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Grassland
greater precipitation, major disturbances are drought and fire
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Tropical grasslands–
–savannahs (Africa’s Serengeti Plain) many grass varieties are tied to rainfall wide spaced patches of drought resistant trees like the acacia
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Temperate grasslands–
tall grass and short grass (Prairies of N. Am.), (Pampas of S. Am), (Veld of Africa), and (steppes of Europe)
Only 1% of US tall grass prairies left, most converted to crop land and hog farms
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Short grass prairies, ....
less H2O and nutrient availability– primarily rangeland or irrigated crop land
- This land was left due to unable to plow and grow crops. Animals include the prairie dog, buffalo, and pronghorn antelope
- Animals are migratory in lifestyle and so are their predators
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Polar grasslands–
- arctic tundra. Covers 1/5 (20%) of the Earth’s surface. Cold, windy, 5" of precipitation/ year– snow (no rain)
- Polar grasslands are really very cold deserts
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Talk more about polar grasslands
- covered with lichens (cyanobacteria– an algae and a fungus), sedges, mosses, grasses, and low shrubs
- -Decomposition slow, permafrost results in summer marshes
- -Slow decomposition, shallow soil, slow plant growth
- -Most fragile ecosystem in the world
- Highly susceptible to human disturbance
- Substantial engineering problems
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Forests–
greater precipitation, less disturbance
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Tropical Rain Forests–
- near the equator, warm year round, heavy rainfall, dominated by evergreen trees, water, heat, sunlight not limiting, soil nutrients low
- **Greatest biodiversity per area on earth
- Soils are poor, when leaves fall and are broken down the nutrients are taken up so quickly there is not build up of material.
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Tropical
rain forest are only__-% of the earth’s surface, but produce ___% of timber, have ___% of all plants and animals
other tropical forests with monsoon season
dry season leaf loss leading to richer soils
7%, 50, 50
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Temperate Deciduous Forests–
- moderate temperatures, four seasons, abundant rainfall, dominant trees (oaks, hickory, maple, sycamore), nutrient rich soils from leaf fall
- 0.1% old growth forests left in the lower 48 states
- Note: an old growth forest has never been harvested
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Chapparal -
unique ecosystem between dry and wet climates
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Boreal forests -
slow tree growth, acidic soils from evergreen needleleaf trees
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