Predictive modeling for allopatric Strix (Strigiformes: Strigidae) owls in South America: determinants of their distributions and ecological niche-based processes

GIRINI, JUAN MANUEL; PALACIO, FACUNDO XAVIER; ZELAYA, PATRICIA

JOURNAL OF FIELD ORNITHOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2017

0273-8570

Strix (Strigidae) is a worldwide genus of 17 owl species typical of forested habitats,including Rusty-barred Owls (S. hylophila), Chaco Owls (S. chacoensis), and Rufous-legged Owls (S. rufipes) inSouth America. These species are distributed allopatrically, but the ecological traits that determine theirdistributions remain largely unknown and their phylogenetic relationships are unclear. We used speciesdistribution models (SDMs) to identify variables explaining their distribution patterns and test hypothesesabout ecological divergence and conservatism based on niche overlap analysis. For Rusty-barred Owls andChaco Owls, climatic factors related to temperature played a major role, whereas a rainfall variable was moreimportant for Rufous-legged Owls. When niche overlaps were compared accounting for regional similarities inthe habitat available to each species, an ecological niche divergence process was supported for Chaco Owl-Rusty-barred Owl and Chaco Owl-Rufous-legged Owl, whereas a niche conservatism process was supportedfor Rusty-barred Owl-Rufous-legged Owl. Different ecological requirements support current speciesdelimitation, but they are in disagreement with the two main hypotheses currently envisaged about theirphylogenetic relationships (Chaco Owls as the sister taxa of either Rufous-legged Owls or Rusty-barred Owls)and support a new phylogenetic hypothesis (Rufous-legged Owls as sister taxa of Rusty-barred Owls). Ourfindings suggest that speciation of Rusty-barred Owls and Rufous-legged Owls was a vicariant event resultingfrom Atlantic marine transgressions in southern South America in the Miocene, but their niche was conservedbecause habitat changed little in their respective ranges. In contrast, Chaco Owls diverged ecologically fromthe other two species as a result of their adaptions to the habitat they currently occupy. Ecological andhistorical approaches in biogeography can be embedded to explain distribution patterns, and results providedby SDMs can be used to infer historical and ecological processes in an integrative way.