Saskatchewan River Delta (MB055)

Saskatchewan River Delta (MB055)

The Pas, Manitoba

Description du site

This site, which encompasses the town of The Pas and a large surrounding area, is situated northwest of Lake Winnipegosis and encompasses all the land between the Saskatchewan-Manitoba border and Cedar Lake. It is a massive area of land dominated by the Saskatchewan River Delta and contains both the mouth of the Saskatchewan River at Cedar Lake and the upper reaches of the river itself. Included in this site are both the Tom Lamb (2,083 km²) and the Saskeram (958 km²) Wildlife Management Areas (WMAs), which lie on either side of The Pas.

Much of this site consists of flat, low-lying and very extensive wetlands, including huge stretches of marshes, tamarack bogs and meadows. These areas support high concentrations of moose and are also tremendously important for spawning fish, including the sturgeon. This latter species is of great value to the local aboriginal community, and the government of Manitoba has given the species special attention. At higher elevations there are deciduous and coniferous boreal forest habitats, and clustered around The Pas and Highway 10 are cultivated lands and improved grasslands. In the Tom Lamb WMA, ridge forests are composed of aspen, Jack Pine, and Black Spruce, while Balsam Poplar, willows, Manitoba Maple and Green Ash grow on the levees.

Oiseaux

The area surrounding The Pas is considered by some biologists to be the most important wetland in the province for breeding waterfowl. The area is such a maze of channels and dense vegetation that it is extremely difficult to estimate the number of some breeding species. But for some, such as the Red-necked Grebe, it is almost certainly the most valuable breeding area in the province.

The Carrot Valley, southwest of The Pas, is a globally significant spring rest area for Tundra Swans. Significant totals of swans were counted in 2011 (8,836), 2015 (3,204) and 2017 (9,216). Other large concentrations of spring migrant waterfowl and other waterbirds in the Carrot Valley include 23,285 Mallard (2017), 6,914 Northern Pintail (2016), 4,706 Canada Goose (2016), 752 Sandhill Crane (2017) and 2,783 Ring-billed Gulls (2016). Given that these counts were from single days during spring migration, the total numbers of birds passing through will be significantly higher.

Data collected from aerial surveys by the Canadian Wildlife Service and U.S. Fish and Wildlife Service since the 1950s estimate that on average nearly 500,000 ducks nest in the Saskatchewan River Delta, including the Cumberland Marshes IBA in Saskatchewan, each year. According to the literature the following numbers of breeding waterfowl have been recorded across these two IBAs: 120,000 Mallards; 84,000 Blue-winged Teal; 66,000 Lesser Scaup; 34,000 American Wigeon; 26,000 Ring-necked Duck; 26,000 Canvasback; 14,000 Common Goldeneye and; 16,000 Redhead.

This area also supports hundreds of thousands of ducks, geese and swans on fall migration. Sandhill Cranes, Bald Eagles and Osprey nest in the area, along with colonial birds such as Eared Grebes, and Common and Black Terns. A survey undertaken in 2007 by Environment and Climate Change Canada estimated that 5,955 Franklin’s Gulls were breeding on Saskeram and North Reader Lake. Several extralimital breeding records of American Avocet have been documented here too. Greater White-fronted Geese formerly concentrated here in large numbers during fall migration, but are rarely seen now due to the artificial flooding of the gravel bars and islands that they used to stage on. This IBA also holds a wide variety of southern boreal region breeding birds.

Enjeux de conservation

Although wildlife management is an important priority at The Pas, this site is a multi-use area since hunting, farming, forestry and gravel extraction are generally allowed in Manitoba Wildlife Management Areas.

Not all parties agree on the manner that the water has been managed here. The river regime formerly included two annual floods, which kept the delta active and productive. Canals and dams were built in the 1930s and 1940s primarily as an aid to muskrat ranching. In the 1960s Manitoba Hydro built a large dam at Grand Rapids that flooded 200,000 acres (81,000 ha) of land that became part of Cedar Lake Reservoir. The project additionally affected the hydrology of a minimum .5 million acres (202,500 ha) of delta. Mitigation for the dams effects on wildlife was primarily left to the Manitoba government who were assisted by Ducks Unlimited (DU). DU has built numerous channels, dykes and water-control structures, as well as fish ladders into two major wetlands near The Pas. Water level management is never easy, and where fishing, agricultural and utility interests compete with wildlife interests, management becomes complex. Ideally, management plans for the marshes are needed that in some manner replicate the historical flood patterns.

Catégories ZICO Habitats Usages Menaces Potencielles ou Existantes Status de Protection

• Cygne siffleur9 216 (max.)
• Oiseaux aquatiques200 000 (max.)