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Sustaining Biodiversity:
The Species Approach
Chapter 9
Passenger Pigeon
Core Case Study: The Passenger Pigeon:
Gone Forever
 Passenger pigeon hunted to extinction by 1900
 Commercial hunters used a "stool pigeon”
 Archeological record shows five mass
extinctions
 Human activities: hastening more extinctions?
9-1 What Role Do Humans Play in the
Premature Extinction of Species?
 Concept 9-1A We are degrading and
destroying biodiversity in many parts of the
world, and these threats are increasing.
 Concept 9-1B Species are becoming extinct
100 to 1,000 times faster than they were before
modern humans arrived on the earth (the
background rate), and by the end of this century,
the extinction rate is expected to be 10,000
times the background rate.
Human Activities Are Destroying and
Degrading Biodiversity
 Human activity has disturbed at least half of the
earth’s land surface
• Fills in wetlands
• Converts grasslands and forests to crop fields
and urban areas
 Degraded aquatic biodiversity
Extinctions Are Natural but Sometimes
They Increase Sharply
 Background extinction
 Extinction rate
 Mass extinction: causes?
 Levels of species extinction
• Local extinction
• Ecological extinction
• Biological extinction
Some Human Activities Cause Premature
Extinctions; the Pace Is Speeding Up (1)
 Premature extinctions due to
• Habitat destruction
• Overhunting
Some Human Activities Cause Premature
Extinctions; the Pace Is Speeding Up (2)
 Conservative estimates of extinction = 0.011.0%
• Growth of human population will increase this
loss
• Rates are higher where there are more
endangered species
• Tropical forests and coral reefs, wetlands and
estuaries—sites of new species—being
destroyed
 Speciation crisis
Animal Species Prematurely Extinct Due
to Human Activities
Passenger
pigeon
Great auk
Dodo
Golden toad
Aepyornis
(Madagascar)
Fig. 9-2, p. 185
Effects of a 0.1% Extinction Rate
Number of
species
existing
Effects of a 0.1% extinction rate
5 million
5,000 extinct per year
14 million
50 million
100 million
0
14,000 extinct per year
50,000 extinct per year
100,000 extinct per year
50
100
150
Number of years until one million
species are extinct
200
Fig. 9-3, p. 186
Endangered and Threatened Species Are
Ecological Smoke Alarms
 Endangered species
 Threatened species, vulnerable species
• Characteristics of such species
Endangered Natural Capital: Species
Threatened with Premature Extinction
Grizzly
bear
Kirkland’s
warbler
Knowlton
cactus
Florida
manatee
African
elephant
Utah prairie Swallowtail Humpback Golden lion Siberian
tiger
dog
tamarin
chub
butterfly
Giant
panda
Mountain
gorilla
Black-footed Whooping Northern Blue whale
crane spotted owl
ferret
Florida
panther
California Hawksbill
Black
condor
sea turtle rhinoceros
Fig. 9-4, p. 187
Characteristics of Species That Are Prone
to Ecological and Biological Extinction
Characteristic
Examples
Low reproductive
rate (K-strategist)
Blue whale, giant
panda, rhinoceros
Specialized
niche
Narrow
distribution
Blue whale, giant
panda, Everglades
kite
Elephant seal,
desert pupfish
Feeds at high
trophic level
Bengal tiger, bald
eagle, grizzly bear
Fixed
migratory
patterns
Rare
Commercially
valuable
Large territories
Blue whale,
whooping crane,
sea turtle
African violet,
some orchids
Snow leopard, tiger,
elephant, rhinoceros,
rare plants and birds
California condor,
grizzly bear, Florida
panther
Fig. 9-5, p. 188
Characteristic
Examples
Low reproductive
rate (K-strategist)
Blue whale, giant
panda, rhinoceros
Specialized
niche
Narrow
distribution
Blue whale, giant
panda, Everglades
kite
Elephant seal,
desert pupfish
Feeds at high
trophic level
Bengal tiger, bald
eagle, grizzly bear
Fixed
migratory
patterns
Rare
Commercially
valuable
Large territories
Blue whale,
whooping crane,
sea turtle
African violet,
some orchids
Snow leopard, tiger,
elephant, rhinoceros,
rare plants and birds
California condor,
grizzly bear, Florida
panther
Stepped Art
Fig. 9-5, p. 188
Percentage of Various Species
Threatened with Premature Extinction
Fishes
34% (51% of freshwater species)
Amphibians
32%
Mammals
25%
20%
Reptiles
Plants
Birds
14%
12%
Fig. 9-6, p. 189
Science Focus: Estimating Extinction
Rates Is Not Easy
 Three problems
• Hard to document due to length of time
• Only 1.8 million species identified
• Little known about nature and ecological roles of
species identified
 Document little changes in DNA
 Use species–area relationship
 Mathematical models
9-2 Why Should We Care about Preventing
Premature Species Extinction?
 Concept 9-2 We should prevent the premature
extinction of wild species because of the
economic and ecological services they provide
and because they have a right to exist
regardless of their usefulness to us.
Species Are a Vital Part of the Earth’s
Natural Capital
 Instrumental value
• Use value
• Ecotourism: wildlife tourism
• Genetic information
• Nonuse value
• Existence value
• Aesthetic value
• Bequest value
 Ecological value
Natural Capital Degradation: Endangered
Orangutans in a Tropical Forest
Natural Capital: Nature’s Pharmacy
Pacific yew
Taxus brevifolia,
Pacific Northwest
Ovarian cancer
Rauvolfia
Rauvolfia sepentina,
Southeast Asia
Anxiety, high blood
pressure
Foxglove
Digitalis purpurea,
Europe
Digitalis for heart
failure
Cinchona
Cinchona ledogeriana,
South America
Quinine for malaria
treatment
Rosy periwinkle
Cathranthus roseus,
Madagascar
Hodgkin's disease,
lymphocytic leukemia
Neem tree
Azadirachta indica,
India
Treatment of many
diseases, insecticide,
spermicide
Fig. 9-8, p. 190
Endangered Scarlet Macaw is a Source
of Beauty and Pleasure
Science Focus: Using DNA to Reduce
Illegal Killing of Elephants for Their Ivory
 1989 international treaty against poaching
elephants
 Poaching on the rise
 Track area of poaching through DNA analysis of
elephants
 Elephants damaging areas of South Africa:
Should they be culled?
Are We Ethically Obligated to Prevent
Premature Extinction?
 Intrinsic value: existence value
 Edward O. Wilson: biophilia phenomenon
 Biophobia
Science Focus: Why Should We Care
about Bats?
 Vulnerable to extinction
• Slow to reproduce
• Human destruction of habitats
 Important ecological roles
• Feed on crop-damaging nocturnal insects
• Pollen-eaters
• Fruit-eaters
 Unwarranted fears of bats
ABC Video: Bachelor pad at the zoo
ABC Video: Hsing Hsing dies
ABC Video: Penguin rescue
9-3 How do Humans Accelerate
Species Extinction?
 Concept 9-3 The greatest threats to any
species are (in order) loss or degradation of its
habitat, harmful invasive species, human
population growth, pollution, climate change,
and overexploitation.
Loss of Habitat Is the Single Greatest
Threat to Species: Remember HIPPCO
 Habitat destruction, degradation, and
fragmentation
 Invasive (nonnative) species
 Population and resource use growth
 Pollution
 Climate change
 Overexploitation
Causes of Depletion and Premature
Extinction of World Species
NATURAL CAPITAL
DEGRADATION
Causes of Depletion and Premature Extinction of Wild Species
Underlying Causes
• Population growth
• Rising resource use
• Undervaluing natural capital
• Poverty
Direct Causes
• Habitat loss
• Pollution
• Commercial hunting and poaching
• Habitat degradation and
fragmentation
• Introduction of nonnative
species
• Climate change
• Sale of exotic pets and decorative
plants
• Overfishing
• Predator and pest control
Fig. 9-10, p. 193
Natural Capital Degradation: Reduction
in the Ranges of Four Wildlife Species
Fig. 9-11a, p. 194
Indian Tiger
Range 100 years ago
Range today
Fig. 9-11a, p. 194
Fig. 9-11b, p. 194
Black Rhino
Range in 1700
Range today
Fig. 9-11b, p. 194
Fig. 9-11c, p. 194
African Elephant
Probable range 1600
Range today
Fig. 9-11c, p. 194
Fig. 9-11d, p. 194
Asian or Indian Elephant
Former range
Range today
Fig. 9-11d, p. 194
Indian
Tiger
Range 100 years ago
Range today
African
Elephant
Probable range 1600
Range today
Black
Rhino
Range in 1700
Range today
Asian or Indian
Elephant
Former range
Range today
Stepped Art
Fig. 9-11, p. 194
Science Focus: Studying the Effects of
Forest Fragmentation on Old-Growth Trees
 Tropical Biologist Bill Laurance, et al.
 How large must a forest fragment be in order to
prevent the loss of rare trees?
Case Study: A Disturbing Message
from the Birds (1)
 Habitat loss and fragmentation of the birds’
breeding habitats
• Forests cleared for farms, lumber plantations,
roads, and development
 Intentional or accidental introduction of
nonnative species
• Eat the birds
Case Study: A Disturbing Message
from the Birds (2)
 Seabirds caught and drown in fishing equipment
 Migrating birds fly into power lines,
communication towers, and skyscrapers
 Other threats
•
•
•
•
Oil spills
Pesticides
Herbicides
Ingestion of toxic lead shotgun pellets
Case Study: A Disturbing Message
from the Birds (3)
 Greatest new threat: Climate change
 Environmental indicators
 Economic and ecological services
Distribution of Bird Species in North
America and Latin America
Number of
bird species
609
400
200
1
Fig. 9-12, p. 195
The Ten Most Threatened Song Birds
in the United States
Cerulean warbler Sprague’s pipit Bichnell’s thrush Black-capped
vireo
Golden-cheeked
warbler
Florida scrub jay
Bachman's warbler
California Kirtland's warbler
gnatcatcher
Henslow's
sparrow
Fig. 9-13, p. 196
Science Focus: Vultures, Wild Dogs, and
Rabies: Unexpected Scientific Connections
 Vultures poisoned from diclofenac in cow
carcasses
 More wild dogs eating the cow carcasses
 More rabies spreading to people
Some Deliberately Introduced Species
Can Disrupt Ecosystems
 Most species introductions are beneficial
•
•
•
•
Food
Shelter
Medicine
Aesthetic enjoyment
 Nonnative species may have no natural
•
•
•
•
Predators
Competitors
Parasites
Pathogens
Some Harmful Nonnative Species
in the United States
Fig. 9-14a, p. 199
Deliberately Introduced Species
Purple
loosestrife
Marine toad
(Giant toad)
European
starling
African honeybee
(“Killer bee”)
Water hyacinth
Japanese
beetle
Nutria
Hydrilla
Salt cedar
(Tamarisk)
European wild
boar (Feral pig)
Fig. 9-14a, p. 199
Fig. 9-14b, p. 199
Accidentally Introduced Species
Sea lamprey
(attached to
lake trout)
Argentina fire
ant
Formosan termite Zebra mussel
Brown tree
snake
Asian longhorned beetle
Eurasian ruffe Common pigeon
(Rock dove)
Asian tiger
mosquito
Gypsy moth
larvae
Fig. 9-14b, p. 199
Deliberately introduced species
Purple
European
loosestrife starling
Marine toad
(Giant toad)
African honeybee Nutria
(“Killer bee”)
Water
hyacinth
Japanese
beetle
Hydrilla
Salt cedar
(Tamarisk)
European wild
boar (Feral pig)
Accidentally introduced species
Sea lamprey
(attached to
lake trout)
Formosan
termite
Argentina
fire ant
Zebra
mussel
Brown tree
snake
Eurasian
ruffe
Common pigeon
(Rock dove)
Asian long- Asian tiger Gypsy moth
horned beetle mosquito
larvae
Stepped Art
Fig. 9-14, p. 199
Case Study: The Kudzu Vine
 Imported from Japan in the 1930s
 “ The vine that ate the South”
 Could there be benefits of kudzu?
Kudzu Taking Over an Abandoned House
in Mississippi, U.S.
Some Accidentally Introduced Species
Can Also Disrupt Ecosystems
 Argentina fire ant: 1930s
• Pesticide spraying in 1950s and 1960s worsened
conditions
 Burmese python
Argentina Fire Ant Accidentally
Introduced into Mobile, Alabama, U.S.
Prevention Is the Best Way to Reduce
Threats from Invasive Species
 Prevent them from becoming established
 Learn the characteristics of the species
 Set up research programs
 Try to find natural ways to control them
Characteristics of Invader Species and
Ecosystems Vulnerable to Invading Species
What Can You Do? Controlling
Invasive Species
Other Causes of Species Extinction (1)
 Population growth
 Overconsumption
 Pollution
 Climate change
Other Causes of Species Extinction (2)
 Pesticides
• DDT: Banned in the U.S. in 1972
 Bioaccumulation
 Biomagnification
Bioaccumulation and Biomagnification
DDT in fish-eating
birds (ospreys)
25 ppm
DDT in large fish
(needle fish)
2 ppm
DDT in small
fish (minnows)
0.5 ppm
DDT in
zooplankton
0.04 ppm
DDT in water
0.000003 ppm,
or 3 ppt
Fig. 9-19, p. 202
DDT in fish-eating
birds (ospreys)
25 ppm
DDT in large fish
(needle fish)
2 ppm
DDT in small
fish (minnows)
0.5 ppm
DDT in
zooplankton
0.04 ppm
DDT in water
0.000003 ppm,
or 3 ppt
Stepped Art
Fig. 9-19, p. 202
Case Study: Where Have All the
Honeybees Gone?
 Honeybees responsible for 80% of insectpollinated plants
 Dying due to?
• Pesticides
• Parasites
• Bee colony collapse syndrome
Case Study: Polar Bears and
Global Warming
 Environmental impact on polar bears
• Less summer sea ice
• PCBs and DDT
 2007: Threatened species list
Polar Bear with Seal Prey
Illegal Killing, Capturing, and Selling of
Wild Species Threatens Biodiversity
 Poaching and smuggling of animals and plants
• Animal parts
• Pets
• Plants for landscaping and enjoyment
 Prevention: research and education
White Rhinoceros Killed by a Poacher
Individuals Matter: Jane Goodall
 Primatologist and anthropologist
 45 years understanding and protecting
chimpanzees
• Chimps have tool-making skills
Rising Demand for Bush Meat Threatens
Some African Species
 Indigenous people sustained by bush meat
 More hunters leading to local extinction of some
wild animals
Bush Meat: Lowland Gorilla
Animation: Humans affect biodiversity
Active Figure: Habitat loss and
fragmentation
Video: Bird species and birdsongs
9-4 How Can We Protect Wild Species
from Premature Extinction? (1)
 Concept 9-4A We can use existing
environmental laws and treaties and work to
enact new laws designed to prevent species
extinction and protect overall biodiversity.
 Concept 9-4B We can help to prevent species
extinction by creating and maintaining wildlife
refuges, gene banks, botanical gardens, zoos,
and aquariums.
9-4 How Can We Protect Wild Species
from Premature Extinction? (2)
 Concept 9-4C According to the precautionary
principle, we should take measures to prevent
or reduce harm to the environment and to
human health, even if some of the cause-andeffect relationships have not been fully
established, scientifically.
International Treaties Help to
Protect Species
 1975: Convention on International Trade in
Endangered Species (CITES)
• Signed by 172 countries
 Convention on Biological Diversity (BCD)
• Focuses on ecosystems
• Ratified by 190 countries (not the U.S.)
Case Study: The U.S. Endangered
Species Act (1)
 Endangered Species Act (ESA): 1973 and later
amended in 1982, 1983, and 1985
 Identify and protect endangered species in the
U.S. and abroad
 Hot Spots
 Habitat Conservation Plan (HCP) colony
Case Study: The U.S. Endangered
Species Act (2)
 Mixed reviews of the ESA
•
•
•
•
•
•
Weaken it
Repeal it
Modify it
Strengthen it
Simplify it
Streamline it
Confiscated Products Made from
Endangered Species
Science Focus: Accomplishments
of the Endangered Species Act (1)
 Species listed only when serious danger of
extinction
 Takes decades for most species to become
endangered or extinct
 More than half of the species listed are stable or
improving
 Budget has been small
Science Focus: Accomplishments
of the Endangered Species Act (2)
 Suggested changes to ESA
• Increase the budget
• Develop recovery plans more quickly
• Establish a core of the endangered organism’s
survival habitat
We Can Establish Wildlife Refuges
and Other Protected Areas
 1903: Theodore Roosevelt
 Wildlife refuges
• Most are wetland sanctuaries
• More needed for endangered plants
• Could abandoned military lands be used for
wildlife habitats?
Gene Banks, Botanical Gardens, and
Wildlife Farms Can Help Protect Species
 Gene or seed banks
• Preserve genetic material of endangered plants
 Botanical gardens and arboreta
• Living plants
 Farms to raise organisms for commercial sale
Zoos and Aquariums Can Protect
Some Species (1)
 Techniques for preserving endangered
terrestrial species
•
•
•
•
•
•
Egg pulling
Captive breeding
Artificial insemination
Embryo transfer
Use of incubators
Cross-fostering
Zoos and Aquariums Can Protect
Some Species (2)
 Limited space and funds
 Critics say these facilities are prisons for the
organisms
What Can You Do? Protecting Species
Case Study: Trying to Save the
California Condor
 Largest North American bird
 Nearly extinct
• Birds captured and breed in captivity
 By 2007, 135 released into the wild
• Threatened by lead poisoning
The Precautionary Principle
 Species: primary components of biodiversity
 Preservation of species
 Preservation of ecosystems

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