GLOBAL BIOME PATTERNS

A. INTRODUCTION

Image credit: NASA Visible Earth http://visibleearth.nasa.gov/view_rec.php?id=2430

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B. FOREST BIOME

TROPICAL RAINFOREST (selva) Climate: tropical rainforest (Af) high PE high AE high NPP chronic surpluses Primary limiting factor: none competition for sunlight and space Soils: oxisols and some ultisols Vegetation broadleaf evergreen trees layered ecosystem: understory, canopy layer, emergent layer thick root mat on forest floor very high diversity

Image credit: Marietta College Department of Biology and Environmental Science's Biomes of the World http://www.marietta.edu/~biol/biomes/biome_main.htm

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TROPICAL DECIDUOUS FOREST & SCRUB WOODLAND Climate: tropical wet and dry (Aw) high PE seasonally high AE relatively high NPP seasonal droughts Primary limiting factor: dry winter Soils: oxisols, ultisols, alfisols Vegetation more open than tropical rainforest; grades into savanna denser understory than tropical rainforest mix of broadleaf evergreen and broadleaf deciduous trees not as diverse as tropical rainforest

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MEDITERRANEAN WOODLAND & SCRUB (chaparral) Climate: Mediterranean (Cs) hot, dry summer high summer PE low summer AE seasonal deficit Primary limiting factor: lack of moisture in summer Soils: alfisols Vegetation drought resistant trees and shrubs small, thick waxy leaves adapted to fire

San Gabriel Mountains, California Image credit: K.A. Lemke Chaparral in Oregon Image credit: US Department of the Interior, Burea of Land Management, Medford District. http://www.blm.gov/or/resources/recreation/tablerock/table-rock-plants-chaparral.php

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MIDLATITUDE DECIDUOUS & MIXED FOREST Climate: humid subtropical (Cfa), marine (Cfb), humid continental (Dfa, Dfb) moderate to moderately high AE and PE depending on seasonal pattern of precipitation & temperature moderate to moderately high NPP seasonal surplus; little deficit Primary limiting factor: cold winter temperatures Soils: ultisols & alfisols Vegetation deciduous broadleaf trees dominate (oak, maple, beech, hickory, elm) also evergreen needleleaf trees understory generally well-developed moderate species diversity

Image credit: K.A. Lemke Image credit: Tom Detwyler, World Biomes CD-ROM, Environmental Views series. Used with permission from Optilearn Inc. Stevens Point, WI.

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NORTHERN CONIFEROUS /BOREAL FOREST (taiga) Climate: Dfc, Dfd cold temperatures (slow photosynthesis, frozen water) moderately low precipitation; primarily in summer moderately low AE and PE moderately low NPP seasonal surplus; no deficit Primary limiting factor: cold temperatures Soils: spodosols; thick litter layer Vegetation: coniferous forests needleleaf evergreen trees (spruce, pine, fir, larch) broadleaf deciduous trees (alder, birch, aspen) in early successional sites sparse understory fire Animals: moose, bear, deer

Image credit: U.S. Fish & Wildlife Service, Digital Library System http://images.fws.gov/

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C. SAVANNA BIOME

Climate: tropical wet and dry/savanna (Aw) and drier margins of tropical rainforest (Af) high PE seasonal AE moderate NPP seasonal drought Primary limiting factor: dry winter Soils: alfisols, some ultisols Vegetation continuous cover of grasses with scattered drought resistant trees trees have deciduous habit or deep tap roots Animals grazing herds of herbivores: buffalos, giraffes, elephants, zebra, oryx, predators: lions, cheetas, leopards, hyenas Moderately high diversity

Tanzania Image credit: B. Wolff, United Nations. World Biomes CD-ROM, Environmental Views series. Used with permission from Optilearn Inc. Stevens Point, WI. Zambia Image credit: M. Boulton, F.A.O. World Biomes CD-ROM, Environmental Views series. Used with permission from Optilearn Inc. Stevens Point, WI.

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D. GRASSLAND BIOME  

Climate: BSh, BSk, drier margins of Cf and Df PE varies depending on temperature moderate to moderately low AE moderate NPP slight seasonal drought Primary limiting factor: moisture Soils: primarily mollisols; some aridisols Vegetation: prairie grassland (tallgrasses; up to 6 ft) steppe grassland (shortgrasses) extensive root systems fire tolerant Animals: herd animals (e.g. bison, antelope) burrowing animals (e.g. prairie dogs) carnivores (e.g. coyotes) Image credit: Jeff Vanuga, USDA Natural Resources Conservation Service http://photogallery.nrcs.usda.gov/Detail.asp

Image credit: Lynn Betts, , USDA Natural Resources Conservation Service http://photogallery.nrcs.usda.gov/Detail.asp Image credit: Bureau of Land Management (BLM), Wyoming http://www.wy.blm.gov/botany/habitats.htm