Factors of Extinction

1
Factors of Extinction

• Why are some species more or less prone to
  extinction?

2
Specialization

• Overspecialization of feeding
• Over specialization of habitat

3
Reproductive Rate

• r versus K strategists

4
Prey/Man

• Man preying on species
• Hunting
• Trade
• Species preying on man or livestock

5
Trophic level

• Higher up in the food chains are more susceptible

Source http//photography.nationalgeographic.com/
staticfiles/NGS/Shared/StaticFiles/Photography/Ima
ges/POD/i/indian-tiger-india-512815-ga.jpg
6
Interspecific Competition

• Nesting sites
• Food
• Breeding
• Habitat

Source http//photography.nationalgeographic.com/
staticfiles/NGS/Shared/StaticFiles/Photography/Ima
ges/POD/a/axis-deer-512754-ga.jpg
7
Behavior

• Migratory Patterns
• Fixed
• Flexible

Source http//www.ag.gov.au/www/agd/rwpattach.nsf
/VAP/(454DFAFE2D6830FB1D0597823A67B5D6)redcrabs
migration.JPG/file/redcrabsmigration.JPG
Source http//www.sciencedaily.com/releases/2008/
01/080108083008.htm
8
Distribution

• The more limited the more prone

Source http//photography.nationalgeographic.com/
staticfiles/NGS/Shared/StaticFiles/Photography/Ima
ges/POD/p/polar-bear-cubs-492324-ga.jpg
Source http//photography.nationalgeographic.com/
staticfiles/NGS/Shared/StaticFiles/Photography/Ima
ges/POD/g/grassland-kangaroos-76934-ga.jpg
9
Overall Numbers

• The lower the numbers the more prone

Source http//photography.nationalgeographic.com/
staticfiles/NGS/Shared/StaticFiles/Photography/Ima
ges/POD/b/baby-gorilla-gabon-651797-ga.jpg
Source http//animals.nationalgeographic.com/stat
icfiles/NGS/Shared/StaticFiles/animals/images/prim
ary/platypus.jpg
10
Strategies for Success

• Generalists over specialists
• Diversity
• Of ecosystems
• Complexity of food webs
• Inertia/Constancy
• Resilience

Source http//www.staringspestandrodentcontrol.co
m/files/images/American-cockroach.preview.jpg
11
Categories and Criteria

• from The IUCN Red List of Threatened Species

12
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

13
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

14
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

15
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

16
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