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Sustaining Biodiversity: The Species Approach

Sustaining Biodiversity: The Species Approach. Chapter 9. Core Case Study: The Passenger Pigeon: Gone Forever. Once the most numerous bird on earth. In 1858, Passenger Pigeon hunting became a big business. By 1900 they became extinct from over-harvest and habitat loss.

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Sustaining Biodiversity: The Species Approach

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  1. Sustaining Biodiversity: The Species Approach Chapter 9

  2. Core Case Study: The Passenger Pigeon: Gone Forever • Once the most numerous bird on earth. • In 1858, Passenger Pigeon hunting became a big business. • By 1900 they became extinct from over-harvest and habitat loss.

  3. Figure 9.1Lost natural capital: passenger pigeons have been extinct in the wild since 1900 because of human activities. The last known passenger pigeon died in the U.S. state of Ohio’s Cincinnati Zoo in 1914.

  4. Core Case Study: The Passenger Pigeon: Gone Forever Passenger pigeon hunted to extinction by 1900 Commercial hunters used a "stool pigeon” Geological record shows five mass extinctions Human activities: hastening more extinctions?

  5. 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.

  6. Human Activities Are Destroying and Degrading Biodiversity • 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 • Degraded aquatic biodiversity

  7. Extinctions Are Natural but Sometimes They Increase Sharply • Background extinction • Extinction rate • Mass extinction: causes? • Poorly understood, but involve global changes in environmental conditions. • Levels of species extinction • Local extinction, or extirpation • Ecological extinction • Biological extinction

  8. Define the terms extinction, extirpation and mass extinction. Extinction: The disappearance of an entire species from the face of the Earth. Extinction Rate: % or # of species that go extinct per unit time. i.e. 0.00001 species/year Extirpation: The disappearance of a particular population from a given area, but not the entire species globally. Mass Extinction: The extinction of a large portion of the world’s species in a very short time period due to some extreme and rapid change or catastrophic event. The Earth has seen five mass extinction events in the past half-billon years.

  9. Extinctions Are Natural But Sometimes They Increase Sharply • Background extinctionandMass extinction • Discussed in Chapter 4 • Extinction rate – the percent of species that go extinct in a given time period. • Background extinction • 1/1,000,000 per year = 0.00001% • Mass extinction • 50 – 95% of all living things on the planet

  10. Extinctions Are Natural But Sometimes They Increase Sharply • Species can become extinct in three ways: • Local Extinction: • A species is no longer found in an area it once inhabited but is still found elsewhere in the world. • Typically the result of habitat destruction and affects more than one species. • Ecological Extinction: • Occurs when so few members of a species are left they no longer play its ecological role. • Biological Extinction (Global Extinction): • Species is no longer found on the earth. • Biological extinction is FOREVER.

  11. Some Human Activities Cause Premature Extinctions; the Pace Is Speeding Up • Estimates of current annual extinction rate: • 0.01-1.0% • 100 to 1,000 times greater than the background extinction rate of 0.0001% • Experts predict extinction rates will increase over the next 50-100 years. • Reason = US!!

  12. Animal Species Prematurely Extinct Due to Human Activities • Many animals have become prematurely extinct because of human activities. • Development, habitat destructions, hunting, etc.

  13. Animal Species Prematurely Extinct Due to Human Activities “The first animal species to go are the big, the slow, the tasty, and those with valuable parts…” – Edward O. Wilson (biodiversity expert)

  14. Some Human Activities Cause Premature Extinctions; the Pace Is Speeding Up (2) • Conservative estimates of extinction = 0.01-0.1% • Growth of human population will increase this loss to 10 000 times (to 1%) • 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

  15. Endangered Natural Capital: Species Threatened with Premature Extinction • Threatened (vulnerable) species: • Still abundant in its natural range but is likely to become endangered in the near future. • Endangered species: • So few individual survivors that it could soon become extinct.

  16. Endangered Natural Capital: Species Threatened with Premature Extinction • ExtinctEx.: Dodo, Passenger Pigeon • Extinct in the wildEx.: Alagoas Curassow • Captive individuals survive, but there is no free-living, natural population • Critically endangeredEx.: Ivory-billed Woodpecker, Javan Rhino • Faces an extremely high risk of extinction in the immediate future • EndangeredEx.: Cheetah, Blue Whale, Snow Leopard • VulnerableEx.: Lion, Wolverine • Conservation DependentEx.: Leopard Shark, Bristlecone Fir • Would be threatened without active conservation programs. • Near ThreatenedEx.: California Red-legged Frog, Silvery Woolly Monkey • Likely to qualify as threatened soon. • Least ConcernEx.:Brown Rat, Rock Pigeon, Common Juniper • No immediate threat to the survival of the species.

  17. Endangered Natural Capital: Species Threatened with Premature Extinction

  18. Endangered Natural Capital: Species Threatened with Premature Extinction

  19. Some Human Activities Cause Premature Extinctions; the Pace Is Speeding Up (1) • Premature extinctions due to • Habitat destruction • Overhunting, or overexploitation

  20. Animal Species Prematurely Extinct Due to Human Activities

  21. Figure 9.3Effects of a 0.1% extinction rate.

  22. Endangered and Threatened Species Are Ecological Smoke Alarms • Endangered species • International Union for the for the Conservation of Nature (IUCN), or the World Conservation Union. • Since 1960, published Red List • In 2007, listed 16, 306 animals and plants that are in danger of extinction—60% higher than in 1995. • Threatened species,vulnerable species • Characteristics of such species

  23. Figure 9.4 Endangered natural capital. Some species that are endangered or threatened with premature extinction largely because of human activities. Almost 30,000 of the world’s species and roughly 1,300 of those in the United States are officially listed as being in danger of becoming extinct. Most biologists believe the actual number of species at risk is much larger. African elephant Kirkland’s warbler Knowlton cactus Florida manatee Grizzly bear Siberian tiger Utah prairie dog Golden lion tamarin Humpback chub Swallowtail butterfly Northern spotted owl Giant panda Whooping crane Black-footed ferret Blue whale Mountain gorilla Florida panther California condor Black rhinoceros Hawksbill sea turtle

  24. Characteristic Examples Low reproductive rate (K-strategist) Blue whale, giant panda, rhinoceros Blue whale, giant panda, Everglades kite Specialized niche Elephant seal, desert pupfish Narrow distribution Bengal tiger, bald eagle, grizzly bear Feeds at high trophic level Fixed migratory patterns Blue whale, whooping crane, sea turtle African violet, some orchids Rare Snow leopard, tiger, elephant, rhinoceros, rare plants and birds Commercially valuable California condor, grizzly bear, Florida panther Large territories Figure 9.5 Characteristics of species that are prone to ecological and biological extinction. Question: Which of these characteristics helped lead to the premature extinction of the passenger pigeon within a single human lifetime?

  25. Figure 9.6Endangered natural capital: percentage of various types of species threatened with premature extinction because of human activities

  26. 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 • Suggests species survive for 1 to 10 million years before going extinct. • Use species–area relationship • On average, 90% loss of habitat results in a 50% loss of species living in that habitat. • Mathematical models

  27. 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. “It will take 5-10 million years for natural speciation to rebuild the biodiversity we are likely to destroy during your lifetime.”

  28. Species Are a Vital Part of the Earth’s Natural Capital Instrumental value – usefulness to us in providing ecological and economic services.

  29. Species Are a Vital Part of the Earth’s Natural Capital • Ecotourism: wildlife tourism

  30. Species Are a Vital Part of the Earth’s Natural Capital http://www.ted.com/talks/cary_fowler_one_seed_at_a_time_protecting_the_future_of_food.html • Use value Genetic information • Loss in diversity of crop species is cause for concern.

  31. Extrinsic Value • Food crops, recreation, scientific information, lumber, paper, etc.

  32. Aesthetic value

  33. Ecological value • Energy flow, nutrient cycling, and population control—the scientific principles of sustainability that sustain and support life on earth.

  34. Intrinsic Value Plants and animals have a right to exist!

  35. Figure 9.7Natural capital degradation: endangered orangutans in a tropical forest. In 1900, there were over 315,000 wild orangutans. Now there are less than 20,000 and they are disappearing at a rate of over 2,000 per year because of illegal smuggling and clearing of their forest habitat in Indonesia and Malaysia to make way for oil palm plantations. An illegally smuggled orangutan typically sells for a street price of $10,000. According to 2007 study by the World Wildlife Fund (WWF), projected climate change will further devastate remaining orangutan populations in Indonesia and Malaysia. Question: How would you go about trying to set a price on the ecological value of an orangutan?

  36. Figure 9.8Natural capital: nature’s pharmacy. Parts of these and a number of other plant and animal species (many of them found in tropical forests) are used to treat a variety of human ailments and diseases. Nine of the ten leading prescription drugs originally came from wild organisms. About 2,100 of the 3,000 plants identified by the National Cancer Institute as sources of cancer-fighting chemicals come from tropical forests. Despite their economic and health potential, fewer than 1% of the estimated 125,000 flowering plant species in tropical forests (and a mere 1,100 of the world’s 260,000 known plant species) have been examined for their medicinal properties. Once the active ingredients in the plants have been identified, they can usually be produced synthetically. Many of these tropical plant species are likely to become extinct before we can study them.

  37. Figure 9.9Many species of wildlife, such as this endangered scarlet macaw in Brazil’s Amazon rain forest, are a source of beauty and pleasure. These and other colorful species of parrots can become endangered when they are removed from the wild and sold (sometimes illegally) as pets.

  38. Are We Ethically Obligated to Prevent Premature Extinction? • Intrinsic value, or existence value • Species have an inherent right to exist and play their ecological roles, regardless of their usefulness to us. • Edward O. Wilson: biophilia phenomenon • Biophobia

  39. 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

  40. 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.

  41. Loss of Habitat Is the Single Greatest Threat to Species: Remember HIPPCO (1) Habitat destruction, degradation, and fragmentation Invasive (nonnative) species Population and resource use growth Pollution Climate change Overexploitation

  42. Figure 9.10 Underlying and direct causes of depletion and premature extinction of wild species (Concept 9-3). The major direct causes of wildlife depletion and premature extinction are habitat loss, degradation, and fragmentation. This is followed by the deliberate or accidental introduction of harmful invasive (nonnative) species into ecosystems. NATURAL CAPITAL DEGRADATION Causes of Depletion and Premature Extinction of Wild 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 • Overfishing • Introduction of nonnative species • Predator and pest control

  43. Figure 9.11 Natural capital degradation: reductions in the ranges of four wildlife species, mostly as the result of habitat loss and hunting. What will happen to these and millions of other species when the world’s human population doubles and per capita resource consumption rises sharply in the next few decades? Question: Would you support expanding these ranges even though this would reduce the land available for people to grow food and live on? Explain. (Data from International Union for the Conservation of Nature and World Wildlife Fund)

  44. Loss of Habitat Is the Single Greatest Threat to Species: Remember HIPPCO (2) The Bali Mynah is distributed and endemic to the island of Bali, where it is the island's only surviving endemic species.  This rare bird was discovered in 1910 and is one of the world's most critically endangered birds.   In fact, it has been hovering immediately above extinction in the wild for several years. • Globally, habitat loss, greatest in temperate biomes, pace picking up in tropics. • Endemic species – Habitat is restricted to one area • Hawaii, the extinction capital of America—63% of species at risk.

  45. Habitat islandsHabitat Islands Habitat Islands - an area of habitat surrounded by an area of unsuitable habitat. Can be treated like an island. Examples of habitat islands: Man made: forest surrounded by area that has been converted to grassland 2. Natural: alpine habitat on mountaintops, isolated from other alpine habitat by lower land 3. Natural, very small scale: dung piles, habitat for dung beetles. 4. Islands generally hold fewer species than an area of the same size in continuous habitat. This is true for genuine oceanic islands and for habitat islands.

  46. Habitat Fragmentation Habitat Fragmentation of Great Apes Habitat fragmentation involves alteration of habitat resulting in spatial separation of habitat units from a previous state of greater continuity.

  47. UnderlyingCauses of Species Extinction Population growth Overconsumption Pollution Climate change

  48. Other Causes of Species Extinction (2) • Pesticides • DDT: Banned in the U.S. in 1972 • Bioaccumulation • Biomagnification

  49. Case Study: A Disturbing Message from the Birds (1) • 70% of the worlds 10,000 birds are declining; 12% are threatened with extinction. • 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

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