Differences Between the 1994 and 2006 Classifications

There are two primary differences between the 1994 and 2006 versions of the provincial ELC framework:

1. The first is a change in mapping concepts due in part to improved digital

information and good visual presentations of various vegetation, soils and climatic trends at the provincial scale.

2. The second is a change in the level of detail to which polygon lines are drawn.

In 1994 and earlier versions, line work was generalized to a scale of

approximately 1:1,000,000; the mapping scale for the current iteration was 1:250,000 and polygons were often mapped to contour lines, giving a very high level of detail.

Table 1-4 summarizes the main differences between the 1994 and 2006 Natural Region and Subregion classifications. “Significant”

changes are those where major re-assignments of Natural Subregion areas or changes in concept occurred. The most significant changes occurred to the Boreal Forest and Rocky Mountain Natural Regions. Figure 1-2 shows examples of line work differences between the 1994 and 2006 classifications.

Figure 1-3 shows the major physiographic regions referred to in Table 1-4 and

throughout the document. Figure 1-4 indicates the location of important topographic and hydrologic features within Alberta.

Detailed 2006 (black) lines based on contour information vs. 1994 (red) lines based on general 1:1,000,000 interpretation.

Detailed 2006 (white) lines based on Landsat imagery vs. 1994 (red) lines based on general 1:1,000,000 interpretation.

Detailed 2006 (black) lines and general 1994 (red) lines overlaid on forest inventory; darker green is lodgepole pine, lines are Upper Foothills- Lower Foothills interface.

Detailed 2006 (black) lines and general 1994 (red) lines overlaid on recent forest inventory; purple is Douglas fir forest, lines are Montane- Foothills Fescue interface.

Figure 1-2. Examples of differences in mapping detail between 1994 and 2006 classification.

Boreal Subarctic and Boreal Highlands

Peace-Athabasca Delta

Alpine-Subalpine

Alpine-Subalpine

Figure 1-3. Physiographic Regions of Alberta.

Figure 1-4. Key topographic features of Alberta.

Table 1-4. Summary of changes between 1994 and 2006 Natural Region and Subregion classification. Natural Region Natural Subregion Area 1994 (km2)Area 2006 (km2) Degree of changeDetails Alpine14,51615,084 Minor Finer-detail mapping at 1:250,000 led to a significant increase in the number of polygons assigned to this Natural Subregion. Subalpine25,76625,218 Significant Lower limit of the Subalpine Natural Subregion set at a higher elevation relative to that of the 1994 Subalpine Natural Subregion south of the Canmore corridor. Polygon delineation in southern Alberta better aligned with differentiating criteria.

Rocky Mountai n

Montane5,9858,768 Significant

1994 Lower Foothills Natural Subregion polygons south of the Bow River were re- assigned to the Montane Natural Subregion because of similarities to Montane vegetation to the south and the absence of Foothills and Subalpine plant indicator species. Upper Foothills 27,55021,537 Moderate See discussion of changes for the Lower Foothills and Upper Boreal Highlands Natural Subregions with respect to elevation adjustments and re-assignment of 1994 Upper Foothills Natural Subregion. Upper Foothills boundary refinements used detailed forest cover maps to differentiate pure conifer-dominated landscapes (Upper Foothills) from conifer–mixedwood–deciduous landscapes (Lower Foothills).

Foothills

Lower Foothills 67,31644,899 Significant

No change in criteria for differentiating the Lower and Upper Foothills Natural Subregions; the Lower Foothills–Upper Foothills Natural Subregion boundary generally adjusted to higher elevations based on better digital forest inventory data and understory indicator plant species information. South of the Bow River, the 1994 Lower Foothills Natural Subregion area was re-assigned to the Montane Natural Subregion based on vegetation indicators. Dry Mixedgrass 47,00446,937 Minor Boundary refinements to reflect more detailed soils information. Mixedgrass19,24020,072 Minor Boundary refinements reflect more detailed soils and vegetation information. Northern Fescue 15,83614,933 Minor Boundary refinements reflect more detailed soils and vegetation information.

Grassland

Foothills Fescue14,90813,623 Minor Small areas reassigned to adjacent Natural Subregions to better align with actual vegetation patterns, particularly in southern portion of Natural Subregion.

Table 1-4 (continued). Natural Region Natural Subregion Area 1994 (km2)Area 2006 (km2) Degree of changeDetails Foothills Parkland 4,3923,921 Minor Boundary changes to reflect vegetation patterns in forest inventory and satellite imagery. Central Parkland 53,40453,706MinorMore detailed soil classifications used as differentiating criteria for boundary change.

Parkland

Peace River Parkland 4,6573,120 Moderate Subregion defined by areas where Chernozemic soils are dominant, as these represent the core Parkland condition. Adjacent south-facing slopes along the Peace and Smoky Rivers are included because of characteristic parkland vegetation structure. Dry Mixedwood 100,55185,321 Moderate The climate and soils of an area west of Edmonton classified as part of the 1994 Dry Mixedwood Natural Subregion better fits the 2006 Central Mixedwood concept.

Boreal Forest

Central Mixedwood 154,549167,856 Significant

Revised concepts resulted in the partial re-assignment of some adjacent Subregions to this Subregion. It now contains the southern part of the 1994 Wetland Mixedwood Natural Subregion, western portions of the Dry Mixedwood, eastern portions of the Lower Foothills west and south of Edmonton, areas along the northern slope of the Swan Hills, the lower south slopes of the Caribou Mountains and areas east of Fort Vermilion belonging to the 1994 Dry Mixedwood and Peace River Lowlands Natural Subregions. Some areas that belonged to the 1994 Central Mixedwood Natural Subregion are now part of the Athabasca Plains Natural Subregion and the newly added Lower Boreal Highlands Natural Subregion. Two slightly higher-elevation areas east of Edmonton formerly classified as Dry Mixedwood (one between Smoky Lake and Lac la Biche, and one east of Bonnyville) have been assigned to the Central Mixedwood Natural Subregion Lower Boreal Highlands

21,217 (total of Boreal Highlands

1994)55,615 Significant

A newly recognized Natural Subregion; includes diverse mixedwood forests at lower elevations at northerly latitudes. Also includes lower-elevation areas of the 1994 Boreal Highlands Natural Subregion and all the area formerly assigned to the 1994 Lower Foothills Natural Subregion in the Clear Hills.

Table 1-4 (continued). Natural Region Natural Subregion Area 1994 (km2)Area 2006 (km2)Degree of changeDetails Upper Boreal Highlands 21,217 (total of Boreal Highlands

1994)11,858 Significant

This new Subregion includes upper elevation areas of closed canopy hybrid lodgepole pine–jack pine and spruce forests at northerly latitudes; includes upper portions of the 1994 Boreal Highlands Natural Subregion and parts of the 1994 Boreal Subarctic Natural Subregion. Areas previously assigned to the Upper Foothills Subregion in the Clear Hills have been re-assigned to this Natural Subregion, based on climate models that suggest these areas have a greater affinity to Boreal than to Cordilleran climatic regimes. Athabasca Plain6,75013,525 Significant

This Subregion was re-assigned from the Canadian Shield Natural Region to the Boreal Forest Natural Region; original boundary was based on bedrock geology and followed the extent of the area underlain by the Athabasca Formation. The new boundary includes a more extensive area of coarse textured sands and gravels that support stands of jack pine. Some areas that formerly belonged to the Central Mixedwood Natural Subregion were reassigned to this Subregion for physiographic reasons. Peace–Athabasca Delta (formerly Peace River Lowlands) 10,1065,535 Significant

The 1994 Peace River Lowlands Natural Subregion included the Peace–Athabasca Delta and fluvial and glaciofluvial terraces of the Birch, Slave and Peace Rivers to the north and west. The newly named Peace–Athabasca Delta Natural Subregion includes only recent fluvial deposits and wetlands. Northern Mixedwood (formerly Wetland Mixedwood) 38,34529,513 Significant This new Subregion replaces the 1994 Wetland Mixedwood Subregion; the former name was misleading, as it incorrectly implied that this area had a higher concentration of wetlands than other Subregions in the Boreal Forest Natural Region. The southwest portion of the former Wetland Mixedwood Subregion is re-assigned to the Central Mixedwood Subregion based on warmer climates and associated mixedwood vegetation. Part of the Cameron Hills previously classified as the Boreal Subarctic Natural Subregion was re-assigned to the Northern Mixedwood Natural Subregion on the basis of climatic models.

Bo re al F or es t

Boreal Subarctic 21,97911,823 Moderate

Reduced in size compared to the 1994 Subregion, and now includes only the highest elevations in the Cameron Hills and the top of the Caribou Mountains. Possibly occurs in the Birch Mountains to the east, but too small to be mapped as part of this Natural Subregion. Canadian Shield Kazan Upland 8,9579,719 Minor Minor boundary changes reflect more detailed mapping (1:250,000) in this revision.