- Holdridge 1.1
Whittaker's biome-type classification scheme 1.2
- Key definitions for understanding Whittaker's scheme 1.2.1
- Whittaker's parameters for classifying biome-types 1.2.2
- Walter system 1.3
- Bailey system 1.4
WWF system 1.5
- Freshwater biomes 1.5.1
- Realms or ecozones (terrestrial and freshwater, WWF) 1.5.2
Marine biomes 1.5.3
- Marine biomes (H) (major habitat types), Global 200 (WWF) 126.96.36.199
- Realms or ecozones (marine, WWF) 188.8.131.52
Other marine habitat types 184.108.40.206
- Major habitats, nonglobal 200 (WWF) 220.127.116.11.1
- Summary – ecological taxonomy (WWF) 1.5.4
Anthropogenic biomes 2
- Major anthropogenic biomes 2.1
Other biomes 3
- Map of biomes 3.1
- Freshwater biomes 3.2
- See also 4
- References 5
- External links 6
Biomes are defined by climate regimes and biogeography.
A 1978 study on North American grasslands found a positive logistic correlation between evapotranspiration in mm/yr and above-ground net primary production in g/m2/yr. The general results from the study were that precipitation and water use led to above-ground primary production, while solar irradiation and temperature lead to below-ground primary production (roots), and temperature and water lead to cool and warm season growth habit. These findings help explain the categories used in Holdridge’s bioclassification scheme (see below), which were then later simplified by Whittaker. The number of classification schemes and the variety of determinants used in those schemes, however, should be taken as strong indicators that biomes do not fit perfectly into the classification schemes created.
Holdridge classified climates based on the biological effects of temperature and rainfall on vegetation under the assumption that these two abiotic factors are the largest determinants of the types of vegetation found in a habitat. Holdridge uses the four axes to define 30 so-called "humidity provinces", which are clearly visible in his diagram. While this scheme largely ignores soil and sun exposure, Holdridge acknowledged that these were important.
Whittaker's biome-type classification scheme
Whittaker classified biomes using two abiotic factors: precipitation and temperature. His scheme can be seen as a simplification of Holdridge's; more readily accessible, but missing Holdridge's greater specificity.
Whittaker based his approach on theoretical assertions and empirical sampling. He was in a unique position to make such a holistic assertion because he had previously compiled a review of biome classifications.
Key definitions for understanding Whittaker's scheme
- The apparent characteristics, outward features, or appearance of ecological communities or species.
- A major kind of community of plants on a given continent.
- Grouping of convergent biomes or formations of different continents, defined by physiognomy.
- A grouping of convergent formations.
- Intertidal levels: The wetness gradient of areas that are exposed to alternating water and dryness with intensities that vary by location from high to low tide
- Climatic moisture gradient
- Temperature gradient by altitude
- Temperature gradient by latitude
- The gradient runs from favorable to extreme, with corresponding changes in productivity.
- Changes in physiognomic complexity vary with how favorable of an environment exists (decreasing community structure and reduction of stratal differentiation as the environment becomes less favorable).
- Trends in diversity of structure follow trends in species diversity; alpha and beta species diversities decrease from favorable to extreme environments.
- Each growth-form (i.e. grasses, shrubs, etc.) has its characteristic place of maximum importance along the ecoclines.
- The same growth forms may be dominant in similar environments in widely different parts of the world.
- Always moist
- Little temperature seasonality
- Evergreen tropical rain forest
- Summer rainy season and cooler “winter” dry season
- Seasonal forest, scrub, or savanna
- Highly seasonal, arid climate
- Desert vegetation with considerable exposed surface
- Winter rainy season and summer drought
- Sclerophyllous (drought-adapted), frost-sensitive shrublands and woodlands
V. Warm temperate
- Occasional frost, often with summer rainfall maximum
- Temperate evergreen forest, somewhat frost-sensitive
- Moderate climate with winter freezing
- Frost-resistant, deciduous, temperate forest
- Arid, with warm or hot summers and cold winters
- Grasslands and temperate deserts
- Cold temperate with cool summers and long winters
- Evergreen, frost-hardy, needle-leaved forest (taiga)
- Short, cool summers and long, cold winters
- Low, evergreen vegetation, without trees, growing over permanently frozen soils
- 100 Polar Domain
200 Humid Temperate Domain
- 210 Warm Continental Division (Köppen: portion of Dcb)
- M210 Warm Continental Division – Mountain Provinces
- 220 Hot Continental Division (Köppen: portion of Dca)
- M220 Hot Continental Division – Mountain Provinces
- 230 Subtropical Division (Köppen: portion of Cf)
- M230 Subtropical Division – Mountain Provinces
- 240 Marine Division (Köppen: Do)
- M240 Marine Division – Mountain Provinces
- 250 Prairie Division (Köppen: arid portions of Cf, Dca, Dcb)
- 260 Mediterranean Division (Köppen: Cs)
- M260 Mediterranean Division – Mountain Provinces
300 Dry Domain
- 310 Tropical/Subtropical Steppe Division
- M310 Tropical/Subtropical Steppe Division – Mountain Provinces
- 320 Tropical/Subtropical Desert Division
- 330 Temperate Steppe Division
- 340 Temperate Desert Division
400 Humid Tropical Domain
- 410 Savanna Division
- 420 Rainforest Division
- 01 Tropical and subtropical moist broadleaf forests (tropical and subtropical, humid)
- 02 Tropical and subtropical dry broadleaf forests (tropical and subtropical, semihumid)
- 03 Tropical and subtropical coniferous forests (tropical and subtropical, semihumid)
- 04 Temperate broadleaf and mixed forests (temperate, humid)
- 05 Temperate coniferous forests (temperate, humid to semihumid)
- 06 Boreal forests/taiga (subarctic, humid)
- 07 Tropical and subtropical grasslands, savannas, and shrublands (tropical and subtropical, semiarid)
- 08 Temperate grasslands, savannas, and shrublands (temperate, semiarid)
- 09 Flooded grasslands and savannas (temperate to tropical, fresh or brackish water inundated)
- 10 Montane grasslands and shrublands (alpine or montane climate)
- 11 Tundra (Arctic)
- 12 Mediterranean forests, woodlands, and scrub or sclerophyll forests (temperate warm, semihumid to semiarid with winter rainfall)
- 13 Deserts and xeric shrublands (temperate to tropical, arid)
- 14 Mangrove (subtropical and tropical, salt water inundated)
- Streams and rivers
- North temperate Atlantic
- Eastern tropical Atlantic
- Western tropical Atlantic
- South temperate Atlantic
- North temperate Indo-Pacific
- Central Indo-Pacific
- Eastern Indo-Pacific
- Western Indo-Pacific
- South temperate Indo-Pacific
- Southern Ocean
- Hydrothermal vents
- Cold seeps
- Benthic zone
- Pelagic zone (trades and westerlies)
- Hadal (ocean trench)
Biosphere (List of ecoregions)
- Ecozones or realms (8)
- Marine ecozones or realms (13)
- Endolithic biome
Ecozone: Palearctic ecozone
- Terrestrial biome: temperate broadleaf and mixed forests
- Ecozone: Palearctic ecozone
- Dense settlements
- The World's Biomes, Retrieved August 19, 2008, from University of California Museum of Paleontology
- Pomeroy, Lawrence R. and James J. Alberts, editors. Concepts of Ecosystem Ecology. New York: Springer-Verlag, 1988.
- Whittaker, Robert H., Botanical Review, Classification of Natural Communities, Vol. 28, No. 1 (Jan–Mar 1962), pp. 1–239.
- Whittaker, Robert H. Communities and Ecosystems. New York: MacMillan Publishing Company, Inc., 1975.
- http://www.fs.fed.us/land/ecosysmgmt/index.html Bailey System, US Forest Service
- Olson et al. (2001); Terrestrial Ecoregions of the World: A New Map of Life on Earth, BioScience, Vol. 51, No. 11., pp. 933–938.
- "Freshwater Ecoregions of the World: Major Habitat Types" . Accessed May 12, 2008.
- WWF: Marine Ecoregions of the World
- Biomes of the world (Missouri Botanic Garden)
- Global Currents and Terrestrial Biomes Map
- WorldBiomes.com is a site covering the 5 principal world biome types: aquatic, desert, forest, grasslands, and tundra.
- UWSP's online textbook The Physical Environment: – Earth Biomes
- Panda.org's Habitats – describes the 14 major terrestrial habitats, 7 major freshwater habitats, and 5 major marine habitats.
- Panda.org's Habitats Simplified – provides simplified explanations for 10 major terrestrial and aquatic habitat types.
- UCMP Berkeley's The World's Biomes – provides lists of characteristics for some biomes and measurements of climate statistics.
- Gale/Cengage has an excellent Biome Overview of terrestrial, aquatic, and man-made biomes with a particular focus on trees native to each, and has detailed descriptions of desert, rain forest, and wetland biomes.
- NASA's Earth Observatory Mission: Biomes gives an exemplar of each biome that is described in detail and provides scientific measurements of the climate statistics that define each biome.
- Phytochorion (flora region)
Whittaker's distinction between biome and formation can be simplified: formation is used when applied to plant communities only, while biome is used when concerned with both plants and animals. Whittaker's convention of biome-type or formation-type is simply a broader method to categorize similar communities.
Whittaker's parameters for classifying biome-types
Whittaker, seeing the need for a simpler way to express the relationship of community structure to the environment, used what he called "gradient analysis" of ecocline patterns to relate communities to climate on a worldwide scale. Whittaker considered four main ecoclines in the terrestrial realm.
Along these gradients, Whittaker noted several trends that allowed him to qualitatively establish biome-types:
Whittaker summed the effects of gradients (3) and (4) to get an overall temperature gradient, and combined this with gradient (2), the moisture gradient, to express the above conclusions in what is known as the Whittaker classification scheme. The scheme graphs average annual precipitation (x-axis) versus average annual temperature (y-axis) to classify biome-types.
The eponymously-named Heinrich Walter classification scheme considers the seasonality of temperature and precipitation. The system, also assessing precipitation and temperature, finds nine major biome types, with the important climate traits and vegetation types. The boundaries of each biome correlate to the conditions of moisture and cold stress that are strong determinants of plant form, and therefore the vegetation that defines the region. Extreme conditions, such as flooding in a swamp, can create different kinds of communities within the same biome.
Robert G. Bailey nearly developed a biogeographical classification system for the United States in a map published in 1976. He subsequently expanded the system to include the rest of North America in 1981, and the world in 1989. The Bailey system, based on climate, is divided into seven domains (polar, humid temperate, dry, humid, and humid tropical), with further divisions based on other climate characteristics (subarctic, warm temperate, hot temperate, and subtropical; marine and continental; lowland and mountain).
A team of biologists convened by the World Wildlife Fund (WWF) developed an ecological land classification system that identified fourteen biomes, called major habitat types, and further divided the world's land area into 882 terrestrial ecoregions (includes new Antarctic ecoregions by Terrauds et al. 2012). Each terrestrial ecoregion has a specific EcoID, format XXnnNN (XX is the ecozone, nn is the biome number, NN is the individual number). This classification is used to define the Global 200 list of ecoregions identified by the WWF as priorities for conservation. The WWF major habitat types are:
Freshwater biomesAccording to the WWF, the following are classified as freshwater biomes:
Realms or ecozones (terrestrial and freshwater, WWF)
Marine biomes (H) (major habitat types), Global 200 (WWF)
Realms or ecozones (marine, WWF)
Other marine habitat types
Major habitats, nonglobal 200 (WWF)
Summary – ecological taxonomy (WWF)
Humans have altered global patterns of biodiversity and ecosystem processes. As a result, vegetation forms predicted by conventional biome systems can no longer be observed across much of Earth's land surface as they have been replaced by crop and rangelands or cities. Anthropogenic biomes provide an alternative view of the terrestrial biosphere based on global patterns of sustained direct human interaction with ecosystems, including agriculture, human settlements, urbanization, forestry and other uses of land. Anthropogenic biomes offer a new way forward in ecology and conservation by recognizing the irreversible coupling of human and ecological systems at global scales and moving us toward an understanding of how best to live in and manage our biosphere and the anthropogenic biomes we live in.
Major anthropogenic 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.
Map of biomes
The drainage basins of the principal oceans and seas of the world are marked by continental divides. The grey areas are endorheic basins that do not drain to the ocean.