Towards inclusion of genetic diversity measures into IUCN assessments: a case study on birds

Abstract

The IUCN Red List categorizes species based on their geographical distribution and population size. However, attributes such as genetic information are not yet considered. We compiled information on genetic diversity (H_E, H_O) and inbreeding coefficient (f) along with their ecological attributes (IUCN category, migratory habit, forest dependence and habitat type) from a literature survey to assess whether bird species categorized as being of highest conservation concern display the lowest genetic diversity. We used generalized linear mixed models (GLMM) to test whether avian species with less inclusive characteristics (e.g., taxa with small geographical distributions or low dispersal capability) display lower genetic diversity than those classified as Least Concern (LC). We used hylogenetic generalized least squares (pGLS) to account for phylogenetic independence of predictor variables and to verify robustness of GLMMs (generalized linear mixed models). In general, GLMM revealed more significant relationships among ecological attributes and genetic diversity patterns. After accounting for phylogenetic independence, the highest average heterozygosity values were observed in species falling under the LC category; non–migratory birds showed lower H_O and H_E average values than migratory birds, while non–forest birds showed lower heterozygosity than forest birds. Hence, we corroborate our hypothesis that genetic diversity of birds is lower in species of high conservation concern. We hope our results promote further studies on genetic diversity of bird populations. Lastly, we propose the incorporation of genetic data as metrics in the assessment of bird conservation status.