Transcript Conditions - Distribution and Abundance

Evolutionary Ecology
Evidence of local adaptation
Environmental or Genetic
Variation in WesternYarrow?
Creeping Bent Grass - Agrostis stolonifera
Adaptation in Trinidad Guppies
Poecilia reticulata
Male and Female
Two males
Adaptation and natural selection in
guppy populations
John Endler
Cline – Bergmann’s Rule
Bergmann’s Rule in Bears
Sun bear, Spectacled bear, Brown bear, Polar bear
Bergmann’s Rule in moose in Sweden
Cline – Allen’s Rule
Arctic
Cool Temperate Warm Temperate
Desert
White clover – Trifolium repens
Cline in
cyanide
production
by white
clover –
dark circle
populations
with
cyanide;
white circle
lack cyanide
Clinal variation in gulls
Herring Gull
Lesser Black-backed Gull
Environment and Abundance;
Biomes
Conditions
• An abiotic factor that influences the
immediate survival of an organism –
temperature, humidity, pH, salinity, wind
velocity, current flow, soil, pollutants, etc.
Law of the Minimum
• The distribution of a species will be
controlled by that environmental factor for
which the organism has the narrowest range
of adaptability or control.
- Carl Sprengel 1828
Liebig’s Law of the Minimum - 1840
Or – the nutrient in lowest supply will set the limit to plant growth
Range of Tolerance Limits
Distribution
• Is there a relationship between geographic
range (distribution) and population size?
Tetraphis pellucida
Rule of thumb: The range of the average
species corresponds to the range of the
average graduate student.
University of Connecticut Ecology Grad Students
south
north
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
Sampling Errors – Rare Species
Knotroot bristlegrass and peregrine falcon
Ecological specialization - generalists
Local population model - dispersal
Climate and distribution
• Climate, particularly
temperature and precipitation,
influences the distribution of
the earth's terrestrial organisms
• In each major kind of climate, a
distinctive type of vegetation
develops - for desert plants
occur in arid (dry) climates,
grasses with semi-arid climates
and forests with moist climates
• Certain animals, fungi and other
organisms are associated with
particular vegetation types
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
Biomes
Limits to Biome Distribution
Limits to Biome Distribution
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
• Plants mostly less than 30 cm tall – mosses,
lichens, sedges, grasses
• Animals – weasels, foxes, snowshoe hares,
ptarmigan, caribou, mosquitoes, blackflies
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 - 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
• Plants – aspen, birch, but spruce and fir dominate
• Animals – caribou, wolves, bears, moose, rodents,
rabbits, lynx, sable, many migratory birds, many
insects
Temperate rain forests
Temperate rain forests
• Occurs on northwest coast of North America,
southwestern Australia, southern South America,
nothern 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
• Plants – evergreen trees – western hemlock,
Douglas-fir, Sitka spruce, western red cedar, many
epiphytes – mosses, lichens, ferns
• Animals – squirrels, deer and numerous birds
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
• In US dominant plants are broad-leaved trees –
oaks, hickory, beech maple – in south broadleaved evergreens – live oak, magnolia
• Animals – deer, bear, wolves, cougars, rodents,
many birds, many reptiles and amphibians
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
• Plants – grasses dominate – tallgrasses where
wetter, shortgrasses where drier – trees only along
rivers
• Animals – bison, antelope, wolves, coyotes,
prairie dogs, ferrets, birds of prey, grouse, reptiles,
many insects
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
• Animals – mule deer, wood rats, chipmunks, lizards, many
songbirds, other birds
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
• Plant cover sparse, much soil exposed – perennial
and annual or ephemeral plants – in North
America – cacti, yucca, Joshua trees, bunchgrass
• Animals – small – rodents, lizards, tortoises,
snakes, birds, insects
Tropical savanna
Tropical savanna
• Savannas are a tropical grassland which typically
have 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
• Tropical savanna found in Africa, South America
and northern Australia
• Plants – grasses, acacia trees – adapted to survive
or recover quickly from fire
• Animals – huge herds of hoofed mammals in
Africa – many predators – lion, leopard, hyena,
wild dog
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 - trees, lianas –
evergreen flowering trees
• Animals – very diverse insects, reptiles,
amphibians, birds, monkeys, sloths
Distribution of Biomes in Current Climate
Possible Distribution of Biomes in Climate with CO2 Doubled
Global Climate Change
Potential climate migration for Illinois
Will my prairie ecosystem change from this
to this?
Illinois tallgrass prairie
East Texas Piney Woods
Or something entirely different?
Dan Janzen has predicted that with increasingly
human dominated ecosystems, global climate
change and the spread of cosmopolitan nonnative species, the entire world will become
ecologically uniform.