Human Impacts on Biodiversity

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Human Impacts on Biodiversity
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Threats to Biodiversity

• Habitat loss
• Invasive species
• Pollution
• Overexploitation
• Climate Change

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Habitat Loss

• Is the greatest threat to the biodiversity of
  life
• As human populations grow and develop land, they
  may harm or destroy natural ecosystems
• If the species that inhabit those ecosystems
  cannot adapt or move to new areas, they will not
  survive

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401 through Dorchester swamp (a Class 1
significant provincial wetland)
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Habitat Fragmentation

• When development split habitats into fragments
• Example building the 401 highway through
  Dorchester swamp
• This creates a barrier which prevents species
  from using resources (food, mates, refuge) in
  all parts of the forest

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Habitat Fragmentation (cont.)

• In Southern Ontario, a soaring population,
  intense agricultural use of land and a high
  density of roads, have all destroyed natural
  ecosystems, significantly reducing biodiversity
• Species such as the Eastern Cougar have vanished
  or become endangered

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Eastern Cougar listed as Endangered Species in
Ontario
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Eastern Cougar Range
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Invasive Species

• Are non-native species that harm ecosystems where
  they are introduced
• Examples
• Emerald ash borer (Asia)
• Purple Loosestrife (Europe)
• Asian Carp
• Zebra Mussels

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Pollution

• Many human activities pollute Earths atmosphere
• Sources of pollution include
• Coal-fired power plants
• Acid rain
• Pesticides

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Coal-Fired Plant Located South of Sarnia, Ontario
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Problems with Coal-Fired Plants

• Emit carbon dioxide, which causes the greenhouse
  effect (global warming)
• Emit sulfur dioxide and mercury, which cause acid
  rain
• Wastes from coal mining include toxic substances
  such as mercury, lead and arsenic

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Overexploitation

• Is the unsustainable use of resources, such as
  harvesting organisms faster than the organisms
  can reproduce
• Example the collapse of the North American cod
  fisheries
• Between 1988 and 1995, the annual catch dropped
  dramatically, prompting the close of the
  fisheries
• The cod population has not recovered

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Effects of Climate Change

• Disease outbreaks
• Plant migration
• Animal migration
• Extreme weather
• Increased CO2 level
• Water availability and quality

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Disease Outbreaks
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Plant Migration Boreal Forest could be replaced
by grassland
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Animal MigrationVirginia Possum
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Extreme weather
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Red River Flood, Manitoba, 2009