Explicit Calculation of the Rarefaction Diversity Measurement and the Determination of Sufficient Sample Size

An explicit means of calculating the expected number of species [E(S n )] and the variance of (S n ) in a random sample of n individuals from a collection containing N individuals and S species is presented. An example illustrates a new use of E(S n ): determination of the sample size required for any desired degree of accuracy in collecting species known to occur in a particular area.