This low-lying area near the village of Saint-Barthelemy is on the northwest shore of Saint-Pierre lake, about 75 km east of Montreal. The site encompasses 11 km of shoreline with a railway and major highway splitting the IBA to the north. This site consists primarily of fields which flood most springs and are cultivated in summer. Ducks Unlimited Canada has built dams and channels to control water levels, and have also created three staging areas, two marshes, and a fish management area.
During spring migration, this site is an important staging area for Greater Snow Geese, Canada Geese, and Northern Pintail. As many as 55,000 Greater Snow Geese – 1% of this species North American population – occur at this site. In 1999, 60,000 Canada Geese used Plaine de Saint-Barthélemy as a spring staging ground, which is over 1% of the Canada Goose world population. In addition, 1% of the Atlantic Flyway population of American Black Ducks (2,000 birds) occurs at this site during fall migration, and nationally significant numbers of Northern Pintail (10,000 birds) occur on spring migration.
In summer and fall, the abundance and diversity of bird species declines, presumably due in part to agricultural activities.
In spring and fall, Rough-legged Hawks and Red-tailed Hawks use the fields for hunting and approximately 12 Snowy Owls winter on the site. In early spring, large flocks of Snow Buntings (with as many as 15,000 individuals) have been recorded.
Water quality is a major conservation issue for the habitats and biodiversity of the Lac Saint-Pierre's IBAs. Surface water quality tests often fail for metals such as lead, chromium, aluminium, copper, and iron. Sediments in the bottom of Lac St-Pierre are frequently over the PCBs and lead safety limits set for dredging operations. Extensive areas of the IBA are used for "profitable" monoculture farming. This type of agricultural activity is not compatible with the flood plains habitat representative of the IBA. Fertilizers and other chemicals used in monoculture have a major impact on the water quality. There has also been some evidence of contamination from pentachlorophenol, hexachlorocenzene, and DDT, but few studies have been done on the potential effects of bio-accumulation on birds. Because the St. Lawrence River is a heavily traveled seaway, there is a constant risk of oil spills; in 1988, 37,600 tons of fuel were spilled into the Sorel port. The site is part of the Lac Saint-Pierre Biosphere Reserve, as designated by UNESCO. It is also recognized as a wetland of international importance under the RAMSAR Convention. This site is designated a Periodically Flooded Area and is included in the Lac Saint-Pierre Priority Intervention Zone. Three non-government organizations are planning to purchase 3.9 km2 of land for an integrated management project for wildlife and farming. Ducks Unlimited Canada is also working to preserve waterfowl in different parts of the IBA.
The Lake Saint-Pierre is essentially a widening of the St. Lawrence River that creates one of the largest wetland in Québec. Its archipelago and shores are covered by vegetation, including marshes, semi-aquatic plants, underwater plants and treed swamps visited by more than sixty species of fish. During spring floods, the floodplain became an important site for spawning and a nursery grounds for many species of fish, such the yellow perch and northern pike. Several fishes found in the lake and its tributaries are listed as endangered. This is the case of the copper redhorse, endangered specie endemic to Québec; the lake sturgeon is also considered as threatened in Québec; and the American eel, a species of least concern. The largest known population of bridle shiner, another species whose status is least concern, exploits the Lake Saint-Pierre.
The availability in habitats has decreased primarily because of wetlands draining to extend the surface available for agriculture and to control of the water levels. The shoreline is eroded by waves created by commercial shipping and pleasure crafts, while dredging of the channel alters the water flow and the structure of habitats. The implementation of an agricultural industry in the watershed, the presence of many industries upstream of Lake Saint-Pierre, the density of population and the presence of resorts are responsible for the degradation of water quality. The population of walleye, a fish very sensitive to pollution, appears to be declining in the past few years. This is also the case for the yellow perch, historically the most important commercial species in the lake.
Major species present:
|80,000 - 300,000||2016||Spring|
|100,000 - 150,000||2015||Spring|
|75,000 - 125,000||2014||Spring|
|30,000 - 250,000||2013||Spring|
|20,000 - 50,000||2012||Spring|
|5,000 - 10,000||1997||Spring|
|2,350 - 6,000||2017||Spring|
|10,000 - 15,000||2016||Spring|
|2,000 - 8,000||2015||Spring|
|7,000 - 10,000||2014||Spring|
|2,000 - 10,000||2013||Spring|
|2,000 - 30,000||2012||Spring|
|2,000 - 5,000||2010||Spring|
|2,000 - 20,000||2008||Spring|
|2,000 - 50,000||2007||Spring|
|2,000 - 5,000||2006||Spring|
|5,000 - 8,000||1996||Spring|
|5,000 - 60,000||1994||Spring|
|5,000 - 40,000||1993||Spring|