Biome

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A biome is not a geographic place so much as it is a major regional group of distinctive plants and animals, discernible at a global scale.

The Earth's biomes comprise the biosphere and are described by the study of ecology. The concept of the biome embraces the idea of community, of interaction among plant and animal populations, and soil. A biome (which is also called a biotic area) may be defined as a major region of distinctive plant and animal communities well adapted to the physical environment of its distribution area.

Major biomes can be defined thanks to the global distribution pattern. It is frequent that local names are given to a biome when related to a specific continent. For example, temperate grassland biome is locally known as steppe, pampa or veld depending on the continent. It is also defined by regional climate, in particular temperature and precipitations. Other aspects are soil characteristics, as well as other physical parameters which might influence the quality of the environment: it might be related to substrate condition (due to periodic flooding for example) or altitude. The biome is naturally defined by the type of vegetation found, vertical stratification, vegetation adaptation, or fauna.

Latitude zonation

Water and temperature are the two ecological factors which make it possible to define the climates. A good correlation exists between the distribution of climates with latitude, and the homogenous vegetation bands which are called the biomes.

This planetary distribution of large biomes might appear to be a simplification, but it is a meaningful scientific response an obvious climatic reality. It is common knowledge that biodiversity increases with latitude, moving away from the poles towards the equator, whether in terms of plant or animal species.

Animal and vegetative biomes' characteristics are related to their latitude and climate. Biomes are also identified according to the climax vegetation type; In fact, a biome is not only composed of the climax vegetation, but also of all the associated, subclimax, or degraded flora, fauna and soils.

Two types of biomes may be defined: 1. Terrestrial (also called continental) biomes and 2. Aquatic biomes.

The most widely used definition of biomes is related to latitude (or temperature zoning) and humidity :

Arctic or Subarctic area

• humid type : Tundra

Subarctic and Boreal area

• humid type: taiga or boreal forest

Temperate cold

• humid type : Temperate broadleaf and mixed forests, Temperate coniferous forests

Temperate warm or sub-tropical

• humid: subtropical moist broadleaf forest
• semi-humid: Subtropical dry broadleaf forests, Subtropical coniferous forests
• semi-arid: Mediterranean forests, woodlands, and shrub, Temperate grasslands, savannas, and shrublands
• Arid: Temperate deserts and xeric shrublands

Tropical

• humid area : Tropical forest or Rainforest
• Semi-arid area : Tropical Grasslands -- Tropical Savannas
• Arid area : Desert

Aquatic

• continental shelf
• littoral
• riparian
• pond
• lake
• coral reef
• pack ice
• hydrothermal vents
• cold seeps
• benthic zone
• pelagic zone

Altitude and latitude zonations

Another, different systm of classification takes into account, altitude and humidity, neglecting the temperature dependent factor.

This classification gives the following terrestrial biomes :

• Tundra (arctic, humid)
• Boreal forests/taiga (subarctic, humid)
• Temperate coniferous forests (temperate cold, humid)
• Temperate broadleaf and mixed forests (temperate, humid)
• Temperate grasslands, savannas, and shrublands (temperate, semi-arid)
• Mediterranean forests, woodlands, and shrub (temperate warm, humid)
• Tropical and subtropical coniferous forests
• Tropical and subtropical moist broadleaf forests
• Tropical and subtropical dry broadleaf forests
• Tropical and subtropical grasslands, savannas, and shrublands
• Deserts and xeric shrublands
• Mangrove
• Flooded grasslands and savannas
• Montane grasslands and shrublands (high altitude)

This classification is the one used to define the Global 200

The Endolithic biome, consisting entirely of microscopic life that lives inside pores and cracks in rock kilometers beneath the surface, has only recently been discovered and does not fit well into most classification schemes.

See also : Ecozone -- Ecotope

External Links

• info on the 14 biomes

ca:Bioma da:Biom de:Biom es:Bioma fr:Biome it:Bioma la:Biotopus pl:Biom pt:Bioma ru:Биом