1. ENVIRONMENTAL SCIENCE
CHAPTER 8: Sustaining Biodiversity: The Species Approach

2. Core Case Study: Polar Bears and Projected Climate Change
20,000 – 25,000 polar bears in Arctic
Hunt seals on winter sea ice
Global warming is quickly reducing the amount of sea ice and how long it lasts in winter
Polar bears have less time to hunt and store fat for summer fasting
Projected 30-35% decline by 2050
Potentially extinct from wild by 2100

3. 8-1 What Role Do Humans Play in the Premature Extinction of Species?
Concept 8-1 Species are becoming extinct 100 to 1,000 times faster than they were before modern humans arrived on earth, and by the end of this century, the extinction rate is expected be 10,000 times higher than the background rate.

4. Human Activities and Extinction
Background extinction rate
Current rate is times background extinction
Rate likely to rise to 10,000 times
Is a mass extinction coming?

5. 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

6. Science Focus: Estimating Extinction Rates (1)
Three difficulties
Not easy to document – takes a long time
Only 2 million species of million identified
Little is known about the 2 million species

7. Science Focus: Estimating Extinction Rates (2)
Study records of post-human extinctions with previous extinctions from the fossil record
DNA copying mistakes
How habitat reduction increases extinction
Mathematical models
Inadequate data and models
Normal: 1 million to 10 million years
Humans have greatly accelerated this

8. 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

9. Case Study: Extinction of the Passenger Pigeon
Audubon, 1813: 3 days for a flock to pass over
Extinct by 1900
Good to eat
Feathers good for pillows
Bones good for fertilizer
Easy to kill

10. 8-2 Why Should We Care about Preventing Species Extinction?
Concept 8-2 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.

11. Value of Species Instrumental value of biodiversity
Food crops
Genetic information
Medicine
Bioprospectors
Ecotourism
Do not know what we lose when species go extinct

12. Ethical Obligations
Intrinsic (existence) value
Stewardship viewpoint

13. 8-3 How Do Humans Accelerate Species Extinction?
Concept 8-3 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.

14. Causes of Endangerment and Premature Extinction (HIPPCO)
Habitat destruction
Invasive species
Population growth
Pollution
Climate change
Overexploitation

15. Habitat Loss
Deforestation of tropical areas greatest eliminator of species
Endemic species
Habitat fragmentation

16. Case Study: Declining Bird Species (1)
Decline of ~70% of ~10,000 known species
12% threatened with extinction
Birds around humans benefited, but forest species declined
Long-distance migrants – greatest decline

17. Case Study: Declining Bird Species (2)
Reasons
Habitat loss
Habitat fragmentation
Climate change
Birds are environmental indicators
Perform economic and ecological services

18. Species Introductions
Most beneficial – food crops, livestock, pest control
500,000 alien invader species globally
50,000 nonnative species in the U.S.
Some definitely not beneficial

19. Case Study: The Kudzu Vine
Kudzu introduced to control erosion
Prolific growth
Uses
Asians use powdered starch in beverages
Edible
Source of tree-free paper
Japanese kudzu farm in Alabama

20. Disruptions from Accidentally Introduced Species
Downside of global trade
Downside of traveling
Argentina fire ant
Burmese python
Zebra mussel

21. Prevention of Nonnative Species (1)
Identify characteristics of successful invaders
Detect and monitor invasions
Inspect imported goods
Identify harmful invasive species and ban transfer

22. Prevention of Nonnative Species (2)
Ships discharge ballast waters at sea
Introduce natural control organisms of invaders

23. Human Choices Drive Extinction
Human population growth
Excessive, wasteful consumption
Use of pesticides
Climate change

24. 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

25. Case Study: Where Have All the Honeybees Gone?
Honeybees responsible for 80% of pollination of insect-pollinated plants
Population down 30% since the 1980s
Pesticides
Parasitic mites
Invasive African honeybees
2008: 36% of honeybee colonies lost
Colony collapse disorder
New nicotine-based pesticides to blame?

26. Illegal Killing and Trading of Wildlife
Poaching endangers many larger animals, rare plants
Over two-thirds die in transit
Illegal trade: $1.1 million per hour
Wild species depleted by pet trade
Exotic plants often illegally gathered

27. 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

28. Rising Demand for Bush Meat
Demand increasing with population growth
Increased road access
Loggers, miners, ranchers add to pressure
Local and biological extinctions
Spread of HIV and Ebola virus

29. 8-4 How Can We Protect Wild Species from Premature Extinction?
Concept 8-4 We can reduce species extinction and help to protect overall biodiversity by establishing and enforcing national environmental laws and international treaties, creating a variety of protected wildlife sanctuaries, and taking precautionary measures to prevent such harm.

30. International Treaties
Convention on International Trade of Endangered Species (CITES)
Convention on Biological Diversity (CBD)

31. 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

32. U.S. Endangered Species Act (2)
Fines violations on private land
Illegal to sell or buy listed species
1,318 species listed
USFWS and NMFS supposed to prepare recovery plan – 86% species in 2009

33. U.S. Endangered Species Act (3)
Successful recovery plans include American alligator, grey wolf, and bald eagle
Lax enforcement of imports and exports
Amended to give private landowners economic incentive to save species

34. Science Focus: Accomplishments of the Endangered Species Act
Biologists defend limited success
Species listed only when gravely threatened
Takes long time for species to recover
>50% endangered species improving
Need more funding
Develop recovery plans more quickly
Core habitat established when listed

35. Protection of Marine Species
ESA and international treaties protect endangered marine reptiles and mammals
Challenges to protecting marine species
Limited knowledge of species
Difficulty in monitoring and enforcing treaties – open oceans

36. Sea Turtles Threatened
Six species critically endangered
Loss or degradation of habitat
Illegal harvest of eggs
Threats from fishing methods
Protection measures have helped

37. Case Study: Protecting Whales (1)
Easy to kill
International Whaling Commission
Sets quotas
Often ignored
No enforcement powers
1986: Whaling ban, although violated, greatly decreased whale kills

38. Case Study: Protecting Whales (2)
Key countries that violate whaling ban
Japan
Norway
Iceland

39. Establish Wildlife Refuges
National Wildlife Refuge System
Wetland refuges: ~75%
40 million American visitors
20% of listed species in refuge system
Many refuges in disrepair, and many allow mining, oil drilling, and off-road vehicles

40. Storing Genetic Information
Gene or seed banks
Botanical gardens and arboreta
Farms – commercial sale of endangered species removes pressure

41. Zoos and Aquariums for Protection
Collect species with long-term goal of returning them into habitat
Egg pulling
Captive breeding
100–500 captive individuals to avoid extinction
10,000 individuals to maintain capacity for biological evolution

42. Case Study: Trying to Save the California Condor
Last 22 individuals captured
Released a few at a time
2009: 167 condors in the wild
Threatened by lead poisoning from animal carcasses and gut piles

43. The Precautionary Principle
When substantial preliminary evidence indicates an activity could harm humans or the environment, we should take precautionary measures to prevent or reduce the harm
Do even if cause-and-effect relationships are not yet clearly established
“Better safe than sorry”

44. Three Big Ideas from This Chapter - #1
We are greatly increasing the premature extinction of wild species by destroying and degrading their habitats, introducing harmful invasive species, and increasing human population growth, pollution, contributing to projected climate change, and over-exploitation.

45. Three Big Ideas from This Chapter - #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.

46. Three Big Ideas from This Chapter - #3
We can work to prevent the premature extinction of species and to protect overall biodiversity by using laws and treaties, protecting wildlife sanctuaries, and making greater use of the precautionary principle.