Woody Plants BI237
Week 13
BIOME:
TEMPERATE FOREST
GEOGRAPHY:
NE US, Mid-latitudes in Eurasia
CLIMATE:
4 seasons; plenty of ppt.
SOILS:
usually fertile, especially under deciduous forests
BIOLOGY:
Lots of biomass. Vertically structured.
Seasonality -- dormancy; migration.
Heavily impacted but resiliant.
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BIOME:
BOREAL FOREST = TAIGA
GEOGRAPHY:
50-65 degrees latitude; 11% of land area of Earth
CLIMATE:
long winters, moderate ppt.
SOILS:
nutrient poor, acidic. decomposition slow.
BIOLOGY:
coniferous forests; ericaceous shrubs.
Caribou, moose, wolves, bears, porcupines, hare, etc.
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BIOME:
TUNDRA
GEOGRAPHY:
N. of Arctic Circle
CLIMATE:
cold and dry (sinking air at poles)
but ppt > evap b/c of low temp
SOILS:
permafrost, but surface thaws
slow decomposition; peat
BIOLOGY:
mosses & lichens, sedges & grasses
dwarf willows & birches; Ericaceous shrubs
swarms of biting insects
caribou, wolves, lemmings, arctic foxes, snowy owls
Woody Plants BI237
Week 13
BIOME:
DESERT
GEOGRAPHY:
30 degrees N and S latitude. Also rain shadows
CLIMATE:
ppt < evapotranspiration most of the year
SOILS:
very low in O.M.
accumulate minerals + salt as water evaps.
BIOLOGY:
adaptations to minimize water loss
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BIOME:
TROPICAL SAVANNAH
GEOGRAPHY:
Towards equator from deserts
CLIMATE:
Short season of rains.
SOILS:
Soils have low permeability; waterlogged during rains.
BIOLOGY:
Migrating herds in Africa: giraffes, zebras, wildebeests, humans.
Kangaroos in Australia.
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BIOME:
TEMPERATE GRASSLANDS
GEOGRAPHY:
much of Eurasia, mid-continent N. America, Argentina
CLIMATE:
cold winters and hot summers. Not enough ppt for forest.
SOILS:
Often quite rich and deep
BIOLOGY:
Grass most of biomass. High diversity
Dense network of roots; 2-3 x more below than above ground.
Grass co-evolved with grazers
Fire encouraged by hot/dry summers.
Breadbasket of world -- sustainable?
Woody Plants BI237
Week 13
BIOME:
TROPICAL DRY FOREST
GEOGRAPHY:
Africa; N. and S. of rainforests
America, S. of Amazon
W. Central America (rain shadow)
Asia -- most of India & Indochina
N and NE Australia
CLIMATE:
Temperature fairly constant; slightly warmer in wet season
Dry season 6-7 months; heavy rain during wet season
SOILS:
Most soils very old and highly weathered
BIOLOGY:
Tree height is related to rainfall.
Grades into savannah in drier areas.
Percent leaf drop related to length of dry season.
Trees often flower during dry season.
Many animals congregate at water sources: parrots, monkeys, cats.
Very heavily utilized biome.
Most benign climate in tropics. Easy to burn.
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BIOME:
TEMPERATE WOODLAND (CHAPPARAL; MEDITERRANEAN)
GEOGRAPHY:
W sides of continents
S. Africa, Mediterranean, central Chile, California, S. Australia
CLIMATE:
Cool & moist during fall, winter, spring.
Summer hot and dry.
SOILS:
Reputation for being fragile. Hot fires a problem.
BIOLOGY:
Evergreen foliage conserves water and nutrients.
Thick, tough bark resistant to fire.
Plants rich in oil and burn easily but resprout readily.
Climate of classical Greece. High population densities of humans.
Woody Plants BI237
Week 13
BIOME:
TROPICAL RAINFOREST
GEOGRAPHY:
Straddle equator.
CLIMATE:
Warm and wet year-round. Can rain even in "dry" season.
SOILS:
Typically clay, heavily weathered, low nutrients.
More nutrients in vegetation than in soil.
Decomposition very rapid.
Roots of plants on surface of soil -- competition for new nutrients.
VAM mycorrizhae important. P limiting nutrient.
Nutrients lost very rapidly when soils cleared/burned.
Some tropical soils on recent volcanos. Much better soil.
BIOLOGY:
Incredibly diverse!
300 tree species/ hectare
Next hectare may add another 50-100 species
Millions of undiscovered insect species
Vertical stratification. Many layers
Vines, epiphytes add to structural complexity.
Monocots are "trees". Palms for example.
No vascular cambium but make a thick stem.
Stem doesn't get wider as grows.
Only one bud at the top of the tree; grows vertically.
Biotic interactions important.
Pollination by many species of bees.
Also by moths, butterflies, birds, bats.
Seed dispersal often by animals. Birds, primates, other mammals.
Seed dormancy rare. Use it or lose it.