Ext2 Download

Transcript
Biology 1229
Extinction II:
The bad news
The four horsemen of the extinction
crisis I: Habitat destruction
 Spoon-billed
sandpiper
 Jamaican blackbird
Jamaican Blackbird
 Nesospar
nigerrimus
 ‘wildpine sergeant’
 Endemic to Jamaica
 2000-10000 remaining
 Mature montane, elfin and mist
forest at high elevations
Blue and John Crow Mountains
National Park
 800
km2 of habitat protected
 Ongoing surveys to establish
basic population biology of
species
 Blue Mountain coffee

~$30/pound…
Spoon-billed sandpiper
 Eurynorhynchus
pygmeus
 Small wading bird
 Migratory
 1000 – 2500 remaining
 Breeds annually
1 clutch + ‘replacement clutch’
 14 % fledging rate

Saemangeum, South Korea
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Dammed in
2006 after
lengthy
legal battle
Spoon-billed sandpiper
 Threats
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Habitat destruction
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Predation at breeding grounds
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Breeding habitat
Staging grounds
Winter habitat
Dogs
Arctic foxes
Predation at wintering grounds

hunting
The four horsemen of the extinction
crisis II: Overkill
 Example:
(some) fisheries
 Example: Bushmeat
Fisheries as overkill…
Fish
Invertebrates
Bushmeat
 The
practice of
eating wild animals
 aka ‘game’
 A serious problem,
particularly in West
Africa
Mountain Gorilla
 Gorilla
beringei
 Critically
endangered
 Central Africa, e.g.
DRC
 ~700 left
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None in captivity
 Population
2002
rising in
Virunga Mountains
 DRC/Rwanda/Uganda
 380
gorillas, population
increasing
 Dian Fossey
Gorillas and bushmeat 2007
Civil war in DRC leads to massive
displacement, need for food and many
people with guns designed for killing
large primates
 Park rangers and anti-poaching
patrols attacked
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Most rangers now pulled out of area
5 gorillas found shot dead in
September
 Many more in bushmeat trade
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Western lowland gorilla
 Double
Whammy
Bushmeat
 Ebola
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The four horsemen of the extinction
crisis III: Invasive species
 Mammals
in New Zealand
Pre-human New Zealand
3
species of land mammals
 All predators were birds
Good vision, poor sense of smell
 Many flightless birds
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Then humans arrived…
Ship rat
Stoat
House mouse
Feral cat
Brush-tailed possum
Kiore
Norway rat
Feral pig
ferret
weasel
European hedgehog
New Zealand extinctions since
European settlement
 57
land birds extinct since
human arrival
 19 since Europeans arrived
"there is very good reason to
believe that the bird is no longer
to be found on the island, and,
as it is not known to exist
anywhere else, it has apparently
become quite extinct. This is
probably a record performance in
the way of extermination." The
Press 16 March 1895
Stephen’s Island wren
Xenicus lyalli
Still endangered due (mainly) to
predation
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Australasian Bittern
Brown Kiwi
Kokako
New Zealand Dotterel
Forbes’s parakeet
Malherbe’s parakeet
Chatham Island Oystercatcher
Black Stilt
Yellowhead
Kaka
Black Robin
Kakapo
+ numerous seabirds, invertebrates, frogs
and reptiles
The four horsemen of the extinction
crisis IV: Climate change
 Polar
bear
Polar Bear
 Ursus
maritimus
 Large carnivore
Eats mainly seals
 Other terrestrial organisms will do
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 Sexually
dimorphic
 Semi-aquatic
 Arctic species
Polar bears are semi-marine
 Hunt
mainly on sea ice
 Swim well (but not indefinitely!)
Climatic changes affecting polar
bears
 Sea
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Decreased extent
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ice
Longer swims – for the first time, polar bears are
being found drowned
Timing of ice formation and breakup
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Results in mums in poorer condition and thus less
reproduction
Prey availability
 Increased human-bear interactions
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