Dune du Sud is located in the Magdalen Islands archipelago. It borders the northeast side of Havre aux Maisons island, and the southeast side of the Grande Entrée Lagoon. A highway (provincial road 199) has been constructed to the lee of the dunes along the southwestern (Île du Havre aux Maisons) portion of this barrier beach and dune system. Short-liguled Ammophila (Ammophila breviligulata) is a common plant on the dunes, while Sea Lime-grass (Elymus arenarius) is less common. These plants are found in sandy areas throughout the region, and are crucial for stabilizing the dunes. On the seaward facing side of Dune du Sud there is a 19.9 km long sand and pebble beach that ranges from 20 to 40 m in width. Farther back from the sea, is an area of more stabilized and relatively heavily vegetated dunes called Les Sillions. Small ponds are sometimes present in between these dunes.
Over the last 20 years, large numbers of Piping Plovers have been reported at Dune du Sud in both the formal and informal birding literature. The population estimates have consistently been well over 1% of the estimated Atlantic Canadian population. Since 1979, the numbers of breeding birds have fluctuated from 6 to peaks of 22 in 1992 and 1994. Over the past five years (1994 to 1998) an average of 6.8 pairs has been recorded. In 1996, during the International Piping Plover census, a total of 21 Piping Plovers was recorded which represents 5% of the estimated Atlantic Canada population, and close to 1% of the entire Atlantic Coast population. During the post-breeding season even higher numbers have been recorded, with as many as 45 birds being present in mid-July 1992.
On occasion, large numbers of Great Cormorants (300) and Northern Gannets (5000) have also been recorded offshore and along the beach. The tip of the Dune du Sud is used as a resting area by Double-crested Cormorants, gulls and seals, while the mature dunes hold breeding Horned Grebes and Short-eared Owls.
Conservation responses/actions for key biodiversity
The Canadian Wildlife Service and Attention FragÎles (an ecological group of the Magdelen Islands) have been conducting research on the Magdalen Islands Piping Plover populations since 1987. The information collected during these studies is being used to develop programs for residents and tourists that outline the threats affecting the Piping Plover populations. Direct measures that have been implemented include the fencing of restricted zones during the breeding season, and installing signs that outline the importance of these areas to the nesting Piping Plovers.
Off-road vehicle use in sensitive areas contributes to both the disturbance of birds and the destruction of nesting habitat. Although municipal regulations prohibit the use of off-road vehicles on beaches in the archipelago, some usage still occurs. The popularity of Dune du Sud and other beaches in the archipelago has increased over the last decade, which increases the threat of disturbance for breeding plovers. The threat of oil spills is also a concern due to the frequency of shipping traffic through the Gulf of St. Lawrence.