Global Change and a Sustainable Future

1
Global Change and a Sustainable Future

• Chapter 18

2
Mass Extinction

• Biodiversity
• a. instrumental and intrinsic value
• Extinctions
• a. last member of the species dies
• b. 5 major
• - 50,000 species extinctions/yr (0.5)
• c. now experiencing the 6th
• - human cause

3
Global Declines in Genetic Diversity

• Wild Organisms
• a. prone to inbreeding depression
• - produces impaired offspring
• b. natural causes v. human causes

4

• Crops and Livestock
• a. producers have started concentrating on
• breeds that are most productive resulting
• in lower genetic variation
• b. forces breeds to become endangered

5
Global Decline in Species Diversity

• Status of species
• a. Data deficient no reliable data to
  assess
• b. extinct no longer exist since 1500
• c. threatened high risk of extinction
• d. near-threatened very likely to become
• 
  threatened
• e. least concern very widespread species

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• Since 1500
• a. birds
• - 10,000 existed, 133 extinct, 21
  threatened
• b. mammals
• - 5,500 existed, 79 extinct, 25
  threatened
• c. amphibians
• - 6,200 existed, 39 extinct, 49
  threatened

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Causes of Declining Biodiversity

• Habitat Loss
• a. greatest cause of decline
• ex) northern spotted owl
• - old growth forests

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• Alien Species
• a. native species native to the land
• b. alien/exotic species
• - species living outside of their normal
  range
• - introduced accidentally or
  intentionally
• c. invasive species
• - no natural enemies
• - 2 most common in North America
• Kudzu vine
• Zebra Mussel
• - act as predators,
• pathogens, competitors
• to native species

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• Overharvesting
• a. removed faster than population can replace
  
• themselves can cause extinction
• b. Dodo bird, sloths, mammoths
• c. poaching
• d. regulations
• - state and federal restrict
  hunting/fishing of
• game animals to particular times of
  the year
• and limit the number that can be
  harvested

10

• Pollution
• a. pesticides, heavy metals, oil spills,
• endocrine disruptors (reproduction),
• release of nutrients (N and P), thermal
• pollution (cooling of power plants)
• Climate Change
• a. changes in patterns of temperature and
• precipitation in different regions of
  the
• world and how it will affect the
  organisms

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Conserving Biodiversity

• Two general approaches
• a. single species approach
• b. ecosystem approach

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• Single Species Approach
• a. focuses on one species at a time
• b. approach
• 1. encourage population rebound
• - improving living conditions
• - providing additional habitat
• - reducing contaminants
• - captive breeding (California Condor)

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• c. legislation
• 1. Marine Mammal Protection Act
• - prohibits killing of all marine
  mammals
• in the US and prohibits the
  import/export
• of an marine mammal body parts
• - exceptions can only be made
  through
• US Fish and Wildlife Service
• National Marine Fisheries

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• 2. Endangered Species Act (1973)
• - authorizes US Fish and Wildlife service
  to
• determine which species can be listed
  as
• threatened/endangered
• - prohibits the harming of the listed
  species as
• well as trade of species
• - authorizes govnt to purchase habitat
  for
• species
• - listed species
• 201 invertebrate 795 plants
• 381 vertebrate

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• 3. Convention of Biological Diversity
• - international treaty
• - 3 objectives
• conserve biodiversity
• sustainably use biodiversity
• equitably share the benefits that
  arise
• from commercial use of genetic
  resources

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• Ecosystem Approach
• a. preserves particular regions (biodiversity
• hotspots) national parks, marine
  reserves
• b. Factors to consider
• 1. size and shape of protected area
• 2. connectedness to other protected
  areas
• 3. recognize how to incorporate
• conservation while seeing the need
  for
• sustainable habitat use for human
  needs

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• c. Island Biogeography applied to protected
  areas
• 1. distance between areas
• - further apart, harder for species
  to travel
• among them
• 2. metapopulations
• 3. edge habitat
• - where two different communities
  come
• together