Life-history traits and effective population size in species with overlapping generations revisited: the importance of adult mortality

摘要

The relationship between life-history traits and the key eco-evolutionary parameters effective population size (N-e) and N-e/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 N-e, N-e/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 (V-k center dot). Although the resulting estimators of N, T and V-k center dot are upwardly biased for species with short adult lifespans, the estimate of N-e/N is largely unbiased because biases in T are compensated for by biases in V-k center dot and N. For the first time, the contrasting effects of T and V-k center dot on Ne and N-e/N are jointly considered with respect to d and.. A simple function of d and a based on the assumption of constant vital rates is shown to be a robust predictor (R-2 = 0.78) of N-e/N in an empirical data set 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 N-e that has been fueled by the genomics revolution.