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CHAPTER 9
Sustaining
Biodiversity:
The Species
Approach
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: leading to more extinctions?
PASSENGER PIGEON
9-1 WHAT ROLE DO HUMANS PLAY IN THE
PREMATURE EXTINCTION OF SPECIES?
 Concept 9-1A We are degrading and destroying biodiversity
in many par ts 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 ear th (the background rate), and by the end of this
centur y, the extinction rate is expected to be 10,000 times
the background rate.
HUMAN ACTIVITIES ARE DESTROYING AND
DEGRADING BIODIVERSIT Y
 Human activity has disturbed at least half of the earth’s land
surface, 83%
 Fills in wetlands
 Converts grasslands and forests to crop fields and urban areas
 Degraded aquatic biodiversity
EXTINCTIONS ARE NATURAL BUT SOMETIMES
THEY INCREASE SHARPLY
 Back ground extinction
 Continuous, low levels of extinction
 Extinction rate
 Expressed as a percent or number of species that go extinct in a given
time period
 .0001% BEFORE hunting came along….
 Mass extinction: causes?
 Global changes in environmental conditions
 Levels of species extinction
 Local extinction – species is no longer found in an area it once inhabited
but is still elsewhere in the world
 Ecological extinction – so few members are left that it no longer plays its
ecological role
 Biological extinction – species is found nowhere on earth (passenger
pigeon)
 FOREVER
SOME HUMAN ACTIVITIES CAUSE PREMATURE
EXTINCTIONS; THE PACE IS SPEEDING UP (1)
 Current extinction rates 100 to 1 ,000 times the background
rate
 Premature extinctions due to
 Habitat destruction
 Overhunting
SOME HUMAN ACTIVITIES CAUSE PREMATURE
EXTINCTIONS; THE PACE IS SPEEDING UP (2)
 Conservative estimates of extinction = 0.01 -1 .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
EFFECTS OF A 0.1% EXTINCTION RATE
ENDANGERED AND THREATENED SPECIES
ARE ECOLOGICAL SMOKE ALARMS
 Endangered species – so few individual survivors that the
species could soon become extinct over all or most of its
natural range
 Threatened species (vulnerable species) – abundant in natural
range but because of declining numbers may become
endangered in future
 Characteristics of such species
 Big, slow, tasty, valuable parts
 Behavioral Characteristics
ENDANGERED NATURAL CAPITAL: SPECIES
THREATENED WITH PREMATURE EXTINCTION
CHARACTERISTICS OF SPECIES THAT ARE
PRONE TO ECOLOGICAL AND BIOLOGICAL
EXTINCTION
PERCENTAGE OF VARIOUS SPECIES
THREATENED WITH PREMATURE EXTINCTION
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 ser vices
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 – economic goods and services, ecological services,
recreation, scientific information
 Ecotourism: wildlife tourism – 950,000 to 1.8 million per MINUTE
 Genetic information
 Nonuse value
 Existence value
 Aesthetic value
 Bequest value
 Ecological value
NATURAL CAPITAL: NATURE’S PHARMACY
ENDANGERED SCARLET MACAW IS A SOURCE
OF BEAUT Y 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
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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:
REDUCTION IN THE RANGES OF FOUR
WILDLIFE SPECIES
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
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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
THE TEN MOST THREATENED SONG BIRDS
IN THE UNITED STATES
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
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Food
Shelter
Medicine
Aesthetic enjoyment
 Nonnative species may have no natural
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Predators
Competitors
Parasites
Pathogens
SOME HARMFUL NONNATIVE SPECIES
IN THE UNITED STATES
Fig. 9-14b, 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
CASE STUDY: WHERE HAVE ALL THE
HONEYBEES GONE?
 Honeybees responsible for 80% of insect -pollinated 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 BIODIVERSIT Y
 Poaching and smuggling of animals and plants
 Animal parts
 Pets
 Plants for landscaping and enjoyment
 Prevention: research and education
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
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.
 Concept 9-4C According to the precautionar y principle , we
should take measures to prevent or reduce harm to the
environment and to human health, even if some of the cause and-effect 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
 Bans hunting, capturing, and selling threatened or endangered
species
 Convention on Biological Diversity (CBD)
 Focuses on ecosystems
 Reversing the global decline of biodiversity and sharing benefits from use
of genetic resources
 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
 Biological factors alone, no economic or political influence
 Forbids federal agencies to carry out, fund or authorize projects
jeopardizing species or destroying/modifying critical habitat
 Hot Spots
 Habitat Conservation Plan (HCP) colony
CASE STUDY: THE U.S. ENDANGERED
SPECIES ACT (2)
 Mixed reviews of the ESA
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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
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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