Another look at confidence limits for species proportions

Abstract

In paleontological investigations the number of individuals of a particular species, n i , is often expressed as a proportion of the total number of individuals, ∑ i=1 S n i = n, for all, S, species. This proportion, p = n i /n expressed in percent, is referred to by various authors as percent species, relative abundance, percentage abundance, species frequency, fractional abundance, and so on. Naturally, researchers are interested in the confidence limits that can be placed on these estimates, and in the number of individuals required to obtain them. The binomial distribution was used by Dryden (1931), Dennison and Hay (1967), Wright and Hay (1971), and Patterson and Fishbein (1989) for this purpose.