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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 Dammed in 2006 after lengthy legal battle Spoon-billed sandpiper Threats Habitat destruction Predation at breeding grounds 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 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 Most rangers now pulled out of area 5 gorillas found shot dead in September Many more in bushmeat trade Western lowland gorilla Double Whammy Bushmeat Ebola 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 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 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 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 Decreased extent ice Longer swims – for the first time, polar bears are being found drowned Timing of ice formation and breakup Results in mums in poorer condition and thus less reproduction Prey availability Increased human-bear interactions
