National Ecological Framework (3 of 23)

Attribute Data Report

Levels of Generalization

Definitions and the number of map units for the four levels of generalization are outlined in the box below.

Ecological Framework Levels
Level Number of Units Definition
Ecozone 15 At the top of the hierarchy, it defines the ecological mosaic of Canada on a sub-continental scale. They represent an area of the earth's surface representative of large and very generalized ecological units characterized by interactive and adjusting abiotic and biotic factors. Canada is divided into 15 terrestrial ecozones.
Ecoprovince 53 A subdivision of an ecozone characterized by major assemblages of structural or surface forms, faunal realms, and vegetation, hydrology, soil, and macro climate. For example, the Newfoundland ecoprovince (no. 6.4) is one of six ecoprovinces within the Boreal Shield Ecozone.
Ecoregion 194 A subdivision of an ecoprovince characterized by distinctive regional ecological factors, including climate, physiography, vegetation, soil, water, and fauna. For example, the Maritime Barrens ecoregion (no. 114) is one of nine ecoregions within the Newfoundland ecoprovince.
Ecodistrict 1021 A subdivision of an ecoregion characterized by a distinctive assemblages of relief, landforms, geology, soil, vegetation, water bodies and fauna. For example, the Jeddore Lake ecodistrict (no. 473) is one of five within the Maritime Barrens ecoregion.

Ecological map units and numbering conventions

There are a number of factors that need to be noted when using the digital maps and attribute database associated with the ecological framework.These concern the numbering of individual map units, non-contiguous map units, and the deletion of some sequential map unit numbers.


When the ecodistricts where originally mapped, they were numbered consecutively from 1 to 1031. In the final review it was necessary to delete a total of ten ecodistricts. Rather than re-number all the ecodistricts, the ten unique numbers (172, 240, 330, 673, 719, 721, 722, 725, 842, and 845) were removed from the map and database.


Although there are 194 named ecoregions, they are not all single contiguous map units. Ecoregion map unit polygons are numbered from 1 to 217. Eleven of the ecoregions consist of two or more non-contiguous map unit polygons. They include the following ecoregions:

  • Ellesmere and Devon Islands Ice Caps ( 1, 2,3,4 )
  • Ellesmere Mountains ( 8, 10)
  • Northern Alberta Uplands ( 66, 67 )
  • Kingurutik-Fraser Rivers ( 77, 81 )
  • Mecatina River ( 80, 83, 86)
  • Long Range Mountains ( 108, 110, 111 )
  • Mid Boreal Uplands ( 139, 140, 141, 144, 147, 150, 151, 152, 153, 154 )
  • Western Alberta Upland ( 145, 146 )
  • Aspen Parkland ( 156, 161)
  • Southwest Manitoba Uplands ( 163, 164 )
  • Northern Coastal Mountains ( 185, 186)

The first number listed, in bold typeface, in the brackets following the ecoregion name above is the identifying map unit number for the ecoregion in the supporting database. Only a single set of attribute characteristics is provided for the combined map unit polygons which comprise the ecoregion. The attribute characteristics for all the individual map unit polygons comprising the ecoregion can be obtained from the ecodistrict database files.


The delineation of ecoprovinces (Marshall, I. B., E. Wiken, and H. Hirvonen, 1998) was not a goal of the Ecological Stratification Working Group (1996). The need arose from the environmental side accord that established the Commission for Environmental Cooperation (CEC) in 1994 by Canada, Mexico and the United States of America under the North American Free Trade Agreement. The CEC needed an ecological framework to address environmental concerns common to the three countries.

The Canadian contribution to the development of an framework depicting the ecosystems for the North American continent was based on the work of the Ecological Stratification Working Group (1996). Some members of this Canadian working group were also members of the CEC North American Ecosystem Working Group. The CECs report, "Ecological Regions of North America: Towards a Common Perspective", was released in 1997 ( Commission for Environmental Cooperation). The North American report reflects the ecosystem concepts and methods that have long been employed in Canadas country-wide efforts to promote ecosystem classification.

The number of ecoprovinces depicted in Canada reflects the demand in Canada for a sub-division of ecozones for broad conservation and resource purposes and the need to correlate the delineation of ecoregions across the Canada - United States boundary. Consequently, cross boundary correlation with the United States resulted in a number of ecoprovinces being composed of only one ecoregion ( Numbers 8.2, 10.1, 11.1, 12.1 and 12.4).

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