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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 •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 1. 2. 3. 4. Hot and Dry Deserts Semi-arid Deserts Coastal Deserts Cold Deserts 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-desertcommunity Hot and Dry Deserts: Animals Thorny devil Moloch horridus http://biology.ucr.edu/people/faculty/Garland.html Hot and Dry Deserts: Animals Kangaroo-rat Dipodomys spectabilis 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 Fennec fox Dorcas gazelle 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 Marco polo sheep Proghorn antelope Basin wildrye 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 Rhubarb Rheum rhabarbarum Tumble weed Fringed sagebrush Salsola collina Artimisia frigida Steppes : Fauna Saiga antelope Northern Lynx Saiga tatarica Felis lynx Prairies: Distribution • Found in North America • Dominated by herbaceous plants and grasses Prairies: Vegetation Indian grass Sorghastrum nutans Milkweed Turkey feet grass Andropogon gerardii Asclepias currasavica Prairies: Fauna American bald eagle Haliaeetus leucophalus Prairie dog Cynomis ludovicianus Pampas: Distribution • Found in South America • Flat, fertile plains; warm, humid climate • Frequent fires Pampas: vegetation Silver pampas grass Geofrroy’s cat Cortaderia selloana 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 Emu Black mamba Egyptian mongoose savanna baboons Forest Biome 1. 2. 3. 4. Tropical forests Deciduous forests Alpine forests 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. Tropical forest: Fauna spider Golden toad 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. Himalayan Alpine: Distribution and climate • Dry air, low precipitation • Harsh environment with long cold winters, mild short summers Himalayan Alpine: Vegetation Rhododendron spp. Himalayan Alpine: Fauna Snow leopard Panthera uncia Himalayan tahr Hemitragus spp. 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, 40100 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: vegetation White Birch Betula populifolia White popular Populus alba Taiga Biome: vegetation Douglas fir Pseudotsuga menziesii White spruce Picea glauca Taiga Biome: Fauna American Black bear Ursus americanus Snow shoe rabbit Bald eagle Haliaeetus leucocephalus Lepus 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 Bear berry Tundra biome: vegetation •Adaptations: low growing plant; fine silky hair, leathery leaves Arctic willow Salix arctica Arctic moss Calliergon giganteum Arctostaphylos uva-ursi Tundra biome: animals Arctic fox Lagopus alopex Caribou / Reindeer Rangifer 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/Experi ments/Biome/Images/pictemperate.jpg