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Effective/census population size ratio estimation: a compendium and appraisal

Friso P. Palstra, Dylan J. Fraser

Ecology and Evolution · 2012 · Review

doi:10.1002/ece3.329

Abstract

With an ecological‐evolutionary perspective increasingly applied toward the conservation and management of endangered or exploited species, the genetic estimation of effective population size ( N e ) has proliferated. Based on a comprehensive analysis of empirical literature from the past two decades, we asked: (i) how often do studies link N e to the adult census population size ( N )? (ii) To what extent is N e correctly linked to N ? (iii) How readily is uncertainty accounted for in both N e and N when quantifying N e / N ratios? and (iv) how frequently and to what degree might errors in the estimation of N e or N affect inferences of N e / N ratios? We found that only 20% of available N e estimates (508 of 2617; 233 studies) explicitly attempted to link N e and N ; of these, only 31% (160 of 508) correctly linked N e and N . Moreover, only 7% (41 of 508) of N e / N ratios (correctly linked or not) reported confidence intervals for both N e and N ; for those cases where confidence intervals were reported for N e only, 31% of N e / N ratios overlapped with 1, of which more than half also reached below N e / N = 0.01. Uncertainty in N e /N ratios thus sometimes spanned at least two orders of magnitude. We conclude that the estimation of N e / N ratios in natural populations could be significantly improved, discuss several options for doing so, and briefly outline some future research directions.

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