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The Loss of Biodiversity

The Loss of Biodiversity. ESC 556 Week 9. Causes and Consequences. Prominent species & causes Endangered Species Overexploitation by humans. Causes and Consequences. Obscure species & causes Habitat destruction Plants & insects Loss of free services Loss of genetic diversity.

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The Loss of Biodiversity

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  1. The Loss of Biodiversity ESC 556 Week 9

  2. Causes and Consequences • Prominent species & causes • Endangered Species • Overexploitation by humans

  3. Causes and Consequences • Obscure species & causes • Habitat destruction • Plants & insects • Loss of free services • Loss of genetic diversity

  4. Habitat Destruction • Thousands threatened vs. a few overexploited • Plowing, logging, overgrazing, flooding, draining…. • Dependence on habitats • Birds  mature tropical forests • Bats  caves • Trout  Can’t breed in acidic or too warm water

  5. Human impact • NPP • 3% of NPP – by one species • Direct + indirect use (40%) • 2/5ths of terrestrial food production • Fires, conversion (forest  pasture), non-used NPP • Human population projection • Seas • Whales & fishes • Extinction crisis not as bad • Open seas safer

  6. Ecosystem Services • Gas cycle disruption • Deforestation • Freshwater supplies, increases danger of floods • Insects – pollination of crops • Biological pest control • Subterranean organisms – fertility of soil • Affected without being endangered

  7. Number of Populations • Ensure persistence vs. short term changes • Spread the risk • Genetic diversity • Evolutionary potential in the long term • Lost even without extinction

  8. Consequences • Food • Climate change, soil erosion, water supplies, decline of pollinators, pest problems • Benefits from genetic diversity • Diseases • e.g. air pollution

  9. Solutions • Human Perception • Natural reserves not adequate • Scarcity, climate change • Control of human population growth • Technology • Attitudes – public awareness

  10. Planetary Killer • Gradual & subtle decline • Red List by IUCN • Extinct • Extinct in the wild • Critically endangered • Sumatran rhino • Endangered • Indian rhino • Vulnerable • Near threatened • Least Concern

  11. Red List

  12. Some Causes • Poaching • Black Rhinos • Overharvesting • Fish • Introduction problem • Rats, ants, mosquitoes, weeds • Conversion of natural environments • Global warming

  13. Trees as critical cases • 976/100,000 • Living dead • One or few individual / species • Chinese hornbeam • Hibiscus • Concentrated endangerment • Juan Fernandez islands • 20 species < 45 indivs

  14. Historical Extinctions by Humans • Extinction without discovery • Po’ouli • Islands • From the top of the foodchain down • Big birds, seals, penguins, songbirds, fish, shellfish

  15. Australia & New Zealand • Australia • 16/263 mammals extinct by European settlers • 34 in the Red List • Aboriginals – 60,000 years ago • Large Mammals first • Ground birds/tortoises • New Zealand • Polynesians • No mammals • Rabbits, deer, rhinos • Moas, New Zealand Eagle

  16. Madagascar • 88 millions years of isolation • Mega animals • Giant lemur • Elephant birds • 1100 AD, first human settlements

  17. Mauritus • Dodo • Extinct in 80 years

  18. Mediterranean Area • Ancestral humans • Tortoises + marine shellfish • Agriculture effects in the Fertile Crescent • Woolly mammoth, woolly rhino, Irish elk

  19. Africa & Asia • Cradle of human species • Humans as native species • Filter principle of conservation biology

  20. Extinction rates • 1000 – 10000x • 1/million year • 1/500,000 years for mammals • 1/6 million years for echinoderms

  21. Current Extinction Rates • Count the number of extinctions observed • Birds/flowering plants • Assume the endangered species go extinct • ¼ mammals, 1/8 birds • Projections/models • Habitat- species relationships • Descent patterns through the red list • Survival probabilities of species • PVA

  22. Some more solutions • Captive breeding • California condor • Mauritus kestrel • Natural reserves • Legislation • CITES

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