ECOLOGICAL REGIONS OF THE NORTHWEST TERRITORIES Taiga Shield Ecosystem Classification Group Department of Environment and Natural Resources Government of the Northwest Territories 2008 ECOLOGICAL REGIONS OF THE NORTHWEST TERRITORIES TAIGA SHIELD This report may be cited as: Ecosystem Classification Group. 2008. Ecological Regions of the Northwest Territories – Taiga Shield. Department of Environment and Natural Resources, Government of the Northwest Territories, Yellowknife, NT, Canada. viii + 146 pp. + insert map. ISBN 978-0-7708-0173-1 Web Site: http://www.enr.gov.nt.ca 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 digital images in the inset boxes are enlarged with captions on pages 24 (Taiga Shield High Subarctic (HS) Ecoregion), 44 (Taiga Shield Low Subarctic (LS) Ecoregion), 66 (Taiga Shield High Boreal (HB) Ecoregion) and 78 (Taiga Shield Mid-Boreal (MB) Ecoregion). Aerial images and main cover image: Dave Downing, Timberline Natural Resource Group. Ground images and plant images: Bob Decker, Government of the Northwest Territories. Document images: Except where otherwise credited, aerial images in the document were taken by Dave Downing, Timberline Natural Resource Group, and ground-level images were taken by Bob Decker, Government of the Northwest Territories. 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. Lane Feschuk GIS Specialist, Timberline Natural Resource Group, Edmonton, Alberta. i Acknowledgements The authors acknowledge the contribution of the following Environment and Natural Resources (ENR) staff to the Taiga Shield mapping revisions and report – Suzanne Carrière, Ray Case, Susan Corey, Susan Fleck, Evelyn Gah and Tom Lakusta. The contribution by regional ENR staff – Ken Mercredi and Richard Olsen (South Slave Region), Roger Fraser and Lance Schmidt (North Slave Region) and Paul Rivard (Sahtu Region) – in the timely placement of fuel caches, critical to the success of the field program, is also acknowledged. We thank David Kroetsch, Agriculture and Agri-Food Canada, for providing the initial classification upon which the Northwest Territories version was built; John Downing, for assistance in obtaining and interpreting bedrock geology information; and Wayne Pettapiece, for compiling most of the glossary of terms in Appendix 5. We also acknowledge members of the 1995 Ecological Stratification Working Group, members of the 1989 Ecoclimatic Regions Working Group and authors of the 1982 report “An Ecological Land Survey of the Lockhart River Mapsheet, Northwest Territories” who provided the original conceptual and mapping framework upon which this version of the Taiga Shield classification is based. Alex Hall provided detailed observations on wildlife. We thank Jim and Margaret Peterson for their valuable logistic support and hospitality. Pilots Dustin Lunde and Jim Archibald provided safe and courteous air transport throughout the 2006 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 Shield Ecosystem Classification Project. The West Kitikmeot/Slave Study (WKKS) provided additional funding support. The WKKS, initiated in 1996, 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. Four of the report’s co-authors (from left to right, Bob Decker, Bas Oosenbrug, Charles Tarnocai and Dave Downing), with James (Jim) Peterson (far right) who passed away on April 15, 2008. We are grateful for his hospitality, good-natured humour and knowledge of the Point Lake area. This photo was taken on the last day of the 2006 field survey (August 1, 2006) at Point Lake, Northwest Territories. Photo: Jim Archibald. ii Preface The Taiga Shield, the ancient bedrock heartland of northern Canada, arcs west from Labrador to the eastern shores of Great Bear Lake. The erosive forces of wind, water and ice have worn down what once were high mountain ranges a billion years ago to rolling bedrock that is blanketed in some areas by clay, sand, gravels and boulders sorted and deposited by receding glaciers. Lakes and rivers are a prominent feature of the Shield. Boreal and Subarctic climates that change from north to south and east to west are modified by bedrock and glacial landforms to produce diverse landscapes with distinctive vegetation and soil features. Broad-scale vegetation cover and geological 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 such as latitude, elevation and parent materials that affect temperature, moisture, light and nutrient conditions, 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 since the 1960s in Canada. Ecosystem classifications 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. In 2004, in response to increasing development pressures in the Mackenzie River Corridor, the 1996 Taiga Plains Ecozone was evaluated. A series of workshops in 2004 – 2006 and an intensive survey of the entire Taiga Plains in 2005 led to significant changes to the 1996 map, and a revised map and report were produced in early 2007 (Ecosystem Classification Group 2007). The same approach was followed in 2006 for the 1996 Taiga Shield Ecozone that borders the Taiga Plains to the east. 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 within a geographic information system. This information allowed participants to view landscapes and existing mapped ecosystem units from a number of different perspectives. A core element of the Taiga Shield classification was the detailed and comprehensive work done by S. W. Bradley, J.S. Rowe, C. Tarnocai and G.R. Ironside for the Lockhart River mapsheet (Bradley et al. 1982). Their map units, descriptive information and classification approach were used with a few modifications for about 60 percent of the Taiga Shield within the Northwest Territories. iii Air and ground verification of the proposed changes was an integral part of the revision process. In the summer of 2006, an intensive float plane and helicopter survey was undertaken throughout the entire Northwest Territories Taiga Shield between the Northwest Territories – Nunavut border, the Northwest Territories – Saskatchewan border, the eastern boundary of the Taiga Plains, and the southern boundary of the Southern Arctic (tree line). Over 25,000 km of transects were flown and a detailed and large-scale record of landscape features was captured in over 15,000 geographically referenced digital images accompanied by text commentaries; site, vegetation and soil information was also collected from 44 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 (Appendix