A biome is the entirety of all the environmental conditions (temperature, humidity, pressure, topography etc.) found in a geographic area, that allow the survival of a particular biota, or set of organisms.
Classification of biomesMost biome classifications are more focused on land biomes, which are better understood than aquatic (and especially oceanic) ones.
The chart created in 1947 by the botanist Leslie Holdridge is based on three factors: biotemperature (the average of the monthly temperatures, where all the temperatures lower than freezing are brought to 0°C); precipitations (measured in mm per year) and the potential evapotranspiration ratio (the ratio between the amount of water lost through transpiration and precipitations).
|<50 cm/y||50-100 cm/y||100-250 cm/y||250-350 cm/y|
|< -5 °C||Tundra|
|-5 - 5°C||Grassland||Taiga (boreal forest)|
|5-20 °C||Steppe||Scrubland||Deciduous for.||Temp. rainforest|
|20-30 °C||Desert||Savannah||Monsoon for.||Tropic. rainforest|
Whittaker's classification (1975) considers the yearly temperature average in °C and average precipitations in cm per year (see on the right).
Lakes and swamps
- Primary productivity:
- Biomass production:
- Example species:
See main article: Rainforest