Biomes
Biomes are the major regional groupings of plants and animals discernible at a global scale. There are several factors which determine the distribution pattern of biomes across the world. These factors correlate strongly with regional climate patterns and are identified according to the climax vegetation type. A biome is not only composed of climax vegetation but also of associated successional communities, persistent subclimax communities, fauna and soils. A biome may be defined as a major region of distinctive plant and animal groups well adapted to the physical environment of its distribution area.
The worlds biomes have changed over history and more recently some have been dramatically altered by human activity. The importance of biomes cannot be over estimated and therefore it is essential that we look towards strategies for conservation and preservation. Biomes can be grouped into six major types:
1. The Freshwater Biome - defined as having a low concentration of salt, usually less than 1%. Plants and animals in these regions are adapted to these conditions. There are different types of freshwater biome: ponds and lakes, streams and rivers and wetlands.
2. The Marine Biome - covers 3/4 of the Earth's surface and includes oceans, coral reefs and estuaries. Marine algae supply much of the world's oxygen supply and take in huge amounts of atmospheric carbon dioxide.
3. The Desert Biome - deserts cover 1/5 of the Earth's surface and occur when rainfall is less than 50cm a year. Most deserts have a significant amount of specialised vegetation as well as specialised vertebrae and invertebrate. Desert biomes can be classified as hot and dry, semi-arid, coastal and cold.
4. The Forest Biome - occupy 1/3 of the Earth's world surface and account for 70% of the carbon present in living things. Forests are becoming a major casualty of civilisation today with an increase in demand for good and therefore extensive deforestation has occurred. There are three types of forest biome - temperate, tropical and boreal.
5. The Grassland Biome - defined as areas dominated by grasses rather than large shrubs or trees. There are two types of grassland: savanna and temperate.
6. The Tundra Biome - the tundra is the coldest of all the biomes. It is noted for its frost molded landscapes, extreme low temperatures, little precipitation, few nutrients and poor growing seasons. There are two types of tundra biome - alpine and arctic.