Boundaries

This ecoregion stretches from Delaware in the United States to the Gaspé Peninsula of Quebec and New Brunswick in Canada.

Topography

This ecoregion lies within the ancient, eroded Appalachian Mountains. Glaciers shaped these mountains, forming plateaus, granite outcrops, and river valleys. In the Gaspé Peninsula peaks reach above 1000 m, whereas the New Brunswick Highlands range from 200-500 m above sea level. To the east are lowlands of sandstone and shale, with small bedrock outcrops forming hills. Southern New Brunswick is characterized by rolling terrain with stony till plains.

Freshwater habitats

The St. John River originates in the forests of Maine and slowly loops into New Brunswick where it flows through the St. John River valley. It drains into the Bay of Fundy where strong tides push back the river and create the famous Reversing Falls. The St. Croix River and the Upper Restigouche River are classified as Canadian Heritage Rivers. The St. Croix River consists of a widespread system of lakes around its headwaters, and extensive wetlands downstream. The Restigouche River is a gently meandering river with floodplains, terraces, islands, rock outcrops, and deep pools.

Terrestrial habitats

This ecoregion is a good example of temperate broadleaf and mixed forests, and is a transition zone between boreal spruce-fir forest to the north and deciduous forest to the south. The Atlantic Ocean strongly influences vegetation, especially in coastal areas. Tundra meadows occur on a few mountain peaks in the Christmas Mountains in New Brunswick. Low mountain slopes support a mixed forest of red spruce (Picea rubens), white spruce (P. glauca), balsam fir (Abies balsamea), red pine (Pinus resinosa), sugar maple (Acer saccharum), American beech (Fagus grandifolia), and yellow birch (Betula allegheniensis). Eastern hemlock (Tsuga canadensis) and eastern white pine (P. strobus) are also present. Along the east coast within the Gulf of St. Lawrence Lowland Forests terrestrial ecoregion, warm summers give rise to hardwood forests of sugar maple, yellow birch, and American beech. Eastern hemlock, balsam fir, and white pine (P. strobus) are also common in the lowlands. 

Description of endemic fishes

An endemic dwarf smelt (Osmerus spp.) in Lake Utopia, New Brunswick has been identified, but not formally described.

Other noteworthy fishes

Some landlocked freshwater populations of the primarily marine tomcod (Microgadus tomcod) are found in this ecoregion.

Ecological phenomena

Many species in this ecoregion exhibit diadromy including lampreys (Lampetra spp.), sturgeons (Acipenser spp.), shads (Alosa spp.), smelts (Osmeridae), American eel (Anguilla rostrata), Atlantic salmon (Salmo salar), and temperate basses (Morone spp.).

Justification for delineation

The ecoregions of Canada were identified based on the faunal similarity of 166 major watersheds based on a cluster analysis of freshwater fish occurrences in these watersheds. The extent of the Northeast US and Southeast Canada Atlantic Drainages ecoregion was determined by including fish occurrence data for watersheds in contiguous watersheds of the northeast United States. The North Atlantic Ecoregion is comprised of watersheds that flow into Gulf of St. Lawrence and the Bay of Fundy in Canada, and directly into the Atlantic Ocean in the United States. The fish fauna of this ecoregion is largely comprised of species originating in the Atlantic Coastal refugium, which was less speciose than the Mississippian refugium. As a result, the fauna is depauparate relative to the faunas of central Canada, and is dominated by saltwater-tolerant freshwater fishes.

Level of taxonomic exploration

Fair