EcoZones, EcoRegions, and EcoDistricts
SLC polygons form the basis of a unique digital product for agricultural and environmental reporting: a nested hierarchy of EcoDistricts, EcoRegions, and EcoZones.
The most generalized level in the framework is the EcoZone. The country was grouped according to very broad physiographic and ecological similarities into 15 EcoZones. These have been described previously by Wicken (1986).
The EcoZone framework is divided into a total of 194 EcoRegions (217 polygons). Each EcoRegion has a name, which is normally based on a prominent biophysical or physiographic feature within the EcoRegion. The elements used to guide the consistent formulation of national EcoRegions were the published national maps on climate (EcoRegions Working Group 1989), physiography (Bostock 1970), and existing provincial ecological frameworks. Wherever available, more detailed provincial climate and physiographic information was used, as well as geologic and vegetation cover information. Consultation between federal and provincial/territorial authorities ensured that local perceptions of the landscape were incorporated into the EcoRegion construction.
EcoDistricts (also known as Land Resource Areas)
A similar process was followed to further subdivide EcoRegions into EcoDistricts. Each EcoDistrict is characterized by relatively homogeneous biophysical and climatic conditions. The differentiating characteristics of EcoDistricts are: regional landform, local surface form, permafrost distribution, soil development, textural group, vegetation cover/land use classes, range of annual precipitation, and mean temperature. EcoDistrict size is a function of regional variability of these defining attributes, and minimum size is approximately 100 k ha. EcoDistricts are designed for use at a map scale of 1:2M.
Soil Landscapes of Canada
In the majority of cases, line placements of all components of the framework followed existing polygon outlines of the Soil Landscapes of Canada. In a few instances, Version 1 SLC polygons were split to accommodate the new framework and maintain the desired nesting of the hierarchy. Since the Ecological Land Classification is a cartographic hierarchy supported by more detailed data from the Soil Landscapes of Canada, they will provide a very powerful tool for environmental reporting, particularly since linkage via the soil development attributes can be used to access the NSDB soil name and soil layer file data.
EcoRegions Working Group 1989. Ecoclimatic Regions of Canada, First Approximation. Ecological Land Classification Series, No. 23, Environment Canada, Ottawa 119p.
Wiken, E.B. 1986. Terrestrial EcoZones of Canada. Ecological Land Classification Series No. 19. Lands Directorate, Environment Canada. 26p and map.