UW Aquatic & Fishery Sciences Quantitative Seminar

Robin Waples

NOAA Northwest Fisheries Science Center

Temporal estimates of effective population size in species with overlapping generations

Robin Waples & Masashi Yokota

Abstract

The standard temporal method for estimating effective population size (N_e) Most species are iteroparous, and for these species Ne is particularly hard to calculate because it requires measuring lifetime reproductive success. Recent improvements in parentage analysis and single-sample genetic methods make it relatively easy to estimate Nb (effective breeders per year or time period); however, nobody has studied the relationship between Nb and Ne in iteroparous species, so it is hard to evaluate these results. We applied a recently developed, hybrid Felsenstein-Hill method (AgeNe) to life tables with vital rates for 63 species from seaweed and mosquitos to chimpanzees and pine trees and find that: a) Nb/N varies widely (over 6-fold) across species, with broad overlap among major taxa; b) for many species, Nb is larger than Ne (contrast with situation in semelparous species, where Nb<> N, if N is defined as the number of adults alive at any given time. These results mean that estimates of Nb can be translated into Ne with just some basic life history information. In a related study, we examine how single-sample, genetic estimates of effective size from iteroparous species relate to Nb and Ne.