Island Biogeography and Landscape Ecology

Abstract

MacArthur and Wilson’s theory (1967) set out to identify and measure the variables involved in the colonisation of islands by biota and their subsequent evolution or extinction. The key biogeographical variables identified by their theory were island size and distance from the mainland. They suggested that an island’s biodiversity is proportionate to the island’s size (i.e. the larger the island the higher the species number) and inversely proportionate to its distance from the mainland (i.e. more remote islands tend to support less species). Equally significantly they argued that the number of species on an island is in a state of dynamic equilibrium – diversity eventually stabilises but turnover remains high as species continually colonise and go extinct. Dynamism is a defining concept when attempting to understand the biogeography of islands and, in the Mediterranean in particular, the impact of human activity over millennia has resulted in very high levels of dynamism with profound consequences for the biota.