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ECOSYSTEMS
1) Grassland
2) Marsh
3) Valley Walls
4) Woodland
(Unless otherwise indicated, photos by Don of www.Wakamow.com)
The steep, south-facing slope represents one of the harshest environments on the prairies. Here, the valley wall faces directly into the sun and creates arid or desert-like conditions. This steep slope limits many plants from taking hold. Wind and water erosion are also constant problems.
Plant cover is sparse; only the hardiest species can survive here. The Prickly Pear (yellow flowers) and the Pincushion or Ball Cactus (purple flowers) are two species of cacti which are able to cope with the hot, dry conditions. Their protective spines are actually modified leaves on a fleshy stem. The stem is covered with a waxy substance that minimizes evaporation and maintains inner moisture. Even the flower petals have a waxy coating. Such adaptations enable these plants to survive.
The west facing slopes provide another challenging growing environment. Though less severe than the south-facing slopes, its wind-swept and sun-dried conditions naturally prevent many plants from surviving. This is another example of an ecotone as it serves in the transition between the desert-like conditions of the south-facing slopes and the lush valley floor.
Raptors such as the Swainson's and the Red-tailed Hawk are often seen during
the spring, summer and early fall riding the thermal air currents above the
Ecological Zone. Their keen eyesight, when combined with a speedy attack, allow
hawks to soar high, undetected by their prey.
http://www.doftw.com/wakamow/ecologicalzone/valleywalls.html