IUCN Red List and the value of integrating genetics

Many species on endangered species lists such as the IUCN Red List (RL) are categorized using demographic factors such as numbers of mature individuals. Genetic factors are not currently used in the RL even though their explicit consideration, including effective population size ( N e ) and expected heterozygosity-loss ( H -loss), could improve the assessment of extinction risk. Here, we consider the estimation of N e and H -loss in the context of RL species. First, we investigate the reporting of number of mature individuals for RL Endangered species, which is needed to estimate N e and H -loss. We found 77% of species assessments studied here did not report methods used to estimate the number of mature adults, and that these assessments rarely report other important determinants of N e (e.g., sex ratio, variance in family size). We therefore applied common rules of thumb to estimate N e , and found that N e was likely