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Indianpipe –Monotropa uniflora
Tetraphis pellucida
Range size and abundance
• Ecologists have long suspected that a
species that is widespread in its distribution
may tend to be more common or abundant
in its population size
• What causes such patterns?
• 1. sampling error
• 2. ecological specialization
• 3. local population model
Biomes
• A Biome is a large, relatively distinct
terrestrial ecosystem characterized by
particular climate, soil, plants and animals,
regardless of where it occurs on earth
• A biome's boundaries are determined by
climate more than by any other factor
Tundra
Tundra
• Tundra occurs in extreme northern latitudes where
the snow melts seasonally (southern hemisphere
has no equivalent)
• Tundra has long, harsh winters and very short
summers - growing season is 50 to 160 days
depending on location – summer days are long
• Tundra soils are young - formed after last ice age,
nutrient poor, little organic matter - have
permafrost - permanently frozen layer of soil
Taiga
Taiga
• Taiga - evergreen forests of the north
• Taiga is found in northern America, Asia and
Europe - covers 11% of land
• Winters cold and severe - growing season longer
than tundra - so greater than 160 days - little
precipitation, about 50 cm (20 inches) per year
• Soil is acidic, mineral-poor, deep layer of poorly
decomposed pine and spruce needles at surface
• Numerous lakes and ponds
Temperate rain forests
Temperate rain forests
• Occurs on northwest coast of North America,
western Australia, southern South America, Japan
• very high precipitation - 200 to 380 cm (80 to 152
inches), much condensation from coastal fogs little seasonal temperature variation - winters mild
and summers cool
• Nutrient poor soil, but may have high organic
content
Temperate deciduous forests
Temperate deciduous forests
• Occur where temperate zone precipitation
ranges from 75 to 125 cm (30 to 50 inches)
• Typically have hot summers and cold
winters
• soil has rich topsoil with much organic
matter, deep clay-rich lower layer
Temperate grasslands
Temperate grasslands
• Occur where annual precipitation is 25 to 75 cm
(10 to 30 inches)
• Summers hot, winters cold, rainfall is often
sporadic
• soil is rich in organic matter, minerals build up in
top layer of soil, dead organic matter from annual
die-back of grasses builds up soil organics, grass
roots may form turf or sod
• shortgrass prairies may be called steppes more
rainfall than deserts but not much - 10 to 15 inches
Mediterranean ecosystems
Mediterranean ecosystems
• Mediterranean - thickets of evergreen shrubs and small
trees
• some temperate areas have climates with mild winters with
abundant rainfall and very dry summers - called
Mediterranean climates - occur around Mediterranean,
California, western Australia, Chile, South Africa
• In California we call this ecosystem chaparral - soil is very
thin and nutrient poor
• Fires are common, frequent in late summer, early autumn
• plants usually dense growth of evergreen shrubs, but may
have short scrubby pines and oaks - often have
sclerophyllous leaves - hard, small, leathery leaves that
resist water loss
Deserts
Deserts
• Deserts are very dry habitats of both temperate
and tropical zones - low water content of the
desert atmosphere leads to wide daily temperature
range
• deserts vary greatly depending upon amount of
precipitation - usually less than 25 cm (10 inches)
per year
• desert soil poor in organics, rich in minerals
• some deserts so dry have virtually no plant life Namib and Atacama desert
Tropical savanna
Tropical savanna
• Savannas are a tropical grassland which typically
has widely scattered trees
• either low rainfall or seasonal rainfall with
prolonged dry periods - often 85 to 150 cm (34 to
60 inches)
• Temperature doesn't change much - often in 80's
or 90's
• Savanna soil is low in mineral nutrients
• Savanna found in Africa, South America and
northern Australia
Tropical rainforest
Tropical rainforest
• Tropical rain forest occurs where temperatures are
high throughout the year and precipitation occurs
almost daily - annual precipitation may be 200 to
450 cm (80 to 180 inches) - much of the rainfall is
locally recycled as water that enters atmosphere
from transpiration quickly falls out again
• Soil is usually very old and nutrient poor, low in
minerals and organics - decomposition and
recycling is very quick due to high temperature
and high availability of water
• extremely diverse forests
Distribution of Biomes in Current Climate
Possible Distribution of Biomes in Climate with CO2 Doubled