Ice‐age persistence and genetic isolation of the disjunct distribution of larch in Alaska
Abstract Larix laricina (eastern larch, tamarack) is a transcontinental North American conifer with a prominent disjunction in the Yukon isolating the Alaskan distribution from the rest of its range. We investigate whether in situ persistence during the last glacial maximum (LGM) or long‐distance po...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Wiley
2020-02-01
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| Series: | Ecology and Evolution |
| Subjects: | |
| Online Access: | https://doi.org/10.1002/ece3.6031 |
| _version_ | 1818946268409364480 |
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| author | Joseph D. Napier Matias C. Fernandez Guillaume deLafontaine Feng Sheng Hu |
| author_facet | Joseph D. Napier Matias C. Fernandez Guillaume deLafontaine Feng Sheng Hu |
| author_sort | Joseph D. Napier |
| collection | DOAJ |
| description | Abstract Larix laricina (eastern larch, tamarack) is a transcontinental North American conifer with a prominent disjunction in the Yukon isolating the Alaskan distribution from the rest of its range. We investigate whether in situ persistence during the last glacial maximum (LGM) or long‐distance postglacial migration from south of the ice sheets resulted in the modern‐day Alaskan distribution. We analyzed variation in three chloroplast DNA regions of 840 trees from a total of 69 populations (24 new sampling sites situated on both sides of the Yukon range disjunction pooled with 45 populations from a published source) and conducted ensemble species distribution modeling (SDM) throughout Canada and United States to hindcast the potential range of L. laricina during the LGM. We uncovered the genetic signature of a long‐term isolation of larch populations in Alaska, identifying three endemic chlorotypes and low levels of genetic diversity. Range‐wide analysis across North America revealed the presence of a distinct Alaskan lineage. Postglacial gene flow across the Yukon divide was unidirectional, from Alaska toward previously glaciated Canadian regions, and with no evidence of immigration into Alaska. Hindcast SDM indicates one of the broadest areas of past climate suitability for L. laricina existed in central Alaska, suggesting possible in situ persistence of larch in Alaska during the LGM. Our results provide the first unambiguous evidence for the long‐term isolation of L. laricina in Alaska that extends beyond the last glacial period and into the present interglacial period. The lack of gene flow into Alaska along with the overall probability of larch occurrence in Alaska being currently lower than during the LGM suggests that modern‐day Alaskan larch populations are isolated climate relicts of broader glacial distributions, and so are particularly vulnerable to current warming trends. |
| first_indexed | 2024-12-20T08:12:19Z |
| format | Article |
| id | doaj.art-09f90f67d0d1485fa1bddf41ee7c22ad |
| institution | Directory Open Access Journal |
| issn | 2045-7758 |
| language | English |
| last_indexed | 2024-12-20T08:12:19Z |
| publishDate | 2020-02-01 |
| publisher | Wiley |
| record_format | Article |
| series | Ecology and Evolution |
| spelling | doaj.art-09f90f67d0d1485fa1bddf41ee7c22ad2022-12-21T19:47:14ZengWileyEcology and Evolution2045-77582020-02-011031692170210.1002/ece3.6031Ice‐age persistence and genetic isolation of the disjunct distribution of larch in AlaskaJoseph D. Napier0Matias C. Fernandez1Guillaume deLafontaine2Feng Sheng Hu3Department of Plant Biology University of Illinois Urbana IL USADepartment of Plant Biology University of Illinois Urbana IL USACanada Research Chair in Integrative Biology of Northern Flora Université du Québec à Rimouski Rimouski QC CanadaDepartment of Plant Biology University of Illinois Urbana IL USAAbstract Larix laricina (eastern larch, tamarack) is a transcontinental North American conifer with a prominent disjunction in the Yukon isolating the Alaskan distribution from the rest of its range. We investigate whether in situ persistence during the last glacial maximum (LGM) or long‐distance postglacial migration from south of the ice sheets resulted in the modern‐day Alaskan distribution. We analyzed variation in three chloroplast DNA regions of 840 trees from a total of 69 populations (24 new sampling sites situated on both sides of the Yukon range disjunction pooled with 45 populations from a published source) and conducted ensemble species distribution modeling (SDM) throughout Canada and United States to hindcast the potential range of L. laricina during the LGM. We uncovered the genetic signature of a long‐term isolation of larch populations in Alaska, identifying three endemic chlorotypes and low levels of genetic diversity. Range‐wide analysis across North America revealed the presence of a distinct Alaskan lineage. Postglacial gene flow across the Yukon divide was unidirectional, from Alaska toward previously glaciated Canadian regions, and with no evidence of immigration into Alaska. Hindcast SDM indicates one of the broadest areas of past climate suitability for L. laricina existed in central Alaska, suggesting possible in situ persistence of larch in Alaska during the LGM. Our results provide the first unambiguous evidence for the long‐term isolation of L. laricina in Alaska that extends beyond the last glacial period and into the present interglacial period. The lack of gene flow into Alaska along with the overall probability of larch occurrence in Alaska being currently lower than during the LGM suggests that modern‐day Alaskan larch populations are isolated climate relicts of broader glacial distributions, and so are particularly vulnerable to current warming trends.https://doi.org/10.1002/ece3.6031Alaskaclimate relictLarix laricinalast glacial maximumrange disjunctionrefugia |
| spellingShingle | Joseph D. Napier Matias C. Fernandez Guillaume deLafontaine Feng Sheng Hu Ice‐age persistence and genetic isolation of the disjunct distribution of larch in Alaska Ecology and Evolution Alaska climate relict Larix laricina last glacial maximum range disjunction refugia |
| title | Ice‐age persistence and genetic isolation of the disjunct distribution of larch in Alaska |
| title_full | Ice‐age persistence and genetic isolation of the disjunct distribution of larch in Alaska |
| title_fullStr | Ice‐age persistence and genetic isolation of the disjunct distribution of larch in Alaska |
| title_full_unstemmed | Ice‐age persistence and genetic isolation of the disjunct distribution of larch in Alaska |
| title_short | Ice‐age persistence and genetic isolation of the disjunct distribution of larch in Alaska |
| title_sort | ice age persistence and genetic isolation of the disjunct distribution of larch in alaska |
| topic | Alaska climate relict Larix laricina last glacial maximum range disjunction refugia |
| url | https://doi.org/10.1002/ece3.6031 |
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