Chapter 18-Conservation of Biodiversity

CORE CASE STUDY:Modern Conservation Legacies

I.We are in the midst of a sixth mass extinction

  • Biological extinction: a species has disappeared from the earth.
  • Background extinction is an historic, continuous, low level of extinction.
  • Extinction rate is the percentage or number of species that go extinct each year.
  • Mass extinction is the loss of many species in a short period of time.
  • Extinction is natural, but there is evidence to suggest that it has accelerated as humans have populated the earth.
  • Humans have disturbed 50-80% of the earth.
  • Human activities increase the pace of extinction.
  • Current rate is 100—1,000 times the background rate (0.01–.1% per year).
  • Predictions hold that this will rise to 10,000 times that background rate during this century.
  • Under this scenario ¼-1/2 of all species will be extinct by the end of the century.
  • Extinction estimates are likely conservative.
  • Rates will likely increase with the growing human population.
  • Rates tend to be much higher in biodiversity hotspots.
  • Habitat fragmentation limits the potential for speciation to occur.
  • Species heading toward biological extinction are either endangered or threatened.
  • Endangered species are so few in number that the species could soon become extinct.
  • Threatened/vulnerable: still abundant but likely to become endangered in the near future.
  1. Global Declines in the Genetic Diversity of Wild Organisms
  2. Global Declines in the Genetic Diversity of Crops and Livestock
  3. Global Declines in Species Diversity
  4. Global Declines in Ecosystem Function
  1. Declining biodiversity has many causes
  2. Habitat Loss
  3. The loss, degradation, and fragmentation of habitat are the greatest threat to a species.
  4. Deforestation in tropical forests is the greatest species eliminator followed by loss of wetlands and plowing of grasslands.
  5. Island species are especially vulnerable to extinction. Many are endemic.
  6. Habitat islands are isolated and surrounded by other habitats.
  7. Habitat fragmentation occurs when large contiguous habitats are divided into isolated patches.
  8. Alien Species
  9. After habitat loss, introduced species are the biggest cause of extinction.
  10. The alien species can be introduced accidentally or deliberately.
  11. Some of these species threaten and endanger native species.
  12. They have no natural predators, competitors, or pathogens in their new habitat.
  13. They can trigger ecological disruptions.
  14. There are an estimated 7,100 invasive species that have caused ecological or economic harm in the U.S.
  15. Invasive species are often introduced accidentally.
  16. Argentine ants aggressively attack native ant populations.
  17. The best control is to prevent the nonnative species from being introduced.
  18. Overharvesting
  19. Overpopulation and excessive consumption of resources eliminate habitat.
  20. The World Conservation Union has kept Red Lists that are the world standard for listing all threatened species throughout the world.
  21. Poaching—illegal killing of protected species.
  22. Some protected species are killed for their valuable parts or are sold live to collectors.
  23. Earns smugglers $600,000 per hour in total.
  24. Low-risk, because smugglers are rarely caught and punished.
  25. Global legal and illegal trade in wild species for pets is a very profitable business.
  26. More than 60 bird species, mostly parrots, are endangered or threatened because of the wild bird trade.
  27. Amphibians, reptiles, mammals, and tropical fish are also being depleted because of pet trade.
  28. Exotic plants (such as orchids and cacti) are often sold to collectors for high prices.
  29. Bushmeat supplies indigenous people with food and has been harvested sustainably, but as demand has gone up illegal hunting has skyrocketed.
  30. Responsible for many local extinctions in West and Central Africa.
  31. These hunting practices have resulted in negative ecological impacts and have driven at least one species to extinction.
  32. Butchering and eating bushmeat has helped spread Ebola and AIDS from animals to humans.
  33. Pollution
  34. Pollution from chemicals like pesticides can have unintended effects on species.
  35. Climate Change
  36. Human activities induce rapid climate changes, increasing extinction rates.
  37. The conservation of biodiversity often focuses on single species
  38. Biologists site four reasons we should prevent our activities from causing extinctions.
  39. Species are a vital part of earth’s life support system.
  40. Species support our economy (materials, medicines, ecotourism).
  41. It will take millions of years for natural speciation to rebuild biodiversity.
  42. Species have a right to exist, regardless of their usefulness.
  43. Conservation Legislation
  44. Treaties help protect endangered and threatened species, but enforcement is difficult and punishment inadequate.
  45. The 1975 Convention on International Trade in Endangered Species (CITES) protects 900 species from being commercially traded and restricts international trade for 29,000 species that may become threatened.
  46. Enforcement is difficult and varies from country to country.
  47. Many countries are not signatories and still trade in animals.
  48. The Convention on Biological Diversity binds governments to reverse the global decline in biological biodiversity. The U.S. has not ratified this treaty. There are no penalties or enforcement mechanisms in place.
  49. The Endangered Species Act of 1973 identifies and legally protects endangered species in the U.S. and abroad.
  50. Identification of endangered, threatened ocean species is made by the National Marine Fisheries Service, and the U.S. Fish and Wildlife Service is responsible for identifying and listing all other endangered and threatened species.
  51. Biological facts form the basis of inclusion on the endangered list.
  52. Habitats of endangered species must be protected.
  53. Efforts have been made to repeal/weaken the Endangered Species Act.
  54. Conservation biologists believe that the ESA should be strengthened and modified to correct deficiencies.
  55. The Convention on Biological Diversity
  56. The conservation of biodiversity sometimes focuses on protecting entire ecosystems
  1. The Size, Shape and Connectedness of Protected Ares
  • The sanctuary approach is being used to protect wild species.
  • 548 federal refuges protect wildlife but the habitats are deteriorating due to invasive species, pollutants, and little operational or maintenance funding.
  • More than three-fourths of the refuges are concentrated along major bird migration corridors.
  • About one-fifth of U.S. endangered and threatened species have habitats in the refuge system.
  • Activities considered harmful to wildlife take place in nearly 60% of wildlife refuges.
  • Gene banks, botanical gardens, and farms can be used to raise threatened species and help protect species from extinction; but funding is inadequate.
  • The world’s 1600 Botanical Gardens and Arboreta contain almost one-third of the world’s known plant species, but only 3% of the world’s rare and threatened species.
  • Raising some threatened or endangered species on farms can take some of the pressure off them and perhaps offer some for commercial sale.
  • Zoos and aquariums can help protect some endangered animal species as well.
  • Egg pulling collects wild eggs laid by endangered bird species and hatches them in zoos/research centers.
  • Captive breeding takes wild individuals into captivity for breeding with the commitment to reintroduce the offspring back into the wild.
  • Artificial insemination, use of surrogate mothers, use of incubators, and cross-fostering by a similar species are other ways to increase populations of rare species.
  • The ultimate goal is to reintroduce these species into the wild.
  • Reintroductions of endangered species to the wild fail because:
  • There is not suitable habitat.
  • Individuals bred in captivity are not able to survive in the wild.
  • There is renewed overhunting/capture of the returned species.

Sustaining Biodiversity: The Species Approach1