Sustaining Biodiversity:
The Species Approach
Chapter 9
Core Case Study: Declining Bird
Species (1)
• Decline of 70% of 9,775 known species
• Birds around humans benefited, but forest species declined
• Long-distance migrants – greatest decline
Core Case Study: Declining Bird
Species (2)
• Reasons
– Climate change
– Habitat loss
– Fragmentation
• Birds environmental indicators
• Perform economic and ecological services
Threatened U.S. Songbirds
9-1 What Role Do Humans Play in the Premature
Extinction of Species?
• Concept 9-1 The current rate of species extinction is at least 100
times the rate that existed before modern humans arrived on
earth, and is expected to increase to between 1,000 and 10,000
times the earlier rate during this century.
Three Types of Extinction
• Local extinction
• Ecological extinction
• Biological extinction
Ecological Smoke Alarms
• Endangered species
• Threatened species
• The first to go large, slow, tasty, or have valuable parts
• Some behaviors make species prone to extinction
Species Prematurely Extinct
Calculating Extinction Rates
• Extinction takes a long time, difficult to document
• Only identified 1.8 million species – most unknown
• Know little of ecological role of most species
• Average species survive 1–10 million years
• Species-area relationship
Endangered or Threatened Species (1)
Endangered or Threatened Species (2)
California Condor - Gymnogyps californianus
Largest North American bird, largest RECOVERY
wingspan
– Opposed by farmers who
– Heavy bird
Vulture => scavenger
Live to 50yrs, sexually mature at 6
– Lay only one egg at a time, every
other year
• Top of food chain
• Causes of endangerment:
– Poaching (farmers incorrectly
assumed they had killed their
livestock, museums)
– Lead poisoning (eating lead shot in
carcasses)
– DDT poisoning
– Habitat destruction (gold mining)
maintained misconception
– Opposed by those who felt birds
had a right to freedom
• Captive breeding in San Diego
and Los Angeles after all 22 wild
birds caught (’87)
– Most expensive program ever
• Released birds killed by lead
and power lines
– Captives trained to avoid lines
– Ridley-Tree Condor Preservation
Act requires non-lead bullets in
range
– As of April 2009, 322 individuals
including 172 wild
Human Activities and Extinction
• Background extinction rate
• Current rate is 100 times background extinction
• Rate likely to rise 1,000–10,000 times with climate change
• Is a mass extinction coming?
Characteristics of Species Prone
to Extinction
Percentage of Various Taxa Endangered
Current Extinction Rate Estimates Are Conservative
• Species and biodiversity decrease in next 50–100 years
• Biodiversity hotspot rates higher than global average
• Degrading, simplifying, and destroying diverse environments
9-2 Why Should We Care about Preventing 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.
Value of Species
• Instrumental value of biodiversity
– Food crops
– Genetic information
– Medicine
• Do not know what we lose when species go extinct
Nature’s Pharmacy
Values of Species Diversity
• Recreational pleasure value
• Eco-tourism >$500 billion per year
• Ethical obligations – intrinsic (existence) value
• Foundation of earth’s ecosystems bacteria and other
microorganisms
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.
Underlying and Direct Causes
of Depletion
Fig. 9-7, p. 183
Secondary Causes of Endangerment and Premature
Extinction (HIPPCO)
• Habitat destruction
• Invasive species
• Population growth
• Pollution
• Climate change
• Overexploitation
Habitat Loss
• Deforestation of tropical areas greatest eliminator of species
• Endemic species
• Habitat fragmentation
Range Reductions in Four Species
Species Introductions
• Most beneficial – food crops, livestock, pest control
• 500,000 alien invader species globally
• 50,000 nonnative species in the U.S.
Deliberately Introduced Species
Accidentally Introduced Species
Case Study: The Kudzu Vine
• Kudzu introduced to control erosion
• Prolific growth
• Uses
– Asians use powdered starch in beverages
– Source of tree-free paper
– Japanese kudzu farm in Alabama
Invasive Kudzu Vine
Fig. 9-10, p. 186
Disruptions from Accidentally
Introduced Species
• Downside of global trade
• Argentina fire ant
• Burmese python
Argentina Fire Ant
Fig. 9-11, p. 186
Prevention of Nonnative Species (1)
• Identify characteristics of successful invaders
• Detect and monitor invasions
• Inspect imported goods
• Identify harmful invasive species and ban transfer
Prevention of Nonnative Species (2)
• ships discharge ballast waters at sea
• introduce natural control organisms of invaders
Characteristics of Successful Invaders
Fig. 9-12, p. 187
What Can You Do?
Fig. 9-13, p. 188
Human Choices Drive Extinction
• Human population growth
• Excessive, wasteful consumption
• Use of pesticides
DDT and Bioaccumulation
• 1950s–1960s fish-eating bird populations drop
• DDT biologically magnified in food webs
• Bird’s eggshells thin and fragile
• Leads to unsuccessful reproduction
Bioaccumulation of DDT
Fig. 9-14, p. 188
Recovery
• Bald eagle recovered
• Factors leading to recovery
– Ban on DDT
– Crackdown on hunting
– Prevention of habitat destruction
Climate Change and Extinction
• More rapid compared to the past
• Expected to eliminate >25% of land animal and plant species
• Polar bears and penguins threatened
Illegal Killing and Trading of Wildlife
• Poaching endangers many larger animals, rare plants
• Over two-thirds die in transit
• Illegal trade $6–$10 billion per year
• Wild species depleted by pet trade
• Exotic plants often illegally gathered
White Rhinoceros Poached for Its Horn
Fig. 9-15, p. 189
The Value of Wild Rare Species
• Declining populations increase black market values
• Rare species valuable in the wild – eco-tourism
• Some ex-poachers turn to eco-tourism
Rising Demand for Bush Meat
• Traditional use of bush meat
• Demand increasing with population growth
• Increased road access
• Loggers, miners, ranchers add to pressure
• Local and biological extinctions
Bush Meat on the Rise
Fig. 9-16, p. 190
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 to protect overall biodiversity.
• Concept 9-4B We can help prevent species extinction by creating
and maintaining wildlife refuges, gene banks, botanical gardens,
zoos, and aquariums.
International Treaties
• Convention on International Trade of Endangered Species (CITES)
• Convention on Biological Diversity (CBD)
Case Study: Controversy over the U.S. Endangered
Species Act (1)
• National Marine Fisheries Services – ocean species
• U.S. Fish and Wildlife Service – other species
• Listings based on biological factors
• Forbids federal agency projects that jeopardize listed species or
habitats
Case Study: Controversy over the U.S. Endangered
Species Act (2)
• Fines violations on private land – 90% listed species on private land
• Illegal to sell or buy listed species
• 1,180 species listed
• USFWS and NMFS supposed to prepare recovery plan – 25% species
have a plan
Case Study: Controversy over the U.S. Endangered
Species Act (3)
• Successful recovery plans include American alligator and grey wolf
• Lax enforcement
• Smugglers not aware of dangerous diseases in exotic species
• Amended to give private landowners economic incentive to save
species
Case Study: Controversy over the U.S. Endangered
Species Act (4)
• ESA protect endangered marine reptiles and mammals
• Challenges to protecting marine species
– Limited knowledge of species
– Difficulty in monitoring and enforcing treaties – open oceans
Hawaiian Monk Seal with Plastic Debris
Fig. 9-17, p. 192
Endangered Green Sea Turtle
Fig. 9-18, p. 192
Opposition to Endangered Species Act
• Opponents want:
– Voluntary protection on private land
– Government compensation for land owners
– Bureaucratic obstacles to listing species
– Elimination of need for critical habitat
– Exemptions granted by Secretary of Interior
• Steps to weaken ESA
New Ecosystems Approach
• Inventory country’s species and ecosystems
• Locate and protect the most endangered ecosystems
• Make development biodiversity-friendly through financial
incentives and technical help
Science Focus: Goals of the Endangered Species Act
• Biologists defend limited success
• Need more funding
• Develop recovery plans more quickly
• Core habitat established when listed
Establish Wildlife Refuges
• National Wildlife Refuge System
• Wetland refuges
• 35 million American visitors
• 20% of listed species in refuge system
Storing Genetic Information
• Gene or seed banks
• Botanical gardens
• Farms – commercial sale of endangered species removes pressure
Zoos and Aquariums for Protection
• Collect species with long-term goal of returning them into habitat
• 100–500 captive individuals to avoid extinction
• 10,000 individuals to maintain capacity for biological evolution
9-5 What Is Reconciliation Ecology?
• Concept 9-5 We can help protect some species from premature
extinction by finding ways to share the places we dominate with
them.
Reconciliation Ecology
• Danger that biodiversity preserve efforts will fail
• Develop reconciliation ecology
Case Study: The Blackfoot Challenge (1)
• Blackfoot River – large Montana watershed
• 600 plant and 21 large animal species
• Seven human communities, 2,500 rural households
• Community established Action Team
Case Study: The Blackfoot Challenge (2)
• Developed Restoration, sustainable grazing, conservation easement
plans
• Created corridor between undeveloped lands
• Restored wetlands, streams
Video: Penguin Rescue
Videos/Penguin_Rescue.mov
Video: Bachelor Pad at the Zoo
Videos/Bachelor_Pad_Zoo.mov