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Edited by Nils Stenseth, Department of Biosciences, Universitetet i Oslo, Oslo, Norway; received November 19, 2020; accepted November 13, 2021
We combine tracks of a long-distance migratory bird with high–temporal resolution climate data to reconstruct habitat availability month by month for the past 120,000 y. The seasonal changes of suitable habitat in the past imply that continued seasonal migration was necessary during the glacial maxima. Genomic-based estimates of effective population size indicate that more generally migratory lifestyles can be beneficially adapted to various climatic conditions. Our results provide a major step forward in understanding how migratory species will fare in the future and have important implications for how we understand the role of migration in the distribution of species and potentially speciation.
Migration allows animals to exploit spatially separated and seasonally available resources at a continental to global scale. However, responding to global climatic changes might prove challenging, especially for long-distance intercontinental migrants. During glacial periods, when conditions became too harsh for breeding in the north, avian migrants have been hypothesized to retract their distribution to reside within small refugial areas. Here, we present data showing that an Afro-Palearctic migrant continued seasonal migration, largely within Africa, during previous glacial–interglacial cycles with no obvious impact on population size. Using individual migratory track data to hindcast monthly bioclimatic habitat availability maps through the last 120,000 y, we show altered seasonal use of suitable areas through time. Independently derived effective population sizes indicate a growing population through the last 40,000 y. We conclude that the migratory lifestyle enabled adaptation to shifting climate conditions. This indicates that populations of resource-tracking, long-distance migratory species could expand successfully during warming periods in the past, which could also be the case under future climate scenarios.
Author contributions: K.T. and C.R. designed research; K.T., L.P., R.R.d.F., B.N., D.N.-B., M.W., S.S., S.F., G.C., A.R.-I., P.F.C., M.B.A., A.J.H., G.Z., A.P.T., and C.R. performed research; K.T., L.P., R.R.d.F., B.N., D.N.-B., M.K., A.M., M.W., S.F., G.C., A.R.-I., P.F.C., R.B., M.B.A., A.J.H., G.Z., and A.P.T. contributed new reagents/analytic tools; K.T., L.P., R.R.d.F., B.N., M.K., M.W., S.F., G.C., A.R.-I., P.F.C., and G.Z. analyzed data; and K.T., L.P., R.R.d.F., D.N.-B., S.S., S.F., P.F.C., A.P.T., and C.R. wrote the paper.
The authors declare no competing interest.
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