Taiga Plains Low Subarctic Ecoregion

---

Overview

The Taiga Plains Low Subarctic (LS) Ecoregion occupies the central third of the Taiga Plains. Level to undulating till plains with white or black spruce stands or regenerating shrub communities are typical of uplands, and peatlands with permafrost are characteristic of low, wet areas.

General Description

The Level III Taiga Plains LS Ecoregion includes fourteen Level IV ecoregions that occupy the central third of the Taiga Plains at elevations of 200 mASL to over 1000 mASL and one outlying Level IV ecoregion along the Northwest Territories-Alberta border. This Ecoregion spans about 650 km in a north-south direction. Toward the north and at higher elevations, the increased incidence of cold-climate permafrost features such as polygonal peat plateaus and runnels and the decreased incidence of relatively tall and dense upland forests indicate harsher climates. Level to gently sloping and undulating imperfectly- to poorly-drained glacial till occurs over much of the Ecoregion. Peatlands are extensive, particularly on plains in the southern half. Recent fires have burned over much of this Ecoregion, and regenerating shrub lands and young regenerating forests share dominance with low-canopied open black or white spruce forests and peat plateaus. Diverse mixed-wood, deciduous or conifer forests are limited to warm and well-drained microsites.

Climate

Norman Wells is the only station from which climate data have been collected over long periods within the Taiga Plains LS Ecoregion, and climate statistics are therefore determined through interpolated models using the limited available data. Polygonal peat plateaus and slow-growing open conifer stands across most of the region are indicative of a Low Subarctic climate, as defined by the Ecoregions Working Group (1989). Climate models (Agriculture and Agri-Food Canada 1997) provide the following general statistics. The mean annual temperature ranges from –3.5 to –9.0ºC. The mean temperature in January, the coldest month, ranges from –25.5 to –29.0ºC, and from 11.0 to 16.5ºC in July, the warmest month. Mean annual precipitation is between 230 and 350 mm, with the wettest period in June through August and the driest period in December through April; about half falls as rain and half as snow. The mean annual daily solar input (refer to Section 1.4.1 for further explanation) ranges between 9.5 and 11 mJ/m²/day, with low values of 0.2 to 1.5 mj/m²/day in December and highs of 21.5 to 22.5 mJ/m²/day in June.

Topography, geology, soils, and hydrology

The Taiga Plains LS Ecoregion includes extensive low-lying plains, uplands, and hill systems embedded in the uplands; slopes are mainly level to very gentle. Devonian limestone underlies the eastern third of the Ecoregion, where numerous calcareous ponds and fens indicate limestone influences on groundwater. Level to undulating and hummocky till is the dominant surficial material; in places it has been deeply grooved by glacial ice movement. Permanently frozen peatlands cover vast areas particularly in the south part of the Ecoregion. Soils are dominantly mineral and Organic Cryosols. Lac la Martre, Keller Lake, and Blackwater Lake are the largest lakes, and there are thousands of small lakes scattered throughout.

Vegetation

Open mixed black and white spruce stands with a shrubby understory of dwarf birch, northern and common Labrador tea, mosses and lichens are the primary upland vegetation type on areas that have not recently burned; dwarf birch-mixed spruce stands are extensive on recently burned areas, with jack pine on coarse-textured materials. Bogs, collapse scar fens and nearly treeless lichen-Labrador tea-peat moss communities occur across vast areas in association with permafrost features such as peat plateaus, polygonal peat plateaus, and runnels. The northern limits of mixed-wood and jack pine forests are reached within the Taiga Plains LS Ecoregion at about 65º N latitude, and diverse stands exhibiting better growth are restricted to warm and well-drained microsites.

Ecoregions

The following are the smaller ecoregions within the Taiga Plains Low Subarctic Ecoregion:

Arctic Red Plain LS Ecoregion North Mackenzie Plain LS Ecoregion Norman Range LS Ecoregion Great Bear Upland LS Ecoregion Great Bear Plain LS Ecoregion Blackwater Upland LS Ecoregion Keller Plain LS Ecoregion Lac Grandin Plain LS Ecoregion Lac Grandin Upland LS Ecoregion Bulmer Plain LS Ecoregion Ebbutt Upland LS Ecoregion Horn Slopes LS Ecoregion Horn Plateau LS Ecoregion Cameron Plateau LS Ecoregion

Click here for more information on the Taiga Plains Low Subarctic Ecoregion and all of the ecoregions within it.