Transcript Climate and Terrestrial Biodiversity

Climate and Terrestrial Biodiversity
Chapter 7
Miller and Spoolman (2010)
Core Case Study: Connections between
Wind, Climate, and Biomes
 Why are some areas of earth’s land surface covered by desert,
another by grassland, and another by forest?
 Climate – long-term differences in average temperature and
precipitation caused by global air circulation.
 Wind
 Indirect form of solar energy
 Circulatory system for heat, moisture, plant nutrients, soil particles,
and long-lived air pollutants.
 Wind as a transport of nutrients
 Carries dust rich in Pi and Fe across the Atlantic Ocean from the Sahara
Desert.
  build ag-soils in Bahamas and rainforests in Brazil
 From China’s Gobi Desert deposits Fe into the Pacific between Hawaii
and Alaska.
  Stimulates growth of phytoplankton—base of ocean food webs.
 Downside of wind
 Transports harmful pollutants
 From Africa’s deserts
 Reddish brown soil and pesticides (banned in U.S.) to sky of Florida
 Some types of Fungi in dust may degrade coral in FL Keys and Caribbean
 Fe-rich dust enhances productivity of toxic algal blooms—called red tide
 From rapidly industrializing China and c. Asia
 Degrades air quality in western U.S.
o 10% of w. coast smog
 May intensify heat trapping by atmosphere
 Ecological lesson: Everything we do affects some other part of
the biosphere because everything is connected.
Figure 7.1
Some of the dust blown from West Africa, shown here, can end up as soil
nutrients in Amazonian rain forests and toxic air pollutants in the U.S. state of
Florida and in the Caribbean. It may also help to suppress hurricanes in the
western Atlantic.
7-1 What Factors Influence Climate?
 Concept 7-1 An area's climate is determined mostly by
solar radiation, the earth’s rotation, global patterns of air and
water movement, gases in the atmosphere, and the earth’s
surface features.
The Earth Has Many Different
Climates
 Weather – is local area’s short-term temperature,
precipitation, humidity, wind speed, cloud cover, and other
physical conditions in the atmosphere as measure over days
and hours.
 Climate – is an area’s general pattern of atmosphere or
weather conditions over long periods of time ranging from
decades to thousands of years.
 Varies in different parts of the earth because patterns in global
air circulation and ocean currents distribute heat unevenly.
 Three major factors determine how air circulates in lower
atmosphere:
 Uneven heating of earth’s surface by the sun.
 Rotation of the earth on its axis (Figure 7.3)
Coriolis effect
 Cells
 Prevailing winds – major surface winds that blow continuously and
help distribute air, heat, and dust over the earth’s surface.
 Properties of air, water, and land (Figure 7.4)
 Convection
 Heat from sun creates giant cyclical convection cells
o Circulates air, heat, and moisture

Figure 7.2
Natural capital: generalized map of the earth’s current climate zones, showing the major
contributing ocean currents and drifts and upwelling areas (where currents bring nutrients
from the ocean bottom to the surface). Winds play an important role in distributing heat
and moisture in the atmosphere, which leads to such climate zones. Winds also cause
currents that help distribute heat throughout the world’s oceans. Question: Based on this
map what is the general type of climate where you live?
Figure 7.4
Energy transfer by convection in the atmosphere. Convection occurs when hot
and wet warm air rises, cools, and releases heat and moisture as precipitation
(right side). Then the denser cool, dry air sinks, gets warmer, and picks up
moisture as it flows across the earth’s surface to begin the cycle again.
 Prevailing winds and the earth’s drive the earth’s major ocean
currents (Figure 7.3)
 Currents redistribute heat from the sun
 Influences climate and vegetation, esp. near coastal areas.
 Heat absorbed by oceans in tropical areas
 Prevailing winds and irregularly shaped continents
  currents flowing in roughly circular patterns
 Clockwise in northern hemisphere
 Counterclockwise in southern
 More on heat transfer
 Vertical mixing in deep and shallow ocean currents
 Creates a loop of deep and shallow water currents
 Like a giant conveyor belt
o Moves heat to and from deep sea
o Transfers warm and cold water between tropics and poles (Fig. 7.5)
Figure 7.5
Connected deep and shallow ocean currents. A connected loop of shallow and deep ocean
currents transports warm and cool water to various parts of the earth. This loop, which
rises in some areas and falls in others, results when ocean water in the North Atlantic near
Iceland is dense enough (because of its salt content and cold temperature) to sink to the
ocean bottom, flow southward, and then move eastward to well up in the warmer Pacific. A
shallower return current aided by winds then brings warmer, less salty—and thus less
dense—water to the Atlantic. This water can cool and sink to begin this extremely slow
cycle again. Question: How do you think this loop affects the climates of the coastal areas
around it?
 The ocean and the atmosphere are strongly linked in two
ways.
 Ocean currents are affected by winds.
 Heat from the oceans affects the atmosphere
 Example: The El Nino-Southern Oscillation
 Occurs every few years when prevailing winds in the tropical Pacific
Ocean weaken and change direction
  above average warming of Pacific waters
  changes distribution of nutrients (Fig. 6, Suppl. 8)
  alters weather patterns of at least 2/3 of the earth for one to two
years (Fig. 5, Suppl. 8)
Figure 6
Locations of flowing masses of warm water in the Pacific Ocean during El Nino.
Figure 5
Typical global weather effects of an El Nino-Southern Oscillation
Figure 7.6
Global air circulation, ocean currents, and biomes. Heat and moisture are distributed over
the earth’s surface via six giant convection cells (like the one in Figure 7-4) at different
latitudes. The resulting uneven distribution of heat and moisture over the planet’s surface
leads to the forests, grasslands, and deserts that make up the earth’s terrestrial biomes.
 Global air circulation
patterns, prevailing winds,
and configuration of
continents and oceans
  Six giant convection
cells (Fig. 7.6)
 3 cells north of equator
 3 cells south of equator
 ` Irregular distribution of
climates and deserts,
grasslands, and forests
Greenhouse Gases Warm the
Lower Atmosphere
 Figure 3.8, Energy flow to and from earth
 Greenhouse gases play a role in determining the earth’s
average temperatures.
 Water vapor (H2O), carbon dioxide (CO2), methane (CH4),
and nitrous oxide (N2O).
 Absorb and re-radiate IR.
 Greenhouse effect is the natural warming caused by ghg.
Figure 3.8
Solar capital: flow of energy to and from the earth.
 Human-enhanced global warming
 Climate models: 90-99% probability that human activities are
increasing ghe.
 Burning fossil fuels, clearing forests, and growing crops
  changes in climate that
could last 100s to 1000s
of years
 Alters precipitation patterns
 Shifts areas where crops can
grow
 Raises sea levels
 Shifts habitats for some types of
plants and animals
The Earth’s Surface Features Affect
Local Climates
 Heat is absorbed and released more slowly by water than by land.
 Creates land and seas breezes
 Moderates climate in coastal and lakeshore areas
 Topography of earth’s surfaces
 Creates local and regional weather and climates that differ the
general climate from the region.
 Example: Mountains, surface winds and the rain shadow effect
 Cities create distinct microclimates
 Bricks, concrete, and asphalt absorb heat
 Buildings block wind
 Motor vehicles and air conditioning units
  haze and smog, higher temperatures and lower winds speeds
Figure 7.7
The rain shadow effect is a reduction of rainfall and loss of moisture from the landscape on
the side of a mountain facing away from prevailing surface winds. Warm, moist air in
onshore winds loses most of its moisture as rain and snow on the windward slopes of a
mountain range. This leads to semiarid and arid conditions on the leeward side of the
mountain range and the land beyond. The Mojave Desert in the U.S. state of California and
Asia’s Gobi Desert are both produced by this effect.
7-2 How Does Climate Affect the
Nature and Locations of Biomes?
 Concept 7-2 Differences in average annual precipitation
and temperature lead to the formation of tropical,
temperate, and cold deserts, grasslands, and forests, and
largely determine their locations.
Climate Affects Where Organisms
Can Live
 Biomes – large terrestrial regions characterized by similar
climate, soil, plants and animals, regardless of where they are
found in the world.
 The worlds major biomes vary with climate (compare Figs.
7.2 and 7.8.
Figure 7.8
Natural capital: the earth’s major biomes—the main types of natural vegetation in various
undisturbed land areas—result primarily from differences in climate. Each biome contains
many ecosystems whose communities have adapted to differences in climate, soil, and other
environmental factors.
 Biomes are not uniform, but consist of a mosaic of patches each
with somewhat different biological communities but with
similarities typical of the biome.
  resources are not evenly distributed
  human activities
 Climate and vegetation vary with latitude and elevation (Fig.
7.9)
 Differences in climate, mostly annual precipitation and
temperature lead to the formation of tropical (hot), temperate
(moderate) and polar (cold) deserts, grasslands and forests (Fig.
7.10)
Figure 7.9
Generalized effects of elevation (left) and latitude (right) on climate and biomes. Parallel
changes in vegetation type occur when we travel from the equator to the poles or from
lowlands to mountaintops. Question: How might the components of the left diagram
change as the earth warms during this century? Explain.
Figure 7.10
Natural capital: average precipitation and average temperature, acting together as limiting
factors over a long time, help to determine the type of desert, grassland, or forest biome in
a particular area. Although each actual situation is much more complex, this simplified
diagram explains how climate helps to determine the types and amounts of natural
vegetation found in an area left undisturbed by human activities.
Science Focus: Staying Alive
in the Desert
 Two main themes for survival in the desert: beat the heat and
every drop of water counts.
 Plant adaptations
 Animal strategies and adaptations
There Are Three Major Types of Deserts
 Deserts are characterized annual precipitation is low and




scattered unevenly throughout the year.
Tropical deserts (examples: Sahara and Namib)
Temperate deserts (example: Mojave; Figure 1, Suppl. 9)
Cold deserts (example: Gobi in Mongolia)
Fragile ecosystem
 Soils are slow to recover because of
 Slow plant growth
 Low species diversity
 Slow nutrient recycling
 Lack of water
Figure 7.11
Climate graphs showing typical
variations in annual
temperature (red) and
precipitation (blue) in tropical,
temperate, and cold deserts.
Top photo: a popular (but
destructive) SUV rodeo in
United Arab Emirates (tropical
desert). Center photo: saguaro
cactus in the U.S. state of
Arizona (temperate desert).
Bottom photo: a Bactrian camel
in Mongolia’s Gobi Desert (cold
desert). Question: What month
of the year has the highest
temperature and the lowest
rainfall for each of the three
types of deserts?
Figure 1, Suppl. 9
Some components and interactions
in a temperate desert ecosystem.
There Are Three Major Types of
Grasslands
 Occur mostly in the interiors
of continents and persist
because of a combination of
seasonal drought, grazing by
large herbivores, and
occasional fires.
 Tropical, Temperate, and
Cold (arctic tundra)
 Tropical
 Savanna
 Resource partitioning
 Grazing animals
 Browsing animals
 Plants adapted to survive heat
and drought.
 Temperate
 Winters, bitterly cold;
summers, hot and dry; annual
rain, unevenly distributed
 Deep fertile soils
  many have disappeared
 Two types
 Tall-grass prairies
 Short-grass prairies
 Arctic tundra: fragile biome
 Adaptations of plants and
animals
 Permafrost
 GW and melting.
 Alpine tundra
Figure 7.12
Climate graphs showing typical
variations in annual
temperature (red) and
precipitation (blue) in tropical,
temperate, and cold (arctic
tundra) grassland. Top photo:
wildebeests grazing on a
savanna in Maasai Mara
National Park in Kenya, Africa
(tropical grassland). Center
photo: wildflowers in bloom on
a prairie near East Glacier Park
in the U.S. state of Montana
(temperate grassland). Bottom
photo: arctic tundra (cold
grassland) in autumn in front of
the Alaska Range, Alaska (USA).
Question: What month of the
year has the highest
temperature and the lowest
rainfall for each of the three
types of grassland?
Figure 2, Suppl. 9
Some components and interactions in
a temperate tall-grass prairie
ecosystem.
Figure 7.13
Natural capital degradation: replacement of a biologically diverse temperate grassland with
a monoculture crop in the U.S. state of California. When humans remove the tangled root
network of natural grasses, the fertile topsoil becomes subject to severe wind erosion unless
it is covered with some type of vegetation.
Figure 3, Suppl. 9
Some components and interactions in
an arctic tundra (cold grassland)
ecosystem.
Temperate Shrubland: Nice Climate,
Risky Place to Live
 Temperate shrubland, or chaparral
 Located in coastal regions that border on deserts.
 Southern CA, USA; the Mediterranean; central Chile; southern Australia; and
southwestern South Africa.
 Closeness to sea provides slightly longer winter rainy season; and fogs during
spring and fall reduce evaporation.
 But, long, warm, dry summers
 Vegetation
 Low growing evergreen shrubs and small trees with leathery leaves.
 Adapted for fires
 Animals: mule deer, chipmunks, jackrabbits, lizards, and variety of
birds.
 Near the sea: nice climate
 Prone to fires in the dry season followed by mudslides on rainy
season.
Figure 7.14
Chaparral vegetation in the U.S. state of Utah and a typical climate graph.
There Are Three Major Types of
Forests
 Tropical, Temperate, Cold
(northern coniferous and
boreal)
 Tropical rain forests
 Year-round uniformly
warm temperatures, high
humidity, and heavy rainfall
almost daily.
 Dominated by broadleaf
evergreen plants.
 Stratification of specialized
plant and animal niches
 Light levels canopy to ground
 Vines (called lianas)
 High NPP
 High species diversity (2% of
earth’s surface but at least
half the terrestrial species
 Because of dense vegetation,
little wind
 Significance?
 Rapid recycling of scarce soil
nutrients
 90% of nutrients released by
decomposers is rapidly taken up
by plants.
 Impact of human activities
 At least half destroyed by
humans
Figure 7.16
Some components and interactions in
a tropical rain forest ecosystem.
When these organisms die,
decomposers break down their
organic matter into minerals that
plants use. Colored arrows indicate
transfers of matter and energy
between producers; primary
consumers (herbivores); secondary,
or higher-level, consumers
(carnivores); and decomposers.
Figure 7.17
Stratification of specialized plant and animal niches in a tropical rain forest. Filling such
specialized niches enables species to avoid or minimize competition for resources and results
in the coexistence of a great variety of species.
 Temperate deciduous forests
 Moderate average temperatures
that change significantly with
season.
 Long, warm summers; cold but
not too severe winters, and
abundant precipitation, often
spread evenly throughout the
year.
 Dominated by few species of
broad-leaf deciduous tree such as
oak, hickory, maple, poplar, and
beech.
 Survive cold winter by
dropping leaves
 Spring, grow leaves whose
colors change in the fall
 Slow decomposition rate 
accumulation of leaf litter, a
storehouse of nutrients.
 On global basis, most human
disturbed terrestrial biome
 Fauna
 In eastern USA, once home to
large predators: bears, wolves,
foxes, wildcats, and mountain
lions
 Today most predators have been
killed; dominant mammals now:
white-tailed deer, squirrels,
rabbits, opossums, raccoons, and
mice
 Migratory bird and their decline 
habitat destruction and
fragmentation
Figure 4, Suppl. 9
Some components and interaction in
a temperate deciduous forest
ecosystem.
 Evergreen coniferous forests, or boreal forests, or taigas
 Located just south of arctic tundra
 Subarctic climate
 Winters are long, dry, and extremely cold; sunlight only 6-8 hours
per day
 Summers, short, cool to warm and sun shines up to 19 hours per day
 Dominated by coniferous evergreen trees (example: spruce, fir,
cedar, hemlock, and pine
 Plant adaptations to climate
 Fauna
 Bears, wolves, moose, lynx, and burrowing rodents
 Caribou spend winter
 Migratory birds such as warblers breed here
Figure 5, Suppl. 9
Some components and interactions
in an evergreen coniferous (boreal
or taiga) forest ecosystem.
 Coastal coniferous forests,
or temperate rainforests
 Scattered in coastal
temperate areas with ample
rainfall or moisture from
dense fogs
 Dense stands of spruce,
Douglas fir, and redwoods
once dominated
undisturbed areas along the
coast of North America
Figure 7.18
Temperate rain forest in Olympic National
Park in the U.S. state of Washington.
Figure 7.15
Climate graphs showing typical
variations in annual temperature
(red) and precipitation (blue) in
tropical, temperate, and cold
(northern coniferous and boreal)
forests. Top photo: the closed
canopy of a tropical rain forest in
the western Congo Basin of Gabon,
Africa. Middle photo: a temperate
deciduous forest in the U.S. state of
Rhode Island during the fall. (Photo
4 in the Detailed Contents shows
this same area of forest during
winter.) Bottom photo: a northern
coniferous forest in the Malheur
National Forest and Strawberry
Mountain Wilderness in the U.S.
state of Oregon. Question: What
month of the year has the highest
temperature and the lowest rainfall
for each of the three types of forest?
Mountains Play Important Ecological Roles
 Highlands cover ¼ of
earth’s land surface
 Dramatic shifts in altitude,
slope, climate, and
vegetation take place over
short distances.
 1.2 billion people live in
mountain ranges
 Major storehouses of water
 Role in hydrologic cycle
 4 billion depend on them
for water.
 Steep slope means soil is
easily eroded with natural
and human disturbances.
 Islands of biodiversity
surrounded by a sea of
human transformed
landscapes.
 Majority of the world’s
forests
 Habitats for endemic
species
 Help regulate the earth’s
climate
 Can affect sea levels
 Major storehouses of water
 Role in hydrologic cycle
7-3 How Have We Affected the Word’s
Terrestrial Ecosystems?
 Concept 7-3 In many areas, human activities are impairing
ecological and economic services provided by the earth’s
deserts, grasslands, forests, and mountains.
Humans Have Disturbed Most of
the Earth’s Lands
 According to the 2005 Millennium Ecosystem Assessment,
62% of the world’s major terrestrial ecosystems are being
degraded or used unsustainably.
 A major question of interest: How long can we keep eating
away at these terrestrial forms of natural capital w/o
threatening our economies and long-term survival of our
own species?
 Protection of remaining wild areas
 Restoration of degraded and destroyed natural areas
 The balance between exploitation and conservation is highly
controversial.
Figure 7.20
Major human impacts on the world’s deserts, grasslands, forests, and mountains. Question:
Which two of the impacts on each of these biomes do you think are the most harmful?