ENWC201 Lecture Notes - Lecture 14: Keystone Species, Local Extinction, Introduced Species
15 Jun 2018
School
Department
Course
Professor
Anthropogenic Causes of Extinction
Overexploitation + habitat degradation + introduced species + disease +
pollution + climate change
When this is too much, they go extinct
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Rag frims limb tree frog
Extinct
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News outlets ignored it - the public cant care about what we don’t
know
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Amphibians are being hit super hard
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We have been causing extinctions since we have stepped on the earth
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Types of Extinction
Ecological Extinction - low density, no longer interacts
So few left that they cant find each other to breed
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Local extinction - species lost in only an area or region (extirpation)
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Global extinction - all of earth
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Some extinctions can lead to others
Cascade effect
Ex sea otter
Urchin predator
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Eat sea urchins
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Had a local extinction
Sea urchins bloomed, ate kelp, caused many
other extinctions
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Some extinctions can have a larger affect than others
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Species With the Greatest Impacts
Dominant species: common, large effects
Ex white tailed deer
Removing them and having them both causes damage
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Ecosystem engineers: modify habitat
Physically alter habitat
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Beavers
Create wetlands, etc
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Critical to other species□
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Keystone species: greater impact than expected
Ex wolves in Yellowstone
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Species Most Vulnerable
Many potential attributes
Rarity
Already closer to extinction□
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Narrow range
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Large area requirements
Less and less of large habitats□
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Low reproduction
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Specialization
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Bad luck!
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Patterns of Endangerment
What and where?
What
International Union for the Conservation of Nature and
Natural Resources (IUCN)
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Red list: systematic listing (scientific method, systematic
detailed process)
Extinct
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Extinct in the wild
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Threatened
Critically endangered
Cuban crocodile
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Endangered
Ethiopian wolf
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Vulnerable
West indian manatee
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Near threatened
Gentoo Penguin
Populations are decreasing
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Least concern
Grey Wolf
Not doing great in the US, but doing well
globally
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No data/not evaluated
Luzon broad-toothed rat
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Ahmanson's sportive lemur
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Ammonite striped rabbit
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Where
Population density of humans correlates with where species
are going extinct
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Marine extinction during the Phanerozoic
Marine extinctions during different extinction events
The great dying - 96% of marine life died - took 10 mill
years to recover
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Our extinction is the 6th extinction event - we are waiting to see
how many extinctions we have created
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We are causing animals to rapidly go extinct!
60% of all vertebrates wiped out since the 70s□
As populations decrease, animals become more and more
prone to extinction
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Insects are rapidly decreasing
Cause for concern - vital part of food web
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We need to have hope
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Extinction
Thursday, May 3, 2018
8:22 PM
Document Summary
Overexploitation + habitat degradation + introduced species + disease + pollution + climate change. When this is too much, they go extinct. News outlets ignored it - the public cant care about what we don"t know. We have been causing extinctions since we have stepped on the earth. Ecological extinction - low density, no longer interacts. So few left that they cant find each other to breed. Local extinction - species lost in only an area or region (extirpation) Sea urchins bloomed, ate kelp, caused many other extinctions. Some extinctions can have a larger affect than others. Removing them and having them both causes damage. International union for the conservation of nature and. Red list: systematic listing (scientific method, systematic detailed process) Not doing great in the us, but doing well globally. Population density of humans correlates with where species are going extinct. The great dying - 96% of marine life died - took 10 mill years to recover.
