View
85
Download
1
Category
Tags:
Preview:
DESCRIPTION
Sustaining Biodiversity: The Species Approach. Chapter 9. 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 - PowerPoint PPT Presentation
Citation preview
Sustaining Biodiversity:
The Species ApproachChapter 9
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?
SELF - STUDY
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 to 83%* of the earth’s land surface– Filling in wetlands– Converting grasslands and forests to
crop fields and urban areas• Degraded aquatic biodiversity*2005 Millennium Ecosystem Assessment
Extinctions Are Natural but Sometimes They Increase
Sharply• Background extinction estimated = 0.0001%
• Extinction rate Can be #/million/year or %/yr.
• Mass extinction: causes?• Levels of species extinction
– Local extinction – extinct in one area, but not others
– Ecological extinction – so few individuals that species can’t fill their ecological role
– Biological extinction – none anywhere on earth… this is forever.
Human Activities Cause Premature Extinctions: Pace
Is Speeding Up• Premature extinctions due to
– Habitat destruction– Overhunting
• Where are the golden toads?
Human Activities Cause Premature Extinctions:
Pace Is Speeding Up• Conservative estimates of extinction = 0.01-1%– 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 – “death is one thing. The lack of births is another.” (loss of genetic biodiversity and diverse habitats can cause speciation to slow)
Effects of a 0.1% Extinction Rate
Endangered and Threatened Species Are Ecological Smoke Alarms• Endangered species – so few indiv. left that it could soon become extinct over all or part of natural range.
• Threatened species (vulnerable species) – likely to become endangered soon… declining numbers
Endangered
Natural Capital: Species
Threatened with
Premature
Extinction
Characteristics of
Species That Are Prone to
Ecological and
Biological Extinction
The big, the slow, the tasty, those with
valuable parts.
Percentage of Various Species Threatened with
Premature Extinction
IUCN• International Union for the
Conservation of Nature and Natural Resources – World Conservation Union
• Red lists – in 2007: 16,306 species of plant and animals listed as in danger of 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 -
90% habitat loss causes 50% of species to become extinct
• 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 (2 forms)– 1) Use value
• Ecotourism: wildlife tourism• Genetic information
– 2) Nonuse value • Existence value – appreciate that it exists• Aesthetic value – it’s pretty• Bequest value – willing to pay so it will be
there for future generations• Ecological value – plays a role in
ecosystem
Natural Capital Degradation: Endangered Orangutans in
Tropical Forest
Natural Capital: Nature’s Pharmacy
Science Focus: Using DNA to Reduce Illegal Killing of Elephants for Their Ivory
• 1989 international treaty against poaching elephants (although, poaching is on the rise)
• Track area of poaching through DNA analysis of elephants
• WWF - Wildlife crime scorecard• 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
Be afraid of this one
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:
Reduction in the
Ranges of Four
Wildlife Species
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?
• Within 100m of the edge of plots, 36% of old-growth biomass is lost.
Case Study: A Disturbing Message
from the Birds• 70% of species declining• 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– Everglades!
SELF - STUDY
Case Study: A Disturbing Message
from the Birds• 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
SELF - STUDY
Case Study: A Disturbing Message
from the Birds• Greatest new threat: Climate change• Environmental indicators• Economic and ecological servicesSELF - STUDY
Distribution of Bird Species in North America and Latin AmericaSELF - STUDY
The 10 Most Threatened Song Birds
in the United States
SELF - STUDY
Science Focus: Vultures, Wild Dogs, and Rabies: Unexpected Scientific
Connections• Vultures poisoned from diclofenac in cow carcasses
• More wild dogs eating the cow carcasses (increases milk production in cows)
• Increase in wild dog population• More rabies spreading to people –
more than ½ of rabies cases in the world
SELF – STUDYBut see
Cats of Borneo
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
Case Study: The Kudzu Vine
• Imported from Japan in the 1930s • “ The vine that ate the South”• Could there be benefits of kudzu?
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
Other Causes of Species Extinction
• Population growth• Overconsumption• Pollution• Climate change
Other Causes of Species Extinction
• Pesticides– DDT: Banned in the U.S. in 1972
• Bioaccumulation- increase in concentration of a pollutant from the environment to the first organism in a food chain
• Biomagnification-increase in concentration of a pollutant from one link in a food chain to another
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
SELF - STUDY
Case Study: Polar Bears and
Global Warming• Environmental impact on polar bears– Less summer sea ice– PCBs and DDT
• 2007: Threatened species listSELF - STUDY
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
Animals Killed by a Poacher
Individuals Matter: Jane Goodall
• Primatologist and anthropologist• 45 years understanding and
protecting chimpanzees– Chimps have tool-making skillsSELF - STUDY
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? • 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 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.
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
• 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
• 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 • 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 • 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? (UXO at Big Oaks in Southeastern Indiana)
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• 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 • Limited space and funds• Critics say these facilities are prisons
for the organisms
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 poisoningSELF - STUDY
The Precautionary Principle
• Species: primary components of biodiversity
• Preservation of species• Preservation of ecosystemsSELF - STUDY
Recommended