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Dundas Valley and Dundas Marsh (ON005)

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Dundas Valley and Dundas Marsh (ON005)

Dundas, Ontario

Latitude 43,252°N
Longitude 79,971°O
Altitude 75 - 475m
Superficie 94,30km²

Description du site

The Dundas Valley is an extensive natural area located in southern Ontario along the Niagara Escarpment. Immediately to the east is the town of Dundas and Dundas Marsh (also called Cootes Paradise). The Spring Creek valley forms a narrow, natural corridor joining Dundas Valley to Dundas Marsh. Most of the Dundas Valley area is comprised of relatively undisturbed deciduous and mixed upland forest. The topography is quite varied, being comprised of rolling hills, deeply incised stream courses, and steep valley walls, with local relief of 30 metres or more being common. Dundas Marsh is located at the western end of Hamilton Harbour, and is a shallow flooded basin of open water and marsh joined to Hamilton Harbour by the Desjardins Canal. The shallow open water pond is dominated by water lilies and Sago Pondweed while the shoreline is dominated by cattail and Manna Grass. The surrounding terrain consists of rolling hills and ravines, covered woods and successional communities.

Also included in the site are Spencer Creek Gorge and Tiffany Falls. The flora and fauna of the valley and marsh have been well studied with an exceptional concentration of significant flora and fauna being present. Over 580 species of vascular plants have been recorded for the valley (17 nationally and/or provincially rare), and over 800 species for the marsh (25 of which are nationally rare).

Oiseaux

The Dundas Valley contains a nationally significant community of forest birds. Breeding evidence for at least five nationally vulnerable, threatened or endangered species has been recorded. Two of these threatened species are regularly present in nationally significant numbers (i.e., greater than 1% of their national population). These species are the Hooded Warbler (two to four pairs annually), and Louisiana Waterthrush (two to four pairs annually). Cerulean Warbler (nationally vulnerable) is also present within the valley, but not in nationally significant numbers. Yellow-breasted Chat (nationally vulnerable) and Acadian Flycatcher (nationally endangered) have also been recorded within the valley, but only on an irregular basis.

During recent years, about 100 species of breeding birds have been recorded within the valley (one of the more species rich areas in southern Ontario). A relatively large proportion of these are neotropical migrants, of which the more abundant species are Red-eyed Vireo, Wood Thrush, Eastern Wood-Peewee, Ovenbird, and Scarlet Tanager. Of additional ornithological interest is the presence of both hybrids of Blue-winged and Golden-winged Warblers.

Dundas Marsh is an important area for migrating waterfowl, shorebirds, herons, raptors, gulls, terns, and songbirds. There is confirmed breeding evidence for three species at risk in Canada: Least Bittern (vulnerable), Cerulean Warbler (vulnerable) and Prothonotary Warbler (endangered), the latter having nested annually for the last five or so years, and has nested here regularly, but not annually, since at least the 1950s. In addition, Yellow-breasted Chat (vulnerable) possibly bred in 1974, as might a pair of King Rails (endangered) in the 1960s. Other breeding species include Double-crested Cormorant (121 nests in 1997), Blue-winged Teal, Common Moorhen, Yellow-billed Cuckoo, Whip-poor-will, Eastern Bluebird, Tufted Titmouse, Carolina Wren, Black-throated Green Warbler and Orchard Oriole.

Enjeux de conservation

The significance of the Dundas Valley (and/or various portions of it) has been recognized through a variety of programs or designations. At the municipal level, it is identified as an Environmentally Sensitive Area in the Hamilton-Wentworth Regional Official Plan; at the provincial level, it is identified as both a Life Science and Earth Science Area of Natural and Scientific Interest, and also as part of the Niagara Escarpment Planning Area; and at the international level it is recognized as part of the Niagara Escarpment World Biosphere Site, and was examined under the International Biological Programme (IBP).

Even with the recognition provided by these programs, the breeding bird community within the valley is under considerable and increasing pressure. The valley is located on the northwest edge of Dundas-Ancaster-Hamilton urban area, and as such is experiencing sustained pressure from development and other land uses. All of the nationally significant bird species present at this site, as well as many of the other neotropical migrants, are susceptible to development related pressures, especially increases in habitat- generalist nest predators such as squirrels, raccoons, opossums, skunks and cats. From a landscape perspective, the valley has more extensive forests and more forest interior than most areas in southwestern Ontario and is relatively well connected to surrounding natural areas by naturally-vegetated corridors.

The aquatic and wetland systems of Dundas Marsh have been adversely impacted by the cumulative effects of off-site manmade changes such as the moderation of fluctuations in the water level in Lake Ontario and increased sedimentation and poor water quality due to rapid urbanization of upstream areas. The extent and quality of the aquatic and wetland vegetation in this area has undergone a dramatic decline during this century, due to excessive sedimentation, excessive turbidity, the spread of non-native species, and feeding and spawning activities by carp (a fish-way has been built to help control the carp, however, and thus restore the native vegetation). Most of the area is public-owned as part of the Royal Botanical Gardens and is managed as a wildlife reserve and conservation education centre.

Catégories ZICO Habitats Usages Menaces Potencielles ou Existantes Status de Protection
Harle huppé
Nombre Année Saison
10 5402011Automne
9 9652009Automne
Fuligule milouinan
Nombre Année Saison
4 874 - 4 8752010Hiver
14 580 - 14 5842009Hiver
7 1942005Hiver
10 8612004Hiver
11 4012003Hiver
13 1312002Hiver
7 1472001Hiver
5 8862000Hiver
17 5561999Hiver
6 256 - 10 0001998Hiver
9 3701997Hiver
10 6001995Hiver
5 0001993Hiver
Quiscale rouilleux
Nombre Année Saison
23 - 442011Automne
27 - 722009Automne
50 - 602007Automne
1992006Automne
252004Automne
9302003Automne
392002Automne
4772001Automne
30 - 1251999Automne
621997Automne
51 - 2001996Automne
601994Automne
401992Automne
251991Automne
Harelde kakawi
Nombre Année Saison
21 954 - 22 0002011Hiver
9 0242009Hiver
24 3042005Hiver
8 8122003Hiver
17 3692002Hiver
10 5002001Hiver
12 8551999Hiver
Mouette pygmée
Nombre Année Saison
42010Printemps
22006Automne
22001Printemps
21993Printemps
41990Printemps
Goéland argenté
Nombre Année Saison
3 6652008Hiver
4 2681990Hiver
Cygne siffleur
Nombre Année Saison
2 0002013Printemps
Garrot à oeil d'or
Nombre Année Saison
10 4561997Hiver
Martinet ramoneur
Nombre Année Saison
352017Automne
472016Automne
402016Été
29 - 302016Printemps
302015Automne
24 - 272015Été
492015Printemps
25 - 522014Printemps
252013Printemps
502011Printemps
33 - 602010Automne
50 - 1002009Printemps
502008Printemps
30 - 752007Automne
352005Automne
252004Automne
452003Automne
25 - 3002001Automne
23 - 1801998Automne
25 - 431997Automne
1001997Printemps
117 - 2001996Automne
251995Automne
2001993Automne
251991Automne
301990Automne
Paruline orangée
Nombre Année Saison
12009Printemps
12008Printemps
1 - 22007Printemps
12006Automne
12006Printemps
12005Automne
12005Printemps
22004Été
12004Printemps
2 - 52003Été
12001Automne
12001Été
12001Printemps
52000Été
1 - 21999Printemps
1 - 81998Été
21998Printemps
1 - 21997Été
11997Printemps
11996Automne
1 - 31996Été
21994Printemps
11991Automne
11990Été
Ictérie polyglotte
Nombre Année Saison
1 - 22006Été
12005Été
12005Printemps
12002Printemps
12001Été
12000Printemps
?1995Été
11991Été
Paruline hochequeue
Nombre Année Saison
42017Été
1 - 21995Printemps
61995Été
Effraie des clochers
Nombre Année Saison
12006Automne
12006Été
12005Hiver
Moucherolle vert
Nombre Année Saison
12013Été
12001Été
11997Été
11994Été
11990Printemps
Pie-grièche migratrice
Nombre Année Saison
12017Printemps
11997Printemps