DNA barcoding of Iberian Peninsula and North Africa Tawny Owls Strix aluco suggests the Strait of Gibraltar as an important barrier for phylogeography

Abstract

Eight subspecies have been proposed within the Tawny Owl (Strix aluco) species. However, recent molecular data have challenged this view, encouraging further work in this species complex. Here we reevaluated the taxonomic status between the North-Western African Tawny Owl, S. a. mauritanica, and its closest Iberian Tawny Owl population (from the S. a. sylvatica to S. a. aluco clade) separated by the Strait of Gibraltar. The Tawny Owl is a non-migratory and territorial species, and juvenile dispersal is restricted to a few kilometers around the natal site. This limited dispersal and the barrier imposed by the Strait of Gibraltar predicted a strong differentiation between the two populations. We tested this using DNA barcoding, Bayesian phylogenetic and species delimitation analysis. We found that an 81.1% of variation is due to the intergroups variation. In addition, the inter–intraspecific distances distribution revealed a barcoding gap among the two subspecies. Also, posterior probabilities and the P_AB value allowed to reject the hypothesis that observed degree of distinctiveness is due to random coalescence processes. These findings clearly support the Strait of Gibraltar as an isolating barrier for this species. The subspecific status is confirmed and species status is even suggested for S. a. mauritanica.

Keywords:

• Bird taxonomy
• DNA barcoding
• mitochondrial control region
• phylogeograpy
• subspecies

Acknowledgements

Authors thank Ricardo Campos for field work logistics. Many thanks to GOES people who collected Iberian samples (in alphabetical order): Ricardo Campos, Francisco Jiménez-Cazalla, Alejandro Colorado, David Cuenca, Darío Delgado, Francisco Delgado, José Luis Garzón, Javier Espinosa, Jaime González, Alberto González, Javier González, Juan Manuel Jiménez, José Manuel Pérez, Antonio Sepúlveda. We also want to thank all CHAGRA ringing group members who collaborated collecting North African samples. Many thanks for Andalusian and Ceutan species recovery centers. Finally, thanks to Isabel Afán (LAST, EBD) for her help with Figure 1.

Declaration of interest

The authors declare that they have no conflicts of interest. Special thanks to all GOES (The Ornithological Group of the Strait of Gibraltar) members for the economic support for the genetic analysis. JD and RJ were supported by the Spanish Ministerio de Economía y Competitividad (Severo Ochoa scholarship SVP-2013-067939 and Ramón y Cajal research contract RYC-2009-03967, respectively).

Supplementary material available online