Study species
The five species examined for phylogeographic structure were selected because they are common in the field and tissue collections and appropriately distributed across the Nanling region. They are residents (or at most local migrants) of the broadleaf forest habitats of southeastern China and are all members of the superfamily Sylvioidea (Alström et al. 2013), a group representing substantial adaptive diversity. They are Huet’s Fulvetta Alcippe hueti (Pellorneidae), Red-billed Leiothrix Leiothrix lutea (Leiothrichidae), Greater Necklaced Laughingthrush Pterorhinus pectoralis (Leiothrichidae), Indochinese Yuhina Staphida torqueola (Zosteropidae), and Mountain Bulbul Ixos mcclellandii (Pycnonotidae), as classified by Gill et al. (2021). All five species reside in evergreen woody forests, but their precise habitats vary. Ixos mcclellandiiinhabits mainly multilayered forest or woods from 800-2700 m near villages (Fishpool and Tobias 2020). Alcippe hueti resides between 400-2500 m in old growth and secondary forest and bamboo (Zhao 2001, Kirwan et al. 2021). Leiothrix lutea inhabits evergreen forest and forest edge at higher elevations, from 900-1200 m (Male et al. 2020). Pterorhinus pectoralis inhabits low elevation hills up to 1800 m (Collar and Robson 2021a) and almost never occurs in man-made habitats. Staphida torqueola resides in rainforest, usually from 350-2200 m (Collar and Robson 2021b) and is well-known as a reluctant flyer (Zhao 2001).
Outgroups were selected based largely on the availability of tissue samples in collections or DNA sequences in public datasets, as well as phylogenetic relatedness. For A. hueti, we used the subspeciesrufescentior, because it is monophyletic and differs fromA. hueti in the Nanling region by >15 base pairs (bp). For the same reasons, we selected the P. pectoralissubspecies semitorquatus. For I. mcclellandii, we usedH. flavala as the outgroup because the two are relatively closely related (Shakya and Sheldon 2017). Similarly, we selected Yuhina nigrimenta (GenBank accession number: NC040991) for S. torqueolaand L. argentauris (GenBank accession number: HQ690245) forL. lutea (Cai et al. 2019).