Manitoba displays a large range of vegetation types that are arranged with a climatically determined north/south zonation. Grass-covered areas in the south give way to parkland and forested areas further north and eventually to shrub tundra in the extreme northeast.
In southern and west central Manitoba, agriculture, grazing, forestry and urban development have drastically altered the natural vegetation, but vast areas in the north and northeast are in near pristine state. Vegetation that often obscures the earth’s surface is clearly shown on air photos; particularly useful are colour infrared images that can detect stressed areas. Wetlands cover about 40 percent of Manitoba and do not conform to the climatically determined zonal distribution of vegetation. They occur in all parts of the province and provide distinctive ground cover well shown on air photos.
Individual animals are too small to appear on all except very large-scale images. However, some animals (e.g. beaver) profoundly affect drainage systems.
5.8: Riverine Gallery Forest on the East Side of Pelican Lake
This infrared photograph shows part of the east shore of PelicanLake 1, a shallow lake on the floor of the Souris-Pembina spillway. Infrared photographs employ a false colour technique in which objects reflecting large amounts of infrared radiation—which the human eye cannot see—are imaged as red. Photo-synthesizing vegetation typically reflects large quantities of infrared so that live healthy vegetation is imaged as bright red.
Here, along the east wall of the spillway, riverine gallery forest, mainly aspen (Populus tremuloides) and bur oak (Quercus macrocarpa), shows up in bright-red tones with mottled texture 2. The scale of the photograph is large enough that rounded shadows thrown by individual trees can be identified 3. A clearing within the forest contains low-lying bushes that are imaged as pink 4. Rounded patches 5 suggest that these are creeping juniper (Juniperus horizontalis).
In the north, crops are growing in five fields 6. In the western-most of these it can be seen that the crop is growing well in some areas 7 but not so well in others 8. Three fields that have been left fallow 9 are imaged as dark green, but in the southernmost field weed growth results in a pink tinge 10.
The v-shaped projection into PelicanLake 11 is one of several similar features located near the mouths of small streams. This point, known locally as Y point, has been used as a summer camp for over 100 years[i] and cottages have been built along the shore 12. A major problem for PelicanLake as a recreational resource is that it is very shallow and has little through-flow of water. Contamination of the water leads to algae growth in the summer; the pink colouring on both sides of the point (13 and 14) are a result of this.
Figure 5.8: Riverine Gallery Forest on the East Side of Pelican Lake
Vertical air photograph: colour infrared
Flight height: ; lens focal length:
Scale: 1:10,300 (approx.)
Location: Township 5; Range 16 WI
Map sheets: 1:250,000 62G Brandon
1:50,000 62G/5 Dunrea
[i] For details see Welsted, J. “The Ups and Downs and Ins and Outs of Pelican Lake: A Water Resource Dispute in Southwestern Manitoba.” Proceedings of the Prairie Division of the Canadian Association of Geographers, ed. M. R. Wilson, Saskatoon: University of Saskatchewan. 1993, 221-229.