Download Chapter 9 Sustaining Biodiversity

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Chapter 9 Sustaining
Biodiversity
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What Role do Humans Play in
Extinction?
 Extinctions:
Biological – no longer exist…anywhere
 Can cause secondary extinction – weakened
ecosystem – extinction of some species that had
strong ties with one deceased
 Background extinction rate – low rate
 1/million species = 0.0001%
 Allowed for balance between extinction and
formation of new species
 Mass extinction – many in a short time
 Recovery can happen, but takes millions of years
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What Role do Humans Play in
Extinction?
 Human
Activities
2005 Millennium assessment – humans have taken
over or disturbed 50-80% of land surfaces
 Polluted or disturbed about ½ of surface waters
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 Extinction
Rates Rising Rapidly
Current rate is 1,000 x times background rate
 Rate due to habitat loss, climate change, etc could rise
to 10,000 times the background rate = 1% extinction
 About 10,000 species/year for every 1million sp
 ¼- ½ of current animal & plant species extinct by
end of century
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What Role do Humans Play in
Extinction?
 Extinction
Rates
Rate of loss and extent of biodiversity loss increase
during next 50-100 years – due to human growth
 Projected rates are higher in areas with highly
endangered centers of biodiversity
 Biodiversity hot-spots
 We are eliminating, degrading, fragmenting, and
simplifying many biologically diverse enviro
 Limiting the long-term recovery – reducing rate of
speciation
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What Role do Humans Play in
Extinction?
 Endangered
and threatened species smoke alarms
Endangered species – so few survivors species soon
become extinct
 Threatened/vulnerable – enough for short term, but
likely to become endangered
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 IUCN
(international union for the conservation of
nature)
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2009 1370 listed as endangered/threatened for ESA
 Behavioral
characteristics – make more prone to
extinction pg 194 fig 9-3
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Passenger Pigeon
 Early
 By
1800’s very abundant
1900 gone
Habitat loss – forests cleared
 Uncontrolled commercial hunting/easy to kill
 Good eats, feathers good pillows
 Easy targets
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WHY should we care about rising
rate of extinction
 Species
vital part of natural capital
Extinction, but speciation (form new ones) replaces at
a natural background extinction rate
 So why care?
 Vital part of earth’s life support system – natural
resources and services – keep us alive
 EX pollination, chemical cycling, upset ecosystem
 Economics – food, fuel, lumber, medicines (62% for
prospectors in rainforests)
 Ecotourism – more money alive/intact than dead
 Will take longer to recover
 Right to exist
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How do we accelerate extinction
 HIPPCO
Habitat destruction, degradation, fragmentation
 Invasive species
 Population growth and increasing use of resources
 Pollution
 Climate change
 Overexploitation
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 Greatest
threat is habitat destruction, degradation,
and fragmentation
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Deforestation, destruction/degradation of coral reefs
and wetlands, plowing grasslands
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How accelerate
 Habitat
fragmentation – large intact areas, divided
Block migration routes
 Decrease tree cover
 Divide populations into too small of species pockets
 Vulnerability to normal pressures
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 Natural
 Use
parks/reserves are habitat islands
theory of island biogeography to help
understand role of fragmentation and species
extinction
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How Accelerate
 98%
of US food supply – corn, wheat, rice, cattle,
poultry; was introduced
 In
new habitat
Face no natural predators, competitors, parasites, or
pathogens
 Crowd-out populations of native species – ecological
disruptions, health problems, economic loss
 US FW 40% of species listed as endangered are due
to invasive species
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How Accelerate
 Kudzu
vine
Imported from Japan and planted to control soil
erosion
 Literally takes over
 Can use useful – starch in beverages, confections,
herbal remedies
 All parts are edible
 Fiber could be used to replace trees in paper
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 Disrupt
ecosystems – try many approaches –
typically not much works
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Prevention for Invasives
 Research
 Ground
surveys and tracking
 International
 Cargo
treaties to ban transfer
ships dump ballast water
 Educate
public
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How accelerate
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Pop growth and excessive and wasteful consumption of
resources =
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increased eco footprint =
eliminated, degraded, and fragmented areas of wildlife
Pollution
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Pesticides
 Annually kill 1/5th of honeybee colonies (pollinate 1/3rd
of crops)
 Kill ~67 millin birds
 6-14 million fish
DDT 50’s -70s especially harmed bald eagle
Biomagnification
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How accelerate
 Read
through case studies for
honeybees,
 illegal killing and selling
 Birds
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 PAY
ATTENTION TO STATS and #s
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How Can we Protect
 Convention
on International Trade in Endangered
Species (CITES)
 US
Endangered Species Act – what’s within the
reading and the science Focus
 Establish
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wildlife refuges and protected areas
Especially vital for migratory waterfoul
 Gene
Banks, Botanical Gardens
 Zoos/Aquariums
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Endangered Species Act
 It’s
not a failure
Species listed only when in serious danger
 Takes decades for most species to become
endangered/threatened, so it can take decades to
come back
 ~ ½ of listed species are stable or improving and 99%
of protected species are still surviving
 Small budget can do a lot
 Recommend to strengthen and modify
 Increase funding
 Develop recovery plans
 Look carefully at the core of its habitat for protection
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Precautionary Principle
 To
avoid causing more extinctions and more loss of
biodiversity
 If
evidence shows it can harm, precautionary
measure to prevent or reduce
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Better safe than sorry
 Look
at 3 important questions:
How do we allocate limited resources between
protecting species and protecting habitats?
 How do we decide which species should get more
attention?
 How do we determine which habitat areas are most
critical to protect
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