This site is located on the south shore of Lac Saint-François, 50 km upstream of Salaberry de Valleyfield in southern Québec. Lac Saint-François is an enlargement of the St. Lawrence River that borders Québec, Ontario, and New York. The lake is shallow (6 m) and does not fluctuate on account of upstream dams.
Two-thirds of the wildlife area is covered by marshlands with scattered ponds and channels. Larch, Red Maple, Silver Maple, alder and willow are present in the marsh. The most mature forest in the remaining area is a Sugar Maple – Basswood forest. Other species present include Beech, White Ash, Eastern Hemlock, Black Ash, poplar, and the rare Rock Elm. This site has a high floral diversity. Forty species of provincially rare or local plants occur in the wildlife area, including Poison Sumac and Nodding Trillium. Lac Saint-François also provides important habitat for amphibians and reptiles, and the shallow, warm waters of the lake are an important spawning ground for 45 fish species. Pickerel Frog, Northern Water Snake and Spring Salamander are just a few of the many reptiles and amphibians that use the lake.
Large numbers of moulting or migrating ducks occur at this site. In spring, the lake supports one of the highest densities of dabbling ducks along the St. Lawrence. Up to 10,000 Greater Scaup have been recorded in the IBA, which is a nationally significant concentration. Large spring flocks of scaup (as many as 7000 individuals) are regular. Lac Saint-François hosts many other waterfowl species, including Canada Goose, American Black Duck, Blue-winged Teal, Northern Pintail, Ring-necked Duck, Common Goldeneye and Red-breasted Merganser. Waterfowls are regularly present in numbers exceeding 10,000 in the spring. Over 232 species and 119 breeding species have been recorded at this site. Veery is the most common forest breeding species, whereas Marsh Wren, Swamp Sparrow, Common Yellowthroat, Yellow Warbler, and Red-winged Blackbird are the most common marsh species. This site is the most important nesting site for Sedge Wren in Québec (28 singing males recorded). It is the only place where nesting occurs annually, among 20 other sites, and is probably one of the best sites for the species in eastern Canada (outside of Hudson and James Bays). However, the Common Tern colony has considerably declined in the past four years; it has fallen from 200 to 24 individuals. Several nationally threatened species breed sporadically at this site. These include Loggerhead Shrike, Red-headed Woodpecker, Least Bittern, Yellow Rail, Red-shouldered Hawk, and Short-eared Owl. Sedge Wren, a species likely to be designated as threatened or vulnerable in Québec, possibly breeds in the IBA. Over the past few years, Blue-grey Gnatcatchers and Sandhill Cranes, two uncommon species in Québec, have been breeding successfully. Peregrine Falcons, classified as a species of special concern in Canada and as a vulnerable species in Québec, are also occasionally seen on migration or in summer.
Fertilizers and pesticides used by farmers are found in the aquatic habitat. Lakeside cottages pose a threat to riparian habitats. The site is a National Wildlife Area, it was designated a RAMSAR site in 1987 and it is part of a Priority Intervention Zone. Trails and boardwalks have been created to protect the area from recreational overuse. A project is currently underway to control the expansion of the alder stand into sedge habitat. The maintenance of a wide area of sedge habitat is essential for the conservation of Yellow Rail and Sedge Wren. In 2013, Les Amis de la réserve nationale de faune du Lac-Saint-François implemented different conservation initiatives in the IBA, including shoreline cleanup, around fifty guided kayaking tours, guided walks organized for local birdwatching clubs and the general public, and a marsh monitoring program at the Digue aux Aigrettes.
A variety of freshwater and diadromous fish coexist in different habitats in the IBA. We found between 70 and 80 species (including historical records) in the area. Several species, such as the northern pike, the yellow perch and the common carp exploit the aquatic vegetation and the floodplains as a spawning ground, a nursery and a feeding ground. Others, such as walleye, freshwater specie with an important economic value in Canada prefer rather to spawn in fast flowing waters. A special feature of this area is the presence of salmonids introduced for sport fishing (brown trout, rainbow tout, and salmons). Salmons were introduced in the Great Lakes and some drift into the St. Lawrence River where they are sometimes caught by anglers. Brown trout and rainbow trout were also stocked in riffles (in the river) for sport fishing.
Several pressures threaten the availability of fish habitats: the creation of embankments, the artificialization of banks, the residential, commercial and industrial development as well as developing the road network, while agricultural, industrial and urban waste deteriorate the water quality. The Eastern sand darter, among others, is very vulnerable to pollution and it is now on the list of endangered species. Among the species listed at risk frequenting the site, we found the lake sturgeon, the channel darter, the bridle shiner, the American eel and some historical records mention the presence of copper redhorse, a fish endemic to Canada designated endangered. In addition, the presence of invasive species such as round goby, threatens the natural dynamics of ecosystems and the water level regulation of the Great Lakes creates risks for the availability of spawning habitats of certain species.
Major species present:
Eastern sand darter
The sector is characterized by clear, alkaline and slow flowing water. Theses conditions promote dense plant bed that can cover up to 50% of the water bodies. Submerged plant beds are dominated by wild celery and Eurasian water-milfoil, while emergent marshes are filled with bulrushes, arrowhead and cattails. Several duck species forage in these areas, including the scaup that is fond of wild celery.
Shoreline erosion, whether due to natural factors (wind, freezing and thawing cycles, absence of ice protecting the river banks in spring) or human actions (waves caused by ships), all threaten the riparian habitat. Water level fluctuations affect the ecology of plant and animal species that live there. A significant and prolonged decrease of bank immersion could affect flora by promoting more land species such as shrubs or even trees. In addition, the spread of invasive species exerts considerable pressures on the native flora of these habitats.
Major species present :
Eurasian water-milfoil – invasive species
Narrow leaf cattail