The Assembly of Species Communities: Chance or Competition?

We challenge Diamond's (1975) idea that island species distributions are determined predominantly by competitions canonized by his "assembly rules." We show that every assembly rule is either tautological, trivial, or a pattern expected were species distributed at random. In order to demonstrate that competition is responsible for the joint distributions of species, one would have to falsify a null hypothesis stating that the distributions are generated by the species randomly and individually colonizing an archipelago.