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Revision as of 17:48, 23 September 2006 by Blobglob (talk | contribs) (rv blanking)(diff) ← Previous revision | Latest revision (diff) | Newer revision → (diff)In ecology, a biome is a major regional group of distinctive plant and animal communities best adapted to the region's physical natural environment, latitude, altitude, and terrain. A biome is made up of communities at stable steady state and all associated transitional, disturbed, or degraded, vegetation, fauna and soils, but can often be identified by the climax vegetation type.
A fundamental classification of biomes is into:
- Terrestrial (or continental) biomes and
- Aquatic biomes.
Biomes are often given local names. For example, a Temperate grassland or shrubland biome is known commonly as steppe in central Asia, savanna or veld in southern Africa, prairie in North America, pampa in South America and outback or scrub in Australia. Sometimes an entire biome may be targeted for protection, especially under an individual nation's Biodiversity Action Plan.
Latitude classification
Latitude is a major climate-influencing factor determining biomes. There is a good correlation between the distribution of climates with latitude, and homogeneous vegetation bands. Another major factor is humidity. This can be illustrated by the fact that biodiversity increases away from the poles towards the equator, and increases with humidity. The most widely used classification 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
The Boreal Forest is the largest of all biomes. It is located in the northern hemishphere just south of the tundra.
Temperate cold
Tropical
- humid area: tropical moist broadleaf forest (tropical rainforest)
- semi-humid area: tropical dry broadleaf forest, tropical coniferous forest
- Semi-arid area: tropical grasslands, savannas, and shrublands
- Arid area: deserts and xeric shrublands; and Dry deciduous forests
Aquatic
Altitude and latitude classification
Another system of classification takes into account altitude and humidity, ignoring temperature as a factor. This classification is used to define the Global 200 list of ecoregions identified by the World Wildlife Fund (WWF) as priorities for conservation.
This classification gives the following terrestrial biomes :
- Tundra (arctic, humid)
- Boreal forests/taiga (subarctic, humid)
- Temperate coniferous forests (temperate cold, humid to semi-humid)
- Temperate broadleaf and mixed forests (temperate, humid)
- Temperate grasslands, savannas, and shrublands (temperate, semi-arid)
- Mediterranean forests, woodlands, and shrub (temperate warm, semi-humid to semi-arid with winter rainfall)
- Tropical and subtropical coniferous forests (tropical and subtropical, semi-humid)
- Tropical and subtropical moist broadleaf forests (tropical and subtropical, humid)
- Tropical and subtropical dry broadleaf forests (tropical and subtropical, semi-humid)
- Tropical and subtropical grasslands, savannas, and shrublands (tropical and subtropical, semi-arid)
- Deserts and xeric shrublands (temperate to tropical, arid)
- Mangrove (subtropical and tropical, salt and brackish water inundated)
- Flooded grasslands and savannas (temperate to tropical, fresh water inundated)
- Montane grasslands and shrublands (temperate to tropical, high altitude)
Other biomes
The Endolithic biome, consisting entirely of microscopic life in rock pores and cracks, kilometers beneath the surface, has only recently been discovered and does not fit well into most classification schemes.