Biome
Overview
 
Biomes are climatically and geographically defined as similar climatic conditions on the Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...

, such as communities
Community (ecology)
In ecology, a community is an assemblage of two or more populations of different species occupying the same geographical area. The term community has a variety of uses...

 of plant
Plant
Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or...

s, animal
Animal
Animals are a major group of multicellular, eukaryotic organisms of the kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life. Most animals are motile, meaning they can move spontaneously and...

s, and soil organisms
Soil biology
Soil biology is the study of microbial and faunal activity and ecology in soil. These organisms include earthworms, nematodes, protozoa, fungi, bacteria and different arthropods...

, and are often referred to as ecosystems. Some parts of the earth have more or less the same kind of abiotic and biotic
Biotic
Biotic is a living component of a community; for example organisms, such as plants and animals.Biotic may also refer to:*Life, the condition of living organisms,*Biology, the study of life,*Biotic material, which is derived from living organisms,...

 factors spread over a large area, creating a typical ecosystem over that area. Such major ecosystems are termed as biomes. Biomes are defined by factors such as plant structures (such as trees, shrubs, and grasses), leaf types (such as broadleaf and needleleaf), plant spacing (forest
Forest
A forest, also referred to as a wood or the woods, is an area with a high density of trees. As with cities, depending where you are in the world, what is considered a forest may vary significantly in size and have various classification according to how and what of the forest is composed...

, woodland
Woodland
Ecologically, a woodland is a low-density forest forming open habitats with plenty of sunlight and limited shade. Woodlands may support an understory of shrubs and herbaceous plants including grasses. Woodland may form a transition to shrubland under drier conditions or during early stages of...

, savanna
Savanna
A savanna, or savannah, is a grassland ecosystem characterized by the trees being sufficiently small or widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach the ground to support an unbroken herbaceous layer consisting primarily of C4 grasses.Some...

), and climate.
Encyclopedia
Biomes are climatically and geographically defined as similar climatic conditions on the Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...

, such as communities
Community (ecology)
In ecology, a community is an assemblage of two or more populations of different species occupying the same geographical area. The term community has a variety of uses...

 of plant
Plant
Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or...

s, animal
Animal
Animals are a major group of multicellular, eukaryotic organisms of the kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life. Most animals are motile, meaning they can move spontaneously and...

s, and soil organisms
Soil biology
Soil biology is the study of microbial and faunal activity and ecology in soil. These organisms include earthworms, nematodes, protozoa, fungi, bacteria and different arthropods...

, and are often referred to as ecosystems. Some parts of the earth have more or less the same kind of abiotic and biotic
Biotic
Biotic is a living component of a community; for example organisms, such as plants and animals.Biotic may also refer to:*Life, the condition of living organisms,*Biology, the study of life,*Biotic material, which is derived from living organisms,...

 factors spread over a large area, creating a typical ecosystem over that area. Such major ecosystems are termed as biomes. Biomes are defined by factors such as plant structures (such as trees, shrubs, and grasses), leaf types (such as broadleaf and needleleaf), plant spacing (forest
Forest
A forest, also referred to as a wood or the woods, is an area with a high density of trees. As with cities, depending where you are in the world, what is considered a forest may vary significantly in size and have various classification according to how and what of the forest is composed...

, woodland
Woodland
Ecologically, a woodland is a low-density forest forming open habitats with plenty of sunlight and limited shade. Woodlands may support an understory of shrubs and herbaceous plants including grasses. Woodland may form a transition to shrubland under drier conditions or during early stages of...

, savanna
Savanna
A savanna, or savannah, is a grassland ecosystem characterized by the trees being sufficiently small or widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach the ground to support an unbroken herbaceous layer consisting primarily of C4 grasses.Some...

), and climate. Unlike ecozone
Ecozone
An ecozone is the broadest biogeographic division of the Earth's land surface, based on distributional patterns of terrestrial organisms.Ecozones delineate large areas of the Earth's surface within which organisms have been evolving in relative isolation over long periods of time, separated from...

s, biomes are not defined by genetic, taxonomic, or historical similarities. Biomes are often identified with particular patterns of ecological succession
Ecological succession
Ecological succession, is the phenomenon or process by which a community progressively transforms itself until a stable community is formed. It is a fundamental concept in ecology, and refers to more or less predictable and orderly changes in the composition or structure of an ecological community...

 and climax vegetation
Climax vegetation
Climax vegetation is the vegetation which establishes itself on a given site for given climatic conditions in the absence of anthropic action after a long time ....

 (quasiequilibrium state of the local ecosystem). An ecosystem
Ecosystem
An ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving , physical components of the environment with which the organisms interact, such as air, soil, water and sunlight....

 has many biotope
Biotope
Biotope is an area of uniform environmental conditions providing a living place for a specific assemblage of plants and animals. Biotope is almost synonymous with the term habitat, but while the subject of a habitat is a species or a population, the subject of a biotope is a biological community.It...

s and a biome is a major habitat
Habitat
* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...

 type. A major habitat type, however, is a compromise, as it has an intrinsic inhomogeneity.

The biodiversity
Biodiversity
Biodiversity is the degree of variation of life forms within a given ecosystem, biome, or an entire planet. Biodiversity is a measure of the health of ecosystems. Biodiversity is in part a function of climate. In terrestrial habitats, tropical regions are typically rich whereas polar regions...

 characteristic of each extinction, especially the diversity of fauna and subdominant plant forms, is a function of abiotic factors and the biomass
Biomass (ecology)
Biomass, in ecology, is the mass of living biological organisms in a given area or ecosystem at a given time. Biomass can refer to species biomass, which is the mass of one or more species, or to community biomass, which is the mass of all species in the community. It can include microorganisms,...

 productivity of the dominant vegetation
Vegetation
Vegetation is a general term for the plant life of a region; it refers to the ground cover provided by plants. It is a general term, without specific reference to particular taxa, life forms, structure, spatial extent, or any other specific botanical or geographic characteristics. It is broader...

. In terrestrial biomes, species diversity tends to correlate positively with net primary productivity
Primary production
400px|thumb|Global oceanic and terrestrial photoautotroph abundance, from September [[1997]] to August 2000. As an estimate of autotroph biomass, it is only a rough indicator of primary production potential, and not an actual estimate of it...

, moisture availability
Ecohydrology
Ecohydrology is an interdisciplinary field studying the interactions between water and ecosystems. These interactions may take place within water bodies, such as rivers and lakes, or on land, in forests, deserts, and other terrestrial ecosystems...

, and temperature
Temperature
Temperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...

.

Ecoregions are grouped into both biomes and ecozones.

A fundamental classification of biomes is:
  1. Terrestrial (land) biomes
  2. Aquatic biomes (including freshwater biomes and marine biomes)


Biomes are often known in English by local names. For example, a temperate grassland or shrubland
Temperate grasslands, savannas, and shrublands
Temperate grasslands, savannas, and shrublands is a terrestrial biome whose predominant vegetation consists of grasses and/or shrubs. The climate is temperate and semi-arid to semi-humid....

 biome is known commonly as steppe
Steppe
In physical geography, steppe is an ecoregion, in the montane grasslands and shrublands and temperate grasslands, savannas, and shrublands biomes, characterized by grassland plains without trees apart from those near rivers and lakes...

in central Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...

, prairie
Prairie
Prairies are considered part of the temperate grasslands, savannas, and shrublands biome by ecologists, based on similar temperate climates, moderate rainfall, and grasses, herbs, and shrubs, rather than trees, as the dominant vegetation type...

 in North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

, and pampas in South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

. Tropical grasslands are known as savanna
Savanna
A savanna, or savannah, is a grassland ecosystem characterized by the trees being sufficiently small or widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach the ground to support an unbroken herbaceous layer consisting primarily of C4 grasses.Some...

 in Australia, whereas in southern Africa it is known as certain kinds of veld
Veld
The term Veld refers primarily to the wide open rural spaces of South Africa or southern Africa and in particular to certain flatter areas or districts covered in grass or low scrub...

(from Afrikaans
Afrikaans
Afrikaans is a West Germanic language, spoken natively in South Africa and Namibia. It is a daughter language of Dutch, originating in its 17th century dialects, collectively referred to as Cape Dutch .Afrikaans is a daughter language of Dutch; see , , , , , .Afrikaans was historically called Cape...

).

Sometimes an entire biome may be targeted for protection, especially under an individual nation's biodiversity action plan.

Climate is a major factor determining the distribution of terrestrial biomes. Among the important climatic factors are:
  • Latitude
    Latitude
    In geography, the latitude of a location on the Earth is the angular distance of that location south or north of the Equator. The latitude is an angle, and is usually measured in degrees . The equator has a latitude of 0°, the North pole has a latitude of 90° north , and the South pole has a...

    : Arctic, boreal, temperate, subtropical, tropical
  • Humidity
    Humidity
    Humidity is a term for the amount of water vapor in the air, and can refer to any one of several measurements of humidity. Formally, humid air is not "moist air" but a mixture of water vapor and other constituents of air, and humidity is defined in terms of the water content of this mixture,...

    : humid, semihumid, semiarid, and arid
    • seasonal variation: Rainfall may be distributed evenly throughout the year or be marked by seasonal variations.
    • dry summer, wet winter: Most regions of the earth receive most of their rainfall during the summer months; Mediterranean climate regions receive their rainfall during the winter months.
  • Elevation
    Elevation
    The elevation of a geographic location is its height above a fixed reference point, most commonly a reference geoid, a mathematical model of the Earth's sea level as an equipotential gravitational surface ....

    : Increasing elevation causes a distribution of habitat types similar to that of increasing latitude.


The most widely used systems of classifying biomes correspond to latitude
Latitude
In geography, the latitude of a location on the Earth is the angular distance of that location south or north of the Equator. The latitude is an angle, and is usually measured in degrees . The equator has a latitude of 0°, the North pole has a latitude of 90° north , and the South pole has a...

 (or temperature zoning) and humidity. Biodiversity
Biodiversity
Biodiversity is the degree of variation of life forms within a given ecosystem, biome, or an entire planet. Biodiversity is a measure of the health of ecosystems. Biodiversity is in part a function of climate. In terrestrial habitats, tropical regions are typically rich whereas polar regions...

 generally increases away from the poles towards the equator
Equator
An equator is the intersection of a sphere's surface with the plane perpendicular to the sphere's axis of rotation and containing the sphere's center of mass....

 and increases with humidity.

Biome classification schemes

Biomes are classification schemes which define biomes using climatic parameters. Particularly in the 1970s and 1980s, there was a significant push to understand the relationships between these climatic parameters and properties of ecosystem energetics because such discoveries would enable the prediction of rates of energy capture and transfer among components within ecosystems. Such a study was conducted by Sims et al. (1978) on North American grasslands. The study found a positive logistic correlation between evapotranspiration
Evapotranspiration
Evapotranspiration is a term used to describe the sum of evaporation and plant transpiration from the Earth's land surface to atmosphere. Evaporation accounts for the movement of water to the air from sources such as the soil, canopy interception, and waterbodies...

 in mm/yr and above-ground net primary production in g/m^2/yr. More general results from the study were that precipitation and water use lead to above-ground primary production, solar radiation and temperature lead to belowground 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, which were then later simplified in Whittaker’s. 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 all fit perfectly into the classification schemes created.

Holdridge scheme

The Holdridge classification scheme, developed by botanist L. R. Holdridge, maps climates based on four categories:
  • Average total precipitation is the potential evapotranspiration divided by the precipitation; the ratio increases from humid to arid regions.
  • Potential evapotranspiration
    Evapotranspiration
    Evapotranspiration is a term used to describe the sum of evaporation and plant transpiration from the Earth's land surface to atmosphere. Evaporation accounts for the movement of water to the air from sources such as the soil, canopy interception, and waterbodies...

     (PET)
  • Mean annual biotemperature (°C): at or below freezing, all have the same effect on plants, and delineating between -10°C and -30°C would yield unrealistic results.


In this scheme, climates are classified 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 type of vegetation found in an area. Holdridge uses the four axes to define 30 so-called "humidity provinces", which are clearly visible in the Holdridge diagram. While his scheme largely ignores soil and sun exposure, Holdridge did acknowledge that these, too, were important factors in biome determination.

Whittaker's biome-type classification scheme

Whittaker appreciated biome-types as a representation of the great diversity of the living world, and saw the need to establish a simple way to classify them. He based his classification scheme on two abiotic factors: precipitation and temperature. His scheme can be seen as a simplification of Holdridge's, one more readily accessible, but perhaps missing the greater specificity that Holdridge's provides.

Whittaker based his representation of global biomes on both previous theoretical assertions and an ever-increasing empirical sampling of global ecosystems. He was in a unique position to make such a holistic assertion because he had previously compiled a review of biome classification.

Key definitions for understanding Whittaker's scheme

  • Physiognomy: The apparent characteristics, outward features, or appearance of ecological communities or species
  • Biome: a grouping of terrestrial ecosystems on a given continent that are similar in vegetation structure, physiognomy, features of the environment and characteristics of their animal communities
  • Formation: a major kind of community of plants on a given continent
  • Biome-type: grouping of convergent biomes or formations of different continents, defined by physiognomy
  • Formation-type: a grouping of convergent formations


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.
  1. 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
  2. Climatic moisture gradient
  3. Temperature gradient by altitude
  4. Temperature gradient by latitude


Along these gradients, Whittaker noted several trends that allowed him to qualitatively establish biome-types.
  • The gradient runs from favorable to extreme, with corresponding changes in productivity.
  • Changes in physiognomic complexity vary with the favorability of the environment (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.


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.

Walter system

The Heinrich Walter classification scheme, developed by Heinrich Walter, a German ecologist, differs from both the Whittaker and Holdridge schemes because it takes into account the seasonality of temperature and precipitation. The system, also based on precipitation and temperature, finds 9 major biomes, with the important climate traits and vegetation types summarized in the accompanying table. 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.
  • I: Equatorial
    • Always moist and lacking temperature seasonality
    • Evergreen tropical rain forest
  • II: Tropical
    • Summer rainy season and cooler “winter” dry season
    • Seasonal forest, scrub, or savanna
  • III: Subtropical
    • Highly seasonal, arid climate
    • Desert vegetation with considerable exposed surface
  • IV: Mediterranean
    • 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
  • VI: Nemoral
    • Moderate climate with winter freezing
    • Frost-resistant, deciduous, temperate forest
  • VII: Continental
    • Arid, with warm or hot summers and cold winters
    • Grasslands and temperate deserts
  • VIII: Boreal
    • Cold temperate with cool summers and long winters
    • Evergreen, frost-hardy, needle-leaved forest (taiga)
  • IX: Polar
    • Very short, cool summers and long, very cold winters
    • Low, evergreen vegetation, without trees, growing over permanently frozen soils

Bailey system

Robert G. Bailey almost developed a biogeographical
Biogeography
Biogeography is the study of the distribution of species , organisms, and ecosystems in space and through geological time. Organisms and biological communities vary in a highly regular fashion along geographic gradients of latitude, elevation, isolation and habitat area...

 classification system for the United States in a map published in 1976. He subsequently expanded the system to include the rest of South 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).
  • 100 Polar Domain
    • 120 Tundra Division
    • M120 Tundra Division - Mountain Provinces
    • 130 Subarctic Division
    • M130 Subarctic Division - Mountain Provinces
  • 200 Humid Temperate Domain
    • 210 Warm Continental Division
    • M210 Warm Continental Division - Mountain Provinces
    • 220 Hot Continental Division
    • M220 Hot Continental Division - Mountain Provinces
    • 230 Subtropical Division
    • M230 Subtropical Division - Mountain Provinces
    • 240 Marine Division
    • M240 Marine Division - Mountain Provinces
    • 250 Prairie Division
    • 260 Mediterranean Division
    • M260 Mediterranean Division - Mountain Provinces
  • 300 Dry Domain
    • 310 Tropical/Subtropical Steppe Division
    • M310 Tropical/Subtropical Steppe Division - Mountain Provinces

WWF system

A team of biologists convened by the World Wide Fund for Nature
World Wide Fund for Nature
The World Wide Fund for Nature is an international non-governmental organization working on issues regarding the conservation, research and restoration of the environment, formerly named the World Wildlife Fund, which remains its official name in Canada and the United States...

 (WWF) developed an ecological land classification
Ecological land classification
Ecological land classification is defined as being a cartographical delineation of distinct ecological areas, identified by their geology, topography, soils, vegetation, climate conditions, living species, habitats, water resources, as well as anthropic factors...

 system that identified fourteen biomes, called major habitat types, and further divided the world's land area into 867 terrestrial ecoregions. Each terrestrial ecoregion has a specific EcoID, fomat XXnnNN (XX is the ecozone
Ecozone
An ecozone is the broadest biogeographic division of the Earth's land surface, based on distributional patterns of terrestrial organisms.Ecozones delineate large areas of the Earth's surface within which organisms have been evolving in relative isolation over long periods of time, separated from...

, nn is the biome number, NN is the individual number). This classification is used to define the Global 200
Global 200
The Global 200 is the list of ecoregions identified by the World Wildlife Fund as priorities for conservation. According to the WWF, an ecoregion is defined as a "relatively large unit of land or water containing a characteristic set of natural communities that share a large majority of their...

 list of ecoregion
Ecoregion
An ecoregion , sometimes called a bioregion, is an ecologically and geographically defined area that is smaller than an ecozone and larger than an ecosystem. Ecoregions cover relatively large areas of land or water, and contain characteristic, geographically distinct assemblages of natural...

s identified by the WWF as priorities for conservation. The WWF major habitat types are:
  • 01 Tropical and subtropical moist broadleaf forests
    Tropical and subtropical moist broadleaf forests
    Tropical and subtropical moist broadleaf forests , also known as tropical moist forests, are a tropical and subtropical forest biome....

     (tropical and subtropical, humid)
  • 02 Tropical and subtropical dry broadleaf forests
    Tropical and subtropical dry broadleaf forests
    The tropical and subtropical dry broadleaf forest biome, also known as tropical dry forest, is located at tropical and subtropical latitudes. Though these forests occur in climates that are warm year-round, and may receive several hundred centimeters of rain per year, they have long dry seasons...

     (tropical and subtropical, semihumid)
  • 03 Tropical and subtropical coniferous forests
    Tropical and subtropical coniferous forests
    Tropical and subtropical coniferous forests are a forest biome. They are located in regions of semi-humid climate at tropical and subtropical latitudes. Most tropical and subtropical coniferous forest ecoregions are found in the Nearctic and Neotropic ecozones, from Mexico to Nicaragua and on the...

     (tropical and subtropical, semihumid)
  • 04 Temperate broadleaf and mixed forests
    Temperate broadleaf and mixed forests
    Mixed forests are a temperate and humid biome. The typical structure of these forests includes four layers. The uppermost layer is the canopy composed of tall mature trees ranging from 33 to 66 m high. Below the canopy is the three-layered, shade-tolerant understory that is roughly 9 to...

     (temperate, humid)
  • 05 Temperate coniferous forests
    Temperate coniferous forests
    Temperate coniferous forest is a terrestrial biome found in temperate regions of the world with warm summers and cool winters and adequate rainfall to sustain a forest. In most temperate coniferous forests, evergreen conifers predominate, while some are a mix of conifers and broadleaf evergreen...

     (temperate, humid to semihumid)
  • 06 Boreal forests/taiga
    Taiga
    Taiga , also known as the boreal forest, is a biome characterized by coniferous forests.Taiga is the world's largest terrestrial biome. In North America it covers most of inland Canada and Alaska as well as parts of the extreme northern continental United States and is known as the Northwoods...

     (subarctic, humid)
  • 07 Tropical and subtropical grasslands, savannas, and shrublands
    Tropical and subtropical grasslands, savannas, and shrublands
    Tropical and subtropical grasslands, savannas, and shrublands are a grassland terrestrial biome located in semi-arid to semi-humid climate regions of subtropical and tropical latitudes. Grasslands are dominated by grass and other herbaceous plants. Savannas are grasslands with scattered trees...

     (tropical and subtropical, semiarid)
  • 08 Temperate grasslands, savannas, and shrublands
    Temperate grasslands, savannas, and shrublands
    Temperate grasslands, savannas, and shrublands is a terrestrial biome whose predominant vegetation consists of grasses and/or shrubs. The climate is temperate and semi-arid to semi-humid....

     (temperate, semiarid)
  • 09 Flooded grasslands and savannas
    Flooded grasslands and savannas
    Flooded grasslands and savannas is a terrestrial biome. Its component ecoregions are generally located at subtropical and tropical latitudes, which are flooded seasonally or year-round...

     (temperate to tropical, fresh or brackish water inundated)
  • 10 Montane grasslands and shrublands
    Montane grasslands and shrublands
    Montane grasslands and shrublands is a biome defined by the World Wildlife Fund. The biome includes high altitude grasslands and shrublands around the world....

     (alpine or montane climate)
  • 11 Tundra
    Tundra
    In physical geography, tundra is a biome where the tree growth is hindered by low temperatures and short growing seasons. The term tundra comes through Russian тундра from the Kildin Sami word tūndâr "uplands," "treeless mountain tract." There are three types of tundra: Arctic tundra, alpine...

     (Arctic)
  • 12 Mediterranean forests, woodlands, and scrub
    Mediterranean forests, woodlands, and scrub
    Mediterranean forests, woodlands, and scrub biome, defined by the World Wildlife Fund, characterized by dry summers and rainy winters. Summers are typically hot in low-lying inland locations but can be cool near some seas, as near San Francisco, which have a sea of cool waters...

     or sclerophyll forests (temperate warm, semihumid to semiarid with winter rainfall)
  • 13 Deserts and xeric shrublands
    Deserts and xeric shrublands
    Deserts and xeric shrublands is a biome characterized by, relating to, or requiring only a small amount of moisture.-Definition and occurrence:...

     (temperate to tropical, arid)
  • 14 Mangrove
    Mangrove
    Mangroves are various kinds of trees up to medium height and shrubs that grow in saline coastal sediment habitats in the tropics and subtropics – mainly between latitudes N and S...

     (subtropical and tropical, salt water inundated)

Freshwater biomes

According to the WWF, the following are classified as freshwater
Freshwater
Fresh water is naturally occurring water on the Earth's surface in ice sheets, ice caps, glaciers, bogs, ponds, lakes, rivers and streams, and underground as groundwater in aquifers and underground streams. Fresh water is generally characterized by having low concentrations of dissolved salts and...

 biomes:

  • Large lakes
  • Large river deltas
  • Polar freshwater
    Freshwater
    Fresh water is naturally occurring water on the Earth's surface in ice sheets, ice caps, glaciers, bogs, ponds, lakes, rivers and streams, and underground as groundwater in aquifers and underground streams. Fresh water is generally characterized by having low concentrations of dissolved salts and...

    s
  • Montane freshwater
    Freshwater
    Fresh water is naturally occurring water on the Earth's surface in ice sheets, ice caps, glaciers, bogs, ponds, lakes, rivers and streams, and underground as groundwater in aquifers and underground streams. Fresh water is generally characterized by having low concentrations of dissolved salts and...

    s
  • Temperate coastal rivers
    Upland and lowland (freshwater ecology)
    In studies of the ecology of freshwater rivers, habitats are classified as upland and lowland.-Definitions:Upland habitats are cold, clear, rocky, fast flowing rivers in mountainous areas; lowland habitats are warm, slow flowing rivers found in relatively flat lowland areas, with water that is...

  • Temperate floodplain rivers and wetland
    Wetland
    A wetland is an area of land whose soil is saturated with water either permanently or seasonally. Wetlands are categorised by their characteristic vegetation, which is adapted to these unique soil conditions....

    s

  • Temperate upland rivers
    Upland and lowland (freshwater ecology)
    In studies of the ecology of freshwater rivers, habitats are classified as upland and lowland.-Definitions:Upland habitats are cold, clear, rocky, fast flowing rivers in mountainous areas; lowland habitats are warm, slow flowing rivers found in relatively flat lowland areas, with water that is...

  • Tropical and subtropical coastal rivers
    Upland and lowland (freshwater ecology)
    In studies of the ecology of freshwater rivers, habitats are classified as upland and lowland.-Definitions:Upland habitats are cold, clear, rocky, fast flowing rivers in mountainous areas; lowland habitats are warm, slow flowing rivers found in relatively flat lowland areas, with water that is...

  • Tropical and subtropical floodplain rivers and wetland
    Wetland
    A wetland is an area of land whose soil is saturated with water either permanently or seasonally. Wetlands are categorised by their characteristic vegetation, which is adapted to these unique soil conditions....

    s
  • Tropical and subtropical upland rivers
    Upland and lowland (freshwater ecology)
    In studies of the ecology of freshwater rivers, habitats are classified as upland and lowland.-Definitions:Upland habitats are cold, clear, rocky, fast flowing rivers in mountainous areas; lowland habitats are warm, slow flowing rivers found in relatively flat lowland areas, with water that is...

  • Xeric freshwaters and endorheic basins
  • Oceanic islands

  • Streams and rivers

Realms or ecozones (terrestrial and freshwater, WWF)

  • NA Nearctic
    Nearctic
    The Nearctic is one of the eight terrestrial ecozones dividing the Earth's land surface.The Nearctic ecozone covers most of North America, including Greenland and the highlands of Mexico...

  • PA Palearctic
    Palearctic
    The Palearctic or Palaearctic is one of the eight ecozones dividing the Earth's surface.Physically, the Palearctic is the largest ecozone...

  • AT Afrotropic
    Afrotropic
    The Afrotropic is one of the Earth's eight ecozones. It includes Africa south of the Sahara Desert, the southern and eastern fringes of the Arabian Peninsula, the island of Madagascar, southern Iran and extreme southwestern Pakistan, and the islands of the western Indian Ocean. It was formerly...

  • IM Indomalaya
    Indomalaya
    The Indomalaya ecozone is one of the eight ecozones that cover the planet's land surface. It extends across most of South and Southeast Asia and into the southern parts of East Asia....


  • AA Australasia
    Australasia ecozone
    The Australasian zone is an ecological region that is coincident, but not synonymous , with the geographic region of Australasia...

  • NT Neotropic
    Neotropic
    In biogeography, the Neotropic or Neotropical zone is one of the eight terrestrial ecozones. This ecozone includes South and Central America, the Mexican lowlands, the Caribbean islands, and southern Florida, because these regions share a large number of plant and animal groups.It is sometimes used...

  • OC Oceania
    Oceania ecozone
    Oceania is one of the WWF ecozones, and unique in not including any continental land mass. The ecozone includes the Pacific Ocean islands of Micronesia, the Fijian Islands, and most of Polynesia...

  • AN Antarctic


Marine biomes (H) (major habitat types), Global 200 (WWF)

Biomes of the coastal andd continental shelf
Continental shelf
The continental shelf is the extended perimeter of each continent and associated coastal plain. Much of the shelf was exposed during glacial periods, but is now submerged under relatively shallow seas and gulfs, and was similarly submerged during other interglacial periods. The continental margin,...

 areas (neritic zone
Neritic zone
The neritic zone, also called coastal waters, the coastal ocean or the sublittoral zone, is the part of the ocean extending from the low tide mark to the edge of the continental shelf, with a relatively shallow depth extending to about 200 meters...

 - List of ecoregions (WWF))
  • Polar
  • Temperate shelves and sea
  • Temperate upwelling
    Upwelling
    Upwelling is an oceanographic phenomenon that involves wind-driven motion of dense, cooler, and usually nutrient-rich water towards the ocean surface, replacing the warmer, usually nutrient-depleted surface water. The increased availability in upwelling regions results in high levels of primary...

  • Tropical upwelling
    Upwelling
    Upwelling is an oceanographic phenomenon that involves wind-driven motion of dense, cooler, and usually nutrient-rich water towards the ocean surface, replacing the warmer, usually nutrient-depleted surface water. The increased availability in upwelling regions results in high levels of primary...

  • Tropical coral
    Coral reef
    Coral reefs are underwater structures made from calcium carbonate secreted by corals. Coral reefs are colonies of tiny living animals found in marine waters that contain few nutrients. Most coral reefs are built from stony corals, which in turn consist of polyps that cluster in groups. The polyps...


Realms or ecozones (marine, WWF)


  • 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
  • Antarctic
  • Arctic
  • Mediterranean


Other marine habitat types
  • Hydrothermal vent
    Hydrothermal vent
    A hydrothermal vent is a fissure in a planet's surface from which geothermally heated water issues. Hydrothermal vents are commonly found near volcanically active places, areas where tectonic plates are moving apart, ocean basins, and hotspots. Hydrothermal vents exist because the earth is both...

    s
  • Cold seep
    Cold seep
    A cold seep is an area of the ocean floor where hydrogen sulfide, methane and other hydrocarbon-rich fluid seepage occurs, often in the form of a brine pool...

    s
  • Benthic zone
    Benthic zone
    The benthic zone is the ecological region at the lowest level of a body of water such as an ocean or a lake, including the sediment surface and some sub-surface layers. Organisms living in this zone are called benthos. They generally live in close relationship with the substrate bottom; many such...

  • Pelagic zone
    Pelagic zone
    Any water in a sea or lake that is not close to the bottom or near to the shore can be said to be in the pelagic zone. The word pelagic comes from the Greek πέλαγος or pélagos, which means "open sea". The pelagic zone can be thought of in terms of an imaginary cylinder or water column that goes...

     (trades and westerlies)
  • Abyssal
  • Hadal (ocean trench)

Major habitats, nonglobal 200 (WWF)
  • Littoral/Intertidal zone
    Intertidal zone
    The intertidal zone is the area that is above water at low tide and under water at high tide . This area can include many different types of habitats, with many types of animals like starfish, sea urchins, and some species of coral...

  • Kelp forest
    Kelp forest
    Kelp forests are underwater areas with a high density of kelp. They are recognized as one of the most productive and dynamic ecosystems on Earth. Smaller areas of anchored kelp are called kelp beds....

  • Pack ice

Summary - ecological taxonomy (WWF)

  • Biosphere
    Biosphere
    The biosphere is the global sum of all ecosystems. It can also be called the zone of life on Earth, a closed and self-regulating system...

     (List of ecoregions)
    • Ecozones or realms (8)
      • Terrestrial biomes (major habitat types, 14)
        • Ecoregions (867) vbn,
          • Ecosystems (biotope
            Biotope
            Biotope is an area of uniform environmental conditions providing a living place for a specific assemblage of plants and animals. Biotope is almost synonymous with the term habitat, but while the subject of a habitat is a species or a population, the subject of a biotope is a biological community.It...

            s)
      • Freshwater biomes (major habitat types, 12)
        • Ecoregions (426)
          • Ecosystems (biotopes)
    • Marine ecozones or realms (13)
      • Continental Shelf
        Continental shelf
        The continental shelf is the extended perimeter of each continent and associated coastal plain. Much of the shelf was exposed during glacial periods, but is now submerged under relatively shallow seas and gulfs, and was similarly submerged during other interglacial periods. The continental margin,...

         biomes (major habitat types, 5)
        • (Marine provinces) (62)
          • Ecoregions (232)
            • Ecosystems (biotopes)
      • Open & Deep Sea Biomes (major habitat types)
    • Endolith
      Endolith
      An endolith is an organism that lives inside rock, coral, animal shells, or in the pores between mineral grains of a rock. Many are extremophiles, living in places previously thought inhospitable to life...

      ic biome


Example
  • Biosphere
    Biosphere
    The biosphere is the global sum of all ecosystems. It can also be called the zone of life on Earth, a closed and self-regulating system...

    • Ecozone
      Ecozone
      An ecozone is the broadest biogeographic division of the Earth's land surface, based on distributional patterns of terrestrial organisms.Ecozones delineate large areas of the Earth's surface within which organisms have been evolving in relative isolation over long periods of time, separated from...

      : Palearctic ecozone
      • Terrestrial biome: temperate broadleaf and mixed forests
        Temperate broadleaf and mixed forests
        Mixed forests are a temperate and humid biome. The typical structure of these forests includes four layers. The uppermost layer is the canopy composed of tall mature trees ranging from 33 to 66 m high. Below the canopy is the three-layered, shade-tolerant understory that is roughly 9 to...

        • Ecoregion
          Ecoregion
          An ecoregion , sometimes called a bioregion, is an ecologically and geographically defined area that is smaller than an ecozone and larger than an ecosystem. Ecoregions cover relatively large areas of land or water, and contain characteristic, geographically distinct assemblages of natural...

          : Dinaric Mountains mixed forests
          Dinaric Mountains mixed forests
          The Dinaric Mountains mixed forests form a terrestrial ecoregion of Europe according to both the WWF and Digital Map of European Ecological Regions by the European Environment Agency. It belongs to the Temperate Broadleaf and Mixed Forests Biome, and to the Palearctic ecozone.-Distribution:The...

           (PA0418)
          • Ecosystem
            Ecosystem
            An ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving , physical components of the environment with which the organisms interact, such as air, soil, water and sunlight....

            : Orjen
            Orjen
            Orjen is a Dinaric Mediterranean limestone mountain range in Montenegro-Bosnia and Herzegovina. At 1894 m , Zubački kabao is the highest peak in the subadriatic Dinarides. The massif of Orjen lies to the Northwest of Risan in Bay of Kotor...

            , vegetation belt between 1,100- 1,450 m, Oromediterranean zone, nemoral zone (temperate zone)
            • Biotope
              Biotope
              Biotope is an area of uniform environmental conditions providing a living place for a specific assemblage of plants and animals. Biotope is almost synonymous with the term habitat, but while the subject of a habitat is a species or a population, the subject of a biotope is a biological community.It...

              : Oreoherzogio-Abietetum illyricae Fuk. (Plant list)
              • Plant: Silver fir (Abies alba)

Anthropogenic biomes

Humans have fundamentally altered global patterns of biodiversity and ecosystem processes. As a result, vegetation forms predicted by conventional biome systems are rarely observed across most of Earth's land surface. Anthropogenic biomes
Anthropogenic biomes
Anthropogenic biomes, also known as anthromes or human biomes, describe the terrestrial biosphere in its contemporary, human-altered form using global ecosystem units defined by global patterns of sustained direct human interaction with ecosystems....

 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 how best to live in and manage our biosphere and the anthropogenic biosphere we live in. The main biomes in the world are freshwater, marine, coniferous, deciduous, ice, mountains, boreal, grasslands, tundra, and rainforests.

Other biomes

The endolith
Endolith
An endolith is an organism that lives inside rock, coral, animal shells, or in the pores between mineral grains of a rock. Many are extremophiles, living in places previously thought inhospitable to life...

ic biome, consisting entirely of microscopic life in rock pores
Porosity
Porosity or void fraction is a measure of the void spaces in a material, and is a fraction of the volume of voids over the total volume, between 0–1, or as a percentage between 0–100%...

 and cracks, kilometers beneath the surface, has only recently been discovered, and does not fit well into most classification schemes.

Map of biomes

Freshwater biomes

The drainage basins of the principal oceans and seas of the world are marked by continental divides. The grey areas are endorheic
Endorheic
An endorheic basin is a closed drainage basin that retains water and allows no outflow to other bodies of water such as rivers or oceans...

 basins that do not drain to the ocean.

See also

  • Altitudinal zonation
    Altitudinal zonation
    Altitudinal zonation in mountainous regions describes the natural layering of ecosystems that occurs at distinct altitudes due to varying environmental conditions. Temperature, humidity, soil composition, and solar radiation are important factors in determining altitudinal zones, which consequently...

  • Biomics
    Biomics
    Biomics is the biological study of Biomes, and the processing that data, such as ecological communities of plants, animals, and soil organisms.-Uses:...

  • Biosphere reserve
    Biosphere reserve
    The Man and the Biosphere Programme of UNESCO was established in 1971 to promote interdisciplinary approaches to management, research and education in ecosystem conservation and sustainable use of natural resources.-Development:...

  • Earth Science
    Earth science
    Earth science is an all-embracing term for the sciences related to the planet Earth. It is arguably a special case in planetary science, the Earth being the only known life-bearing planet. There are both reductionist and holistic approaches to Earth sciences...

  • Ecoregion
    Ecoregion
    An ecoregion , sometimes called a bioregion, is an ecologically and geographically defined area that is smaller than an ecozone and larger than an ecosystem. Ecoregions cover relatively large areas of land or water, and contain characteristic, geographically distinct assemblages of natural...

  • Ecology
    Ecology
    Ecology is the scientific study of the relations that living organisms have with respect to each other and their natural environment. Variables of interest to ecologists include the composition, distribution, amount , number, and changing states of organisms within and among ecosystems...

  • Ecosystem
    Ecosystem
    An ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving , physical components of the environment with which the organisms interact, such as air, soil, water and sunlight....

  • Ecosystem diversity
    Ecosystem diversity
    Ecosystem diversity refers to the diversity of a place at the level of ecosystems. The term differs from biodiversity, which refers to variation in species rather than ecosystems...

  • Ecotope
    Ecotope
    Ecotopes are the smallest ecologically-distinct landscape features in a landscape mapping and classification system. As such, they represent relatively homogeneous, spatially-explicit landscape functional units that are useful for stratifying landscapes into ecologically distinct features for the...

  • Ecozone
    Ecozone
    An ecozone is the broadest biogeographic division of the Earth's land surface, based on distributional patterns of terrestrial organisms.Ecozones delineate large areas of the Earth's surface within which organisms have been evolving in relative isolation over long periods of time, separated from...

  • Climate classification
    Climate classification
    Climate classification systems are ways of classifying the world's climates. A climate classification may correlate closely with a biome category, as climate is a major influence on biological life in a region...

  • Altitudinal zonation
    Altitudinal zonation
    Altitudinal zonation in mountainous regions describes the natural layering of ecosystems that occurs at distinct altitudes due to varying environmental conditions. Temperature, humidity, soil composition, and solar radiation are important factors in determining altitudinal zones, which consequently...

  • Effect of climate change on plant biodiversity
    Effect of climate change on plant biodiversity
    Environmental conditions play a key role in defining the function and distribution of plants, in combination with other factors. Changes in long term environmental conditions that can be collectively coined climate change are known to have had enormous impacts on plant diversity patterns in the...

  • Gene pool
    Gene pool
    In population genetics, a gene pool is the complete set of unique alleles in a species or population.- Description :A large gene pool indicates extensive genetic diversity, which is associated with robust populations that can survive bouts of intense selection...

  • Genetic pollution
    Genetic pollution
    Genetic pollution is a controversial term for uncontrolled gene flow into wild populations. This gene flow is undesirable according to some environmentalists and conservationists, including groups such as Greenpeace, TRAFFIC, and GeneWatch UK.-Usage:...

  • Genetic erosion
    Genetic erosion
    Genetic erosion is a process whereby an already limited gene pool of an endangered species of plant or animal diminishes even more when individuals from the surviving population die off without getting a chance to meet and breed with others in their endangered low population.Genetic erosion occurs...

  • Growing region
    Growing region
    A growing region is an area suited by climate and soil conditions to the cultivation of a certain type of crop or plant group.Most crops are cultivated not in one place only, but in several distinct regions in diverse parts of the world...

  • Habitat
    Habitat (ecology)
    A habitat is an ecological or environmental area that is inhabited by a particular species of animal, plant or other type of organism...

  • Kuchler plant association
    A.W. Kuchler
    A. W. Kuchler is an American geographer and naturalist who is noted for developing a plant association system in widespread use in the USA. Some of this database has become digitized for integration into GIS mapping systems.-References:* *...

  • Life zones
  • Natural environment
    Natural environment
    The natural environment encompasses all living and non-living things occurring naturally on Earth or some region thereof. It is an environment that encompasses the interaction of all living species....

  • Nature
    Nature
    Nature, in the broadest sense, is equivalent to the natural world, physical world, or material world. "Nature" refers to the phenomena of the physical world, and also to life in general...

  • Pedology
    Pedology (soil study)
    Pedology is the study of soils in their natural environment. It is one of two main branches of soil science, the other being edaphology...

  • Pliocene
    Pliocene
    The Pliocene Epoch is the period in the geologic timescale that extends from 5.332 million to 2.588 million years before present. It is the second and youngest epoch of the Neogene Period in the Cenozoic Era. The Pliocene follows the Miocene Epoch and is followed by the Pleistocene Epoch...

  • World Network of Biosphere Reserves
    World Network of Biosphere Reserves
    The UNESCO World Network of Biosphere Reserves covers internationally-designated protected areas, known as biosphere reserves, that are meant to demonstrate a balanced relationship between man and nature The UNESCO World Network of Biosphere Reserves covers internationally-designated protected...



External links

  • 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
    Exemplar
    Exemplar, in the sense developed by philosopher of science Thomas Kuhn, is a well known usage of a scientific theory.According to Kuhn, scientific practice alternates between periods of normal science and extraordinary/revolutionary science...

     of each biome that is described in great detail and provides scientific measurements of the climate
    Climate
    Climate encompasses the statistics of temperature, humidity, atmospheric pressure, wind, rainfall, atmospheric particle count and other meteorological elemental measurements in a given region over long periods...

    statistics that define each biome.
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