Extinction selectivity obscures patterns of trait-dependent endangerment in Columbiformes

Aim

Understanding how extinction has occurred in the recent past is crucial to unravel its main drivers as well as to implement effective conservation practices to minimize global biodiversity loss. It has long been hypothesized that extinction risk is not randomly distributed among traits of species. However, the actual traits making species more prone to extinction may have been overlooked because already extinct species are often not considered in comparative analyses of extinction risk. We characterized the drivers of extinction in a cosmopolitan bird clade, including Holocene and contemporary extinctions potentially related to human impacts and provided evidence of an ‘extinction selectivity’ in species traits.

Location

Global.

Time period

Anthropocene.

Major taxa studied

Columbiformes clade, pigeons and doves.

Methods

We constructed a new phylogenetic hypothesis of the Columbiformes, a cosmopolitan bird clade consisting of 33 recently extinct and 351 extant species. Then, we integrated data on geography, behaviour and morphology to reveal the drivers of extinction risk. We used phylogenetic generalized least square models to test the effect of geography, behaviour and morphology in the risk of extinction and identified differences in the drivers of extinction when including versus excluding recently extinct species.

Results

Our analysis revealed that Columbiformes endemic to islands with ground-foraging habits, weak flying abilities, migratory behaviour and larger body sizes are more vulnerable to extinction. Our results also show that excluding recently extinct species identifies extinction drivers different from those when including recently extinct species.

Main conclusions

Only by accurately identifying the traits that increase extinction risk we can develop targeted conservation measures that promote the long-term persistence of threatened species. Extinction selectivity has important implications for the conservation of biological communities and ultimately ecosystem functioning, considering the critical role Columbiformes often play as seed dispersers.