1. Sustaining Biodiversity: The Species Approach5
Sustaining Biodiversity: The Species Approach

2. 5-1 What Are the Trends in Species Extinction?
Extinction is a natural process that sometimes accelerates
Background extinction
Natural low rate of extinction
Species extinction
Local extinction
Ecological extinction
Biological extinction: irreversible loss

3. According to the UN, the Earth is in the midst of a mass extinction of life. Scientists estimate that species of plant, insect, bird and mammal become extinct every 24 hours. This is nearly 1,000 times the “natural” or “background” rate and, say many biologists, is greater than anything the world has experienced since the vanishing of the dinosaurs nearly 65m years ago.

4. Case Study ─ The Passenger Pigeon: Gone Forever
Once one of the world’s most abundant birds
Audubon (1813): flock took 3 days to fly over
Hunted to extinction by 1900
Contributing factors
Habitat loss
Commercial hunting
Easy to kill: flew in large flocks and nested in dense colonies

5. Some Human Activities Are Causing Extinctions
Human activity has taken over, disturbed, or polluted
60 to 80 percent of the earth’s land surface
50 percent of surface waters
Current annual extinction rate
0.1 percent per year

6. Some Human Activities Are Causing Extinctions
Projected 1.0 percent extinction rate in next 50 to 100 years may be too low
Species loss rate and biodiversity losses likely to increase sharply
Highly endangered biodiversity centers already exist
Many biologically diverse environments have already been degraded

7. Science Focus: Estimating Extinction Rates
Challenges
Natural extinction takes a very long time
Only 2 million species have been identified
Scientists know little about the ecological roles of identified species
Scientists strive to get better data and to improve mathematical models

8. Table 11_02

9. Endangered and Threatened Species Are Ecological Smoke Alarms
Endangered species
So few members that the species could soon become extinct
Threatened species (vulnerable species)
Still enough members to survive, but numbers declining ─ may soon be endangered

10. Characteristic Examples Low reproductive rate
Blue whale, giant panda, rhinoceros
Characteristic
Examples
Specialized niche
Blue whale, giant panda, Everglades kite
Narrow distribution
Elephant seal, desert pupfish
Feeds at high trophic level
Bengal tiger, bald eagle, grizzly bear
Fixed migratory patterns
Blue whale, whooping crane, sea turtle
Rare
African violet, some orchids
Figure 5-3 Some species have characteristics that can put them in greater danger of becoming extinct. Question: Which of these characteristics might possibly have contributed to the extinction of the passenger pigeon?
Commercially valuable
Snow leopard, tiger, elephant, rhinoceros, rare plants and birds
Large territories
California condor, grizzly bear, Florida panther
Stepped Art
Fig. 5-3

11. 5-2 Why Should We Care about the Rising Rate of Species Extinction?
A diversity of species is a vital part of the earth’s natural capital
Reasons to prevent extinctions
Instrumental value, e.g., pollination, natural pest, economically valuable products, ecotourism, genetic information, etc.
Amount of time required for natural speciation to rebuild lost biodiversity

12. Science Focus: Where Have All the Honeybees Gone?
Honeybees’ ecosystem service: pollination
One-third of human food supply from insect-pollinated plants
U.S. growers rent European honeybees from beekeepers
Colony collapse disorder (CCD)
Decline in honeybee populations
Scientists seeking the cause

14. Pacific yew Taxus brevifolia, Pacific Northwest Ovarian cancer
Rosy periwinkle Cathranthus roseus, Madagascar Hodgkin's disease, lymphocytic leukemia
Rauvolfia
Rauvolfia sepentina, Southeast Asia Anxiety, high blood pressure
Neem tree
Azadirachta indica, India Treatment of many diseases, insecticide, spermicides
Foxglove
Digitalis purpurea, Europe Digitalis for heart failure
Cinchona
Cinchona ledogeriana, South America Quinine for malaria treatment
Figure 5-4 Natural capital: These plant species are examples of nature’s pharmacy. Parts of these plants (many of them found in tropical forests) are used to treat a variety of human ailments and diseases.
Fig. 5-4

15. Are We Ethically Obligated to Prevent Premature Extinction?
Species’ intrinsic (existence) value
Inherent right to exist and play its ecological roles
Ethical dilemma
Which species should we protect?
Biologists urge caution
True foundation of the earth’s ecosystems and ecological processes are invisible microorganisms

16. How do Humans Accelerate Species Extinction?
Loss of habitat is the single greatest threat to species: remember HIPPCO
Habitat destruction, degradation, and fragmentation
Invasive (nonnative) species
Population growth and increasing use of resources
Pollution
Climate change
Overexploitation

17. Asian or Indian Elephant
Indian Tiger
Range 100 years ago
Range today
Black Rhino
Range in 1700
Range today
African Elephant
Probable range 1600
Range today
Asian or Indian Elephant
Former range
Range today
Figure 5-6 Natural capital degradation: Reductions in the habitat areas, or ranges, of four wildlife species. Question: Would you support expanding these ranges even though this would reduce the land available for human habitation and farming? Explain. (Compiled by the authors using data from International Union for the Conservation of Nature and World Wildlife Fund)
Stepped Art
Fig. 5-6

18. Some Deliberately Introduced Species Can Disrupt Ecosystems
Most species introductions are beneficial
Such as corn, wheat, cattle, poultry, and trees
Nonnative species may have no natural controls
Predators
Competitors
Parasites
Pathogens

19. Some Accidentally Introduced Species Can Disrupt Ecosystems
Most arrive from other continents as stowaways
Example: Argentina fire ant
Introduced into the U.S. in the 1930s
Can overtake native ant populations
Have killed deer fawns, birds, people allergic to their venom, etc.

20. Deliberately Introduced Species
Purple loosestrife
African honeybee (“Killer bee”)
Kudzu
Nutria
European wild boar (Feral pig)
Accidentally Introduced Species
Figure 5-7 Some of the more than 7,100 harmful invasive (nonnative) species that, after being deliberately or accidentally introduced into the United States, have caused ecological and economic harm.
Sea lamprey (attached to lake trout)
Argentina fire ant
Burmese python
Formosan termite
Zebra mussel
Fig. 5-7

21. Case Study: Burmese Pythons Eating Their Way through the Florida Everglades
Burmese and African pythons
Sold as pets
Dumped in Everglades by some owners
Reproduce rapidly
Huge appetites
Feed on birds, mammals, and some reptiles
Tens of thousands now in Everglades
Fear of spreading to other swampy wetlands

22. Prevention Is the Best Way to Reduce Threats from Invasive Species
Prevent them from being introduced
Learn the species’ characteristics
Inspect incoming goods
Pass international laws to prevent transfer
Require cargo ships to be free of invader organisms before entering ports
Increase research
Individual awareness and efforts

23. Figure 5-10 Individuals matter: Some ways to prevent or slow the spread of harmful invasive species. Questions: Which two of these actions do you think are the most important ones to take? Why?
Fig. 5-7
Fig. 9-12, p. 202

24. Other Causes of Species Extinction
Human population growth
Overconsumption
Pollution
Climate change

25. Case Study: Polar Bears and Global Warming
20,000-25,000 in the arctic regions
Primary winter food
Seals found on floating ice
Live on body fat during summer and fall
Resume hunting when ice expands in winter
Environmental impact on polar bears
Shortened winter: shrinking ice
Placed on threatened species list (2008)

26. Illegal Killing, Capturing, and Selling of Wild Species Threatens Biodiversity
Poaching
Wildlife smuggling
For each animal smuggled many others die in transit
Prevention through education
Show financial benefit of preserving a species as opposed to poaching

27. Case Study: A Disturbing Message from the Birds
Twelve percent of all bird species
Threatened with extinction
Species’ loss: main cause is H in HIPPCO
One-third of 800 bird species in U.S. are endangered or threatened
Second leading danger: intentional or accidental nonnative species’ introduction

28. Case Study: A Disturbing Message from the Birds
Other threats
Oil spills
Pesticides and herbicides
Lead poisoning from shotgun pellets
Fishing nets
Climate change
Overexploitation
Birds serve as environmental indicators

29. 5-4 How Can We Protect Wild Species from Extinction from Our Activities?
International treaties and national laws can help to protect species
1975 Convention on International Trade in Endangered Species (CITES)
Signed by 175 countries
Convention on Biological Diversity (BCD)
Focuses on ecosystems
Ratified by 193 countries (not the U.S.)

30. Case Study: The U.S. Endangered Species Act
Endangered Species Act (ESA): 1973
Amended in 1982, 1985, and 1988
National Marine Fisheries Service (NMFS)
Identifies and lists endangered and threatened ocean species
U.S. Fish and Wildlife Service (USFWS)
Identifies and lists all other endangered and threatened species

31. Case Study: The U.S. Endangered Species Act
Federal agencies (except Defense)
Forbidden from funding or authorizing projects that jeopardize endangered or threatened species
2012: 1,374 species officially listed
USFWS and NMFS
Prepare recovery plans
Incentives for private property owners

32. Case Study: The U.S. Endangered Species Act
ESA proponents point out reasons the agency is not a failure
Species listed only when in serious danger
Takes decades to help endangered species
2011: average expenditure is 8 cents per U.S. citizen

33. Case Study: The U.S. Endangered Species Act
Ways to improve ESA
Greatly increase funding
Develop recovery plans more quickly
When a species is first listed, establish the core of its habitat that is critical for survival and give that area the maximum protection
New law needed to focus on sustaining biodiversity and ecosystem health

34. We Can Establish Wildlife Refuges and Other Protected Areas
1903: Theodore Roosevelt
Established U.S. federal wildlife refuge at Pelican Island, Florida
2012: 555 refuges in the National Wildlife Refuge System
Most are wetland sanctuaries
More needed for endangered plants

35. Seed Banks / Botanical Gardens / Wildlife Farms Can Help to Protect Species
Preserve endangered plants’ genetic material
Botanical gardens and arboreta
Living plants
Farms to raise some endangered or threatened species for commercial sale

36. Zoos and Aquariums Can Protect Some Species
Long-term goal
Reintroducing the species into protected wild habitats
Techniques for preserving endangered terrestrial species
Egg pulling
Captive breeding
Non-feasible solutions: limited space and funds

37. We Can Use the Principles of Sustainability to Protect Species
Actions needed to:
Prevent the factors that will hasten species’ extinction
Slow climate change
Reduce the size and impact of our ecological footprints