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Abstract In high-latitude species with high dispersal ability, such as long-distance migratory birds, populations are often assumed to exhibit little genetic structure due to high gene flow or recent postglacial expansion. We sequenced over 120 low-coverage whole genomes from across the breeding range of a long-distance migratory bird, the Veery (Catharus fuscescens), revealing strong evidence for isolation by distance. Additionally, we found distinct genetic structure between boreal, western montane U.S., and southern Appalachian sampling regions. We suggest that population genetic structure in this highly migratory species is detectable with the high resolution afforded by whole-genomic data because, similar to many migratory birds, the Veery exhibits high breeding-site fidelity, which likely limits gene flow. Resolution of isolation by distance across the breeding range was sufficient to assign likely breeding origins of individuals sampled in this species’ poorly understood South American nonbreeding range, demonstrating the potential to assess migratory connectivity in this species using genomic data. As the Veery’s breeding range extends across both historically glaciated and unglaciated regions in North America, we also evaluated whether contemporary patterns of structure and genetic diversity are consistent with historical population isolation in glacial refugia. We found that patterns of genetic diversity did not support southern montane regions (southern Appalachians or western U.S. mountains) as glacial refugia. Overall, our findings suggest that isolation by distance yields subtle associations between genetic structure and geography across the breeding range of this highly vagile species even in the absence of obvious historical vicariance or contemporary barriers to dispersal.
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Simulations reveal climate and legacy effects underlying regional beta diversity in alpine vegetation
Introduction Whether the distribution and assembly of plant species are adapted to current climates or legacy effects poses a problem for their conservation during ongoing climate change. The alpine regions of southern and central Europe are compared to those of the western United States and Canada because they differ in their geographies and histories. Methods Individual-based simulation experiments disentangled the role of geography in species adaptations and legacy effects in four combinations: approximations of observed alpine geographies vs. regular lattices with the same number of regions (realistic and null representations), and virtual species with responses to either climatic or simple spatial gradients (adaptations or legacy effects). Additionally, dispersal distances were varied using five Gaussian kernels. Because the similarity of pairs of regional species pools indicated the processes of assembly at extensive spatiotemporal scales and is a measure of beta diversity, this output of the simulations was correlated to observed similarity for Europe and North America. Results In North America, correlations were highest for simulations with approximated geography and location-adapted species; those in Europe had their highest correlation with the lattice pattern and climate-adapted species. Only SACEU correlations were sensitive to dispersal limitation. Discussion The southern and central European alpine areas are more isolated and with more distinct climates to which species are adapted. In the western United States and Canada, less isolation and more mixing of species from refugia has caused location to mask climate adaptation. Among continents, the balance of explanatory factors for the assembly of regional species pools will vary with their unique historical biogeographies, with isolation lessening disequilibria.
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- Award ID(s):
- 1853665
- PAR ID:
- 10401234
- Date Published:
- Journal Name:
- Frontiers in Ecology and Evolution
- Volume:
- 11
- ISSN:
- 2296-701X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.3389/fevo.2023.1053017
