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.
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).
EcoRegions
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.
REFERENCES
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.
Source: Schut et
al., 1994b
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