1 / 29

Chapter 12

Chapter 12. Sustaining Biodiversity: The Species Approach . Key Concepts. Human effects on biodiversity Importance of biodiversity How human activities affect wildlife Management of wildlife. 1% Probably extinct. 7% Critically imperiled. 8% Imperiled. 16% Vulnerable.

ross
Télécharger la présentation

Chapter 12

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chapter 12 Sustaining Biodiversity: The Species Approach

  2. Key Concepts • Human effects on biodiversity • Importance of biodiversity • How human activities affect wildlife • Management of wildlife

  3. 1% Probably extinct 7% Critically imperiled 8% Imperiled 16% Vulnerable 1% Other 67% Secure or apparently secure US Diversity

  4. What Increases Biodiversity? • Physically diverse habitat • Moderate environmental disturbance • Small variations in conditions • Middle stages of ecological succession

  5. What Decreases Biodiversity? • Environmental stress • Large environmental disturbance • Extreme environmental conditions • Severe limiting factors • Introduction of alien (exotic) species • Geographic isolation

  6. Arctic Circle Arctic Circle 60° EUROPE NORTH AMERICA ASIA 30°N Tropic of Cancer Atlantic Ocean AFRICA Pacific Ocean Pacific Ocean 0° 150° 120° 90° 30°W 0° 60°E 90° 150° SOUTH AMERICA Indian Ocean Tropic of Capricorn AUSTRALIA 30°S Antarctic Circle 60° ANTARCTICA Critical and endangered Threatened Stable or intact Projected Status of Biodiversity 1998–2018

  7. Strategies for Protecting Species

  8. Species Extinction • Local Extinction: when a species is no longer found in the area that it once inhabited (but is still found elsewhere in the world) • Ecological Extinction: so few members of a species are left that it can’t play its ecological role • Biological Extinction: species is not found anywhere on earth (permanent)

  9. Endangered and Threatened Species • Endangered Species: so few survivors that the species could soon become extinct • Threatened Species: still abundant in its natural range but is likely to become endangered due to declining numbers

  10. Extinction Risks • Low reproductive rate (K-strategists): blue whale, giant panda • Specialized niche: giant panda • Narrow distribution: island species • Feeds at high trophic level: Bengal tiger, bald eagle • Rare: island species, orchids • Commercially valuable: elephant

  11. How Do We Estimate Extinction Risks? • Population viability analysis (PVA): risk assessment to predict whether a population will persist for a certain # of generations • PVA is based on: resource needs, current and predicted habitat conditions, genetic variability, interactions with other species, reproductive rates

  12. Continued… • Minimum viable population (MVP): smallest number of individuals necessary for the survival of a population in a region • Minimum dynamic area (MDA): the minimum area of habitat needed to maintain the MVP

  13. Why Should We Care About Biodiversity? • Humans value nature in different ways • Instrumental value: usefulness to us • Intrinsic value: because they exist, regardless of use • Utilitarian (use): goods, services, recreation • Nonutilitarian (nonuse): aesthetic

  14. Value of Nature Instrumental Intrinsic (human centered) (species or ecosystem centered) Utilitarian Nonutilitarian Existence Goods Ecological services Aesthetic Information Recreation

  15. Causes of Depletion of Wild Species • Human population growth • Failure to value the environment • Increasing resource use • Poverty

  16. Habitat loss Habitat degradation Overfishing Basic Causes Introducing nonnative species Climate change • Population growth • Rising resource use • No environmental accounting • Poverty Commercial hunting Pollution Sale of exotic pets and decorative plants Predator and pest control

  17. Type of Nonnative Organism Annual Losses and Damages Crop disease $23.5 billion Crop weeds $23.4 billion Rats $19 billion Feral cats and outdoor pet cats $17 billion Crop insects $14 billion Livestock diseases $9 billion Forest insects and diseases $4.8 billion Zebra mussels $3 billion Common pigeon $1.1 billion Formosan termite $1.1 billion Damage from Nonnative Species Fishes $1.1 billion Asian clam $1.1 billion Feral pigs $0.8 billion Starlings $0.8 billion Fire ant $0.6 billion

  18. Characteristics of Successful Invader Species Characteristics of Ecosystems Vulnerable to Invader Species • High reproductive rate, short generation time (r-selected species) • Pioneer species • Long lived • High dispersal rate • Release growth- inhibiting chemicals into soil • Generalists • High genetic variability • Similar climate to habitat of invader • Absence of predators on invading species • Early successional species • Low diversity of native species • Absence of fire • Disturbed by human activities

  19. What Can Be Done to Reduce Threat from Nonnative Species? • Identify characteristics that make species successful invaders and use this information to screen out invaders • Increase inspections of goods coming into a country • Pass laws to ban the transfer of harmful invader species

  20. Biome % of Area Disturbed Temperate broadleaf forests 94% Temperate evergreen forests 94% Temperate grasslands 72% Mixed mountain systems 71% Tropical dry forests 70% Subtropical and temperate rain forests 67% Cold deserts and semideserts 55% Mixed island systems 53% Warm deserts and semideserts 44% Habitat Disturbance by Biome Tropical humid forests 37% Tropical grasslands 26% Temperate boreal forests 18% Tundra 0.7%

  21. Hunting and Poaching

  22. Wild African Elephant • 1970: 2.5 million • Today: 300,000 • Killed for tusks (worth about $500-1500) • Bleed to death • 1989 ban on sale of ivory from elephants • Caused increased killing of walruses and hippos for ivory

  23. DO NOT POST TO INTERNET

  24. Protecting Wild Species I • Bioinformatics: managing, analyzing, and communicating biological information • Involves: 1. building computer databases 2. developing computer tools to analyze the information 3. communicating the information • Example: Species 2000- global research project with the goal of providing information about all species on earth

  25. Protecting Wild Species II • International Treaties • Convention on International Trade in Endangered Species (CITES) 1972 • Signed by 152 countries • Lists 900 species that cannot be commercially traded • Restricts international trade of 29,000 other at-risk species

  26. Protecting Wild Species III • National Laws • Lacey Act of 1900: prohibits transportation of live or dead animals (or their parts) across state borders without a permit • Endangered Species Act of 1973: illegal for Americans to import or trade any product made from an endangered or threatened species

  27. Protecting Wild Species IV • Habitat Conservation Plans • Compromise between endangered species and private landowners • Landowners are allowed to kill a certain # of endangered species on private land in exchange for taking steps to protect the species Possible steps: setting aside a preserve for the species, paying to relocate the species, paying for government buy habitat elsewhere

  28. Other Approaches to Protecting Wild Species • Wildlife refuges and protected areas • Gene banks (storing plant seeds), botanical gardens (cultivation of rare and endangered plants), and farms (raise for commercial sale) • Zoos and aquariums

  29. Wildlife Management • Laws regulating hunting and fishing • Harvest quotas • Population management plans • Improving habitat • Laws for migrating species

More Related