Estuary Islands National Wildlife Area Management Plan: chapter 3


3. Management challenges and threats

Estuary Islands National Wildlife Area is exposed to numerous threats and presents several management challenges, including wildlife diseases, habitat degradation, the impact of predators, the impact of human activities, invasive plant species, accidental spills, area fragmentation, facility, infrastructure, and lands maintenance, as well as gaps in scientific knowledge. These are described below in approximate order of importance since the scope of several of them is not well known.

3.1 Wildlife diseases

The National Wildlife Area’s colonial seabirds are susceptible to animal diseases, which can strike a species or a group of species. The Common Eider is occasionally affected by avian cholera, a bacterial disease that triggers potentially devastating epidemics within the species, such as one that decimated close to 10,000 individuals in 2002 (Giroux et al., 2002 in Canadian Wildlife Service, 2003). Factors that contribute to this disease and its spread among the Common Eider are still not well understood. An emergency plan in the event of mass bird mortality was put forward by the Canadian Wildlife Service in order to react to epizootic diseases and to mitigate their impacts.

3.2 Habitat degradation

Some of the National Wildlife Area’s animal populations become so abundant at times that they can cause habitat deterioration and affect other species. The increase in the Double-crested Cormorant’s population between 1978 and 1990 in the St. Lawrence and the impact of its droppings on the ecosystems of the estuary islands prompted the Quebec Ministère du Loisir, de la Chasse et de la Pêche (MLCP) to launch a species control program in 1989 (Bédard et al., 1995). The Canadian Wildlife Service is also concerned with the impacts of this species on the evolution of the National Wildlife Area’s habitats and the integrity of bird populations that nest there. Other animals can also disrupt vegetation on the National Wildlife Area’s islands, especially the Snowshoe Hare through its intense grazing (Bédard, 2010). Cyclical insect epidemics periodically affect the National Wildlife Area’s forests, such as the Spruce Budworm epidemic that caused major damage on all of the National Wildlife Area’s islands during the 1970s (Canadian Wildlife Service, 2003). In the last three years, large areas where trees have blown down have appeared on the south side of Île Bicquette as a result of strong winds (M. Lapointe, pers. comm., 2014).

In recent years, shore erosion, leading to the degradation of coastal habitats (receding by more than 5 m), has been observed on some of the National Wildlife Area’s low-lying islands, especially Île aux Fraises and Île Blanche, where the underlying rock is covered with unconsolidated materials (sand and gravel). This phenomenon has also been observed in the eastern part of Île Bicquette (M. Lapointe, pers. comm., 2014). This erosion could be due to storm frequency and intensity as well as high tides, which can be exacerbated by climate change.

3.3 Impact of predators

Terrestrial predators can occasionally access the National Wildlife Area’s islands (e.g. by swimming or via ice bridges that form between the mainland and the islands). These predators, especially the Red Fox, and certain species of birds, such as gulls, can significantly reduce colonial seabird populations through egg or chick predation (Bédard, 2010). Although the presence of these predators on the islands and their predation of birds is a natural phenomenon, controlling certain ones, particularly the fox, is occasionally necessary in order to avoid significant impacts on the affected populations of nesting seabirds. Predator control can, however, have repercussions on prey. For example, controlling the Red Fox can promote increased Snowshoe Hare populations, which can result in an increase in the grazing of the islands’ vegetation. Predator control is subject to Environment Canada's “Predator Management Policy”, which takes into account a series of factors to guide interventions.

3.4 Human impact

Despite regulations prohibiting public access (except on Le Pot du Phare), the presence of boaters and kayakers in the National Wildlife Area can have harmful consequences for the integrity of ecosystems and successful reproduction among colonial seabirds. Trampling by these visitors can disturb wildlife and degrade riparian habitats and flora. These types of unauthorized activities take place primarily on Le Long Pèlerin, within the National Wildlife Area’s boundaries, where visitors have left their mark (tent prints, fires and garbage). Visitors are also frequently seen on the Îles de Kamouraska (Bédard, 2010), but no records are kept of these sightings.

Resource operations around the National Wildlife Area (fishing, seaweed and sea urchin harvesting) could also have an impact on National Wildlife Area’s wildlife, such as the Common Eider or the Surf Scoter. A project to develop oil and gas reserves (exploration and production) in the sub-surface of the St. Lawrence, specifically in the basin of the Lower Estuary and the north-western Gulf of St. Lawrence, raises fears about the possible impact these activities might have on wildlife and the environment (AECOM Tecsult Inc., 2010).

Finally, the proposed construction of an oil pipeline and a transshipment could lead to increased maritime traffic and wildlife disturbances and an increased risk of accidental toxic substance spills.

3.5 Invasive plant species

No comprehensive studies have been done on the National Wildlife Area’s invasive species, but floral surveys conducted on three islands (Île Blanche, Île aux Fraises and Le Pot du Phare) show that exotic (introduced) plants make up 25 to 35% of the vegetation in these islands’ open environments (Morisset, 2010 in Bédard, 2010). Some of these species are invasive or cover large areas, including the Reed Canary Grass, the Wild Radish and the Smooth Bedstraw, and can result in loss of biodiversity and natural habitats (Bédard, 2010).

3.6 Accidental spills

A large number of commercial and passenger cruise vessels travel close to the National Wildlife Area on the St. Lawrence Seaway every year. An accidental oil or chemical spill in the estuary could result in aquatic bird mortality and have serious consequences for the National Wildlife Area’s shores and ecosystems. Environment Canada and its collaborators have established an emergency response plan (ERP) to implement relevant bird protection measures if such a spill were to occur.

3.7 National Wildlife Area fragmentation

The National Wildlife Area’s management and conservation challenges are, in large part, related to its geography. The National Wildlife Area forms a discontinuous entity made up of islands and portions of islands interspersed with other islands or parts of islands that are not part of the National Wildlife Area. Some of the islands without National Wildlife Area status are protected, but others are inhabited or used as vacation spots and could be developed and exploited. For example, on Île Bicquette, the lighthouse owned by Fisheries and Oceans Canada was recently declared surplus and could be turned into a development project. In addition, the National Wildlife Area’s islands are spread out over a long distance (120 km) and are relatively far from the mainland (2 to 10 km from the coast). This limits the ecological connectivity of both habitats and species, which is already naturally weak in island environments. Finally, the National Wildlife Area’s discontinuity, sprawl and remoteness make posting its boundaries, monitoring the area and law enforcement challenging.

3.8 Facility, infrastructure and land maintenance

The National Wildlife Area has some facilities and infrastructure that require maintenance and restoration, including trails, boardwalks and stairs on Le Pot du Phare, and some buildings (former lighthouse keeper’s house, foghorn building, pump building and boathouse) and a cross on Île Bicquette. In addition, rehabilitation work are necessary on Île Bicquette, Le Pot du Phare, Le Long Pèlerin, La Grande Île and Île de la Providence due to the presence of garbage and small quantities of contaminants left behind before the National Wildlife Area was created.

3.9 Gaps in scientific knowledge

Since its creation, the National Wildlife Area has been the subject of several surveys by the Canadian Wildlife Service and Société Duvetnor. However, gaps remain in the scientific knowledge regarding habitats, flora, plant species at risk, certain animals (including amphibians and reptiles), and threats to the National Wildlife Area’s integrity. Ecological monitoring of the National Wildlife Area and more knowledge is required to support habitat and species management as well as conservation decisions, such as those concerning the decreasing population of Common Eiders in the estuary.

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