Correlation of number of transient species with island size and its relation to the species-area relationship.

Köchy, M., and H. Rydin (1993)

The equilibrium theory of island biogeography predicts that the number of transient species increases with island area. Thus, species richness in quadrats of constant size should increase with island area. We counted vascular plant species in 16 m² quadrats on 24 islands (10 - 10,000 m²) of natural vegetation surrounded by cultivated land. The number of speciesfound on each island increased with island area, but the number of species per quadrat remained constant. Further, the species-area relationship did not differ between island and contiguous habitat. As isolation, and therefore colonization, had no significant influence on the number of species, we argue that either the number of transient species or the extinction rate of the whole island are not correlated to island area as assumed by the equilibrium theory.