Migration-tracking integrated phylogeography supports long-distance
dispersal-driven divergence for a migratory bird species in the Japanese
archipelago
Abstract
Aim: In theory, long-distance dispersal (LDD) outside a species’ range
contributes to genetic divergence. However, previous studies have not
discriminated this process from vicariant speciation in migratory bird
species. We conducted an integrative phylogeographic approach to test
the LDD hypothesis, which predicts that a Japanese migratory bird
subspecies diverged from a population in the coastal region of the East
China Sea (CRECS) via LDD over the East China Sea (ECS). Location: East
Asia Taxon: Brown Shrike (Lanius cristatus) Methods: Both a
haplotype network and a multi-locus gene network of its three subspecies
were reconstructed to examine from which continental population the
Japanese subspecies diverged. A species distribution model (SDM) for the
Japanese subspecies was constructed using bioclimatic variables under
the maximum entropy algorithm. It was projected to the climate of the
last glacial maximum (LGM) to infer the candidate source area of
colonisation. A migratory route of the Japanese subspecies, which
possibly reflects a candidate past colonisation route, was tracked by
light-level geolocators. Results: Molecular phylogenetic networks
suggest that the Japanese subspecies diverged from a population in the
CRECS. The SDM inferred that the emerged continental shelf of the ECS
and the present CRECS were suitable breeding areas for the Japanese
subspecies during the LGM. A major migratory route for the Japanese
subspecies was inferred between the CRECS and the Japanese archipelago
across the ECS. Main conclusions: Our integrative approach supported the
LDD hypothesis for divergence of the Japanese subspecies of the Brown
Shrike. Shrinkage and expansion of the ECS may have been responsible for
successful colonisation and isolation of the new population. Vicariance
was inferred for divergence of the subspecies in the northeast Asian
continent from the Japanese population. Our framework provides a new
phylogeographic scenario in this region, and discriminating LDD and
vicariance models should improve our understanding of the
phylogeographic histories of migratory species.