Island biogeography

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Ratio of extinction rate to size and distance of the populated island from the mainland (Mac Arthur & Wilson)

Island biogeography is a branch of biogeography that is heavily based on components of ecology and evolutionary biology .

It describes and analyzes the species balance between immigration and extinction on islands or other ecosystems spread across islands .

The island biogeography is ultimately based on studies from the middle of the 19th century, namely by Alfred Russel Wallace . In its modern and partly mathematical form, it was developed in the third quarter of the 20th century by Robert H. MacArthur and Edward O. Wilson and has since been expanded.

The core statement is, in a simplified form, that islands that are close to the area of ​​origin of the colonizing species tend to have comparatively higher numbers of species than those that are further away from the area of ​​origin. Furthermore, larger islands in the equilibrium state accommodate a greater number of species than smaller islands ( species-area relationship ). These findings are also of considerable importance for the practical protection of species and biotopes .

In the model of island biogeography, connectivity plays a decisive role as a function of the size and arrangement of individual patches: the flow of genes is ensured through these corridors and the probability of a species becoming extinct is considerably reduced. Real corridors, in terms of their characteristics and function, are closely related to the organism under consideration.


  • Alfred Russel Wallace: On the Natural History of the Aru Islands. The Annals and Magazine of Natural History, December 1857
  • Robert H. MacArthur, Edward O. Wilson: The Theory of Island Biogeography . Princeton University Press, Princeton 1967.
  • David Quammen: The Song of the Dodo . Scribner, New York 1996 / German at List / Ullstein 2004