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Chapter 38

Chapter 38. Conservation Biology. Saving the Tiger Tigers once roamed across Asia, but hunting has drastically reduced their populations Intense conservation efforts by the Myanmar government have begun to save the tigers

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Chapter 38

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  1. Chapter 38 Conservation Biology

  2. Saving the Tiger • Tigers once roamed across Asia, but hunting has drastically reduced their populations • Intense conservation efforts by the Myanmar government have begun to save the tigers • The story of the tiger illustrates the biodiversity crisis, a rapid decrease in Earth's plant and animal diversity • Conservation biology is a goal-oriented science that seeks to counter the biodiversity crisis

  3. THE BIODIVERSITY CRISIS: AN OVERVIEW • 38.1 Human activities threaten Earth's biodiversity • Scientists have described about 1.8 million species • Global extinction rates may be 1,000 times higher than any time in the past 100,000 years • Biodiversity has three levels • Genetic diversity • Species diversity • Ecosystem diversity

  4. Human activities threaten diversity at all levels • Alter trophic structure, energy flow, chemical recycling, and natural disturbances • Many species are endangered or threatened Video: Coral Reef

  5. 38.2 Biodiversity is vital to human welfare • There are practical as well as ethical and aesthetic reasons for preserving biodiversity • Provides food, fiber, medicines, etc. • Loss of genetic diversity means loss of opportunities for future benefits • Large-scale alterations in the biosphere threaten the human population • Ecosystem services have been valued at $33 trillion annually

  6. 38.3 Habitat destruction, introduced species, and overexploitation are the major threats to biodiversity • Human alteration of habitat is the greatest single threat to biodiversity • Introduced species can disrupt communities by competing with or preying on native species • Overexploitation of wildlife by harvesting has threatened various animal and plant species

  7. CONNECTION • 38.4 Pollution of the environment compounds our impact on other species • Human release of pollutants can have local, regional, and global effects • CFCs leading to depletion of the ozone layer • Eutrophication of lakes and streams • Biological magnification of chemicals • Synthetic chemicals that cannot be biodegraded

  8. LE 38-4 Herring gull eggs 124 ppm Lake trout 4.83 ppm Concentration of PCBs Smelt 1.04 ppm Zooplankton 0.123 ppm Phytoplankton 0.025 ppm

  9. CONNECTION • 38.5 Rapid global warming could alter the entire biosphere • Burning of fossil fuels is increasing the amount of CO2 and other greenhouse gases in the air • Correlation with increased global temperature • The greenhouse effect • Natural phenomenon is essential for life on Earth • Rapidly increasing CO2 is making global warming a danger

  10. LE 38-5a 1.05 390 0.90 380 0.75 370 Temperature 0.60 360 0.45 350 CO2 concentration (ppm) Temperature variation (°C) 0.30 340 CO2 0.15 330 0 320 –0.15 310 –0.30 –0.45 300 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 Year

  11. LE 38-5b Human activities and natural processes add CO2 to the atmosphere, increasing the effect. Global warming: CO2 lets sunlight through but retains the heat radiated from Earth. Photosynthesis removes CO2 from the atmosphere, decreasing the effect. CO2 CO2 in the atmosphere CO2 CO2

  12. Possible consequences of increased global warming • Melting of polar ice and rising sea levels • Changing climate patterns • Habitat alteration and consequent loss of species • Effects on human health • Most scientists and world leaders believe global warming must be combated immediately • Lifestyle changes necessary

  13. CONSERVATION OF POPULATIONS AND SPECIES • 38.6 Two ways to study endangered populations are the small-population approach and the declining-population approach • Population fragmentation is one of the most harmful effects of habitat loss • Small-population approach • Attempts to prevent extinction vortex • Identifies minimum viable population size • Focuses on preserving genetic variation

  14. Declining-population approach • Follows logical series of steps to halt population declines • Confirm that species is in decline • Determine species' environmental requirements • Develop hypotheses for causes of decline • Test most likely hypotheses first • Apply results of diagnosis to management of threatened species

  15. 38.7 Identifying critical habitat factors can guide conservation efforts • Preserving critical habitat may help endangered species recover • Example: red-cockaded woodpecker • Management for one species can affect other species negatively or positively • Human demands conflicting with habitat preservation must be considered

  16. MANAGING AND RESTORING ECOSYSTEMS • 38.8 Sustaining ecosystems and landscapes is a conservation priority • Landscape ecology • Application of ecological principles to the study of a collection of ecosystems • Goal to study human land-use patterns to make biodiversity conservation a priority

  17. Edges between ecosystems are prominent features of landscapes • Have distinct features and species • Human-caused edge communities may be dominated by few edge-adapted species • Movement corridors can connect fragmented habitats • May be important in preserving biodiversity • Can promote dispersal and prevent inbreeding • Can sometimes be harmful

  18. 38.9 Protected areas are established to slow the loss of biodiversity • Biodiversity hot spots • Small areas with many endangered or threatened species • Have large concentrations of endemic species • Highly sensitive to habitat degradation • Provide an opportunity to protect many species in very limited areas

  19. Migratory species may require international protection • National parks and reserves are generally too small to achieve minimal viable population size

  20. LE 38-9a Equator

  21. CONNECTION • 38.10 The Yellowstone to Yukon Conversation Initiative seeks to preserve biodiversity by connecting protected areas • The Y2Y Initiative is creating ways to give creatures more room • Aims to preserve web of life that has defined the Rocky Mountains of the United States and Canada • Seeks to connect parks with protected wildlife corridors • Return of gray wolves is a program success

  22. LE 38-10a Yellowstone to Yukon Ecoregion YUKON TERRITORY NORTHWEST TERRITORIES ALBERTA BRITISH COLUMBIA YELLOWSTONE TO YUKON CONSERVATION INITIATIVE MONTANA LEGEND Major Highways WASHINGTON Protected areas Y2Y Ecoregion 420 105 0 105 210 315 Km OREGON IDAHO WYOMING

  23. 38.11 The study of how to restore degraded habitats is a developing science • Restoration ecology uses ecological principles to return degraded ecosystems to conditions similar to their natural state • Bioremediation uses living organisms to detoxify polluted ecosystems • Removes harmful substances • Bioaugmentation uses organisms to add essential materials to degraded ecosystems

  24. CONNECTION • 38.12 The Kissimmee River project is a case study in restoration ecology • Population growth and development put ecological pressures on the Kissimmee River • The Kissimmee River Restoration Project is one of the world's largest restoration projects • Restoring natural river flow • Reclaiming wetlands • Improving water quality and wildlife habitat

  25. LE 38-12a Former canal

  26. 38.13 Zoned reserves are an attempt to reverse ecosystem disruption • A zoned reserve is an extensive region of land that includes • One or more areas undisturbed by humans • Surrounding buffer zones of compatible economic development • Shield against further development

  27. Zoned reserves contribute to sustainable development • Long-term prosperity of human societies and the ecosystems that support them • Costa Rica an example of success • Commitment to conservation is challenged by growing population

  28. LE 38-13a Nicaragua Caribbean Sea Costa Rica National parkland ma Buffer zone na Pa Pacific Ocean

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