Geographic mode of speciation in a mountain specialist Avian family endemic to the Palearctic

Abstract

Mountains host greater avian diversity than lowlands at the same latitude due to their greater diversity of habitats stratified along an elevation gradient. Here we test whether this greater ecological heterogeneity promotes sympatric speciation. We selected accentors (Prunellidae), an avian family associated with mountains of the Palearctic, as a model system. Accentors differ in their habitat/elevation preferences and south-central Siberia and Himalayan regions each host 6 of the 13 species in the family. We used sequences of the mtDNA ND2 gene and the intron 9 of the Z chromosome specific ACO1 gene to reconstruct a complete species-level phylogeny of Prunellidae. The tree based on joint analysis of both loci was used to reconstruct the family's biogeographic history and to date the diversification events. We also analyzed the relationship between the node age and sympatry, to determine the geographic mode of speciation in Prunellidae. Our data suggest a Miocene origin of Prunellidae in the Himalayan region. The major division between alpine species (subgenus Laiscopus) and species associated with shrubs (subgenus Prunella) and initial diversification events within the latter happened within the Himalayan region in the Miocene and Pliocene. Accentors colonized other parts of the Palearctic during the Pliocene-Pleistocene transition. This spread across the Palearctic resulted in rapid diversification of accentors. With only a single exception dating to 0.91 Ma, lineages younger than 1.5 Ma are allopatric. In contrast, sympatry values for older nodes are >0. There was no relationship between node age and range symmetry. Allopatric speciation (not to include peripatric) is the predominant geographic mode of speciation in Prunellidae despite the favorable conditions for ecological diversification in the mountains and range overlaps among species.

Diversification of the cold-adapted butterfly genus Oeneis related to Holarctic biogeography and climatic niche shifts

“…2), contemporary to the uplift of the Himalayas and adjacent ranges (Valdiya, 2002;De Grave et al, 2007). The uplift promoted the speciation of mountain birds (Fjeldsa et al, 2012;Drovetski et al, 2013), plants (Xu et al, 2010), but also cold-adapted butterflies (Kodandaramaiah and Wahlberg, 2009;Leneveu et al, 2009). Our dating suggests that the early speciation of Oeneis provides another example of diversification associated with the Himalayan uplift.…”

The role of geography, environment, and genetic divergence on the distribution of pikas in the Himalaya

“…Overall, O. nubrica and O. sikimaria show higher niche overlap when compared with other pairs (Figure ), which suggests that speciation of the most recently diverged species pair is probably driven by geographic isolation (allopatry). Allopatry appears to be a common mode of speciation in alpine plants and birds in mountainous region (Drovetski et al, ; Schneeweiss, Winkler, & Schönswetter, ). Geographic isolation of recently diverged species with similar niche relationships has been observed in other herbaceous plants (Boucher, Zimmermann, & Conti, ).…”

Explosive radiation and spatial expansion across the cold environments of the Old World in an avian family

“…Drovetski et al. 's () ND2 + ACO1 tree inferred P. montanella and P. rubida as sisters with PP .97. The same clade was found with PP 1.00 in their ND2 tree, but not in their ACO1 tree, again suggesting that this was based exclusively on mtDNA, and for that reason requires corroboration.…”