Recovered after an extreme bottleneck and saved by ex situ management: Lessons from the Alagoas curassow (Pauxi mitu [Linnaeus, 1766]; Aves, Galliformes, Cracidae).

A pivotal debate on biodiversity conservation is whether the scarce budgets must be invested in critically endangered taxa or in those with higher chances to survive due to larger population sizes. Addressing the fate of extremely bottlenecked taxa is an ideal way to test this idea, but empirical cases are surprisingly limited. The reintroduction of the extinct-in-the-wild Alagoas curassow (Pauxi mitu) by Brazilian scientists in September 2019 added to the two other known cases of survival to bottlenecks of only two or three individuals. We exploit the reasons why this species has survived, and we report how investments to rescue the Alagoas curassow resulted in the protection of many other taxa, suggesting that in the face of the dramatic number of extinctions expected for the Anthropocene, integration must prevail over a choice.

Recovering the Genetic Identity of an Extinct-in-the-Wild Species: The Puzzling Case of the Alagoas Curassow.

The conservation of many endangered taxa relies on hybrid identification, and when hybrids become morphologically indistinguishable from the parental species, the use of molecular markers can assign individual admixture levels. Here, we present the puzzling case of the extinct in the wild Alagoas Curassow (Pauxi mitu), whose captive population descends from only three individuals. Hybridization with the Razor-billed Curassow (P. tuberosa) began more than eight generations ago, and admixture uncertainty affects the whole population. We applied an analysis framework that combined morphological diagnostic traits, Bayesian clustering analyses using 14 microsatellite loci, and mtDNA haplotypes to assess the ancestry of all individuals that were alive from 2008 to 2012. Simulated data revealed that our microsatellites could accurately assign an individual a hybrid origin until the second backcross generation, which permitted us to identify a pure group among the older, but still reproductive animals. No wild species has ever survived such a severe bottleneck, followed by hybridization, and studying the recovery capability of the selected pure Alagoas Curassow group might provide valuable insights into biological conservation theory.