This ecoregion includes lowland areas of New York and Vermont surrounding the Adirondacks, portions of Quebec along the St. Lawrence River, and much of southern Ontario between Lake Ontario and Lake Huron/Georgian Bay. Suburban development and pollution of the St. Lawrence have severely harmed natural areas here, and less than 5 percent of the ecoregion remains as intact habitat.
This ecoregion is characterized by warm summers and cold, snowy winters that are milder to the south. In the Canadian portion of the ecoregion, the climate ranges from humid mid cool temperate in the south to humid high cool temperate in the northeast. The mean annual temperature ranges from 4.5°C to 6°C, mean summer temperature is approximately 16°C, and the mean winter temperature ranges from -4.5°C to -7°C. Mean annual precipitation ranges from 700-1,000 millimeters (mm). Areas to the lee of the Great Lakes, both in the United States and Canada, lie in major snowbelt areas.
The Eastern Great Lakes lowland forests lie between the boreal forests and the broadleaf deciduous zones and are therefore transitional. Part of these forests consist of a few coniferous species (mainly eastern hemlock (Tsuga canadensis) and pine (Pinus spp.) and a few deciduous species, mainly yellow birch (Betula alleghaniensis), sugar maple (Acer saccharum), red maple (Acer rubrum), red oak (Quercus rubra), eastern hemlock, and American beech (Fagus grandifolia); the rest is a mosaic of pure deciduous stands in favorable habitats with good soils, and pure coniferous forests in less favorable habitats with poorer soils. In the northeast, beech is restricted to warmer sites. Drier sites contain red oak and red (Pinus resinosa) and white pine (P. strobus), as well as eastern white cedar (Thuja occidentalis). Moist sites are dominated by red maple, elms (Ulmus spp.) eastern cottonwood (Populus deltoides), and ashes (Fraxinus spp.). Eastern white cedar occurs in wet depressions and near streams. Early successional species include white pine, quaking aspen (Populus tremuloides) and paper birch (B. papyrifera). Pine trees are often the pioneer woody species that flourish in burned-over areas or on abandoned arable land. Fires started by lightning are common in this ecoregion, particularly where soils are sandy and there is a layer of dry litter in summer.
The St. Lawrence Lowlands are underlain by carbonate-rich Palaeozoic bedrock. The landscape is a mix of bedrock outcrops and deeper marine and lacustrine clay deposits. The southern region is divided by the Niagara Escarpment, which extends northeast to Manitoulin Island. The area to the west of the escarpment slopes to the southwest in rolling topography, and the area to the east of the escarpment rises from Lake Ontario north to Georgian Bay. Consequently, most of this ecoregion has low relief. Lakes, poorly drained depressions, morainic hills, drumlins, eskers, outwash plains, and other glacial features are typical of the area, which was entirely covered by glaciers during parts of the Pleistocene. The greatly varying soils include peat, muck, marl, clay, silt, sand, and gravel.
This ecoregion contains numerous rare ecological or evolutionary phenomena. Pronounced is the mosaic of freshwater marshes and dunes, bogs, and fens, hardwood and conifer swamps as well as the rare and unique alvar communities (also called pavement barrens) restricted primarily to this ecoregion in North America. These alvar communities support a suite of prairie species that reach the eastern edge of their range here. These alvar communities are the most extensive in the world, and represent a habitat type that is globally endangered. Elsewhere in the world, such communities are known to occur only on islands in the Baltic Sea of Sweden and in Estonia. Other rare phenomena include ancient eastern white cedar trees growing on the exposed limestone cliffs of the Niagara escarpment. Some trees have been aged at 700 to 800 years, making them among some of the oldest in eastern North America. The St. Lawrence lowlands of Quebec are the most northeastern distribution of many plant species, and the fresh tidal wetlands along the St. Lawrence are high in species endemism. The Eastern Great Lakes lowland forests are a moderately rich example of temperate broadleaf and mixed forests. The mosaic of forest types and habitats supports 225 bird species, making these forests the second richest ecoregion within this major habitat type, and among the 20 richest ecoregions in the continental United States and Canada.
Many large mammals, such as black bear (Ursus americanus), moose (Alces alces), and wolf (Canis lupus) have been extirpated from much of this region. White-tailed deer (Odocoileus virginianus), coyote (Canis latrans), snowshoe hare (Lepus americanus), chipmunk (Tamias striatus), red (Tamiasciurus hudsonicus) and eastern gray squirrel (Sciurus carolinensis) represent a few of the more common species. Some characteristic breeding birds include northern cardinal (Cardinalis cardinalis), green-backed heron (Butorides virescens), mourning dove (Zenaida macroura), eastern screech owl (Otus asio), wood thrush (Hylocichla mustelina), pileated woodpecker (Dryocopus pileatus), wood (Aix sponsa) and American black duck (Anas rubripes).
Over 95 percent of the habitat in this ecoregion has been lost to suburban development and pollution of the St. Lawrence. Much of the remaining habitat consists of wetlands or abandoned farmlands undergoing reforestation. In some locations, recovery of abandoned agricultural land is beginning to occur, but these lands remain unprotected. Other areas continue to be converted to agriculture or are succumbing to widespread urban sprawl throughout this ecoregion.
Remaining Blocks of Intact Habitat
This ecoregion contains no blocks of intact habitat more than 250 square kilometers (km2) in area. Important blocks include:
- Bald Mountain - Vermont - 4 km2
- The Diameter - South Basin - New York
- Missisquoi National Wildlife Refuge - Vermont
- Split Rock - New York
- Chaumont Barrens; 6.5 km2 (1600 acres) of alvar in Northern New York
- Bruce Peninsula - south-central Ontario, between Georgian Bay and Lake Huron
- Alfred Bog - eastern Ontario
- Luther Marsh - south-central Ontario
- Ganaraska Forest - south-central Ontario
- Carden Plain - south-central Ontario - 200 km2
- Mont St. Hilaire - southern Quebec - 11 km2
- Lac St. Francois National Wildlife Area - southern Quebec - 13.47 km2
- Cap Tourmente National Wildlife Area - eastern Quebec - 24 km2
Degree of Fragmentation
The Eastern Great Lakes lowland forests are highly fragmented, with effectively no connectivity in most areas and little core habitat due to edge effects. The individual fragments and clusters that remain are highly isolated, and the intervening urban and suburban landscape precludes dispersal for most taxa.
Degree of Protection
None of the protected areas in this ecoregion exceed 250 km2. Important areas include:
- Split Rock (New York State) and Coon Mountain (Adirondack Land Trust)
- Eastern Lake Ontario. A network of reserves here protect dunes, marshes, and fens.
- Rome Sand Plains, 12 km2 (3000 acres) of upland and wetland pitch pine communities
- Albany Pine Barrens, a good example of pitch pine, scrub oak woodland containing occurrences of Karner Blue butterfly.
- Missisquoi National Wildlife Refuge - Vermont. This site protects ecologically important marshland, floodplain forests, and a large pitch pine bog - 22 km2
- Bald Mountain, Vermont/South Bay, New York. The upland dry forests of this reserve are regionally important for their unusual plant communities.
- Bruce Peninsula National Park - south central Ontario: 266.3 km2
- Cabot Head Provincial Nature Park - Ontario: 45.14 km2
- Awenda Provincial Natural Environment Park: 29.17 km2
- Oka Provincial Park - southern Quebec: 23.7 km2
- Rouge Valley Provincial Park Reserve - southern Ontario: 22 km2
- Wasaga Beach Provincial Recreation Park - Ontario: 15.29 km2
- Sandbanks Provincial Natural Environment Park - Ontario: 15.09 km2
- Carillon Provincial Recreation Park - Ontario: 14.65 km2
- Murphy’s Point Provincial Natural Environment Park - Ontario: 12.4 km2
- MacGregor Point Provincial Natural Environment Park - Ontario: 12.04 km2
- Mont St. Hilaire Nature Reserve - McGill University - southern Quebec: 11 km2
- Indian Point Provincial Natural Environment Park - Ontario: 9.47 km2
- Presqu’ile Provincial Park - southeastern Ontario: 9.37 km2
- Charleston Lake Provincial Natural Environment Park - Ontario: 9.02 km2
- Iles de Boucherville Provincial Park - southern Quebec: 8.20 km2
- St. Lawrene Islands National Park - eastern Ontario: 5.90 km2
- Mont-St-Bruno Provincial Park - Quebec - 5.90 km2
Types and Severity of Threats
Development, particularly construction of summer homes and suburbanization, pose the greatest conversion threat to the Eastern Great Lakes lowland forests. Montreal (population greater than 2 million), Ottawa (population greater than 700,000), and Quebec City (population greater than 700,000) are some of the larger urban centers. Suburbs of other urban centers such as Toronto, Ontario, Syracuse, and Albany, New York spill out into this region as well, despite their city centers being in adjacent ecoregions. Widespread farming occurs on much of the rest of the landscape (along with smaller manufacturing centers). Principal crops are corn, grains, soybeans, and apple orchards.
Degradation due to pollution, however, is a more serious concern. The St. Lawrence is one of the most polluted waterways in North America, with high levels of mirex, PCBs, DDT, and its derivatives. In spite of this, the area still supports a diversity of faunal populations including breeding populations of common and black terns, caspian terns, and least and American bittern. The shoreline of Lake Ontario and the St. Lawrence is important migratory bird habitat including land birds, shore birds, and waterfowl.
Suite of Priority Activities to Enhance Biodiversity Conservation
- Connect Split Rock in New York and Coon Mountain (Adirondack Land Trust), both of which were recently acquired.
- Protect South Bay area in New York
- Acquire North and South Bouquet Mountains in Essex Country, New York, which contain valuable wildlife habitats with wetlands, more than 200 species of nesting birds, diverse plant communities, and black bear habitat on the west side of Lake Champlain in Adirondack State Park.
- Complete acquisition of Alfred Bog in Ontario, to ensure protection of the area’s moose population.
- Protect alvar sites in New York and Ontario.
- Protect the Albany Pine Barrens through land conservation and improved land management.
- Ensure representation of viable examples of all landscapes, natural community types, and native species in conservation areas throughout the ecoregion
- Restoration and conservation of woodlots - ecoregion wide
- Protect Mont Rigaud - Quebec
- Protect Minising Swamp & Grenoch Swamp - Ontario
- Greater protection and enforcement of the entire Niagara Escarpment - Ontario
- Increase protection for the Oak Ridges Moraine - Ontario
- Wetlands - no further net loss - several important sites exist between Drummondville and Quebec City.
- Protect the Carden Plain - Ontario
- Adirondack Council
- Association pour la Protection de l'Environnement de Rigaud (APER)
- Bereton Field Naturalists’ Club
- Bouquet River Association
- Canadian Parks and Wilderness Society, Ottawa Valley Chapter
- Durham Region Field Naturalists
- Federation of Ontario Naturalists
- Federation of Ontario Naturalists
- Great Lakes Program, The Nature Conservancy
- Le Centre de Donnees sur le Patrimoine
- McIlwraith Field Naturalists of London
- Ministere de l’Environnement
- Natural Heritage Information Centre
- Nature Action
- The Nature Conservancy of Canada
- The Nature Conservancy of New York, Central and Western NY Chapter
- The Nature Conservancy of New York, Eastern New York Chapter
- The Nature Conservancy of Vermont
- The Nature Conservancy, Adirondacks
- The Nature Conservancy, QuebecNaturel du Quebec
- New York Natural Heritage Program
- Orillia Naturalists’ Club
- Presqu’ile-Brighton Naturalists
- Quinte Field Naturalists
- Regroupement National des Conseils Régionaux de l'Environnement du Québec (RNCREQ)
- Residents Committee to Protect the Adirondacks
- Rideau Valley Field Naturalists
- Sierra Club, Northeast Regional Office
- Strategies Saint-Laurent
- Thousand Islands Land Trust
- UQCN - Union Québecoise pour la Conservation de la Nature
- Vermont Nongame & Natural Heritage Program
- Wild Earth
- The Wildlands League
- World Wildlife Fund Canada, Quebec Region
Relationship to Other Classification Schemes
The Eastern Great Lakes lowland forests'ecoregion represents a subdivision of Bailey’s Laurentian Mixed Forest Province. This ecoregion extends Omernik’s Erie/Ontario Lake Plain to the north and west of Lake Ontario. The forests north of the lake are distinct from those along the lake’s southern edge so we chose to classify all forests south of Lake Ontario as part of a single ecoregion, the Southern Great Lakes forests.
In Canada, the Eastern Great Lakes lowland forests are distributed through east-central Ontario and southern Quebec. This region encompasses the St. Lawrence Lowlands, the Frontenac Axis, and the Manitoulin-Lake Simcoe area (TEC 132, 133, and 134). This ecoregion includes a part of the Niagara section of the Deciduous forest region 1, and Great Lakes-St. Lawrence regions 1-3 and 4c: Huron-Ontario, Upper St. Lawrence, Middle St. Lawrence, and Middle Ottawa.
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