Basin and Middle Lakes (SK075)

Basin and Middle Lakes (SK075)

Middle Lake, Saskatchewan

Site Description

Basin and Middle Lakes are large saline parkland lakes located about 40 km north of Humboldt, Saskatchewan. The main water sources for these lakes are intermittent creeks that only carry water during spring runoff, or periods of heavy rains. As such, these sites are subject to severe water level fluctuations. Basin Lake, has an average depth of 9 m, and the shoreline has extensive rocky and sandy areas, and extensive mudflats. This lake is essentially devoid of emergent vegetation.

Middle Lake, has an average depth of 1 m, and a similar shoreline profile. There are also extensive wet meadow zones on the east and south shores. The marjority of Middle Lake is open water with extensive stands of cattail and bulrush in the shallow marshy bay in the southwest corner of the lake.

Birds

This site is important for waterfowl and shorebirds. During surveys completed in 1988 and 1989, an average of 9,578 shorebirds were recorded during three one-day surveys (5,830 May 25, 1988; 10,282 May 30, 1988; and 12,623 May 1989). Undoubtedly, thousands of additional shorebirds would be observed during long study periods. Over 30,000 ducks have also been recorded at this site during the summer moulting period (20,000 on Basin Lake, and 10,000 on Middle Lake).

Surveys of breeding colonial waterbirds have also been completed at this site with 227 American White Pelicans, and 745 Double-crested Cormorants recorded during the early 1990s. Piping Plovers (globally near threatened, and nationally endangered) also nest at the lake in small numbers. During the 1996 International Piping Plover Census, two pairs were observed. There have not been any recent sightings recorded.

Other birds known or believed to breed on these lakes include several grebe species (Pied-billed, Horned, Eared, Western and Red-necked) along with California Gulls, Black Terns, Common Terns, and Black-crowned Night Herons.

Conservation Issues

These lakes are severely affected by drought. While this may benefit some birds (such as shorebirds), others, like ducks, pelicans, and grebes are adversely affected during such periods. Due to the high concentrations of waterfowl, botulism outbreaks could be a major threat to the health of thousands of birds. Basin and Middle Lake were identified as Migratory Bird Sanctuaries in 1925. More recently, one polygon on the east side of Basin Lake, and the east, north, and part of the west shorelines (except the south arm) of Middle Lake were designated as critical Piping Plover habitat, and are protected under the provincial Wildlife Habitat Protection Act.

IBA Criteria Habitats Land Uses Potential or Ongoing Threats Conservation Status

• Waterbirds30,000 (max.)