Page 686 - Geosystems An Introduction to Physical Geography 4th Canadian Edition

650 part IV Soils, Ecosystems, and Biomes
TABLE 20.1 Terrestrial Biomes and Their Characteristics
Biome and Ecosystems
Vegetation Characteristics
Soil Orders of Soil Taxonomy*
Climate Type
Annual Precipitation Range
Temperature Patterns
Water Balance
Tropical Rain Forest
Evergreen broadleaf forest Selva
leaf canopy thick and continuous; broadleaf evergreen trees, vines (lianas), epiphytes, tree ferns, palms
Oxisols Ultisols (on well-drained uplands)
Tropical
180–400 cm (>6 cm/mo)
Always warm (21°–30°C; avg. 25°C)
Surpluses all year
Tropical Seasonal Forest and Scrub
Tropical monsoon forest Tropical deciduous forest Scrub woodland and thorn forest
Transitional between rain forest and grassland; broadleaf, some deciduous trees; open park- land to dense undergrowth; acacias and other thorn trees
in open growth
Oxisols Ultisols Vertisols
(in India) Some Alfisols
Tropical mon- soon, tropical savanna
130–200 cm (>40 rainy days during 4 driest months)
Variable, always warm (>18°C)
Seasonal surpluses and deficits
Tropical Savanna
Tropical grassland Thorn tree scrub Thorn woodland
Transitional between seasonal forests, rain forests, and semiarid tropical steppes and desert; trees with flattened crowns, clumped grasses, and bush thickets; fire association
Alfisols Ultisols Oxisols
Tropical savanna
9–150 cm, seasonal
No cold- weather limitations
Tending toward deficits, therefore fire- and drought-susceptible
Midlatitude Broadleaf and Mixed Forest Temperate broadleaf Midlatitude deciduous Temperate needleleaf
Mixed broadleaf and needle- leaf trees; deciduous broad- leaf, losing leaves in winter; southern and eastern ever- green pines demonstrating fire association
Ultisols Some Alfisols
Humid sub- tropical (warm summer) Humid conti- nental (warm summer)
75–150 cm
Temperate with cold season
Seasonal pattern with summer-maximum PrECIP and POTET; no irrigation needed
Boreal and Montane Forest
Taiga
Needleleaf conifers, mostly evergreen pine, spruce, fir; russian larch, a deciduous needleleaf
Spodosols Histosols Inceptisols Alfisols
Subarctic Humid continental (cool summer) Highland
30–100 cm
Short summer, cold winter
low POTET, moderate PrECIP; moist soils, some waterlogged and frozen in winter; no deficits
Temperate Rain Forest
West Coast forest U.S. coast redwoods
Narrow margin of lush ever- green and deciduous trees on windward slopes; redwoods, tallest trees on Earth
Spodosols Inceptisols (mountainous environs)
Marine west coast
150–500 cm
Mild summer and mild winter for latitude
large surpluses and runoff
Mediterranean Shrubland
Sclerophyllous shrub Australian eucalyptus forest
Short shrubs, drought- adapted, tending to grassy woodlands and chaparral
Alfisols Mollisols
Mediterranean
(dry summer)
25–65 cm
Hot, dry sum- mers, cool winters
Summer deficits, winter surpluses
Midlatitude Grassland
Temperate grassland Sclerophyllous shrub
Tallgrass prairies and short- grass steppes, highly modified by human activity; major areas of commercial grain farming; plains, pampas, and veld; fire association
Mollisols Aridisols
Humid sub- tropical Humid continental (hot summer)
25–75 cm
Temperate con- tinental regimes
Soil-moisture utilization and recharge balanced; irrigation and dry farming in drier areas
Warm Desert
and Semidesert Subtropical desert and scrubland
Bare ground graduating into xerophytic plants including succulents, cacti, and dry shrubs
Aridisols Entisols (sand dunes)
Arid desert
<2 cm
Average annual temperature, around 18°C, highest tem- peratures on Earth
Chronic deficits, irregu- lar precipitation events, PrECIP <1/2 POTET
Cold Desert and Semidesert
Midlatitude desert, scrub- land, and steppe
Temperate desert vegetation including short grass and dry shrubs
Aridisols Entisols
Semiarid steppe
2–25 cm
Average annual temperature around 18°C
PrECIP >1/2 POTET
Arctic and Alpine Tundra
Treeless; dwarf shrubs, stunted sedges, mosses, lichens, and short grasses; alpine, grass meadows
gelisols Histosols Entisols (permafrost)
Tundra Subarctic (very cold)
15–180 cm
Warmest months >10°C, only 2 or 3 months above freezing
Not applicable most of the year, poor drainage in summer
Polar Desert
Mosses, lichens
Permafrost
Ice sheet, ice cap
<25 cm
Warmest months <10°C
Not applicable
* For Canadian Soil Classification System (CSSC) equivalents, see Table 18.3 in Chapter 18.