Néarctique

The nearctic is one of the eight écozone terrestrial S or biogeographic areas. It is sometimes gathered with the Paléarctique and then forms the Holarctique. It covers the essence of the North America, and includes the Greenland and the northern part of the Mexico. The parts more in the south of Mexico and Florida, the Central America and the Caribbean Islands belong to the écozone Néotropique, with the remainder of South America.

Climatic and geological characteristics

Although North America and that of the South are now joined together by the Isthme of Panama, these continents were separate one of the other during tens of million years, and their fauna and flora evolved/moved independently one of the other. When the old one supercontinent, the Pangée, separated into two, 200 million years ago, the ancestor of North America was connected to the Eurasia, and formed the Laurasia, whereas the part become South America belonged to the Gondwana. North America then separated from Eurasia and of the bridges were formed with Asia and South America, which authorized exchanges of animal and vegetable Espèce S between the two continents.

The Bering Strait allowed the passage of many species between the Asia and North America; thus, the néarctique one divides it many plants and animal species with the Paléarctique. These two écozones are often joined together and called écozone Holarctique .

The area extends from the sea level to 1.000 m of altitude. It especially consists of tropical forests and subtropical. The temperatures are of 20 °C with 26 °C on average during all the year. Average annual precipitations vary between 1.500 and 3.000 mm, although they can exceed 4.000 mm at certain places. The number of dry months is in general lower than three.

The néarctique one especially metamorphic (pre-cenozoic period) and is covered with a thin layer of Alluvion S. the plain of the Gulf of Mexico includes/understands many rivers. The peninsula of the Yucatán watch rather a ic relief Karst.

Biological history

Many great animalist species (Mégafaune) are extinct in North America at the end of the time Pléistocène, among which the Cheval, the Chameau, the Mammouth… That corresponds to the appearance of the man. One has a long time that the climate change was at the origin of this massive extinction. Many scientists allot today these disappearances above all to the hunting of the men (directly or by intermediary, by disappearance consequently causes preys of certain species), then only with the climate. The American bison, the brown bear or bears grizzly and the wapiti arrived to North America more or less at the same moment that the first human ones, and quickly extended, by filling the “holes” left in the ecosystem following the recent extinction of the mégafaune of North America.

A family of birds, breadcrumbs Timaliinae , is endemic with the Néarctique area.

Among the animals being at the origin single in Néarctique:

the family Canidae , Dog S, wolves, Fox S, and Coyote S
the family Camelidae , Camel X, their cousins of South America of which the LAMA.
the family Equidae , horses and related
the family Antilocapridae , Antilope and related
the black bears
the cheetah ( Acinonyx jubatus ) evolved/moved in Néarctique, before extending on all Eurasia.

Écorégions terrestrial nearctic

Flora of Néarctique

Plants with seeds by scientific name
Plants with spores by scientific name

External bonds

chart of the écozones

Simple: Nearctic Ecozone

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