Ancient bears provide insights into Pleistocene ice age refugia in Southeast Alaska
Abstract During the Late Pleistocene, major parts of North America were periodically covered by ice sheets. However, there are still questions about whether ice‐free refugia were present in the Alexander Archipelago along the Southeast (SE) Alaska coast during the last glacial maximum (LGM). Numerou...
Published in: | Molecular Ecology |
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Online Access: | http://dx.doi.org/10.1111/mec.16960 https://onlinelibrary.wiley.com/doi/pdf/10.1111/mec.16960 |
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crwiley:10.1111/mec.16960 2024-06-23T07:48:06+00:00 Ancient bears provide insights into Pleistocene ice age refugia in Southeast Alaska da Silva Coelho, Flavio Augusto Gill, Stephanie Tomlin, Crystal M. Papavassiliou, Marilena Farley, Sean D. Cook, Joseph A. Sonsthagen, Sarah A. Sage, George K. Heaton, Timothy H. Talbot, Sandra L. Lindqvist, Charlotte National Geographic Society Education Foundation National Science Foundation 2023 http://dx.doi.org/10.1111/mec.16960 https://onlinelibrary.wiley.com/doi/pdf/10.1111/mec.16960 en eng Wiley http://creativecommons.org/licenses/by-nc/4.0/ http://creativecommons.org/licenses/by-nc/4.0/ Molecular Ecology volume 32, issue 13, page 3641-3656 ISSN 0962-1083 1365-294X journal-article 2023 crwiley https://doi.org/10.1111/mec.16960 2024-05-31T08:13:37Z Abstract During the Late Pleistocene, major parts of North America were periodically covered by ice sheets. However, there are still questions about whether ice‐free refugia were present in the Alexander Archipelago along the Southeast (SE) Alaska coast during the last glacial maximum (LGM). Numerous subfossils have been recovered from caves in SE Alaska, including American black ( Ursus americanus ) and brown ( U. arctos ) bears, which today are found in the Alexander Archipelago but are genetically distinct from mainland bear populations. Hence, these bear species offer an ideal system to investigate long‐term occupation, potential refugial survival and lineage turnover. Here, we present genetic analyses based on 99 new complete mitochondrial genomes from ancient and modern brown and black bears spanning the last ~45,000 years. Black bears form two SE Alaskan subclades, one preglacial and another postglacial, that diverged >100,000 years ago. All postglacial ancient brown bears are closely related to modern brown bears in the archipelago, while a single preglacial brown bear is found in a distantly related clade. A hiatus in the bear subfossil record around the LGM and the deep split of their pre‐ and postglacial subclades fail to support a hypothesis of continuous occupancy in SE Alaska throughout the LGM for either species. Our results are consistent with an absence of refugia along the SE Alaska coast, but indicate that vegetation quickly expanded after deglaciation, allowing bears to recolonize the area after a short‐lived LGM peak. Article in Journal/Newspaper Archipelago Alaska Wiley Online Library Molecular Ecology 32 13 3641 3656 |
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Open Polar |
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Wiley Online Library |
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crwiley |
language |
English |
description |
Abstract During the Late Pleistocene, major parts of North America were periodically covered by ice sheets. However, there are still questions about whether ice‐free refugia were present in the Alexander Archipelago along the Southeast (SE) Alaska coast during the last glacial maximum (LGM). Numerous subfossils have been recovered from caves in SE Alaska, including American black ( Ursus americanus ) and brown ( U. arctos ) bears, which today are found in the Alexander Archipelago but are genetically distinct from mainland bear populations. Hence, these bear species offer an ideal system to investigate long‐term occupation, potential refugial survival and lineage turnover. Here, we present genetic analyses based on 99 new complete mitochondrial genomes from ancient and modern brown and black bears spanning the last ~45,000 years. Black bears form two SE Alaskan subclades, one preglacial and another postglacial, that diverged >100,000 years ago. All postglacial ancient brown bears are closely related to modern brown bears in the archipelago, while a single preglacial brown bear is found in a distantly related clade. A hiatus in the bear subfossil record around the LGM and the deep split of their pre‐ and postglacial subclades fail to support a hypothesis of continuous occupancy in SE Alaska throughout the LGM for either species. Our results are consistent with an absence of refugia along the SE Alaska coast, but indicate that vegetation quickly expanded after deglaciation, allowing bears to recolonize the area after a short‐lived LGM peak. |
author2 |
National Geographic Society Education Foundation National Science Foundation |
format |
Article in Journal/Newspaper |
author |
da Silva Coelho, Flavio Augusto Gill, Stephanie Tomlin, Crystal M. Papavassiliou, Marilena Farley, Sean D. Cook, Joseph A. Sonsthagen, Sarah A. Sage, George K. Heaton, Timothy H. Talbot, Sandra L. Lindqvist, Charlotte |
spellingShingle |
da Silva Coelho, Flavio Augusto Gill, Stephanie Tomlin, Crystal M. Papavassiliou, Marilena Farley, Sean D. Cook, Joseph A. Sonsthagen, Sarah A. Sage, George K. Heaton, Timothy H. Talbot, Sandra L. Lindqvist, Charlotte Ancient bears provide insights into Pleistocene ice age refugia in Southeast Alaska |
author_facet |
da Silva Coelho, Flavio Augusto Gill, Stephanie Tomlin, Crystal M. Papavassiliou, Marilena Farley, Sean D. Cook, Joseph A. Sonsthagen, Sarah A. Sage, George K. Heaton, Timothy H. Talbot, Sandra L. Lindqvist, Charlotte |
author_sort |
da Silva Coelho, Flavio Augusto |
title |
Ancient bears provide insights into Pleistocene ice age refugia in Southeast Alaska |
title_short |
Ancient bears provide insights into Pleistocene ice age refugia in Southeast Alaska |
title_full |
Ancient bears provide insights into Pleistocene ice age refugia in Southeast Alaska |
title_fullStr |
Ancient bears provide insights into Pleistocene ice age refugia in Southeast Alaska |
title_full_unstemmed |
Ancient bears provide insights into Pleistocene ice age refugia in Southeast Alaska |
title_sort |
ancient bears provide insights into pleistocene ice age refugia in southeast alaska |
publisher |
Wiley |
publishDate |
2023 |
url |
http://dx.doi.org/10.1111/mec.16960 https://onlinelibrary.wiley.com/doi/pdf/10.1111/mec.16960 |
genre |
Archipelago Alaska |
genre_facet |
Archipelago Alaska |
op_source |
Molecular Ecology volume 32, issue 13, page 3641-3656 ISSN 0962-1083 1365-294X |
op_rights |
http://creativecommons.org/licenses/by-nc/4.0/ http://creativecommons.org/licenses/by-nc/4.0/ |
op_doi |
https://doi.org/10.1111/mec.16960 |
container_title |
Molecular Ecology |
container_volume |
32 |
container_issue |
13 |
container_start_page |
3641 |
op_container_end_page |
3656 |
_version_ |
1802638539053072384 |