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Limited geographic range is the most important determinant of genus extinction at background rates but becomes increasingly irrelevant as mass extinction arises. [45] Limited geographic range is a cause both of small population size and of greater vulnerability to local environmental catastrophes.
Extinctions are a normal part of the evolutionary process, and the background extinction rate is a measurement of "how often" they naturally occur. Normal extinction rates are often used as a comparison to present day extinction rates, to illustrate the higher frequency of extinction today than in all periods of non-extinction events before it. [1]
Local extinction, also extirpation, is the termination of a species (or other taxon) in a chosen geographic area of study, though it still exists elsewhere. Local extinctions are contrasted with global extinctions. [1] [2] Local extinctions mark a change in the ecology of an area.
For example, in an article published in 2004, Otso Ovaskainen and Ilkka Hanski explained with an empirical example that when factors such as Allee effect or Rescue effect were included in modeling the extinction threshold, there were unexpected extinctions in a high number of species. A more complex model came up with different results, and in ...
Ceballos pointed to the extinction of the passenger pigeon, which was the only species in its genus, as an example of how losing a genus can have a cascading effect on a wider ecosystem.
[27]: 2321 For example, the decline of sea ice in the Arctic has been accelerating during the early twenty‐first century, with a decline rate of 4.7% per decade (it has declined over 50% since the first satellite records). [28] [29] [30] One well known example of a species affected is the polar bear, whose habitat in the Arctic is threatened ...
By Brad Brooks (Reuters) -A leading conservation research group found that 40% of animals and 34% of plants in the United States are at risk of extinction, while 41% of ecosystems are facing collapse.
There are two types of processes that can lead to habitat fragmentation. There are exogenous processes and endogenous processes. Endogenous is a process that develops as a part of species biology so they typically include changes in biology, behavior, and interactions within or between species.