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Ecoregions of North America, featuring the 50 United States, the District of Columbia and the five inhabited territories. The following is a list of ecoregions in the United States as identified by the World Wide Fund for Nature (WWF). The United States is a megadiverse country with a high level of endemism across a wide variety of ecosystems.
In comparison with other biomes, however, the taiga has low botanical diversity. Coniferous trees are the dominant plants of the taiga biome. Very few species, in four main genera, are found: the evergreen spruce, fir and pine, and the deciduous larch. In North America, one or two species of fir, and one or two species of spruce, are dominant.
Fire is the dominant type of disturbance in boreal North America, but the past 30-plus years have seen a gradual increase in fire frequency and severity as a result of warmer and drier conditions. From the 1960s to the 1990s, the annual area burned increased from an average of 1.4 to 3.1 million hectares per year.
The Tundra of North America is a Level I ecoregion of North America designated by the Commission for Environmental Cooperation (CEC) in its North American Environmental Atlas. One of the planet's most recent biomes , a result of the last ice age only 10,000 years ago, the tundra contains unique flora and fauna formed during the last glaciation ...
Canada's boreal forest is a vast region comprising about one third of the circumpolar boreal forest that rings the Northern Hemisphere, mostly north of the 50th parallel. [1] Other countries with boreal forest include Russia , which contains the majority; the United States in its northernmost state of Alaska ; and the Scandinavian or Northern ...
The tropical wet forests of North America have an average year-round temperature between 68 and 78.8 °F (26.0 °C). Thus, frost does not occur under these conditions. [2] The temperatures remain fairly uniform throughout the year; therefore there is not a change of seasons. There is also no dry season, as all months experience precipitation.
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There are common patterns of hydrological cycles throughout the North American Deserts, but specifics of times and source of water range. All four deserts rely on rivers, precipitation, and underground aquifers to replenish their water supply. [8] The water in the North American desert is mainly freshwater.