ECOLOGICAL REGIONS OF THE NORTHWEST TERRITORIES Southern Arctic Ecosystem Classification Group Department of Environment and Natural Resources Government of the Northwest Territories 2012 ECOLOGICAL REGIONS OF THE NORTHWEST TERRITORIES SOUTHERN ARCTIC This report may be cited as: Ecosystem Classification Group. 2012. Ecological Regions of the Northwest Territories – Southern Arctic. Department of Environment and Natural Resources, Government of the Northwest Territories, Yellowknife, NT, Canada. x + 170 pp. + insert map. Library and Archives Canada Cataloguing in Publication Northwest Territories. Ecosystem Classification Group Ecological regions of the Northwest Territories, southern Arctic / Ecosystem Classification Group. ISBN 978-0-7708-0199-1 1. Ecological regions--Northwest Territories. 2. Biotic communities--Arctic regions. 3. Tundra ecology--Northwest Territories. 4. Taiga ecology--Northwest Territories. I. Northwest Territories. Dept. of Environment and Natural Resources II. Title. QH106.2 N55 N67 2012 577.3'7097193 C2012-980098-8 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 28 (Tundra Plains Low Arctic (north) Ecoregion) and 82 (Tundra Shield Low Arctic (south) Ecoregion). Aerial images: Dave Downing. Main cover image, 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 and ground-level images were taken by Bob Decker, Government of the Northwest Territories. Members of the Ecosystem Classification Group Dave Downing Ecologist, Onoway, Alberta. Bob Decker Forest Ecologist, Forest Management Division, Department of Environment and Natural Resources, Government of the Northwest Territories, Hay River, Northwest Territories. Tom Chowns Environmental Consultant, Powassan, Ontario Dr. Suzanne Carrière Wildlife Biologist (Biodiversity), 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. Brian Maier Resource Analyst, The Forestry Corp, Edmonton, Alberta Bas Oosenbrug Habitat Conservation Biologist (retired), Wildlife Division, Department of Environment and Natural Resources, Government of the Northwest Territories, Yellowknife, Northwest Territories. Jeff Christiansen Resource Analyst, Edmonton, Alberta. i Acknowledgements The authors acknowledge the contribution of the following Environment and Natural Resources (ENR) staff to the Southern Arctic mapping revisions and report: Kim Ullyot and Aingeal Stone (ENR library – reference documents); Ainsley Zock (ENR Information Services – photographs); Kathleen Groenewegen (ENR Forest Management – ongoing GIS support and revisions to final coverages and NWT boundaries); Norm Mair (GNWT Geomatics Centre – imagery); Steve Matthews and Chandra Venables (ENR Daring Lake Research Station – accommodation and fuel logistics). The Forest Management Division and Wildlife Division of ENR provided the primary funding for the Southern Arctic Ecosystem Classification Project. Tom Lakusta, Susan Corey, Nicole McCutchen and Susan Fleck provided management and administrative support. Chris Hunter (Manager, Tuktut Nogait National Park (TNNP), Paulatuk) loaned materials from Parks Canada’s Paulatuk library and Joachim Obst (private contractor) provided useful reports from TNNP. David Kroetsch (Agriculture and Agri-Food Canada) provided the initial classification upon which the 1996 Northwest Territories version was built. John Downing provided assistance in obtaining and interpreting bedrock geology information. Wayne Pettapiece compiled most of the glossary of terms in Appendix 5. Members of the 1995 Ecological Stratification Working Group, members of the 1989 Ecoclimatic Regions Working Group and all researchers who compiled various geologic and natural resource assessments for the area are also acknowledged for their contribution. Field support and accommodation throughout the Southern Arctic was courteously provided by: Margaret and Amanda Peterson (Owners, Point Lake Lodge, NWT); Shane Jonker (Camp Manager, Plummer’s Great Bear Lake Lodge, NWT); Bob Huitikka (Owner, Tukto Lodge, NWT); and staff of the Paulatuk Visitor Centre. Safe and reliable helicopter transportation was provided by Great Slave Helicopters (pilot Chuck Burcke). Dave Taylor (GIS consultant) provided support services for navigation equipment. Susanne Downing provided data entry services for the Southern Arctic photo themes and for approximately 50,000 previous thematic records for the Taiga Plains, Taiga Shield and Cordillera ecosystem classifications. ii Preface A vast circumpolar complex of tundra and polar deserts lies north of the tree line in Canada, Alaska, Russia and Europe. In Canada, the Southern Arctic includes the southern part of this complex, forming a wide belt with the southern boundary defined broadly by tree line, extending north within the Northwest Territories to the Arctic coast. It is home to herds of barren-ground caribou and muskox that range across sparse to continuous shrub, herb and lichen tundra on permanently frozen soils, to barren-ground grizzlies, wolves and other carnivores and to upland birds and waterfowl. Coniferous trees are restricted to locally warm, dry places on slopes and along rivers where they usually occur as stunted individuals or groves, twisted and sheared by cold winter winds bearing sharp ice crystals that cut needles and branchlets. Low-elevation wet coastal plains, glacial till blankets, glacial outwash features, weather-worn plateaus that have been ice-free for hundreds of thousands of years, rocky barrens and river valleys add physical, biological and visual diversity to this unique northern landscape. The Southern Arctic is the collective term for a region within the Northwest Territories that includes two extensive tundra landscapes differentiated by climate, geology and topography. The Tundra Plains lies north and west of Great Bear Lake. It is a cold mostly treeless northern extension of the Taiga Plains that is affected by both coastal and continental climates and that includes coastal and upland plains, plateaus and hill systems. It is generally covered by glacial till and wetlands are common and locally extensive. The Tundra Shield lies east of Great Bear Lake at lower latitudes than the Tundra Plains. Extending from tree line to the Northwest Territories – Nunavut border and beyond, it is a cold, mostly treeless northern extension of the Taiga Shield. Continental climates influence the Tundra Shield and its level to hilly landscapes include Precambrian rocklands, ice-modified till deposits a few centimetres to several metres deep that blanket the bedrock, extensive outwash deposits and thousands of lakes and ponds. Climate, geology and topography affect ecosystem development in the Southern Arctic in the same way as they do in boreal ecosystems to the south. Abiotic factors such as latitude, elevation, slope and parent materials control temperature, moisture, light and nutrient levels, all of which determine the type of plant communities and soils that can develop. Biotic factors such as competition between plant species or the influence of grazing animals on plant communities also play a role. In tundra environments where plant community development is strongly controlled by regional climate and microsite conditions and where growth is restricted to a few weeks in July and early August, competition is usually a less significant influence than it is in Taiga and Boreal ecosystems. The influence of biotic and abiotic factors is determined by the interplay of atmospheric and terrain elements – climate, topography, parent materials and biotic elements – acting over short to very long periods, as described by Major (1951) and Jenny (1941) for vegetation and soils, respectively. Vegetation and terrain patterns can be delineated and represented as abstract ecological map units and 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 and processes in a geographic context. They also provide 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