Greenology: Island Biogeography Theory
January 29, 2008
This info is paraphrased from Corridor Ecology by Hilty, Lidicker, & Merenlender at Island Press 2006.
Island biogeography theory was coined by MacArthur and Wilson in the 1960s. They developed a method to determine species richness (the amount of species) on islands. They proposed that island size and distance from the mainland were the two most important factors.
Islands closer to the mainland will have more species richness, because in theory there is a higher probability of successful migrations over shorter distances. Also, the larger islands will have more species richness, because in theory large islands contain more resources, habitats, and niches.
The theory is not limited to actual islands and is applicable to any suitable habitat surrounded by unsuitable matrix space. Island-like habitats include mountaintops surrounded by deserts, lakes surrounded by dry land, forest fragments surrounded by subdivisions, and prairies surrounded by farmland.
Figure 1 from http://ocw.tufts.edu/data/5/241030/72026_medium.jpg