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CHAPTER 5: ASSESSING THREAT IN CONSERVATION (Population Viability Analysis…

- - - - o Theory of island biogeography to estimate the number of species that can be maintained in a given area
      - o Used to predict the effects of habitat loss and fragmentation on species and to estimate the size of reserves necessary to preserve species.
      - o Have a high level of uncertainty, used with caution
    - - o Uses collections of organisms in herbariums and museums. Classifies an organism as extinct if it has not been collected for some period time. (50 years) – does not consider that some species live in very remote areas.
        
         Data used to calculate the probability a species is extinct (or not) if the fact that they have been collected over time is taken into account.
        
         If not extinct, calculated by considering time since the last collection or sighting, the time since the species was first collected and no. of specimens collected.
        
        • If last collection is recent, high probability species is not extinct
- - - -  Used in managing several Australian mammals (e.g eastern barred bandicoot and Leadbeater’s Possum)
- - - -  Population size – density of no. of individuals within a local area (high to low)
      -  Geographic Range – the spatial distribution of the species (restricted to widespread)
      -  Specificity of habitat – the variety of ecological conditions within which a species can survive (wide or general / specific or narrow)