Sustaining Biodiversity: The Species Approach

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Sustaining Biodiversity The Species Approach

• Chapter 9

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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?

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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.

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Human Activities Are Destroying and Degrading
Biodiversity

• Human activity has disturbed at least half of the
  earths land surface
• Fills in wetlands
• Converts grasslands and forests to crop fields
  and urban areas
• Degraded aquatic biodiversity

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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

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Some Human Activities Cause Premature
Extinctions the Pace Is Speeding Up (1)

• Premature extinctions due to
• Habitat destruction
• Overhunting

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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
  estuariessites of new speciesbeing destroyed
• Speciation crisis

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Endangered and Threatened Species Are Ecological
Smoke Alarms

• Endangered species
• Threatened species, vulnerable species
• Characteristics of such species

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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 speciesarea relationship
• Mathematical models

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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.

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Species Are a Vital Part of the Earths Natural
Capital

• Instrumental value
• Use value
• Ecotourism wildlife tourism
• Genetic information
• Nonuse value
• Existence value
• Aesthetic value
• Bequest value
• Ecological value

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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?

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Are We Ethically Obligated to Prevent Premature
Extinction?

• Intrinsic value existence value
• Edward O. Wilson biophilia phenomenon
• Biophobia

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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

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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.

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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

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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?

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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

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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

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Case Study A Disturbing Message from the Birds
(3)

• Greatest new threat Climate change
• Environmental indicators
• Economic and ecological services

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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

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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

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Case Study The Kudzu Vine

• Imported from Japan in the 1930s
• The vine that ate the South
• Could there be benefits of kudzu?

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Some Accidentally Introduced Species Can Also
Disrupt Ecosystems

• Argentina fire ant 1930s
• Pesticide spraying in 1950s and 1960s worsened
  conditions
• Burmese python

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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

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Other Causes of Species Extinction (1)

• Population growth
• Overconsumption
• Pollution
• Climate change

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Other Causes of Species Extinction (2)

• Pesticides
• DDT Banned in the U.S. in 1972
• Bioaccumulation
• Biomagnification

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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

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Case Study Polar Bears and Global Warming

• Environmental impact on polar bears
• Less summer sea ice
• PCBs and DDT
• 2007 Threatened species list

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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

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Individuals Matter Jane Goodall

• Primatologist and anthropologist
• 45 years understanding and protecting chimpanzees
• Chimps have tool-making skills

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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

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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.

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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-and-effect
  relationships have not been fully established,
  scientifically.

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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.)

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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

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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

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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

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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 organisms
  survival habitat

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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?

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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

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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

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Zoos and Aquariums Can Protect Some Species (2)

• Limited space and funds
• Critics say these facilities are prisons for the
  organisms

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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

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The Precautionary Principle

• Species primary components of biodiversity
• Preservation of species
• Preservation of ecosystems