Estuary Islands National Wildlife Area Management Plan: chapter 2
2. Ecological resources
2.1 Terrestrial and aquatic habitats
The Estuary Islands National Wildlife Area’s underlying bedrock is made up of alternating layers of shale, sandstone blocks and conglomerates formed between the beginning of the Cambrian and the Ordovician, 570 to 440 million years ago.
This protected area is subject to daily semi-diurnal tides (two high tides and two low tides per lunar day). The majority of the National Wildlife Area’s islands are located in the St. Lawrence’s Upper Estuary, which is characterized by brackish, turbid waters of low productivity. Île Bicquette, located in the Lower Estuary, is surrounded by rich, more productive salt water. The National Wildlife Area’s islands do not have any freshwater river systems.
The National Wildlife Area is part of the Atlantic Maritime Ecoregion. It has a continental subpolar, subhumid climate. While most of the National Wildlife Area’s islands are located in the Sugar Maple - Yellow Birch bioclimatic zone, marine and weather conditions primarily support a Balsam Fir - White Birch vegetation type. Within the National Wildlife Area, variation can be seen in the plant composition of terrestrial habitats from west to east. This variation depends on several factors, including substrate, type of soil, area and drainage. In general, the terrestrial portions of the National Wildlife Area’s islands are covered with Balsam Fir - White Birch stands and White Spruce stands (Canadian Wildlife Service [Canadian Wildlife Service], 2003) (Figure 9). Other common tree species include the American Mountain-Ash (Sorbus americana), the Pin Cherry (Prunus pensylvanica), the Trembling Aspen (Populus tremuloides) and the Balsam Poplar (Populus balsamifera).
The herbaceous vegetation that characterizes some of the non-forested islands and parts of islands was described by Reed (1975 in Canadian Wildlife Service, 2003) as being dominated by reedgrass (Calamagrostis) and a mixture of annual plants. Muskrats (Ondatra zibethicus) may be abundant in these herbaceous areas, and their digging can contribute to the presence of plants typical of disturbed environments such as the Great Burdock (Arctium lappa) (Bédard and Guérin, 1991 in Canadian Wildlife Service, 2003).
More recently, plant surveys were carried out on three of the National Wildlife Area’s islands by Morisset (2010a, b and c in Bédard, 2010). Within the scope of the study 88 species of plants were identified on Île aux Fraises, 50 species on Île Blanche, and 151 species on Le Pot du Phare and the southern edge of Le Gros Pot, including several open country introduced species (Morisset, 2010a and b in Bédard, 2010). Morisset did not identify any rare plants on the three islands, but Asselin (1994 in Bédard, 2010) reports the presence of a very rare primrose, the Cowslip Primrose (Primula veris), on Le Gros Pot, located only a few dozen metres away from the National Wildlife Area.
On all of the National Wildlife Area’s islands, the forest stands are highly disturbed as a result of multiple factors, such as intense grazing by the Snowshoe Hare (Lepus americanus), which has destroyed or severely reduced large numbers of forest perennials characteristic of similar stands on the mainland (Bédard et al., 1997 in Bédard, 2010). In addition, the Spruce Budworm (Choristoneura fumiferana) caused major damage on all of the islands during the 1970s, particularly to the fir stands on Îles de Kamouraska and on Le Pot du Phare. However, this insect's impact was not as severe in the archipelago of Les Pèlerins, the forests of which are dominated by the Black Spruce (Picea mariana). It spared a portion of the Balsam Fir (Abies balsamea) forest on Île Bicquette, which is otherwise in decline for unknown reasons. This forest is unique because of its old age (up to 136 years old), the absence of regeneration, the extreme density of its trees and the absence of herbaceous and moss flora on the ground (Bélanger and Bédard, 1997 in Bédard, 2010). The Double-crested Cormorant (Phalacrocorax auritus) has also had a significant impact on the forest habitat. Its excrement (or guano) kills trees and has already destroyed forests on several occasions on certain islands, especially Île Blanche, Île Brûlée, La Grande Île and Le Pot du Phare (Canadian Wildlife Service, 2003). Spatio-temporal changes in the National Wildlife Area’s riparian and terrestrial vegetation, which have been observed since the 1970s, are well documented in the Labrecque and Jobin study (2012).
The succession, community composition and biomass of macrophyte algae in nearshore marine environments has been described in several parts of the estuary (Himmelman et al., 1983 and Bourget et al., 1994 in Canadian Wildlife Service, 2003), but never within the boundaries of the National Wildlife Area or on equivalent coastal points (St. Lawrence Centre, 1996 in Canadian Wildlife Service, 2003). The macrophyte algae communities differ widely from one substrate to another. Very large beds of Laminaria can be found surrounding Île du Bic, between Île du Bic and Île Bicquette, and surrounding the Brandypot Islands. In addition, various sized beds of Ascophyllum and Fucus can be found in all of the islands’ nearshore environments (Figure 10) and in the top portion of the sublittoral zone. These algal beds seem better developed and more widespread downstream than upstream (Canadian Wildlife Service, 2003).
2.2 Wildlife species
The National Wildlife Area’s wildlife is described in this section based on knowledge gathered over the past 30 years as a result of studies and surveys conducted by the Canadian Wildlife Service and various contributors such as Société Duvetnor. In addition, data on the organisms found in the waters adjacent to the National Wildlife Area, including invertebrates, fish, and marine mammals, are presented as complementary information, given their ecological links with the National Wildlife Area.
Mollusks and crustaceans
Several species of mollusks and crustaceans could be expected to be found in the sediments bordering the National Wildlife Area. Softshell Clam (Mya arenaria) deposits are likely to be found in the Île Blanche and Île aux Fraises intertidal flats, while the Stimpson’s Surfclam (Mactromeris polynyma) can be found around Île Bicquette and the Green Sea Urchin (Strongylocentrotus droebachiensis) is plentiful around Île Bicquette and Le Pot du Phare (Fisheries and Oceans Canada [DFO-SIGHAP], 2002 in Canadian Wildlife Service, 2003). Green Sea Urchins are fished in the spring (April and May) and the fall (from the end of October until ice formation begins) almost exclusively near Île Blanche and Île Bicquette. Some of the urchins are taken at the lower boundary of the intertidal flats (Bédard, 2010). Other species, such as the Atlantic Razor Clam (Ensis directus), Sea Cucumber (Cucumaria frondosa), Sand Shrimp (Crangon septemspinosa), Icelandic Scallop (Chlamys islandic), Rock Crab (Cancer irroratus) and Waved Whelk (Buccinum undatum) are found in the National Wildlife Area (Brunel et al., 1998 in Canadian Wildlife Service, 2003). It appears that the American Lobster (Homarus americanus) and the Snow Crab (Chionoecetes opilio) also inhabit the waters surrounding Île Bicquette. It should be noted that these data (Pêches et Océans Canada [MPO-SIGHAP], 2002 in Canadian Wildlife Service, 2003) were extracted for a one-kilometre zone around the National Wildlife Area.
Insects and spiders
In 1994 and 1995, sampling of insects and spiders was performed on approximately twenty islands in the estuary, including five islands that are part of the National Wildlife Area (Nadeau et al., 2009). Insects from at least four orders (Coleoptera, Diptera, Hymenoptera and Orthoptera) and Arachnids (the class of animals that includes spiders) were identified in the area. In 1995, this sampling dealt more specifically with beetles from the Carabidae family. Forty species of insects in this family were identified. The most harvested species (47% of captured individuals) found on the greatest number of islands (17 out of 20 islands) was the Pterostichus adstrictus beetle (Nadeau et al., 2009).
No studies have been carried out on benthic fauna in the National Wildlife Area’s mud and rock intertidal flats.
The National Wildlife Area’s islands are too small to have any permanent freshwater river system that would support a community of fish. However, the surrounding waters of the St. Lawrence Estuary support several species of marine fish, including forage species consumed by various aquatic birds that use the area. The main species found are the Atlantic Herring (Clupea harengus), which has two seasonal spawning cycles around the western islands (Les Pèlerins, Île aux Lièvres) and at least one spawning site around Île aux Lièvres (Munro et al., 1998 in Canadian Wildlife Service, 2003), as well as the American Sand Lance (Ammodytes americanus) and the Capelin (Mallotus villosus). The latter may spawn around the Îles de Kamouraska (DFO-SIGHAP, 2002 in Canadian Wildlife Service, 2003). The Atlantic Sturgeon (Acipenser oxyrinchus) has been subject to significant fishing, especially on the Saint-André bank (DFO-SIGHAP, 2002 and Caron, 2002 in Canadian Wildlife Service, 2003), between the archipelagos of Kamouraska and Les Pèlerins. The Atlantic Herring, Blackspotted Stickleback (Gasterosteus wheatlandi), Threespine Stickleback (Gasterosteus aculeatus) and Winter Flounder (Pseudopleuronectes americanus) inhabit the waters surrounding the National Wildlife Area’s islands. The Atlantic Halibut (Hippoglossus hippoglossus) was commercially fished near the Brandypot Islands (until approximately 1999) and near the Îles de Kamouraska. The American Shad (Alosa sapidissima) is also found in the Kamouraska and Les Pèlerins archipelagos. Finally, the American Eel (Anguilla rostrata) is found in the Îles de Kamouraska area in the fall, and the Atlantic Cod (Gadus morhua) is present off the coast of Île Bicquette (DFO-SIGHAP, 2002 in Canadian Wildlife Service, 2003).
2.2.3 Amphibians and reptiles
The National Wildlife Area provides very little habitats suitable for amphibians and reptiles owing to the absence of freshwater. No surveys of herpetofauna have been carried out in the National Wildlife Area. To date, only one species of amphibian has been identified on the islands of the upper estuary: the Blue-spotted Salamander (Ambystoma laterale), which was observed on Île aux Lièvres (Société Duvetnor, unpublished data in Canadian Wildlife Service, 2003). Only one species of reptile, the Common Garter Snake (Thamnophis sirtalis), is common and widely distributed across the island. It is possible that both of these species were introduced while transporting forage and agricultural equipment during agroforestry activities practised on Île aux Lièvres from 1920 to 1923 and from 1950 to 1953.
The islands in the estuary are essential for bird conservation because of their location in a significant migratory bird flyway and their role in bird reproduction and feeding. They are also critical in maintaining populations of several species of colonial birds (Chapdelaine and Rail, 2002). Five of the islands in Estuary Islands National Wildlife Area (Bicquette, Blanche, Le Pot du Phare, aux Fraises and Le Long Pèlerin), as well as other surrounding islands, have been designated Important Bird Areas (IBA).
Significant proportions of certain populations of colonial seabirds in Quebec reproduce in the National Wildlife Area (Table 4). The numbers and distribution of the most common species on these islands - including the Common Eider, the Herring Gull (Larus argentatus), the Great Black-backed Gull (Larus marinus), the Great Blue Heron (Ardea herodias), the Black-crowned Night Heron (Nycticorax nycticorax), the Black-legged Kittiwake (Rissa tridactyla), the Common Murre (Uria aalge), the Black Guillemot (Cepphus grylle), and the Razorbill (Alca torda) - have experienced continual fluctuations (Bédard, 2010). Nonetheless, the main colonies have generally remained concentrated in the same areas.
The Common Eider population (dresseri subspecies) that nests in the estuary is thought to be one of the largest in North America. In 2009, it numbered 19,100 nesting pairs (Savard and Lepage, in prep.). Approximately 55% of these pairs nest in the National Wildlife Area, mainly on Île Bicquette (16,214 individuals in 2012), Île Blanche (2,890 individuals in 2010) and Île aux Fraises (2,092 individuals in 2010) (Table 4). This bird is, therefore, the most abundant in the National Wildlife Area despite significant fluctuations in its numbers owing to epidemics of avian cholera, hunting and juvenile mortality (Joint Working Group on the Management of the Common Eider, 2004). It appears, however, that the population in the estuary has decreased at a rate of approximately 2% per year over the last 25 years, which is worrisome (Bédard, 2010).
Impressive synchronous fluctuations in the Common Eider population in the estuary in recent decades suggest that common factors are at work on all islands, including the ones within the National Wildlife Area (Giroux, 2008 in Bédard, 2010): three severe declines (1984 to 1985, 1992 to 1994, 2001 to 2002) coincided with three avian cholera outbreaks followed by a slow recovery. In 2002, approximately 10,000 birds (out of a total of close to 64,000) died from this bacterial disease (Giroux et al., 2002 in Canadian Wildlife Service, 2003). That year, the foci of mortality were more extensive than ever (Île Bicquette, Île Blanche, Île aux Pommes and Île aux Fraises), but the colonies on the north shore of the estuary were not affected (Canadian Wildlife Service, 2003).
Between 1985 and 1990, a joint effort by the Canadian Wildlife Service, Société Duvetnor and Ducks Unlimited Canada resulted in a major redevelopment of the Île Blanche habitat in order to eliminate the suspected cause of the infestation. These projects were followed by an intervention program on several islands in the estuary, which included planting shrubs and coniferous trees, controlled burning, and installing nest boxes for the Common Eider (Joint Working Group on the Management of the Common Eider, 2004). In addition, drainage swales were dug to prevent the formation of stagnant water ponds, which is conducive to the development of avian cholera (Jean-François Giroux, pers. comm., 2012). Epidemiological factors of this disease among the Common Eider are still not well understood. There may be a carry-over effect (an epidemic at the end of the summer that could lead to another epidemic the following spring). The characteristics of the habitat appear to have fewer effects than what was believed in the 1980s (e.g. the Île Blanche redevelopment did not eliminate the problem even though it reduced the incidence and the scope) (Joint Working Group on the Management of the Common Eider, 2004).
Gulls and Black-legged Kittiwake
The Herring Gull is an important species in the National Wildlife Area because of its abundance; however, its numbers have significantly declined over the years (Bédard, 1999 in Canadian Wildlife Service, 2003) for undetermined reasons (Canadian Wildlife Service, 2003). A significant decline has been observed for several decades: the number of pairs identified on Île aux Fraises went from 2200 in 1967 to only 67 in 1999; however, it was at 146 in 2001 (Base Informatisée des Oiseaux Marins du Québec [BIOMQ], 2012). Further, on other islands like Le Pot du Phare, the number of individuals in the species remained stable during the same period (Bédard, 1999 in Canadian Wildlife Service, 2003). The Herring Gull competes with a larger species in the same genus, the Great Black-backed Gull. These two species of gulls exert predation pressure on the majority of aquatic birds. Predation on juvenile Common Eiders by Great Black-backed Gulls is a real concern throughout the National Wildlife Area, but especially on Île Blanche and Île Bicquette (Bédard, 2010). Ring-billed Gulls (Larus delawarensis) attempted to establish themselves on Île aux Fraises and Île Blanche at the end of the 1980s but failed to do so because of predation by the other two species of gulls.
The Black-legged Kittiwake nests on the Brandypot Islands and Les Pèlerins, but outside the National Wildlife Area (Canadian Wildlife Service, 2003). Inside the National Wildlife Area, this species nests on Île Bicquette where varying numbers of pairs were identified between 1986 and 2007, including 130 pairs in 1986, 693 pairs in 2001 and 350 pairs in 2007. It also uses La Grande Île, in the Îles de Kamouraska, where 18 pairs were observed in 2011 (BIOMQ, 2012). This is the westernmost colony of this species in Quebec.
Razorbill, Black Guillemot and Common Murre
Data collected between 1990 and 2001 indicate that there were only a few pairs of Razorbills in the National Wildlife Area, on Le Long Pèlerin, Île Brûlée, La Grande Île, Le Pot du Phare (Bédard, 2002 in Canadian Wildlife Service, 2003) and Île Bicquette (Société protectrice des eiders de l'estuaire (SPEE), 1998). In 1999, the Razorbill colony in the archipelago of Les Pèlerins (the part outside the National Wildlife Area) was the second largest in Canada with more than 1800 pairs identified (Bédard, 1999 and Chapdelaine et al., 2001 in Canadian Wildlife Service, 2003). Recent data show that it is still the main colony in this sector with approximately 331 pairs identified in 2011 (BIOMQ, 2012).
Some nesting pairs of Black Guillemots were observed on the Îles de Kamouraska (La Grande Île, Île Brûlée and Les Rochers), Le Long Pèlerin, Le Pot du Phare (63 pairs observed in 2011) and Île Bicquette (BIOMQ, 2012). The Common Murre can be found in small numbers among groups of Razorbills on Le Pot du Phare and Le Long Pèlerin, but there is now a large concentration of this species on the other Brandypot islands (Le Petit Pot and Le Gros Pot), with more than 1000 individuals observed in each location in 2011 (BIOMQ, 2012).
Occasional surveys of the Double-crested Cormorant show that several hundred pairs nest on the National Wildlife Area’s islands, mainly Île Bicquette, Île aux Fraises and La Grande Île (Table 4) (BIOMQ, 2012). Significant increases in numbers for this species were observed between 1978 and 1990 in the St. Lawrence. These were due in part to the decrease in human disturbance and persecution of the species as well as the abundance of food near the colonies (Chapdelaine and Bédard, 1995). The Double-crested Cormorant has an impact on the islands’ forests, because its droppings can kill trees and alter the physical and chemical characteristics of the soil. As such, it devastated the National Wildlife Area’s forests in places where it had established colonies, including on Île Blanche between 1970 and 1985, Île Brûlée, La Grande Île, Le Pot du Phare and other islands located outside the National Wildlife Area (Canadian Wildlife Service, 2003). In 1989, owing to the impact this species was having on the ecosystems, Quebec’s Ministère du Loisir, de la Chasse et de la Pêche (MLCP) undertook a control program aimed at reducing its numbers on Île Brûlée, La Grande Île, Île aux Fraises, Île Blanche and the reefs of Île Bicquette. This program included culling adults and spraying eggs with oil (Bédard et al., 1995). Despite the effectiveness of this control, the Double-crested Cormorant’s population remains present and continues to impact the environment.
Great Blue Heron and Black-crowned Night Heron
Aerial surveys conducted in 2001 identified 34 Great Blue Heron nests on Île Bicquette, 2 on Le Long Pèlerin, 31 on La Grande Île and 3 on Île Brûlée (Alain Desrosiers, pers. comm. in Canadian Wildlife Service, 2003). Le Gros Pot (outside the National Wildlife Area, Brandypot Islands) has long supported a large colony of this species. Surveys carried out on this island identified three nests in 1977, 112 in 1992 and 24 in 2010, but no nests were seen in 2011 (BIOMQ, 2012).
The Black-crowned Night Heron’s numbers have declined sharply on three of the National Wildlife Area’s islands, where the species had previously been abundant. On Le Pot du Phare, 443 nests were identified in 1991 and only 38 nests in 2002 (unpublished data, Duvetnor in Canadian Wildlife Service, 2003). On Île aux Fraises, close to 200 nests were observed in 1988, but the species was not seen there again. On Île Brûlée, the number of nests went from 537 in 1975 to only 6 in 1990 and the species was not seen there again (no nests between 2006 and 2008 and in 2011) (BIOMQ, 2012).
Waterfowl (other than the Common Eider)
Waterfowl species, other than the Common Eider, are uncommon in the National Wildlife Area during nesting season, but significant numbers halt there during migration. Thousands of Brants (Branta bernicla) stage on Île Blanche during the spring, and hundreds of individuals were also observed on Île Bicquette in spring 1998 (Canadian Wildlife Service, 2003). Several thousand Snow Geese (Chen caerulescens) stage near Île aux Fraises and Île Bicquette in the spring and close to the Îles de Kamouraska in the fall (Guy Verreault and Annie Bérubé, pers. comm., FAPAQ [Société de la faune et des parcs du Québec] de Rivière-du-Loup in Canadian Wildlife Service, 2003). The Black Scoter (Melanitta americana) and the Surf Scoter (Melanitta perspicillata) are also common in the islands’ subtidal zone during migration. In addition, the Surf Scoter uses the Saint-André bank sector (between the Îles de Kamouraska and Les Pèlerins) during moulting (Canadian Wildlife Service, 2003). Thousands of American Black Ducks (Anas rubripes) use the intertidal flats surrounding Île Blanche, Île aux Fraises, Île aux Lièvres, the Brandypot Islands and the Îles de Kamouraska from mid-July to the beginning of November (approximately 5000 birds around these islands) (Bédard, Ouellet and Giroux, 1987 and Bédard, Ouellet, Giroux and Savard, 1988 in Canadian Wildlife Service, 2003), and small numbers winter in the sector (Gauthier, Choinière and Savard, 1992 in Canadian Wildlife Service, 2003).
In both spring and fall, tens of thousands of scoters, eiders and Long-tailed Ducks (Clangula hyemalis) gather in large numbers in the St. Lawrence Lower Estuary (Lepage and Savard, in prep.; Savard and Lepage, in prep.; Lepage and Cotter, in prep.). The estuary is also a major wintering site for several duck species, including the Long-tailed Duck (Canadian Wildlife Service, 2003), the Red-breasted Merganser (Mergus serrator) and the American Black Duck. The latter is particularly abundant between Tadoussac and Cap de Bon-Désir, and is especially common in the National Wildlife Area’s Île Bicquette sector (Robert et al., 2003). Canadian Wildlife Service surveys (Robert et al., 2003) showed that the St. Lawrence Estuary is also home to a large number of Common Goldeneyes (Bucephala clangula) and Barrow's Goldeneyes (Bucephala islandica, Eastern population) in winter and serves as the latter’s main wintering ground (see 2.3 Species at Risk).
Many species of shorebirds are common along the St. Lawrence during fall migration (Aubry and Cotter, 2007) and several of these species more than likely stopover in the National Wildlife Area, especially the Red Knot (Calidris canutus rufa). No systematic survey of shorebirds has been carried out on the National Wildlife Area’s islands. However, one-time data collected by the Canadian Wildlife Service in fall 2008 (S. Giguère, pers. comm., 2012) helped to identify 11 species of shorebird on three of the National Wildlife Area’s islands or nearby (Île aux Fraises, Île Blanche, Île Bicquette), including the Semipalmated Plover (Charadrius semipalmatus), the Black-bellied Plover (Pluvialis squatarola), the Semipalmated Sandpiper (Calidris pusilla), the Dunlin (Calidris alpina), the Sanderling (Calidris alba), and the Least Sandpiper (Calidris minutilla). In addition, large numbers of Purple Sandpipers (Calidris maritima) are common on some of the National Wildlife Area’s islands (Île Blanche, Île aux Fraises, Île Bicquette) during the winter (Robert et al. 2003; Aubry and Cotter, 2007).
In 2008, the Canadian Wildlife Service surveyed landbirds on the National Wildlife Area’s eight main islands (S. Giguère, pers. comm., 2012). The initial analysis indicates the presence of 40 species of landbirds, even though the data collected are preliminary and were collected in a single season. Since this survey was conducted in June, during the nesting season, the species identified possibly breed there. The data indicate that the large islands are home to a more diverse range of species than the smaller islands. La Grande Île (Îles de Kamouraska) is where the largest number of species (25) was identified, followed by (in descending order): Île Bicquette (19 species), Le Long Pèlerin (13 species), Île Brûlée (12 species), Le Pot du Phare (11 species), Île de la Providence (9 species) and, finally, Île aux Fraises (3 species) and Île Blanche (2 species). Only 8 of the 40 species identified were observed on four or more islands, with the most common being the American Crow (Corvus brachyrhynchos) (8 islands), the Song Sparrow (Melospiza melodia) (8 islands), the White-throated Sparrow (Zonotrichia albicollis) (6 islands), the Fox Sparrow (Passerella iliaca) (5 islands) and the Golden-crowned Kinglet (Regulus satrapa) (5 islands). Among birds of prey, only the Rough-legged Hawk (Buteo lagopus) was observed (on La Grande Île), but the only nesting bird of prey confirmed in the area is the Peregrine Falcon (Falco peregrinus anatum/tundrius) (see 2.3 Species at Risk).
|Location||Sub location||Common Eider||Great Black-backed Gull||Herring Gull||Black-legged Kittiwake||Black Guillemot||Common Murre||Razorbill||Double-crested Cormorant|
|Îles de Kamouraska||Île Brûlée||130 (2008)||14 (2011)||370 (2011)||-||20 (2011)||-||8 (2011)||2 (2011)|
|Îles de Kamouraska||Les Rochers||70 (2011)||34 (2011)||732 (2011)||-||2 (2011)||-||78 (2011)||0 (2011)|
|Îles de Kamouraska||La Grande Île||380 (1996)||12 (2011)||472 (2011)||36 (2011)||30 (2011)||-||152 (2011)||1,332 (2011)|
|Les Pèlerins||Le Long Pèlerin||0 (2008)||14 (2011)||252 (2011)||0 (2011)||16 (2011)||2 (2011)||663 (2011)||-|
|Brandypot Islands (Îles du Pot à l’Eau-de-Vie)||Le Pot du Phare||620 (2010)||22 (2011)||1,126 (2011)||-||126 (2011)||1 (2011)||9 (2011)||0 (2011)|
|Other islands||Île Blanche||2,890 (2010)||336 (2001)||292 (2001)||-||-||-||-||-|
|Other islands||Île aux Fraises||2,092 (2010)||394 (2001)||292 (2001)||-||-||-||-||64 (2010)|
|Other islands||Île Bicquette||16,214 (2012)||518 (2007)||964 (2007)||700 (2007)||90 (2007)||-||120 (2007)||654 (2007)|
g The figures shown indicate the number of nesting individuals and the year of the last data entry. For the Common Eider, Great Black-backed Gull, Herring Gull, Black-legged Kittiwake and Double-crested Cormorant, the number of individuals was obtained by multiplying the number of nests identified (therefore, the number of nesting pairs) by two. For the Black Guillemot, Common Murre and Razorbill, the number of individuals and not the number of nests was identified.
h The Great Blue Heron and the Black-crowned Night Heron, colonial waterbirds (not necessarily marine), do not appear in the table, but they are briefly described above.
i The Banque informatisée des oiseaux marins du Québec (BIOMQ, 2012; contact: Jean-François Rail, Canadian Wildlife Service) contains the survey results for 28 species of seabirds during reproduction in Quebec, mostly since 1976, but also data extracted from literature going back to 1833. These data mostly cover the Estuary and the Gulf of St. Lawrence. For the islands where only a portion is located in the National Wildlife Area (e.g. Le Long Pèlerin), the survey data apply to the entire island.
The quality of the National Wildlife Area’s islands as habitat for colonial seabirds is primarily determined by the relative lack of terrestrial predators. However, small numbers of such predators sometimes access the islands, where they have a considerable impact on the abundance of birds (Bédard, 2010). The Red Fox (Vulpes vulpes), the Long-tailed Weasel (Mustela frenata) and the American Black Bear (Ursus americanus) were all reported in various parts of the National Wildlife Area, but the Red Fox in particular is responsible for the largest decline in nesting seabirds. It’s population persists on Île du Bic and Île aux Lièvres (outside the National Wildlife Area), where it feeds on a variety of prey and, when ice cover allows for movement between the islands, it also invades the National Wildlife Area’s other islands spreading out from the population "hubs" (Bédard, 2010).
The Muskrat and the American Mink (Neovison vison) are present in the wildlife area, especially on Île aux Fraises and Île Blanche. The Snowshoe Hare is also present. Intense grazing by this species has decimated or eliminated an assemblage of the National Wildlife Area’s forest plants that characterize similar communities on the mainland (Bédard et al., 1997b in Bédard, 2010). The White-tailed Deer (Odocoileus virginianus) was spotted on several occasions swimming various distances off the shore of the National Wildlife Area. A juvenile moose (Alces americanus) wintered on Le Gros Pèlerin (outside the reserve) in 1986-1987 (Canadian Wildlife Service, 2003) and another individual was observed on La Grande Île (within the area’s boundaries) in 2012 (Jean Bédard, pers. comm., 2012).
During a survey of micromammals conducted in 2007 by the Canadian Wildlife Service on several of the National Wildlife Area’s islands, only the Meadow Vole (Microtus pennsylvanicus) was captured on Île de la Providence, Île Brûlée and La Grande Île in the Kamouraska archipelago (S. Giguère, pers. comm., 2012). No micromammals were captured on Île Bicquette, Île aux Fraises, or Île Blanche. During a survey conducted in 1995, the Meadow Vole was also identified on the portion of Le Long Pèlerin that is within the National Wildlife Area (Nadeau et. al., 2009). This same survey identified several species of micromammals on some of the islands in the estuary that are not part of the National Wildlife Area, including the Masked Shrew (Sorex cinereus), the Deer Mouse (Peromyscus maniculatus), the Southern Red-backed Vole (Myodes gapperi), and the Meadow Vole (Nadeau et al., 2009).
A significant number of Grey Seals (Halichoerus grypus) use the National Wildlife Area as a haul-out site, particularly on the intertidal flats of Île aux Fraises and at the western point of the intertidal flats on Île Blanche. Harbour Seals (Phoca vitulina vitulina) also haul out on the Îles de Kamouraska and Les Pèlerins. These two pinniped species coexist in several locations, including the reefs and intertidal flats surrounding Île Bicquette and Île Blanche. Moreover, baby Harbour Seals are observed regularly in May on the shore of several islands (Bédard, 2010). Finally, the brackish and salt waters that surround the National Wildlife Area’s islands are used by several species of cetaceans, including the Beluga Whale (Delphinapterus leucas), a permanent resident of the St. Lawrence Estuary, whose population is threatened according to Quebec's Act respecting threatened and vulnerable species (ARTVS) and Canada's Species at Risk Act (SARA).
2.3 Species at Risk
Table 5 presents species at risk that carry out part of their life cycle in the National Wildlife Area (islands and intertidal flats) or in its surrounding waters.
Between 2002 and 2010, the Peregrine Falcon, a species of special concern in Canada, was observed repeatedly on a cliff on Le Long Pèlerin, in the archipelago of Les Pèlerins, where its nesting has been confirmed. In addition, in July and August 2002, the species was observed on a few occasions on Le Pot du Phare, in the Brandypot Islands (Bédard, 2002 in Canadian Wildlife Service, 2003). One or several juvenile Bald Eagles (Haliaeetus leucocephalus) and Golden Eagles (Aquila chrysaetos) sometimes spend long periods on Le Pot du Phare in June and July (Bédard, 2002 in Bédard, 2010), but no nesting by these species has been confirmed in the National Wildlife Area. Both are species of special concern in Quebec.
The St. Lawrence Estuary is the main wintering ground for the eastern population of the Barrow's Goldeneye (Robert et al., 2003), a species of special concern in Canada. Its numbers are estimated at a maximum of 4500 individuals, of which at least half find refuge in the estuary during the colder months. The species is then observed in the waters adjacent to Île aux Fraises, Île Blanche, the Brandypot Islands (a portion of this archipelago is not part of the National Wildlife Area) and Île aux Lièvres (outside the National Wildlife Area).
The Red Knot of the rufa sub-species is found in the St. Lawrence Upper Estuary and Lower Estuary primarily during fall migration (Aubry and Cotter, 2007). Although this shorebird most likely uses the intertidal flats on the National Wildlife Area’s islands during this period, its presence has not yet been documented. This sub-species is endangered in Canada and is likely to be designated as threatened or vulnerable in Quebec.
The Centre de données sur le patrimoine naturel du Québec (CDPNQ, 2012) does not contain any entries of plants, amphibians, reptiles, or mammals at risk (in Canada or Quebec) within the National Wildlife Area.
|Common and scientific names of the species
Committee on the Status of Endangered Wildlife in Canada (COSEWIC)k
Falco peregrinus anatum/tundrius
|Special concernn||Special concernn||Vulnerableo
|Special concern||Special concern||Vulnerable|
Calidris canutus rufa
j Loi sur les espèces en péril du Canada (Registre public des espèces en péril, 2014)
k Comité sur la situation des espèces en péril au Canada (COSEPAC, 2014)
l Loi sur les espèces menacées ou vulnérables du Québec (Ministère du Développement durable, de l’Environnement et de la Lutte contre les changements climatiques [MDDELCC], 2014)
m Espèce susceptible d’être désignée menacée ou vulnérable au Québec (MDDELCC, 2014)
n Statut attribué aux deux sous-espèces anatum/tundrius confondues (F. peregrinus anatum/tundrius)
o Statut attribué à la sous-espèce anatum
p Sous-espèce tundrius
2.4 Invasive species
No complete study on invasive species has been conducted in the National Wildlife Area. However, Morisset’s work (2010a, b, c in Bédard, 2010) highlighted the significance of exotic plants (referred to as introduced plants by the author) in open environments on three of the National Wildlife Area’s islands: Île Blanche, Île aux Fraises and Le Pot du Phare (one of the Brandypot Islands). On the first two islands, 35% of the flora is made up of exotic species while 25% of the species on the Brandypot Islands are exotic.
On Île Blanche, one of these plants, the Reed Canary Grass (Phalaris arundinacea) invaded the entire surface of the island to the extent that it made up almost the entire herbaceous layer. This plant was sown in 1985 and 1986 on the entire island, except for the coastal belt, during work carried out after the avian cholera epidemic to encourage nesting of the Common Eider (J.-F. Giroux, pers. comm. in Morisset, 2010). The Canada Reedgrass (Calamagrostis canadensis), a native grass species which would be expected to occur here, has not even been observed, possibly owing to the introduction and expansion of the Reed Canary Grass.
On Île aux Fraises, the Purple Loosestrife (Lythrum salicaria), an exotic plant considered to be invasive, was found in a single location (a single individual observed south of the western cove); other introduced species such as the Common Timothy (Phleum pratense) and the Canada Thistle (Cirsium arvense) are distributed throughout the island but are not considered invasive (Morisset, 2010 in Bédard, 2010). On this same island, invasive exotic species like the Wild Radish (Raphanus raphanistrum) and the Smooth Bedstraw (Galium mollugo) often cover a considerable area. In places, the radish invades the entire area normally occupied by Sea Lymegrass (Elymus arenarius) or forms a band up to three metres wide in the zone of typical coastal shoreline plants, such as the Beach Pea (Lathyrus japonicus). It seems that this island was used during the early and mid-20th century by farmers from Saint-Siméon who came to graze their livestock. This could explain, in part, the presence of certain exotic species (Bédard, 2010).
On Île aux Lièvres, close to the National Wildlife Area, small colonies of the Purple Loosestrife and the European Reed (Phragmites australis, exotic) have been observed on some shorelines (Canadian Wildlife Service, 2003).
Report a problem or mistake on this page
- Date modified: