Phylogenetic evidence that migratory behavior increases ungulate extinction rates

Widespread instances of migratory collapse have been documented within the past several decades, indicating that migration may be a fragile strategy in the Anthropocene. Yet the fragility of migration as a strategy for navigating seasonally variable resource availability may extend deeper into evolutionary time. We used phylogenetic imputation to infer the migratory habits of 51 ungulate species that went extinct during the late Quaternary and evaluated whether migration enhances extinction rates on macroevolutionary timescales. We found that ~80% (41 of 51) of recently extinct species were migratory, whereas only 46% (95 of 207) of extant ungulates are migratory. Furthermore, Hidden State Speciation and Extinction modeling indicated that migratory species likely experienced higher speciation and extinction rates compared to nonmigratory species, resulting in elevated lineage turnover for migratory ungulates, though diversification parameter estimates depended strongly upon whether extinct species were included in analyses. The extinctions of these ungulates led to negligible declines in global ungulate functional richness (0.8%) but more substantial declines (2.7%) across Africa. Altogether, our findings indicate that migration has complex macroevolutionary consequences, enhancing both speciation and extinction rates, which may render migration an evolutionarily fragile strategy, particularly as increasingly widespread and intensive anthropogenic activity cause gradients of resource availability to become severed (e.g., via human infrastructure) and more unpredictable (e.g., via climate change).