Blackstrap Coulee (SK078)

Blackstrap Coulee (SK078)

Dundurn, Saskatchewan

Site Description

Blackstrap Coulee is close to the town of Dundurn, and about 50 km south of Saskatoon in Saskatchewan. The coulee, which was carved by an ice age river, features a man-made, steep-sided reservoir (Blackstrap Lake), a large shallow-banked, marshy lake (Indi Lake) and wooded valley slopes. It is about 25 km long by one km wide, and also contains a channel connecting the two lakes. Two dams hold back canal water to form Blackstrap Lake, making it much less marshy than Indi Lake. Before the dams were built, the bottom of Blackstrap Coulee was farmed. The west valley slopes are covered by a mixed grass prairie with wooded draws while the east slope contains extensive aspen and shrub woods. Blackstrap Lake contains a provincial park, a ski hill, a summer camp and two townsites, Thode and Shields, each with 20 or so year-round residences on the waters edge.

Birds

Spring through fall, the lakes and marshes that run through Blackstrap Coulee support a variety of waterbirds. Most impressive are the 10,000 non-breeding or post-breeding Franklins Gulls that spend time at Blackstrap Lake during the summer. This is about 2% the global population of this species. They may nest at nearby Indi Lake. In the spring, 600 Western Grebes use the lakes, while in summer about 250 Black Terns nest in the valley; this number is perhaps 2% or more of the Canadian population. Then, in the fall, 2,000 Tundra Swans stop here on their way south. This number is 2.3% of the Eastern Tundra Swan subpopulation (those that nest in the Canadian Arctic), and almost 1% of the North American population. In general, Blackstrap Lake is more important for migrating waterbirds, while the more natural marshes of Indi Lake are more important for breeding waterbirds.

Many other birds use these wetlands. For instance Bufflehead, Stilt Sandpiper, and Red-necked Phalarope are all found here in good numbers in the fall. Also, six pairs of Forsters Tern breed here. In total, as of 1992, 239 species of birds have been identified in the Blackstrap area (an area probably larger than this IBA).

Conservation Issues

Indi Lake has been noted as an area of worth for wildlife previously, when it was identified as a candidate wildlife area under the International Biological Programme. Nonetheless, the coulee does not have any official protection, apart from a small section, which lies on the east shore of Blackstrap Lake, that is a provincial park.

As a result of the heavy recreational use of this Blackstrap Lake by boaters, fishermen and campers, there is the possibility that birds may be overly disturbed. Indi Lake, however, is a naturally developed, extensive marsh that is relatively undisturbed. Also, drought is always a possibility in this region; this may affect the primary productivity of the lakes.

IBA Criteria Habitats Land Uses Potential or Ongoing Threats Conservation Status

• Snow Goose200,000 (max.)
• Franklin's Gull10,000 (max.)
• Tundra Swan2,000 (max.)
• Rusty Blackbird25 (max.)