A description of each ecozone and ecoregion is included in this report. These descriptions are intended to provide the map user with general comments about the climatic, physical and biological properties of each ecozone and ecoregion. In addition, comments about unique features or those that help to distinguish adjacent ecoregions are included where possible.

The information used to construct the descriptions has come from a variety of national and regional reports on ecological regionalization. In addition, data and expert knowledge from other sources were used. In particular, the following explanatory notes offered about some of the principal technical sources.

Climate All values reported for temperature come from the Land Potential Database for Canada (Kirkwood et al. 1983), a compilation of climate normals for 1951-1980, recompiled on an ecoregion map polygon basis. Three values have been provided: mean annual temperature, mean summer temperature (May through August), and mean winter temperature (November through February). Value ranges for precipitation were interpolated from precipitation contour maps based on 1951-1980 climate normals (Environment Canada 1986). A range of values for climate parameters describes the geographic variation in the ecoregion. Additional comments on climate features have been derived from The Climates of Canada (Phillips 1990) where appropriate. The terminology and definitions used to describe ecoclimate units come from the Ecoclimatic Regions of Canada (Ecoregions Working Group 1989). For the cordilleran ecozones, unless stated otherwise, all climate values are for valley bottom locations.

Geology Rock types and their distribution are derived from the Geology Map of Canada (Douglas 1970), 1:5 000 000 map and text. Surface materials, their origin and distribution from the Surficial Materials of Canada (Fulton 1995).

Permafrost The extent and nature of permafrost, including estimated ice content and typical ground ice forms are derived from the map "Canada - Permafrost" (Natural Resources Canada 1995). References in the text to low, medium and high ice contents correspond to volume percentages of <10%, 10-20% and >20% respectively as presented in the map legend. The extent of permafrost is given as a percentage of land area underlain by permafrost. The five classes of extent are: continuous (90-100%); extensive discontinuous (50-90%); sporadic discontinuous (10-50%); isolated patches (<10%); and no permafrost (0%).

Wetlands The extent and forms of wetlands in each ecoregion are synthesized from three maps, The Distribution of Wetlands, Wetland Regions of Canada (National Wetlands Working Group 1986), and the Wetlands of Canada (National Wetlands Working Group 1988).

Vegetation Local expert knowledge and published national references related to the distribution of vegetation species were used. These references include: Native Trees of Canada (Hosie 1969); Plants from Sea to Sea (Montgomery 1966); Forest Regions of Canada (Rowe 1972); and The Shrub Identification Book (Symonds 1963).

Soils Classification of soils follows The Canadian System of Soil Classification (Agriculture Canada Expert Committee on Soil Survey 1987). The distribution of soil types is based on Soil Landscapes of Canada map series (Shields et al. 1991) supplemented by local information sources where they exist.

Wildlife Local expert knowledge and published national references related to the distribution of wildlife and fish species were used. The references include: The Mammals of Canada (Banfield 1974); The Birds of Canada (Godfrey 1966); and Freshwater Fishes of Canada (Scott and Crossman 1973).

Population and Land Use Values are drawn directly from 1991 Census of Canada data recompiled on an ecoregion map polygon basis by Statistics Canada for State of the Environment Directorate, Environment Canada. Values are reported rounded to the nearest 100 where populations are <1 000 000, and rounded to the nearest 1000 where populations are >1 000 000. Values for agriculture are given as a percent of the ecoregion. Local expert knowledge was used to describe land use.

Table 1 Definitions and examples of criteria used for the highest levels of the Canada Committee on Ecological Land Classification system (adapted fromIronside 1991)

Definitions for the Levels of Generalization
ECOZONE	an area of the earth's surface representative of large and very generalized ecological units characterized by interactive and adjusting abiotic and biotic factors.
ECOREGION	a part of a province characterized by distinctive regional ecological factors, including climatic, physiography, vegetation, soil, water, fauna, and land use.
ECODISTRICT	a part of an ecoregion characterized by distinctive assemblages of relief, geology, landforms and soils, vegetation, water, fauna, and land use.

Level of Generalization / Map Scale*	Examples
	Geomorphology	Soils**	Vegetation	Climate
ECOZONE 1:7.5 M	Physiographic or macro landforms	Soil order group(s)	Broad physiognomic types	Macro
ECOREGION 1:5 M to 1:2 M	Large-order landforms or assemblages of regional landforms	Great groups or associations thereof	Plant regions or assemblages thereof	Meso or small order macro
ECODISTRICT 1:3 M to 1:1 M	Regional landforms or assemblages thereof	Subgroups or associations thereof	Plant districts or assemblages thereof	Meso or large order micro

*  Map scales should not be taken too restrictively, as they vary with settings and objectives. (M = million).
**  Terminology according to Agriculture Canada Expert Committee on Soil Survey (1987).

Table 2 A list of descriptive attributes contained in the database for each level of the framework

Level	Attributes	Source
Ecozone	name area incorporated ecoregions	Wiken 1986
Ecoregion	parent ecozone name area ecoclimatic region regional physiography land cover mean annual temperature mean winter temperature mean summer temperature mean annual precipitation population	Ecoregions Working Group 1989 Bostock 1970 AVHRR imagery Atmospheric Environment Service 1993 Census of Canada 1991
Ecodistrict	parent ecoregion area land cover regional landform surface form material soil texture soil development permafrost	AVHRR imagery Soil Landscapes of Canada 1995a,1995b* Natural Resources Canada 1995

* The Soil Landscapes of Canada maps (1:1 million scale) and data are part of the Canadian Soil Information System (CanSIS).