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Global Climate
Vegetation Relationships
Weather vs. Climate
• Weather
– short-term condition of the atmosphere
– days, weeks
– meteorologists
• Climate
– long-term (30 year) average of weather
conditions and extremes
– climatologists
Climate Determinants
• Insolation and Temperature
– latitude, altitude, land-water, ocean
currents, mountain barriers
• Precipitation
– Air pressure (ITCZ and Subtropical
– Air mass influences
– Prevailing winds
The Köppen Climate
• A Tropical (equatorial regions)
• B Deserts (arid, semiarid)
• C Mesothermal (mild winter)
• D Microthermal (boreal, cold winter))
• E Polar (always cold)
• H Highland (mountains, plateaus)
The Köppen Climate
3 letter system
First letter = temperature
Second letter = precipitation
Third letter = finer shades of temp
Csb = mediterranean
C = middle latitude temps
s = summer dry
b = warm summers (as opposed to hot [a])
Reading a Climograph
Climate Regions
Koppen’s Categories
Vegetation Regions
Tropical Climates (A)
Tropical Humid Climates (Af)
1/3 of Earth’s total surface (about 20 ºN to 20 ºS)
Consistently warm (all months > 18ºC/64.4 ºF)
Annual precipitation exceeds evaporation
Daily temp range exceeds annual temp range
Subcategories based on rainfall (ITCZ influence)
– Tropical rainforest
– Tropical monsoon
– Tropical savanna
Tropical Rainforest (Af)
• High rainfall all year (>2” /
• Straddles Equator by 5o - 10o
Tropical Rainforest
– Vegetation : Highest biomass on earth! Highest
biodiversity on earth! Thousands of species, tall trees, many
canopy layers, evergreen, broadleaf trees, epiphytes, lianas
(vines), climbers, stranglers, ferns
– Fauna: More species than all other biomes combined!, colorful
insects, amphibians, reptiles, and birds, few large animals, high
density of biomass and incredible species diversity
• Other: Among most threatened biomes
Deforestation, Malaysia
Strangler Fig
3-Toed Sloth, Panama
Savanna (Aw) – Tropical Grassland Climates
• Region/Distribution: Subequatorial Africa,
and South America, Southern India (25° N
and S Latitude)
• Vegetation: Continuous cover of grasses,
scattered trees or shrubs
• Fauna: Large grazing animals; antelope,
zebra, giraffe, elephant, Predators: lions,
leopards, cheetahs, hyenas
Masai Reserve, Kenya
• Other: Susceptible to desertification
Acacia and Wildebeest
Serengeti Plain, Tanzania
Dry / Semiarid Climates (B)
• Occupy about 1/3 of Earth’s land area
(Most extensive climate over land surface)
• Evaporation exceeds precipitation
(water deficit)
• Subcategories
– Desert (BW)
– Steppe (BS)
Dry Arid / Semiarid Climates (B)
Deserts (BW): dry
Deserts (BW):
• Widest range: up to 100oF/day!
• Hot at low latitudes, wide
variation at higher latitudes
• Scarce: <10 inches/year
• Unreliable: wide variation
from average
• Intense: convective downpours
Desert Causation:
• High Pressure Cells and
resultant stability
• Rainshadows
• Vegetation: Widely scattered thorny bushes,
cacti, small flowers, extensive shallow roots
or long tap roots, shrubs, succulents
• Fauna: Many rodents, lizards, toads, snakes
and other reptiles, many birds, owls,
vultures, many insects (adaptive strategies)
• Other: Deserts cover roughly 1/3 of earth.
May be growing due to desertification.
• Steppe: semi-arid high elevation or high
Desert Plant Survival Strategies
 schlerophyllous adaptations
- small, waxy leaves or thorns
replace leaves
 succulents - stems modified
to spongy water storage
 ephemerals (obligate seeders)
- fast reproductive cycle
 wide spacing with shallow
roots - collect sparse rainfall
Animal survival strategies?
Death Valley, CA
Anza-Borrego State Park, CA
Winter 2004/2005
Organ Pipe Cactus
Organ Pipe National Monument, Arizona
Steppe (BS): temperate grasslands
• more precipitation than BW
• narrower temperature ranges
• grasslands
Grassland (temperate)
• Region/Distribution: Central North America, parts
of Africa, Australia, SE South America (Pampas)
• Soil: very fertile soils, best on earth
• Vegetation: Grass tall to short prairie, pampas,
steppe. Sod forming grasses, Sparse bushes,
occasional trees in some areas
• Fauna: large grazing animals, bison, antelope, wild
horses, kangaroos, giraffes, burrowing animals:
rabbits, prairies dogs…; predators: coyotes, lions,
• Other: Most N. American grasslands have been
converted to agricultural fields. Wild grazers replaced
by cattle, sheep, goats. Less than 1% of original grasses
Mesothermal Climates (C)
• “Middle temperature”
• True seasonality
(air mass conflict)
• Subdivisions based on
precipitation variation
– humid subtropical
– marine west coast
– Mediterranean
Marine West Coast
Temperate Rainforest
Olympic Peninsula, Washington
Subtropical Forest
Sarasota, Florida
Mesothermal Climates (C)
Humid Subtropical
Marine West Coast
• Hot summer, substantial
Humid Subtropical year-round precipitation
• Low latitude east coasts
Midlatitude Forests
(warm currents).
• Summer max precipitation.
• Cold spells
Cfa - New Orleans, LA
Temperate Forest (Deciduous)
• Region/Distribution: Western Europe, East Asia,
Eastern U.S.. Between 30-50° north or south
• Soil: brown soils, good for agriculture
• Vegetation: Broad-leafed deciduous trees, (120150’ tall), oaks, hickories, maples,…
• Fauna: mammals such as white tail deer,
porcupines, raccoons, rabbits, squirrels, most
carnivores eliminated by hunting i.e. wolf,
mountain lion, bobcat; many birds; frogs and
salamanders, snakes
• Other: Biota well adapted to seasonality
including hibernation, migration
• Dry summers (shifting
subtropical highs)
• Surrounds Mediterranean
• Also on west coasts near 30o N
and S (Australia, S. Africa,
• Region/Distribution: West coast and Central
California, SW. Australia, tip of S. Africa, West
Peru. Chile, Mediterranean (good wine places!)
• Vegetation: Grassland, scattered trees (oaks,
eucalyptus), scrub. Fire tolerant, sclerophyllous
(hard leaf) evergreens, chaparral (scrubby
• Fauna: Burrowers like ground squirrels, gophers;
deer, mountain lions, coyotes, many birds
• Other: Susceptible to fire during dry season, some
species need fire to regenerate, Susceptible to
erosion and desertification, development,
Microthermal Climates (D)
Virtually restricted to Northern Hemisphere.
• 50o-70o N latitude
• long, bitterly cold winters
• highest annual temp range: up to
100O F
•Great annual temperature ranges
(continentality, air mass conflicts)
Dw – Calgary, Canada
Coniferous (Boreal) Forest – Koppen D
• Region/Distribution: Northern parts of
North America, Europe and Asia, South So.
America, much of Russia
• Vegetation: Coniferous (mostly evergreen)
forest, ex. Spruce, Fir, Pine, Larch, needleleaved
• Fauna: Large herbivores: moose, elk; small
herbivores: squirrels snowshoe hare, beaver;
Predators: wolves, foxes, bears, lynx, weasel
family; Mosquitoes in summer
• Other: Acid rain, logging , oil drilling,
hunting of predators
Fir Trees, Alaska
Spruce Needles
British Columbia
Polar Climates (E)
- all months < 50OF
Polar Climates (E)
- all months < 50OF
• Tundra (ET)
– warmest month 32-50F
• Ice caps (EF)
– warmest month below 32F
• Both have very low precipitation
Highland Climates (H)
How are these like the poles? How different?
Highland Climates (H)
How are these like the poles? How different?
• Lower temperatures
• More moisture available
• More insolation
• High winds in both
Where in the world is?…..
Verkhoyansk, Russia (67.4 N, 133.3 E)
Where in the world is?…..
Iquitos, Peru (3.4 S, 73.2 W)
Where in the world is?…..
Hilo, Hawaii
Where in the world is?…..
West Point, NY
Where in the world is?…..
San Francisco, California
The Köppen Climate
• A Tropical (equatorial regions)
• B Deserts (arid, semiarid)
• C Mesothermal (mild winter)
• D Microthermal (boreal, cold winter)
• E Polar (always cold)
• H Highland (mountains, plateaus)
The Köppen Climate
• A Tropical (equatorial regions)
• B Deserts (arid, semiarid)
• C Mesothermal (mild winter)
• D Microthermal (boreal, cold winter)
• E Polar (always cold)
• H Highland (mountains, plateaus)
Vegetation that grows along
water courses.
Often supports richer
diversity of plant and
animal life, including
more hardwood trees in a
dry environment.
Vertical Zonation of Vegetation
Vegetation Succession
Pioneer Stage
Climax Stage
Occurs after disturbances: fires, storms, landslides, etc.
Ecological Invasions
California Invasive Species: Old World Grape, livestock,
Eucalyptus (Gum Trees), wild hog, mustards, horse,
Mediterranean grasses/mustards
Methods of Transfer
• Domesticated animals (fur,
• Ornamentals
• International tourism/migrations
(New Zealand)
Problems with Invasives
• Often out-compete endemics.
• Don’t provide habitat for local
• Upset balance of ecosystem.
The American Chestnut
100 feet tall, thick symmetrical branches, over an acre of
greenery, about a million lush leaves in all. Massive
quantities of protein-rich nuts.
In 1904 a handful of Asian chestnut trees were planted in
New York City at the Bronx Zoo. An Asian chestnut blight
quickly destroyed over 99.99 percent of the American
Chestnut population - almost all of four billion trees annihilating at least six specialized insect species,
decimating wild turkey populations, and depriving humans
of a priceless resource in a single generation.
This loss represented one fourth of the tree cover in
the Appalachians!