Northwest Fisheries Science Center

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Document Type: Journal Article
Center: NWFSC
Document ID: 8533
Title: Life history traits and effective population size in species with overlapping generations revisited: the importance of adult mortality
Author: Robin S. Waples
Publication Year: 2016
Journal: Heredity
Abstract:

The relationship between life-history traits and the key eco-evolutionary parameters Ne and Ne/N is revisited for iteroparous species with overlapping generations, with a focus on the annual rate of adult mortality (d).  Analytical methods based on populations with arbitrarily long adult lifespans are used to evaluate the influence of d on Ne, Ne/N, and the factors that determine these parameters: adult abundance (N), generation length (T), age at maturity (alpha), the ratio of variance to mean reproductive success in one season by individuals of the same age (phi), and lifetime variance in reproductive success of individuals in a cohort (Vk*).  Although the resulting estimators of N, T, and   are upwardly biased for species with short adult lifespans, the estimate of Ne/N is largely unbiased because biases in T are compensated for by biases in Vk*  and N.  For the first time, the contrasting effects of T and  Vk* on Ne and Ne/N are jointly considered with respect to d and phi.  A simple function of d and alpha based on the assumption of constant vital rates is shown to be a robust predictor (R2 = 0.78) of Ne/N in an empirical dataset of life tables for 63 animal and plant species with diverse life histories.  Results presented here should provide important context for interpreting the surge of genetically-based estimates of Ne that has been fueled by the genomics revolution.

Theme: Recovery and rebuilding of marine and coastal species
Foci: Develop methods to use physiological, biological and behavioral information to predict population-level processes.
Characterize the population biology of species, and develop and improve methods for predicting the status of populations.
Official Citation:

Waples, R.S.  2016.  Life history traits and effective population size in species with overlapping generations revisited: the importance of adult mortality.  Heredity 117:241-250