Planet of Weeds

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Planet of Weeds

• P. 58
• Focus on biodiversity
• Crisis of mass extinction
• Were headed to mass extinction
• P. 59
• 1970s growing awareness
• But barely recognized
• Whooping crane, tiger, blue whale, peregrine
  falcon

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• P. 59
• Realized narrowly endemic (unique, localized)
  tropical forest species extinct
• 1600-1900 75 species
• 1900-1979 75 more
• 1979 25,000 plant species
• Jeopardized
• 100s of thousands of insects
• Broad denial of crisis
• no evidence of what had gone extinct

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Causes of Extinction

1. Habitat destruction
2. Habitat fragmentation
3. Overkill
4. Invasive species
5. Secondary (cascading) effects

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Habitat destruction

• Complete or partial removal of natural habitat
• Forestry,
• Mining
• human development
• Roads
• Industry
• Ex0ploration
• tourism

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2. Habitat fragmentationp. 60

• Consigns species to small parcels
• Surrounded by human impact
• Small risks accumulate
• Inbreeding
• Human intervention
• Climate fluctuations
• Catastrophe
• Cascading effects
• Parks, preserves, zoos
• Especially island species
• 50 of forest bird species lost by 2050
• 1/3 to 2/3 of all species

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Two critical issues in Habitat Fragmentation
and Overkill

• 1. Landscape conversion 2. population growth
• 1. Landscape conversion
• Draining wetlands
• Plowing prairie grasses
• Fencing savannahs
• Overgrazing
• Cutting second grwoth forests
• Ski resports, golf courses
• Burning forests for rice production

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Stages of Landscape conversion p. 61

• 1. Wild lands
• Native flora and fauna untouched
• 2. Extensively used areas
• natural grasslands lightly grazed
• Lightly grazed land, light forestry,
• 3. Intensively used areas
• Farming, villages, roads, industry
• 4. Degraded Land
• Used and left without value, no purpose
• Dumps, quarries, abandoned mines
• P. 62
• Most impact from intensive use
• South America lost 6.2 million hectares
• Philippines lost 92 of rain forest
• Trend for protected rain forest only in parks,
  conserves, official reserves
• Larges species unable to survive (fragmented)

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• 2. Population growth p. 63
• Almost 10 billion by 2150 in Africa, Latin
  America,Caribbean, Asia
• 80 million per year
• Three variables in population
• Population size
• Consumption level
• 3. Technology
• America uses 10 X energy used in Chile
• 100 X used in Angola
• High consumption increases impact of population

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• Technology increase or decrease population
  impacts
• Car
• Air conditioner
• Chain saws
• or
• Emissions decrease (paper production)
• Computer
• But more people consume so emissions go up
• Deforestation increases and consumption
• Ecological classes
• 1. Consumers
• 1.1 Billion earn gt 7,500/yr
• 2. Middle income
• 3. Poor
• 1.1 billion earn lt 700/yr
• 30 of world population
• P. 64
• No education, no economy, no resources, no hope
• Use all lands and resources to survive

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• Environmental scarcity
• International, political instability
• Environmental refugees
• Cities encroach on natural areas
• Depletion of nur6titrients
• Acidification
• Compacting
• Desertification
• water logging over irrigation
• Future
• 2 billion starving
• 2 Billion consuming
• Climate change impacts on habitat, intolerant
  species
• Loss of earths biodiversity

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• 4. Invasive Species
• Dislocations mingling of million species
• Travel by horse, camel, canoe
• Lice, fleas, dogs, goats, cows rabbits, foxes
• island bird extinctions
• European ships brought rats, pigs, Asian monkey
• Most invasive rats and cats
• Atlantic sea lamprey in Lake Erie
• Modern shipping and air transportation
• Brown tree snake on military plane from New
  Guinea eaten most of the native forest birds in
  Guam
• Purple loose strife
• red deer imported to New Zealand
• The weedy species