A biome (of the Greek bios = life), also called biotic surface, écozone or écorégion, is a whole of ecosystem S characteristic of a surface biogeographic and named starting from the Végétation and of the species Animal be which prevail there and are adapted there. It is the expression of the ecological conditions of the place to the regional scales or continental: the climate which induces the ground, both inducing themselves the ecological conditions which the communities of the plants and the animals of the biome in question will answer.

The terrestrial biomes are described by the science of the Biogéographie. The ecological Classification of the grounds definite the vocabulary used to evaluate the size of these zones of the Microphone-habitat to the Biosphere. Their concept embraces the concepts of community, of interaction between grounds, plants and animals.

Delimitations

On a sphere scale, the dense tropical forest, savanna, the steppe, the moderate décidue or mixed forest, the tundra is large the biomes characterizing the biosphere, which have a zonal distribution, i.e. they do not exceed certain athwartship values.

On a continental or regional scale, they can be complex to delimit, on the one hand because various practices of name exist, and on the other hand because their borders can be fuzzy (see the concept of écotone). In addition, same a biome can be named in a variable way according to the continent on which it is. For example, the biome “meadows moderate” is locally known under the names of Steppe , Pampa or Veld according to its localization.

Characteristics

The biome is basically characterized by its Climat, in particular Température S and precipitations. It is besides the zonal distribution of the climates which resulted in highlighting the zonation of the ground at the end of the XIXe century, then biomes. Other physical parameters can intervene, like a particular altitude or a periodically submerged ground for example.

Indeed, water and the temperatures whose distribution on a sphere scale is largely conditioned by the rotation of the ground on its axis, are two fundamental factors of determination of a climate. They present, on a total and continental scale, of the variations according to the Latitude. This distribution is consequently correlated with homogeneous bands of vegetation. These athwartship bands (observed initially by Dokoutchaev, father of Russian pedology), are called zones (of the Greek Zonê which wants to say girdles) and gave rise to the concept of Zonalité, fundamental in geography of the natural environments. Thus for example, the Biodiversité is increasing since the poles to the equator, whether it is from an animal or vegetable point of view. The dense Equatorial forest is the richest biome and most various.

Two types of biomes

According to WWF, there would exist two great types of biomes, the terrestrial and watery biomes. If there exist watery biomes, they answer much less the criteria of the zonality because of the vast marine currents which traverse the oceans on all the levels of depth. They are more difficult to define in space, in particular for these seamen circles. In the meaning of the " biome" such as defines above, the study of the aquatic environments would concern rather the Océanographie, or the Limnologie. Indeed, for questions of scale, a delta and an marine ecosystem marked by the presence of upwellings seem rather not very comparable. Or then that amounts comparing biomes and natural environments to all the scales, which biogeography or ecology does not make.

Biomes terrestrial

  • Arctic and Subarctiques
    • Tundra (Arctic, wet) 37 écorégions
    • Taïga (subarctic, wet) or northern forest of conifers - 28 Moderate écorégions
    • moderate Forests conifériennes (moderate cold, wet) - 52 or 53 écorégions
    • caducifoliées and mixed moderate Forests (moderate, wet) - 84 écorégions
    • Meadows, savannas and undergrowth moderate (moderate, semi-arid) - 45 écorégions
    • Forests, wood and undergrowth Mediterranean (moderate heat, wet) or sclerophyllous forest - 39 to 50 Tropical and subtropical écorégions
    • Tropical forests and subtropical conifériennes - 17 écorégions
    • Tropical forests and subtropical wet caducifoliées or ombrophilous forest - 231 écorégions
    • caducifoliées dry Tropical forests and subtropical or tropophilous forest - 59 écorégions
    • Meadows, savannas and undergrowth tropical and subtropical (semi-arid) - 49 écorégions
    • Mangrove (tropical - flooded) - 50 écorégions
    • Meadows and flooded savannas (tropical) - 26 Azonal écorégions

Biomes watery

  • Of fresh water
  • Of sea water
    • Polar Mediums (of which Ice-barrier)
    • continental Shelves and inland seas
    • Gone up moderate water or moderate Upwelling
    • Gone up tropical water or tropical Upwelling
    • coral Reefs

See too

Internal bonds

External bonds

  • Infos on the 26 large biomes.
  • 200 '' large '' écorégions
  • World Biomes

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