theory of island biogeography

The theory of island biogeography is a biological concept that explains species distribution on islands. It considers factors like island size, distance from the mainland, and the number of species in surrounding areas to predict how many species will inhabit an island. This theory also applies to "islands" on land, such as mountaintops or forest fragments.1

The theory posits that when immigration and extinction rates are equal, the number of species on an island is directly related to its size and inversely related to its distance from the mainland. Examples like the colonization of Surtsey and Krakatoa after volcanic eruptions illustrate how species gradually establish themselves on islands over time, eventually reaching a dynamic equilibrium. This concept is also linked to adaptive radiation, where colonizers on remote islands with few competitors can rapidly diversify into new species, as seen with the finches on the Galapagos Islands.12