Population connectivity buffers genetic diversity loss in a seabird

Oscar Ramírez,Iñigo Olalde,Juan Illera,Juan Rando,Carles Lalueza-Fox,Elena Gómez-Díaz,Jacob González-Solís

doi:10.1186/1742-9994-10-28

Abstract

BackgroundAncient DNA has revolutionized conservation genetic studies as it allows monitoring of the genetic variability of species through time and predicting the impact of ecosystems’ threats on future population dynamics and viability. Meanwhile, the consequences of anthropogenic activities and climate change to island faunas, particularly seabirds, remain largely unknown. In this study, we examined temporal changes in the genetic diversity of a threatened seabird, the Cory’s shearwater (Calonectris borealis).FindingsWe analysed the mitochondrial DNA control region of ancient bone samples from the late-Holocene retrieved from the Canary archipelago (NE Atlantic) together with modern DNA sequences representative of the entire breeding range of the species. Our results show high levels of ancient genetic diversity in the Canaries comparable to that of the extant population. The temporal haplotype network further revealed rare but recurrent long-distance dispersal between ocean basins. The Bayesian demographic analyses reveal both regional and local population size expansion events, and this is in spite of the demographic decline experienced by the species over the last millennia.ConclusionsOur findings suggest that population connectivity of the species has acted as a buffer of genetic losses and illustrate the use of ancient DNA to uncover such cryptic genetic events.

Highlights

Ancient DNA has revolutionized conservation genetic studies as it allows monitoring of the genetic variability of species through time and predicting the impact of ecosystems’ threats on future population dynamics and viability
Our findings suggest that population connectivity of the species has acted as a buffer of genetic losses and illustrate the use of ancient DNA to uncover such cryptic genetic events
Over the last millennia island faunas have been progressively decimated by human exploitation, biological invasions and habitat destruction [1]

Summary

Introduction

Ancient DNA has revolutionized conservation genetic studies as it allows monitoring of the genetic variability of species through time and predicting the impact of ecosystems’ threats on future population dynamics and viability. Using an heterochronous sampling consisting of Cory’s shearwater bone samples from late-Holocene from the Canary Islands together with current sequences representative of the entire breeding range of two sister Calonectris species, the Cory’s and the Scopoli’s (C. diomedea) shearwaters, we aim: (i) to estimate levels of genetic diversity and relationships between ancient and modern Cory’s shearwater populations, and (ii) to reconstruct the population demographic history of the Cory’s shearwater and estimate population size changes within the Canary archipelago through time.

Results

Conclusion