Irreplaceable lineages in antpittas: an integrative approach to the conservation of Grallariidae (Aves) through evolutionary diversity

Incorporating evolutionary history into conservation enables the identification of species whose loss would disproportionately reduce the phylogenetic diversity of a clade (Isaac & Pearse, 2018). Recently, the EDGE2 framework has advanced this approach by integrating species' phylogenetic complementarity, while the BED metric weights evolutionary history according to species' geographic distributions (Cadotte & Davies, 2010; Gumbs et al., 2023). Owing to its Andean diversification, high endemism, and restricted distributions, Grallariidae represents an ideal model for applying this approach (Carneiro et al., 2018). Here, we identified global conservation priorities within this family using the EDGE2 and BED metrics. The list of 70 species and 5 genera of Grallariidae was compiled from Winkler et al. (2020). GE2, ED2, EDGE2, and BED values were estimated using IUCN Red List threat categories, distribution ranges, and 1,000 time-calibrated phylogenetic trees obtained from BirdTree (Jetz et al., 2012). Threat categories were converted into extinction probabilities, and phylogenetic uncertainty was incorporated through 10,000 simulations. Biodiversity loss was evaluated through 1,000 rank-based species removal simulations, integrating evolutionary metrics with IUCN threat categories. Grallaria chthonia emerged as the only species combining high evolutionary distinctiveness, Critically Endangered status, and a highly restricted geographic distribution, identifying it as the most irreplaceable lineage among the antpittas. The 2,000–2,500 m elevational band harbored the highest species richness as well as the highest EDGE2 and BED values, highlighting montane forest antpittas with restricted distributions and high vulnerability to habitat fragmentation as top conservation priorities. Overall, our findings demonstrate that conservation prioritization in Grallariidae requires a multidimensional framework integrating evolutionary distinctiveness, extinction risk, and ecological–geographical context. Furthermore, the lack of a relationship between body mass and the EDGE2 and BED indices suggests that spatial variables and habitat specialization may play a more important role in explaining extinction risk within this family.