Island Biogeography
Island species richness is determined by the balance between immigration (new species arriving) and extinction (current species dying out).
Island Filter 1: Distance
Near Far
Distance from mainland primarily affects the Immigration Rate. Farther islands are harder to reach.
Island Filter 2: Size (Area)
Small Large
Island size primarily affects the Extinction Rate. Smaller islands have fewer resources, smaller populations, and higher extinction risk. (It also slightly acts as a larger "target" for immigration).
Equilibrium Point (S)
50
Stable number of species when Immigration = Extinction.