Evolutionary distinctiveness and conservation priorities in a large radiation of songbirds

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AbstractHuman‐induced impacts such as climate change and habitat alterations, coupled with limits on funding, have forced conservation actions into a mode of triage. Although no current method has been agreed upon as the best approach to select species for conservation, many studies have demonstrated the utility of incorporating phylogenetic diversity into these decisions. In many cases, degree of phylogenetic relatedness is thought to provide a measure of functional diversity, and greater phylogenetic distinctiveness is likely linked to ecosystem stability. Despite recent debate over the validity of this notion, phylogenetic information remains an important factor to consider in evaluating species and regions for conservation attention. Emberizoidea is a large radiation of 830 species, representing roughly 17% of all songbirds and 8% of all birds. Species in this clade are found throughout the Americas and occur in all terrestrial biomes in the region. The large distribution of this clade, coupled with its morphological and ecological diversity, makes it an important radiation to study from an evolutionary and conservation perspective. This study provides conservation priorities for all species in Emberizoidea using evolutionary distinctiveness (ED) and Evolutionarily Distinct and Globally Endangered (EDGE) values from a pseudoposterior distribution of time‐calibrated supertrees. We found that threat level is not correlated with degree of ED, indicating that the most threatened species do not represent a disproportionate amount of ED. In addition, threatened species are slightly clustered across the phylogeny, indicating similar threats may be affecting groups of closely related species such as island radiations or geographically restricted radiations in highly disturbed regions.