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Lecture 5 (1)
- 1. EHN 617: AppliedEcology Sustaining Biodiversity: The Species Approach
- 2. 5-1 What Arethe Trends in Species Extinction? • Concept 5-1 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 1.000-10,000 times that background rate during this century.
- 3. Extinctions Are Naturalbut Sometimes They Increase Sharply (1) • Biological extinction – No species member alive • Background extinction – Natural low rate of extinction (0.0001% per year – or 1 per million species per year) • Extinction rate – Percentage or number of species that go extinct in a certain time period
- 4. Extinctions Are Naturalbut Sometimes They Increase Sharply (2) • Mass extinction – 5 events – 50-95% of species became extinct – Millions of years to return to previous levels of biodiversity • Levels of species extinction – Local extinction – Ecological extinction – Biological extinction
- 5. Species Prematurely Extinctbecause of Human Activities Passenger pigeon Great auk Dodo Golden toad Aepyornis (Madagascar) Fig. 5-1, p. 93
- 6. Case Study: ThePassenger Pigeon: Gone Forever • Once one of the world’s most abundant birds • Audubon: flock took 3 days to fly over • Passenger pigeon hunted to extinction by 1900 – – – – Habitat loss Commercial hunting Easy to kill: flew in large flocks and nested in dense colonies One person made $60,000 by killing 3M birds (1878)
- 7. Some Human ActivitiesAre Causing Extinctions • Human activity has disturbed at least half of the earth’s land surface – Fills in wetlands – Converts grasslands and forests to crop fields and urban areas – Pollution of land and water
- 8. Extinction Rates AreRising Rapidly (1) • Current extinction rate is at least 100 times higher than typical background rate of .0001% • Will rise to 10,000 times the background rate by the end of the century – Rate will rise to 1% per year – Cause ¼ to ½ of the world’s plant and animal species to vanish
- 9. Extinction Rates AreRising Rapidly (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 estuaries—sites of new species—being destroyed • Speciation crisis
- 10. Endangered and ThreatenedSpecies Are Ecological Smoke Alarms (1) • 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 • http://www.iucnredlist.org
- 11. Endangered Natural Capital:Species Threatened with Premature Extinction Grizzly bear Kirkland’s warbler Knowlton cactus Florida manatee African elephant Utah prairie dog Swallowtail butterfly Humpback chub Golden lion tamarin Siberian tiger Fig. 5-2a, p. 95
- 12. Giant panda Mountain gorilla Black-footed ferret Whooping crane Northern spotted owl Floridapanther California condor Hawksbill sea turtle Blue whale Black rhinoceros Fig. 5-2a, p. 95
- 13. Endangered and ThreatenedSpecies Are Ecological Smoke Alarms (2) • Characteristics – – – – – – – – Big Slow Tasty Valuable parts Behaviors that make them easy to kill Low reproductive rate Specialized niche Fixed migratory patterns
- 14. Characteristic Low reproductive rate Specializedniche Characteristics of Species That Are Prone to Ecological and Biological Extinction Examples Blue whale, giant panda, rhinoceros 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 Rare Commercially valuable Large territories Blue whale, whooping crane, sea turtle African violet, some orchids Snow leopard, tiger, elephant, rhi noceros, rare plants and birds California condor, grizzly bear, Florida panther Fig. 5-3, p. 96
- 15. Plants 70% 34% (37% offreshwater species) Fishes Amphibians 30% Reptiles 28% Mammals Birds 12% 21% Endangered Natural Capital
- 16. Science Focus: EstimatingExtinction Rates • Three problems 1. Hard to document due to length of time 2. Only 1.9 million species identified (of estimated 8-100 million!) 3. Little known about nature and ecological roles of species identified • Approaches 1. Study extinction rates over last 10,000 years and then compare with the fossil record 2. Use species–area relationship (90% loss in habitat causes a 50% extinction of species living in the area) 3. Mathematical models
- 17. 5-2 Why ShouldWe Care about the Rising Rate of Species Extinction? • Concept 5-2 We should avoid speeding up the extinction of wild species because of the economic and ecological services they provide, and because many people believe they have a right to exist regardless of their usefulness to us.
- 18. Species Are aVital Part of the Earth’s Natural Capital (1) • 3 reasons to prevent extinctions 1. Species provide natural resources and natural services – instrumental value – – – – Insects for pollination Birds for pest control Plants for food, fuel, lumber, medicine Ecotourism (eg. One male lion to age 7 = $0.5M in tourist revenue, but only $1000 if killed for skin)
- 19. Species Are aVital Part of the Earth’s Natural Capital (2) 2. Genetic information in diverse species 3. It will take 5-10 million years to regain species biodiversity lost this century
- 20. Natural Capital: Nature’sPharmacy Pacific yew Taxus brevifolia, Pacific Northwest Ovarian cancer Rauvolfia Rauvolfia sepentina, Southeast Asia Anxiety, high blood pressure Foxglove Digitalis purpurea, Europe Digitalis for heart failure Cinchona Cinchona ledogeriana, South America Quinine for malaria treatment Rosy periwinkle Cathranthus roseus, Madagascar Hodgkin's disease, lymphocytic leukemia Neem tree Azadirachta indica, India Treatment of many diseases, insecticide, spermicide Fig. 5-4, p. 97
- 21. Are We EthicallyObligated to Prevent Premature Extinction? • Intrinsic value: existence value – Inherent right to exist – We have an ethical obligation to protect species – But which species should we protect?
- 22. 5-3 How doHumans Accelerate Species Extinction? • Concept 5-3 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.
- 23. Loss of HabitatIs 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
- 24. Habitat Fragmentation • Habitatfragmentation – Large intact habitat divided by roads, crops, urban development – Leaves habitat islands – Blocks migration routes – Divides populations – Inhibits migrations and colonization – Inhibits finding food • National parks and nature reserves as habitat islands (fresh water lakes?)
- 25. Causes of Depletionand Premature Extinction of World Species Underlying causes • Population growth • Rising resource use • Undervaluing natural capital • Poverty Direct causes • Habitat loss • Pollution • Commercial hunting and poaching • Habitat degradation and fragmentation • Climate change • Sale of exotic pets and decorative plants • Introduction of nonnative species • Overfishing • Predator and pest control Fig. 5-5, p. 99
- 26. Natural Capital Degradation: Reduction in the Ranges ofFour Wildlife Species Range 100 years ago Range today Fig. 5-6a, p. 100
- 27. Black Rhino Range in1700 Range today Fig. 5-6b, p. 100
- 28. African Elephant Probable range1600 Range today Fig. 5-6c, p. 100
- 29. Asian or IndianElephant Former range Range today Fig. 5-6d, p. 100
- 30. Some Deliberately IntroducedSpecies Can Disrupt Ecosystems • Most species introductions are beneficial – – – – Food Shelter Medicine Aesthetic enjoyment • Nonnative species may have no natural – – – – Predators Competitors Parasites Pathogens
- 31. Some Harmful NonnativeSpecies in the United States Deliberately Introduced Species Purple loosestrife Marine toad (Giant toad) European starling Water hyacinth African honeybee (“Killer bee”) Japanese beetle Nutria Hydrilla Salt cedar (Tamarisk) European wild boar (Feral pig) Fig. 5-7, p. 101
- 32. Accidentally Introduced Species Sealamprey (attached to lake trout) Formosan termite Argentina fire ant Zebra mussel Brown tree snake Eurasian ruffe Asian long-horned beetle Asian tiger mosquito Common pigeon (Rock dove) Gypsy moth larvae Fig. 5-7, p. 101
- 33. Invasive Species: ArgentinaFire Ant Fig. 5-8, p. 102
- 34. Some Accidentally IntroducedSpecies Can Also Disrupt Ecosystems • Argentina fire ant: 1930s – Reduced populations of native ants – Painful stings can kill – Pesticide spraying in 1950s and 1960s worsened conditions – 2009: tiny parasitic flies may help control fire ants
- 35. Case Study: Snakesin the Everglades • Burmese and African pythons dumped in Everglades by people • Tens of thousands now in Everglades • Kill many animals, including alligators • Could spread to other swampy wetlands in South
- 36. Prevention Is theBest 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 International treaties Public education
- 37. Characteristics of SuccessfulInvader Species and Vulnerable Ecosystems Fig. 5-9, p. 102
- 38.
- 39. Other Causes ofSpecies Extinction (1) • Human population growth • Overconsumption – Ecological footprint • Pollution • Climate change
- 40. Other Causes ofSpecies Extinction (2) • Pesticides – DDT: Banned in the U.S. in 1972 • Bioaccumulation • Biomagnification
- 41. Bioaccumulation and Biomagnification DDT infish-eating birds (ospreys) 25 ppm DDT in large fish (needle fish) 2 ppm DDT in small fish (minnows) 0.5 ppm DDT in water 0.000003 ppm, or 3 ppt DDT in zooplankton 0.04 ppm
- 42. Case Study: PolarBears and Global Warming • 20,000-25,000 in the Arctic (19 populations) • Most calories in winter from seals on sea ice • Environmental impact on polar bears – Less summer sea ice from global warming – Could be gone from wild by 2100 • 2008: Threatened species list. 2050?
- 43. 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 – Ecotourism: Thailand, Great Indian Hornbills poachers
- 44. Case Study: ADisturbing Message from the Birds (1) • 1/3 of 800 bird species in U.S. are endangered or threatened • 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 (eg. Bird eating rats)
- 45. Case Study: ADisturbing 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
- 46. Case Study: ADisturbing Message from the Birds (3) • Greatest new threat: Climate change • Environmental indicators – Birds live in every biome and climate • Economic and ecological services
- 47. Distribution of BirdSpecies in the Americas Fig. 5-12, p. 105
- 48. 5-4 How CanWe Protect Wild Species from Extinction Resulting from Our Activities? • Concept 5-4 We can reduce the rising rate of 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.
- 49. International Treaties andNational Laws 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.) • Enforcement problems
- 50. Endangered Species Act •Endangered Species Act (ESA): 1973 and later amended in 1982, 1985, and 1988 • Identify and protect endangered species in the U.S. and abroad • National Marine Fisheries Service for ocean species • U.S. Fish and Wildlife Service for all others
- 51. Endangered Species Act(2) • Forbids federal agencies (except Defense) from funding or authorizing projects that jeopardize endangered or threatened species • 2010: 1,370 species officially listed • USFWS and NMFS prepare recovery plans • Incentives for private property owners
- 52. Science Focus: Accomplishmentsof the Endangered Species Act (1) • Four reasons ESA not a failure for removing only 46 species from endangered list 1. Species listed only when in serious danger 2. Takes decades to help endangered species 3. Conditions for more than half of listed species are stable or improving 4. 2010: spend only 9 cents per American
- 53. Science Focus: Accomplishmentsof the Endangered Species Act (2) • Three ways to improve ESA 1. Greatly increase funding 2. Develop recovery plans more quickly 3. When a species is first listed, establish the core of its habitat that’s critical for survival • New law needed to focus on sustaining biodiversity and ecosystem health
- 54. We Can EstablishWildlife 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?
- 55. Gene Banks, BotanicalGardens, and Wildlife Farms Can Help Protect Species • Gene or seed banks – Preserve genetic material of endangered plants • Botanical gardens and arboreta – Living plants – 3% of the world’s rare and threatened species, little funding • Farms to raise organisms for commercial sale • Arctic storage site: power, weather, war.
- 56. Zoos and AquariumsCan Protect Some Species • Techniques for preserving endangered terrestrial species – Egg pulling – Captive breeding • Goal of ultimately releasing/reintroducing populations to the wild • Limited space and funds
- 57. We Can Usethe Principles of Sustainability to Protect Species • Species: primary components of biodiversity • Preservation of species • Preservation of ecosystems • Need to reduce our ecological footprints