Lecture Twelve - Rarity and Red Listing Flashcards
What might habitat specitivity influence about a species’ range?
How widely a species exists within its geographic range.
What is the extent of occurrence?
The total area that is included within the limits of the geographic range.
What is the area of occupancy?
Thea area where populations of the species occur within the geographic range.
What can be said about specialist species for a given size of geographic range?
They have a smaller area of occupancy
Give the combination that produces a common species.
- Large geographic range
- Low habitat specitivity (being a generalist)
- Large population size
Who said that rarity is the precursor to extinction?
Darwin
In the IUCN Red List, how often are species assessed?
Every 5 years
When can a species be declared extinct?
When there is no doubt that the last individual has died after systematic exhaustive surveys
Give a species that is extinct in the wild.
Scimitar-horned Oryx
Give the three categories of threatened species.
- Critical
- Endangered
- Vulnerable
Give the risk of extinction of threatened species.
Minimum risk of extinction of 10% probability within 100 years.
Give the probability of extinction of critically endangered species.
50% probability in 5 years
Give the probability of extinction of endangered species.
20% probability in 20 years
Give the probability of extinction of vulnerable species.
10% probability in 100 years
What is Criteria A for a threatened species?
Reduction in population size
How many ways are there in which criteria A for extinction can be defined?
Four
Name a species that qualifies as critically endangered under Criteria A.
Indian Gharial
>80% reduction in population size leading up to 2007.
What is Criteria B for a threatened species?
Decline of distribution or fluctuation
How many categories of Criteria B are there?
How many must it meet?
There are 3 categories.
It must meet 2.
What is criteria C for threatened species?
Small population size and decline
Under what criteria does the Indian Gharial qualify as endangered?
A and C
What is criteria D for threatened species?
Very small or restricted - less than 50 mature individuals.
What is criteria E for critically endangered species?
A probability of extinction of 50% over 10 years/3 generations
By what criteria does Nassau Grouper class as endangered?
Criteria A
By which criteria does Ascension frigatebird class as vulnerable?
Criteria D
How does a species qualify as Near Threatened or Least Concern?
No evidence of over 10% extinction risk in 100 years.
Give a Near Threatened UK species.
Common Otter
Give the definition for Near Threatened.
Close to qualifying for a threatened category and likely to qualify in the future.
When did otters become Near Threatened?
2004
Give an example of two Least Concern species.
- Long Tailed Tit
- Eurasian Badger
Give an example of a Data Deficient species.
Orcinus orca
What proportion of species that have been assessed are threatened?
1/3
What percentage of species are Data Deficient?
14%
What percentage of amphibians are classified as threatened?
30%
What is the Red List Index?
An index used to monitor the changing state of biodiversity.
If there are 100 species at the beginning, and all but one stayed the same in 5 years, what would the Red List Index be?
It would decline by 1%.
What is the difference between Living Planet Index and Red List Index?
Living Planet Index is based on vertebrate population sizes, as opposed to Red List Index which is based on Red List status.
