abundance4

Generally exclude accidental species in the count. Does not take into account abundance patterns among the various species. Species counts depend on the sample size or sample area (rarely do you get every one!) Equilibrium model of island biogeography (MacArthur & Wilson, 1967) # of species (species richness) on an island is determined by immigration and emigration of species. Larger islands and islands closer to mainland will have greater species richness.