteristic birds include king eider, snow goose, rock ptarmigan, northern fulmar, various plovers, sandpipers, seabirds, hoary redpoll, snow bunting, and, especially in the south, gyrfalcon, snowy owl, and species of jaegers. Breeding populations of Ross’s gulls and ivory gulls also occur in this ecoregion.
The largely intact habitat but poor protection status make this ecoregion a high priority for a vast expansion of protected areas. Although the extreme climate and remoteness have spared it from intense development, exploitation of oil and gas has occurred and is bound to increase. Priority conservation actions for the next decade are 1) greatly expand the network of protected areas across the ecoregion, 2) prohibit incompatible uses, including oil production, within designated protected areas, and 3) protect vulnerable species from over-harvest and develop and implement recovery plans for the most imperiled species, such as Peary caribou.
1. Ricketts, T.H. et al. 1999. Terrestrial Ecoregions of North America: A Conservation Assessment. Island Press, Washington, D.C.
2. Ecological Stratification Working Group. 1995. A National Ecological Framework for Canada. Environment Canada and other agencies, Ottawa.
3. Qausuittuq National Park. https://en.wikipedia.org/wiki/Qausuittuq_National_Park