Sturgeon River Gorge
Location
Common Fauna:
Fauna typical of mesic northern forest and riverine communities is expected in the RNA.
Ecological and Physical Description
The primary features of the Sturgeon River Gorge RNA are the large virgin stand of mature eastern hemlock and the oxbow lake. The RNA includes a cross-section of the gorge from river to rim, and includes transverse ridges, terraces and an abandoned oxbow basin. There are a variety of plant communities present that represent seral to mature types, including the following cover types: balsam fir-aspen/paper birch; hemlock; paper birch; quaking aspen; sugar maple-beech/yellow birch; and open (oxbow lake).
The RNA is within the Sturgeon River Gorge Wilderness Area and the Sturgeon River is designated as a Wild River.
Annual precipitation averages 34 inches (86 cm), 62% of which falls between April and September. Average seasonal snowfall is 155 inches (394 cm).
The Alberta weather station is 9 miles east of the RNA.
Tills of considerable depth, at least to the depth of the gorge, were deposited in this area. The Portage Lake Moraine crosses the gorge at about the RNA. The moraine became a shoreline of proglacial Lake Duluth, which formerly inundated the RNA. The gorge was formed when the lake breached the moraine and drained through the gorge with the water flowing southward toward Lake Algonquin. The subsequent northward retreat of the shoreline toward the Lake Superior basin and the isostatic rebound of the area caused the drainage to reverse and flow northward. Several landforms in the RNA were shaped in these later stages. The terrace appears to have been an oxbow that drained and filled after continuous downcutting left it perched above the river level. The small ridge appears to be a terrace escarpment that formed at an earlier, higher river stage also.
No mapped rivers or streams are within the RNA. The Sturgeon River forms part of the south and the east boundary of the RNA. The only lake in the RNA is the unnamed 5 acre (2 ha) oxbow lake.
Flora and Fauna
Common Plant Species
| Scientific Name | Common Name | Category | At Risk | Notes |
|---|---|---|---|---|
| Acer spicatum | Mountain maple | Common Shrub Species | ||
| Cornus canadensis | Bunchberry dogwood | Common Shrub Species | ||
| Lonicera canadensis | American fly honeysuckle | Common Shrub Species | ||
| Aralia nudicaulis | Wild sarsaparilla | Common Herbaceous Species | ||
| Lycopodium obscurum | Obscure (rare) clubmoss | Common Herbaceous Species | ||
| Brachyelytrum erectrum | Bearded shorthusk | Common Herbaceous Species | ||
| Maianthemum canadense | Canada mayflower | Common Herbaceous Species | ||
| Clintonia borealis | Bluebead | Common Herbaceous Species | ||
| Mitchella repens | Partridgeberry | Common Herbaceous Species | ||
| Coptis trifolia | Threeleaf goldthread | Common Herbaceous Species | ||
| Oryzopsis asperifolia | Roughleaf ricegrass | Common Herbaceous Species | ||
| Osmunda claytonia | Interrupted Fern | Common Herbaceous Species | ||
| Corylus cornuta | Beaked hazelnut | Common Herbaceous Species | ||
| Oxalis montana | Mountain woodsorrel | Common Herbaceous Species | ||
| Dryopteris intermedia | Intermediate woodfern | Common Herbaceous Species | ||
| Phegopteris connectilis | Long beechfern | Common Herbaceous Species | ||
| Eurybia macrophylla | Bigleaf aster | Common Herbaceous Species | ||
| Rubus pubescens | Dwarf red blackberry | Common Herbaceous Species | ||
| Streptopus lanceolatus var. roseus | Twistedstalk | Common Herbaceous Species | ||
| Huperzia lucidula | Shining clubmoss | Common Herbaceous Species | ||
| Trientalis borealis | Starflower | Common Herbaceous Species |