Influence of past climate change on phylogeography and demographic history of narwhals, Monodon monoceros

• Main Authors: Louis, Marie, Skovrind, Mikkel, Castruita, Jose Alfredo Samaniego, Garilao, Cristina, Kaschner, Kristin, Gopalakrishnan, Shyam, Haile, James, Lydersen, Christian, Kovacs, Kit, Garde, Eva, Heide-Jørgensen, Mads Peter, Postma, Lianne, Ferguson, Steve, Willerslev, Eske, Lorenzen, Eline
• Format: Dataset
• Language: unknown
• Published: 2021
• Subjects: Arctic; Arctic marine mammals; Climate change; Monodon monoceros; narwhal*
• Online Access: https://zenodo.org/record/5016366; https://doi.org/10.5061/dryad.4qrfj6q72

The Arctic is warming at an unprecedented rate, with unknown consequences for endemic fauna. However, Earth has experienced severe climatic oscillations in the past, and understanding how species responded to them might provide insight into their resilience to near-future climatic predictions. Little is known about the responses of Arctic marine mammals to past climatic shifts, but narwhals (Monodon monoceros) are considered one of the endemic Arctic species most vulnerable to environmental change. Here, we analyze 121 complete mitochondrial genomes from narwhals sampled across their range, and use them in combination with species distribution models to elucidate the influence of past and ongoing climatic shifts on their population structure and demographic history. We find low levels of genetic diversity and limited geographic structuring of genetic clades. We show that narwhals experienced a long-term low effective population size, which increased after the Last Glacial Maximum (LGM), when the amount of suitable habitat expanded. Similar post-glacial habitat release has been a key driver of population size expansion of other Polar marine predators. Our analyses indicate that habitat availability has been critical to the success of narwhals, raising concerns for their fate in an increasingly warming Arctic. Funding provided by: CarlsbergfondetCrossref Funder Registry ID: http://dx.doi.org/10.13039/501100002808Award Number: CF16-0202Funding provided by: Villum FondenCrossref Funder Registry ID: http://dx.doi.org/10.13039/100008398Award Number: 13151 Details about DNA extraction, library preparation, bioinformatics can be found in the methods of our manuscript. The data file is the fasta alignment of the 121 mitochondrial genomes of narwhals, which was used for the analyses.