• Tropical Rain Forests:
• near equator in northern South America, western Africa, and islands between SE Asia and Australia
• broad-leaved evergreens
• richest species diversity of any ecosystem -- also have high biomass
• relatively shallow soils (most nutrients tied up in biomass)
• Temperate Rain Forests
• e.g., NW coast of North America
• conifers and broad-leaved evergreens (lower species richness than tropical rain forests)

Temperate Deciduous Forests

• eastern North America, Europe, and eastern China
• broad-leaved deciduous trees
• precipitation ~30-60" per year; summer and winter seasons
• soils reasonably well developed (leaf fall)

Wilson's Creek National Battlefield, Missouri (photograph by Mark Eberle)

Taiga (Northern and Montane Coniferous Forests)

• Canada, Scandinavia, and Russia (also N-S mountain ranges, such as Rockies)
• conifers (low species richness)
• most precipitation comes as snow
• relatively long winters (short growing season)
• soils relatively thin and acidic

    Calaveras Big Tree (Sequoia) State Park, California  (photograph by Mark Eberle)

Tundra (Alpine and Arctic Tundras)

• Alpine Tundra on highest mountains; Arctic Tundra farthest north in North America, Europe, and Asia
• few trees; mostly shrubby due to soil permafrost
• flora dominated by lichens (fungus + alga) and low-growing plants
• little annual precipitation in Arctic Tundra (<10" per year)

Temperate Grasslands

• central North America, western China, and smaller areas in South America, South Africa, and Australia
• dominated by grasses, with some clumps of trees (e.g., along streams)
• similar climate to temperate deciduous forests, but less precipitation (10-40" per year)
• drier conditions and wildfires limit tree growth
• soils relatively deep (extensive fibrous grass roots)

    Big Creek, Kansas  (photographer unknown)

Savannas (Tropical Grasslands)

• relatively large areas South America, eastern & south-central Africa, and eastern Australia
• dominated by grasses and small trees
• climate with 3 general seasons
• cool-dry, hot-dry, and warm-wet
• ~30-60" of precipitation per year (similar to temperate deciduous forest), but regular drought
• soils somewhat less fertile than those of temperate grasslands

Deserts

• western North America, North Africa, Middle East, central Asia (Mongolia), and central Australia
• dominated by shrubs, succulents (e.g., cacti), and bunchgrasses
• defined primarily by limited precipitation (generally <10" per year)
• "hot deserts" -- short or absent winter season; "cold deserts" -- relatively long winter season

    "Hot Desert", Arizona-Sonora Desert Museum, Tucson, Arizona  (photograph by Mark Eberle)

    "Cold Desert", Great Basin, Nevada  (photograph by Jenn Nylund)

Estuaries (Ecotone)

• ecotones = area of transition between 2 adjacent ecosystems
• estuary = ecotone between freshwater from land and saltwater of ocean
• low species richness
• high productivity (comparable to tropical rain forests)