BIOMES

An Introduction to the Biomes of the World

Definition of a Biome

Terrestrial – referring to land

Climatically controlled sets of ecosystems

Characterized by distinct vegetation

In a Biome

There is an exchange of: Air,Water,Nutrients & Biological components, And yes . . . This includes people

Definition of an Ecosystem

Major systems within a biome - interacting communities of organisms

Involves interaction of living organisms and physical environment

The Biomes:

Tundra

Taiga

Temperate Mixed & Coniferous Forests

Temperate Deciduous Forests

Grasslands

Chaparral / Mediterranean Scrub / Mediterranean Chaparral

Desert / Desert Scrub

Savanna & Deciduous Tropical Forests

Rainforests

Alpine

Distribution of Biomes

Results from 3 major factors1) Global patterns of air circulation

Distribution of Biomes

Results from 3 major factors2) Distribution of heat from sun

The relative seasonality of different portions of earth

Distribution of Biomes

Results from 3 major factors3) Geological factors – inc.

mountains—both heights and orientation

Tundra and Its Climate

Fragile, cold environment20% of Earth’s surfaceWinters – long, cold dark to – 90° F (-70° C)Summers – “land of the midnight sun” to 50° F

The Tundra

A Northern Hemisphere Phenomenon

Tundra Soils

Permafrost – ground permanently frozen

Shallow soils – poor drainage

Soils low in nutrients

Soils are acidic to neutral pH

Tundra - Finnish word for barren or treeless

Tundra Habitat

Upper permafrost thaws in summer – soggy environment

Marshy, bogs, lakes and streamsMultitudes of insects makes habitat

for migratory birdsVegetation – lichens, mosses, heathsLow annual precipitation - <10”Most moisture held close to ground

Taiga

A.K.A Northern Coniferous Forestor Boreal Forestor Needle-Leaf ForestLargest biome on planetAcross Europe, Asia & North America

Taiga and Its Climate

Located below TundraWinters: -65° F to 30° F (-54° C to –1° C)Summers: to 70° F (21°C)Warm, rainy and humidAverage precipitation 12” to 33” per year as rain, dew and snow

Taiga

The Boreal Forest

Taiga Habitat

Precipitation mostly as summer rainfall

Permafrost in higher latitudesLess than 3’ of soilSoils highly acidic, low in nutrientsVegetation mostly coniferous

(conifers – cone bearing plants)

Taiga Habitat (cont.)

Coniferous plants – Spruce (Picea), Larch (Larix), Fir (Abies), Pine (Pinus)

Deciduous trees & shrubs – Poplars (Populus), Willows, (Salix), Alders (Alnus), Birch (Betula)

Various perennials, mosses and lichens

No annual plants

Taiga Pond in Ontario, Canada

Grasslands

Zones between Temperate Deciduous Forests and DesertsGenerally occurs over large portions of continental interiors

Grasslands and Its Climate

Precipitation as much as 40” per yearPrecipitation types and amounts governed by adjacent BiomesTemperatures range from –40°F to over 80°F

Grasslands of

China

Grasslands Habitat

“Tall Grass Prairies” most productive temperate farming lands

Lacks trees except in riparian areas

Disturbed grasslands can evolve into Deserts or Forests

Grasslands Habitat (cont.)

Native vegetation—bunch grasses, sod-forming grasses perennials and no annuals

Where Biomes converge a wide variety of plant communities are sustained

Integration occurs with Temperate Deciduous Forests, Savannas and Rainforests where adjacent

Temperate Deciduous Forests

Almost entirely in northern hemisphereRegions of warm summers and cold wintersNorth America – 38° to 45° N. latitudesEurope & Asia – 45° to 60° N. latitudes

Temperate Deciduous Forest Climate

Precipitation mostly as rainfall – 30” to 60” per yearFour distinct seasonsLow available moisture in winterDeciduous nature of plants a function of water conservation Fall Color

Temperate Deciduous Forest Habitat

Shallow soils, acidic, low in nutrients

Vegetation—broadleaf deciduous trees, shrubs & perennials

Virtually no annuals due to limited light

Annuals cannot store enough nutrients in seed to survive from germination to reproduction

Temperate Mixed Deciduous & Coniferous Forests

Narrow band between Temperate Deciduous Forests and Taiga

Conifers mixed with deciduous plants

Winters colder than Temperate Deciduous Forests

Precipitation—winter rainfall, fog and some snow

Temperate Mixed Deciduous & Coniferous Forest Habitat

Considered harvestable timber regions

Notable species inc.: Coast RedwoodGiant Sequoia or Big

TreeDouglass FirSugar Pine

Chaparrals

A.K.A Mediterranean or Chaparral or Mediterranean ScrubCharacterized by regions along the Mediterranean Sea

Chaparral

Associated with cool ocean currents

Chaparral Locations

30° and 40° north and south latitudesChaparrals occur in:Central Coastal ChileSouthwestern Coastal AfricaSouthern and Southwestern Australia and Southern California

Coastal Sage Scrub

Chaparral Climate & Habitat

Average annual rainfall: 10” to 20”Winters rarely below 30°FSummers to 100°FEvergreen or summer deciduous

plantsShort growing seasonFire plays an important part

Chaparral Climate & Habitat

Plant adaptations include:Small foliageGray foliageSummer- or drought-deciduousFurry foliageGreen trunks/branchesThick, resinous or leathery foliage

Deserts

Covers 20% of planetAtmospheric high pressure areasContinental interiorsFlanks tropics 30° north and south latitudes – towards poles

Desert Climate

< 7” rainfall per yearSome deserts < 1”Rainfall determined by adjacent BiomesEquatorial sides – summer precipitationPolar sides – winter precipitationTemperatures from range below freezing to 120°F+

No predictable annual rainfall !!!

Desert Habitat

Specialized vegetation with various adaptations

Plants able to store water or reduce water loss

Leathery foliage reduces water lossPlants go deciduous when dryPhotosynthesis can occur without

leaves

Desert Habitat

Plant adaptations include:Small foliageGray or fuzzy foliageSummer- or drought-deciduousGreen trunks/branchesThick, resinous or leathery foliageSwollen/expandable trunksSpines

Savanna / Deciduous Tropical Forests

Grasslands and scattered deciduous and evergreen treesLarge variation in temperaturesTemperature swings account for seasonal droughts and sparse vegetation35” to 60” annual rainfall

Savanna / Deciduous Tropical Forests Locations

Acts as “transitional zones” Between Tropical Rainforests and DesertsBetween Prairies and Temperate Deciduous ForestsBetween Prairies and Taiga

A large Savanna runs along the southern

Sahara Desert

Savanna / Deciduous Tropical Forests Habitat

Mostly perennialsNearly all plants

are deciduousMost have small

leavesPeriodic burning

revitalizes Baobab Trees on the Savanna of

Madagascar

Savanna / Deciduous Tropical Forests Habitat

Plant adaptations include:Small foliageGray foliage / furry foliageSummer- or drought-deciduousGreen trunks/branchesThick, resinous or leathery foliageSwollen trunksSpines

Tropical Rainforests

Region roughly parallels equator

Occupies regions 15° to 25° north and south of the equator

Tropical Rainforests Climate

Excess of 250” annual rainfallHi relative humidityDistinct “monsoon” season in some regionsAverage temperatures 73°F Temperatures range from 64°F to 93°F

Monsoon – seasonal wind and

rain associated with southern Asia

Tropical Rainforests Habitat

More plant species per acre than other BiomesTrees can exceed 150’Low light on forest floor

Tropical Rainforests Habitat Forest Floor

Forest divided into “stories” or horizontal sections

Understory – lowest levels, forest floor

Plants adapted to low light

Large, dark green foliage

Tropical Rainforests Habitat

Lower canopy – more light than forest floor – filtered light

Limited biodiversity Upper canopy higher levels of lightTops of the upper canopy in full sunHighly diverse plant and animal

populationUpper canopy rich with epiphytes

Tropical Rainforests Habitat Epiphytes

Epiphytes—“air plants” grow on surfaces of other plantsDon’t require soil to surviveLive attached to rocks or other plantsDon’t harm host plantsIncludes ferns, orchids and bromeliads Epiphytes

Alpine Regions

Mountainous regions world wideSimilar to Tundra but drier

Above “tree line” and below permanent snow lineGritty, fast-draining soils – low in nutrients

Alpine Regions Climate

Long winters – October to MayShort summers – June to SeptemberTemperatures well below freezing to above 60°FCold and dry slows decomposition

Gritty Alpine Soils

Alpine Regions Habitat

Few, very specialized plant speciesAble to withstand cold, dry winds, snow pack, little available waterPlants tend to hug the ground Alpine Flora

Biome Websites

A few websites for Biome research

http://www.blueplanetbiomes.org/world_biomes.htmhttp://www.blueplanetbiomes.org/climate.htmhttp://www.geo.arizona.edu/Antevs/biomes/