ECOLOGICAL REGIONS OF THE NORTHWEST TERRITORIES Taiga Plains Ecosystem Classification Group Department of Environment and Natural Resources Government of the Northwest Territories Revised 2009 ECOLOGICAL REGIONS OF THE NORTHWEST TERRITORIES TAIGA PLAINS This report may be cited as: Ecosystem Classification Group. 2007 (rev. 2009). Ecological Regions of the Northwest Territories – Taiga Plains. Department of Environment and Natural Resources, Government of the Northwest Territories, Yellowknife, NT, Canada. viii + 173 pp. + folded insert map. ISBN 0-7708-0161-7 Web Site: http://www.enr.gov.nt.ca/index.html For more information contact: Department of Environment and Natural Resources P.O. Box 1320 Yellowknife, NT X1A 2L9 Phone: (867) 920-8064 Fax: (867) 873-0293 About the cover: The small photographs in the inset boxes are enlarged with captions on pages 22 (Taiga Plains High Subarctic (HS) Ecoregion), 52 (Taiga Plains Low Subarctic (LS) Ecoregion), 82 (Taiga Plains High Boreal (HB) Ecoregion), and 96 (Taiga Plains Mid-Boreal (MB) Ecoregion). Aerial photographs: Dave Downing (Timberline Natural Resource Group). Ground photographs and photograph of cloudberry: Bob Decker (Government of the Northwest Territories). Other plant photographs: Christian Bucher. Members of the Ecosystem Classification Group Dave Downing Ecologist, Timberline Natural Resource Group, Edmonton, Alberta. Bob Decker Forest Ecologist, Forest Management Division, Department of Environment and Natural Resources, Government of the Northwest Territories, Hay River, Northwest Territories. Bas Oosenbrug Habitat Conservation Biologist, Wildlife Division, Department of Environment and Natural Resources, Government of the Northwest Territories, Yellowknife, Northwest Territories. Charles Tarnocai Research Scientist, Agriculture and Agri-Food Canada, Ottawa, Ontario. Tom Chowns Environmental Consultant, Powassan, Ontario. Chris Hampel Geographic Information System Specialist/Resource Analyst, Timberline Natural Resource Group, Edmonton, Alberta. i Acknowledgements The Ecosystem Classification Group acknowledges the contribution of the following Environment and Natural Resources staff to the Taiga Plains mapping revisions, report and poster – Terrianne Berens, Suzanne Carrière, Ray Case, Evelyn Gah, Tom Lakusta, John Nagy, Richard Popko, Paul Rivard, and Alasdair Veitch. Additional advice and support was gratefully received from David Kroetsch, Agriculture and Agri-Food Canada, for providing the initial classification upon which the Northwest Territories version was built, and advice at the December 2004 workshop; John Downing, for assistance in obtaining and interpreting bedrock geology information; and Wayne Pettapiece, for compiling most of the glossary of terms in Appendix 4. We also acknowledge members of the 1995 Ecological Stratification Working Group and members of the 1989 Ecoclimatic Regions Working Group, who provided the original conceptual and mapping framework from which this version of the Taiga Plains classification was derived. Darcy King, Stuart Poirier, Dawson Somerville and Wayne Sorghe provided safe and courteous air transport throughout the summer field season. The Forest Management Division and Wildlife Division of Environment and Natural Resources, Government of the Northwest Territories (GNWT) provided the primary funding for the Taiga Plains Ecosystem Classification Project. The Western NWT Biophysical Study, a joint GNWT/Federal research program, provided additional funding support. The Western NWT Biophysical Study, initiated in 2003, provides funding to assist in the collection of necessary baseline data to help industry, regulators, communities and government assess, mitigate, monitor and manage environmental impacts of proposed developments in the western Northwest Territories. ii Preface The vast landscapes of the Northwest Territories include a remarkable array of terrain and climate conditions interacting to produce an abundance of ecosystems ranging in size from a few square meters to thousands of square kilometers. Productive and diverse forests and wetlands on the rich terraces of the Liard River in the southwest, an intricate complex of alpine and subalpine communities in the western mountains, open and stunted black spruce forests on permanently frozen soils in the northern interior plains, low-growing tundra communities in dry arctic areas north of tree line, and huge expanses of treeless or sparsely forested Canadian Shield rock are but a few of the ecosystems that define the land north of 60. These broad-scale vegetation cover and terrain features provide, in part, the basis for defining and understanding the climatic and physiographic patterns that control vegetation and soil distribution. Both plant communities and soils develop in response to abiotic factors (those which affect temperature, moisture, light, and nutrient conditions, such as latitude, elevation, and parent materials), and biotic factors (for example, competition between species, or individual species tolerances to climatic conditions). The relative influence of each factor at any place in the landscape is determined by the interaction of atmospheric and landscape attributes – climate, topography, parent materials, and biotic elements – all acting over time, as described by Major (1951) and Jenny (1941) for vegetation and soils, respectively. These attributes can be delineated and represented as abstract ecological map units, and may be described at various scales. At the global scale, the Biome or Vegetation Zone is recognized (Walter 1979, Scott 1995, Commission for Environmental Cooperation 1997). At the national scale in Canada, Ecozones, Ecoregions and Ecodistricts are described (Ecological Stratification Working Group 1995). The Northwest Territories has modified the Canadian national scale and classification framework to match the multi-level continental ecosystem classification framework – Ecological Regions of North America – developed by the Commission for Environmental Cooperation in 1997. The Canadian and continental systems are outlined in Section 1 of this report. The value of regional ecosystem classification systems as a foundation for sustainable resource management has been recognized for at least four decades in Canada; they provide a means of presenting and understanding biophysical patterns in a geographic context, and a common basis for communication. The Government of the Northwest Territories has used the national ecosystem classification framework since 1996 as the basis for identifying candidate protected areas, forest management planning, wildlife habitat management and environmental impact assessment and mitigation. Increasing pressures from non-renewable resource development in the southern portion of the Taiga Plains, and the planned Mackenzie Gas Project along the Mackenzie River corridor prompted an evaluation of the national framework within the Taiga Plains and Boreal Plains Ecozones that together comprised most of the south-central Northwest Territories south of tree line and lying between the mountains on the west and the Canadian Shield to the east. This evaluation, undertaken in 2004, concluded that the national framework was appropriate for these purposes and suggested changes to improve its usability. Recommended changes included the re-assignment of ecosystem units that were part of the 1995 Taiga Plains to adjacent geographic areas, the re-assignment of Boreal Plains ecosystem units within the Northwest Territories to the Taiga Plains, and the creation of new ecosystem units to better reflect regional climatic, physiographic and biotic variations (Downing 2004). Proposed revisions to the classification system were modeled and assessed through a series of workshops in 2004, 2005 and 2006 at which experts from the Government of the Northwest Territories, Agriculture and Agri-Food Canada, and consulting firms participated. A variety of spatial data sources including Landsat imagery, digital elevation models, hydrology, permafrost, bedrock and surficial geology, soils, and interpolated climate models were brought together iii within a geographic information system. This information allowed participants to view landscapes and existing mapped ecosystem units from a number of different perspectives. Air and ground verification of the proposed changes was an integral part of the revision process. In the summer of 2005, an intensive float plane and helicopter survey was undertaken throughout the entire Taiga Plains, including the eastern border of the Taiga Cordillera, the western border of the Taiga Shield, and the southern boundary of the Southern Arctic. Over 35,000 km of transects were flown, and a detailed and large-scale record of landscape features was captured in over 16,000 geographically located digital images accompanied by text commentaries; site, vegetation and soil information was also collected from 57 ground plots. Both the photographs and thematic maps derived from the commentaries proved to be indispensable for the revision process. This report and the accompanying map (map pocket inside back cover and Appendix 3) provide a summary of ecoregions within the Taiga Plains. Better spatial information and an improved understanding of climate and landscape patterns and processes through intensive aerial surveys have resulted in the delineation of 45 Level IV1 ecoregions within the Taiga Plains, compared with 16 ecoregions described by the Ecological Stratification Working Group in 1995. Some significant re-assignments