A new study, published in Journal of Ornithology, examined gene flow across a secondary contact zone between Green Woodpecker and Iberian Green Woodpecker and backs up the proof for the latter as a full species.
Iberian Green Woodpecker is endemic to Portugal and Spain (Marc FASOL).
The research looked at 20 males from both species from secondary contact zones – natural systems which can be efficiently used to measure genetic differentiation and gene flow and thus provide a good opportunity to assess the level of reproductive isolation between divergent evolutionary lineages. The two species form a secondary contact zone in southern France.
The results of the study indicated there was no hybridisation among populations on either side of the contact zone, thus acting as a sufficient barrier to gene flow.
All males sampled within the contact zone and one male sampled near its eastern border were slightly admixed, however, revealing that reproductive isolation between the two species has not been entirely achieved.
In accordance with the geographical range of each lineage, the two admixed males sampled near the western border of the contact zone harboured a large proportion of Iberian Green Woodpecker genes, whereas admixed males sampled eastwardly near the Rhone Valley had a high proportion of Green Woodpecker genes.
Overall the results further support treating Green Woodpecker and Iberian Green Woodpecker as two biological species. The two lineages of Green Woodpecker diverged some 1 million years ago, and Iberian Green Woodpecker has recently been treated as a full species by many taxonomic authorities, including the IOC.
Pons, J-M, Masson, C, Olioso, G & Fuchs, J. 2019. Gene flow and genetic admixture across a secondary contact zone between two divergent lineages of the Eurasian Green Woodpecker Picus viridis. Journal of Ornithology. 160, 4. DOI: https://doi.org/10.1007/s10336-019-01675-6