Hubbell's unified neutral theory is a zero‐sum ecological drift model in which population
sizes change at random in a process resembling genetic drift, eventually leading to
extinction. Diversity is maintained within the community by speciation. Hubbell's model
makes predictions about the distribution of species abundances within communities and the
turnover of species from place to place (beta diversity). However, ecological drift cannot be
tested adequately against these predictions without independent estimates of speciation …