Module 4:

Biomes of the World(Part-I)

Biomes are the the world's major communities, classified according to the predominant

vegetation and characterized by adaptations of organisms to that particular environment

(Campbell )

Biome is a large geographical region whose climate produces a characteristic climax

association of plants and animals

Major Biomes of the World

• Desert• Grassland• Forest• Tundra• Aquatic

– Freshwater– Marine

Distribution of major biomes of the world

Key points to understand a biome

• Climate• Distribution and geography• Special adaptations of vegetation• Types of animals found and their

adaptations

Desert Biome: Distribution

Desert Biome

1. Hot and Dry Deserts

2. Semi-arid Deserts

3. Coastal Deserts

4. Cold Deserts

• Covers one fifth of the land surface

• Rainfall is less than 50 cm per year

• Specialized vegetation and animals

• Soils have abundant nutrients, but little or no organic matter

• Disturbances are fairly common

Hot and Dry Deserts: Distribution

• North America: Chihuahua, Sonoran, Mojave and Great Basin; Southern Asia: Thar; Africa: Sahara, and Australia

                                     

Hot and Dry Deserts

• Climate is warm throughout the year and very hot during summers

• Evaporation rates exceeds rainfall• Soils are course-textured, shallow, rocky or gravely

with good drainage; no subsurface water• Flora: Cactus, ocotillo, turpentine bush, prickly pears, false mesquite, sotol, ephedras, agaves and brittlebush• Fauna: Small nocturnal carnivores, insects, reptiles, birds

Sonoran desert

http://mwsu-bio101.ning.com/forum/topics/a-sonoran-desert-community

Thorny devil

Moloch horridus

Hot and Dry Deserts: Animals

http://biology.ucr.edu/people/faculty/Garland.html

Kangaroo-rat

Dipodomys spectabilis

Hot and Dry Deserts: Animals

Semi arid Deserts

• Montana and Great Basin; North America, Newfoundland, Greenland, Russia, Europe and northern Asia.

• Summers are moderately long and dry• Soil ranges from sandy to fine textured

Semi arid Deserts

• Flora:Creosote bush, bur sage (Franseria deltoidea), Acacia constricta, cat claw cactus, Prosopis spp., brittle bushes (Encelia farinosa), Zizyphus spp.

• Fauna:Rabbits; insects like grasshoppers and ants; lizards and snakes; burrowing owls and the California thrasher

Semi arid Deserts

Coastal deserts• Occur in moderately cool to warm

areas• Soil is fine-textured with a moderate

salt content; fairly porous with good drainage

Coastal Desert

• Flora:

salt bush, buckwheat bush, black bush, rice grass, little leaf horsebrush, black sage, and Euphorbia spp.• Fauna:

spoonbill, sandpiper, coyote and badger, toads, great horned owl, golden eagle and the bald eagle, lizards and snakes

Coastal Desert: Fauna

spoonbill

Dorcas gazelle

Fennec fox

Cold Deserts• Cold winters with snowfall less than 10

inches; short, moist and moderately warm summers

• Soil is heavy, silty and salty

Cold Deserts

• Flora:

Bunchgrass, Artemisia spp.(sagebrush), Chrysothamnus spp. (rabbit bush)

• Fauna:

Proghorn antelope, bighorn sheep, marco polo sheep, mountain lion

Basin wildrye

Marco polo sheep

Proghorn antelope

Grassland Biome: Distribution• Large terrains of grasses, herbs and grasses

• Average annual precipitation is enough to support grasses; erratic..drought and fires prevent growing of trees

• Soil is thin and dry

Steppes

• Dry, cold grassland• Found in USA, Mongolia, Siberia, Tibet

and China • Found between forest and desert biome• Grasses dominate

                                                                                          

Steppes

Steppes: vegetation

Tumble weed

Salsola collina

Fringed sagebrush

Artimisia frigida

Rhubarb

Rheum rhabarbarum

Steppes : Fauna

Saiga antelope

Saiga tatarica

Northern Lynx

Felis lynx

Prairies: Distribution

• Found in North America• Dominated by herbaceous plants and

grasses

                                                                                                

Turkey feet grass

Andropogon gerardii

Indian grass

Sorghastrum nutans

Milkweed

Asclepias currasavica

Prairies: Vegetation

American bald eagle

Haliaeetus leucophalusPrairie dog

Cynomis ludovicianus

Prairies: Fauna

Pampas: Distribution

• Found in South America• Flat, fertile plains; warm, humid climate• Frequent fires

                                                                                                

Silver pampas grass

Cortaderia selloana

Pampas: vegetation

Geofrroy’s cat

Oncifelis geoffroyi

Ombu

Phytolacca dioica

Savanna

• Also known as tropical grasslands• Warm temperature year around with a

very long dry winter,and a lots of rain in the summer

                                                                                                

savanna

Savanna: Flora and Fauna

• Flora:

• Cynodon dactylon, Pennesetum perpureum (napier grass/ elephant grass), Eucalyptus cinerea, Acacia tortilis, Acacia senegal

• Fauna:

• Elephant, buffaloes, antelopes, rhino, Giraffe, Wild Dog, Black Mamba, Caracal, Chacma Baboon, Egyptian Mongoose, Emu, Grant's Zebra, Koala Bear, Lion, leopard, cheetah, Nigriceps Ants, Nile Crocodile

Savanna: vegetation

Euphorbia ingens

Acacia tortilis

Savanna: Fauna

Black mamba

savanna baboons

Egyptian mongoose

Emu

Forest Biome

1. Tropical forests

2. Deciduous forests

3. Alpine forests

4. Boreal forests OR Taiga

Tropical forest: Distribution

                                                        

Tropical Forest Biome

• Occur near the equator

• Cover around 6% of the earth’s surface• Distinct seasonality: winter is absent, and

only two seasons are present (rainy and dry). • Temperature and water are not limiting• Soil is nutrient-poor and acidic.

Decomposition is rapid and soils are subject to heavy leaching

• Greatest diversity of species

Tropical Forest Biome

• Canopy is multilayered and continuous, allowing little light penetration

• Vegetation: mostly evergreen, with large dark green

leaves. Plants such as orchids, bromeliads, vines (lianas), ferns, mosses, and palms are present

• Fauna:numerous birds, bats, small mammals, and insects

Tropical forest: vegetation

Bambusa tulda Ceiba pentandra Ficus spp.

Golden toadspider

Tropical forest: Fauna

Temperate deciduous Forest Biome

• Occur in eastern North America, northeastern Asia, and western and central Europe

• Well-defined seasons with a distinct winter

• Moderate climate and a growing season of 140-200 days during 4-6 frost-free months

Temperate deciduous Forest Biome• Temperature varies from -

30° C to 30° C• Precipitation (75-150 cm)

is distributed evenly throughout the year

• Soil is fertile, enriched with decaying litter

Temperate deciduous Forest Biome

• Flora:Broad leaved deciduous plants-oak, hickory, pine, beech, hemlock, maple, basswood, cottonwood, elm, willow, and spring-flowering herbs

• Fauna:squirrels, rabbits,

skunks, birds, deer, mountain lion, bobcat, timber wolf, fox, and black bear.

Alpine Forests: Distribution

                                                                                                

• Himalayan mountains• Andes mountains…South America• Rocky mountains…western North America

Alpine: Climate

• Found in the high mountains all over the world usually above 10,000 ft.

• Cold and dry throughout the year• Soil is well drained• Vegetation:

Alpine Phaceli, Bear Grass, Bristle cone Pine, Moss Campion, Polylepis Forest, Pygmy Bitterroot, Wild Potato

• Fauna: mountain goat, snow leopard, Yak, Himalayan tahr, takin, marmot etc.

• Dry air, low precipitation• Harsh environment with long cold

winters, mild short summers

Himalayan Alpine: Distribution and climate

                                                                                            

Himalayan Alpine: VegetationRhododendron spp.

Himalayan Alpine: Fauna

Himalayan tahr

Hemitragus spp.

Snow leopard

Panthera uncia

Yak

Bos grunniens

Himalayan Alpine: Fauna

Takin Budorcas taxicolor

Marmot

Marmota himalayana

Taiga biome: Distribution

                                                        

Boreal forests/ Taiga biome

• Largest terrestrial biome, covers 11% area • Broad belt of Eurasia and North America: two-

thirds in Siberia with the rest in Scandinavia, Alaska, and Canada

• short, moist, and moderately warm summers and long, cold, and dry winters

• The length of the growing season is 130 days• Precipitation is primarily in the form of snow,

40-100 cm annually.

Boreal forests/ taiga

• Soil is thin, nutrient-poor, and acidic

• Canopy permits low light penetration, and as a result, under story is limited.

• Flora :Evergreen conifers with needle-like leaves: Balsam Fir, Black Spruce, Douglas-fir, Eastern Red Cedar, Jack Pine, Paper Birch, Siberian Spruce, White Fir, White Poplar, White Spruce

• Fauna: American Black Bear, Bald Eagle, Bobcat, Canadian Lynx, Gray Wolf, Grizzly Bear, Long-Eared Owl, Red Fox, River Otter, Snowshoe Rabbit, Wolverine

Taiga Biome: vegetation

Balsam fir Abies balsamea Jack pine Pinus banksiana

Taiga Biome: vegetationWhite Birch Betula populifolia White popular Populus alba

Taiga Biome: vegetationDouglas fir Pseudotsuga menziesii

White spruce Picea glauca

Taiga Biome: Fauna

American Black bear Ursus americanus Bald eagle

Haliaeetus leucocephalus

Snow shoe rabbitLepus americanus

Tundra biome: Distribution• Tundra Finnish word ‘tunturia’ barren land• Bleak and treeless place• World’s youngest, coldest and driest biome..formed

10,000 years ago• Covers 20% of the Earth’s surface..Northern

hemisphere

Tundra biome: Climate

• The ground is permanently frozen 10 inches to 3 feet

• Main seasons: Winter..summer• Average annual temperature -280C [ max –700C; max 120C]

• Land of midnight sun• Strong winds; 6-10 inches of precipitation each year

• One of the major sinks of carbon

Tundra biome: Lichens

Tundra biome: vegetation

Arctic willowSalix arctica

• Adaptations: low growing plant; fine silky hair, leathery leaves

Arctic mossCalliergon giganteum

Bear berry

Arctostaphylos uva-ursi

Tundra biome: animals

Arctic foxLagopus alopex

Caribou / ReindeerRangifer tarandus

References

• Campbell, N.A. 1996. Biology, 4th Edition. The Benjamin/Cummings Publishing Company, Inc., Menlo Park, California.

• http://www.ucmp.berkeley.edu/exhibits/biomes/marine.php

• http://earthobservatory.nasa.gov/Experiments/Biome/Images/pictemperate.jpg