biomes an introduction to the biomes of the world
TRANSCRIPT
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/