Factors of Extinction

Factors of Extinction

Why are some species more or less prone to extinction?

Specialization

Source: http://www.destination360.com/north-america/us/alaska/alaska-whale-watching.php

Source: http://www.koalas.org/koala-australia.html

Source: http://www.biojobblog.com/tags/panda/

Overspecialization of feeding Over specialization of habitat

Reproductive Rate

Source: http://www.pbase.com/johncarol/image/73692533

Source: http://www.srgc.org.uk/bulblog/log2007/100107/log.html

r versus K strategists

Prey/Man

Source: http://www.awf.org/section/wildlife/elephants

Source: http://www.nytimes.com/2006/07/16/world/europe/16tuna.html

Source: http://animals.nationalgeographic.com/animals/mammals/wolf.html

Man preying on species Hunting Trade

Species preying on man or livestock

Trophic level

Higher up in the food chains are more susceptible

Source: http://photography.nationalgeographic.com/staticfiles/NGS/Shared/StaticFiles/Photography/Images/POD/i/indian-tiger-india-512815-ga.jpg

Interspecific Competition

Nesting sites Food Breeding Habitat

Source: http://photography.nationalgeographic.com/staticfiles/NGS/Shared/StaticFiles/Photography/Images/POD/a/axis-deer-512754-ga.jpg

Behavior

Migratory Patterns Fixed Flexible

Source: http://www.sciencedaily.com/releases/2008/01/080108083008.htm

Source: http://www.ag.gov.au/www/agd/rwpattach.nsf/VAP/(454DFAFE2D6830FB1D0597823A67B5D6)~red+crabs+migration.JPG/$file/red+crabs+migration.JPG

Distribution

The more limited the more prone

Source: http://photography.nationalgeographic.com/staticfiles/NGS/Shared/StaticFiles/Photography/Images/POD/g/grassland-kangaroos-76934-ga.jpg

Source: http://photography.nationalgeographic.com/staticfiles/NGS/Shared/StaticFiles/Photography/Images/POD/p/polar-bear-cubs-492324-ga.jpg

Overall Numbers

The lower the numbers the more prone

Source: http://animals.nationalgeographic.com/staticfiles/NGS/Shared/StaticFiles/animals/images/primary/platypus.jpg

Source: http://photography.nationalgeographic.com/staticfiles/NGS/Shared/StaticFiles/Photography/Images/POD/b/baby-gorilla-gabon-651797-ga.jpg

Strategies for Success

Generalists over specialists Diversity

Of ecosystems Complexity of food webs

Inertia/Constancy Resilience

Source: http://www.staringspestandrodentcontrol.com/files/images/American-cockroach.preview.jpg

Categories and Criteria

from: The IUCN Red List of Threatened Species

Conservation Status

Extinct (EX) – there is no reasonable doubt that the last individual has died

Extinct in the Wild (EW) – Known only to survive in cultivation, in captivity, or as a naturalized population well outside the past range

Threatened

Critically Endangered (CR) – Facing an extremely high risk of extinction in the wild

Endangered (EN) – Facing a very high risk of extinction in the wild

Vulnerable (VU) – Facing a high risk of extinction in the wild

Criteria for CR, EN and VU

Reduction of population size by W% over 10 years or 3 generations

Size of geographic range Population size of mature individuals

less than X with continued decline of Y% over 10 years or 3 generations

Population size of mature individuals less than Z

Quantitative analysis showing the probability of extinction in the wild

Conservation Status

Near Threatened (NT) – Close the qualifying for a threatened category in the near future

Least Concern (LC) – Widespread abundant taxa are included in this category

Conservation Status

Data Deficient (DD) - there is inadequate information to make an assessment of the risk of extinction

Not Evaluated (NE) – has not been evaluated against criterion