Evolutionary Processes Shaping Postglacial Gene Pools of High-Altitude Forests: Evidence from the Endemic Eucalypts of Tasmania
Climatic changes during the Pleistocene were responsible for dramatic redistributions of plant species worldwide. On the rugged southern hemisphere island of Tasmania, temperature increases following the last glaciation saw upslope migration of climatically suitable species from lowland refugia and...
| Main Authors: | , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-05-01
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| Series: | Forests |
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| Online Access: | https://www.mdpi.com/1999-4907/14/6/1072 |
| _version_ | 1797594814866259968 |
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| author | Rebecca C. Jones Peter A. Harrison Corey J. Hudson Cate A. Hirst Alexander T. Matthews Romuald Rouger Sascha L. Wise Julianne M. O’Reilly-Wapstra Robert J. E. Wiltshire Gregory J. Jordan René E. Vaillancourt Brad M. Potts |
| author_facet | Rebecca C. Jones Peter A. Harrison Corey J. Hudson Cate A. Hirst Alexander T. Matthews Romuald Rouger Sascha L. Wise Julianne M. O’Reilly-Wapstra Robert J. E. Wiltshire Gregory J. Jordan René E. Vaillancourt Brad M. Potts |
| author_sort | Rebecca C. Jones |
| collection | DOAJ |
| description | Climatic changes during the Pleistocene were responsible for dramatic redistributions of plant species worldwide. On the rugged southern hemisphere island of Tasmania, temperature increases following the last glaciation saw upslope migration of climatically suitable species from lowland refugia and the expansion of eucalypt-dominated forests and woodlands in the Central Highlands. We integrate multiple lines of evidence (chloroplast and nuclear DNA markers, seedling morphology, and survival in common garden experiments) from a group of closely related endemic eucalypts (the alpine white gums) to argue that (i) the Central Highlands of the island were colonised by multiple glacial refugia with hybridisation among species and previously separated populations, and (ii) natural selection has filtered the admixed populations, resulting in local adaptation to the harsh sub-alpine environment. Chloroplast haplotype diversity decreased and nuclear microsatellite diversity increased with altitude, chloroplast sharing among taxa was common, and nuclear DNA differentiation of morphologically distinct taxa was lower in the Central Highlands compared with lowland regions. Local adaptation in the highlands was signalled by evidence from (i) a glasshouse trial in which directional selection (Q<sub>ST</sub> > F<sub>ST</sub>) had shaped seedling morphological trait variation and (ii) population survival differences in 35-year-old reciprocal plantings along the major environmental gradients. We conclude that the evolutionary response of these island endemic trees to past climate change has involved the interplay of both hybridisation and natural selection, highlighting the importance of maintaining species interactions under future climate change. |
| first_indexed | 2024-03-11T02:27:51Z |
| format | Article |
| id | doaj.art-a10249d0d420435c96c6ddda61bed2a2 |
| institution | Directory Open Access Journal |
| issn | 1999-4907 |
| language | English |
| last_indexed | 2024-03-11T02:27:51Z |
| publishDate | 2023-05-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Forests |
| spelling | doaj.art-a10249d0d420435c96c6ddda61bed2a22023-11-18T10:25:59ZengMDPI AGForests1999-49072023-05-01146107210.3390/f14061072Evolutionary Processes Shaping Postglacial Gene Pools of High-Altitude Forests: Evidence from the Endemic Eucalypts of TasmaniaRebecca C. Jones0Peter A. Harrison1Corey J. Hudson2Cate A. Hirst3Alexander T. Matthews4Romuald Rouger5Sascha L. Wise6Julianne M. O’Reilly-Wapstra7Robert J. E. Wiltshire8Gregory J. Jordan9René E. Vaillancourt10Brad M. Potts11School of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, TAS 7001, AustraliaSchool of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, TAS 7001, AustraliaSchool of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, TAS 7001, AustraliaSchool of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, TAS 7001, AustraliaSchool of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, TAS 7001, AustraliaSchool of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, TAS 7001, AustraliaSchool of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, TAS 7001, AustraliaSchool of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, TAS 7001, AustraliaSchool of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, TAS 7001, AustraliaSchool of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, TAS 7001, AustraliaSchool of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, TAS 7001, AustraliaSchool of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, TAS 7001, AustraliaClimatic changes during the Pleistocene were responsible for dramatic redistributions of plant species worldwide. On the rugged southern hemisphere island of Tasmania, temperature increases following the last glaciation saw upslope migration of climatically suitable species from lowland refugia and the expansion of eucalypt-dominated forests and woodlands in the Central Highlands. We integrate multiple lines of evidence (chloroplast and nuclear DNA markers, seedling morphology, and survival in common garden experiments) from a group of closely related endemic eucalypts (the alpine white gums) to argue that (i) the Central Highlands of the island were colonised by multiple glacial refugia with hybridisation among species and previously separated populations, and (ii) natural selection has filtered the admixed populations, resulting in local adaptation to the harsh sub-alpine environment. Chloroplast haplotype diversity decreased and nuclear microsatellite diversity increased with altitude, chloroplast sharing among taxa was common, and nuclear DNA differentiation of morphologically distinct taxa was lower in the Central Highlands compared with lowland regions. Local adaptation in the highlands was signalled by evidence from (i) a glasshouse trial in which directional selection (Q<sub>ST</sub> > F<sub>ST</sub>) had shaped seedling morphological trait variation and (ii) population survival differences in 35-year-old reciprocal plantings along the major environmental gradients. We conclude that the evolutionary response of these island endemic trees to past climate change has involved the interplay of both hybridisation and natural selection, highlighting the importance of maintaining species interactions under future climate change.https://www.mdpi.com/1999-4907/14/6/1072hybridisationnatural selectionlocal adaptationchloroplast DNAmicrosatellite variationpopulation genetics |
| spellingShingle | Rebecca C. Jones Peter A. Harrison Corey J. Hudson Cate A. Hirst Alexander T. Matthews Romuald Rouger Sascha L. Wise Julianne M. O’Reilly-Wapstra Robert J. E. Wiltshire Gregory J. Jordan René E. Vaillancourt Brad M. Potts Evolutionary Processes Shaping Postglacial Gene Pools of High-Altitude Forests: Evidence from the Endemic Eucalypts of Tasmania Forests hybridisation natural selection local adaptation chloroplast DNA microsatellite variation population genetics |
| title | Evolutionary Processes Shaping Postglacial Gene Pools of High-Altitude Forests: Evidence from the Endemic Eucalypts of Tasmania |
| title_full | Evolutionary Processes Shaping Postglacial Gene Pools of High-Altitude Forests: Evidence from the Endemic Eucalypts of Tasmania |
| title_fullStr | Evolutionary Processes Shaping Postglacial Gene Pools of High-Altitude Forests: Evidence from the Endemic Eucalypts of Tasmania |
| title_full_unstemmed | Evolutionary Processes Shaping Postglacial Gene Pools of High-Altitude Forests: Evidence from the Endemic Eucalypts of Tasmania |
| title_short | Evolutionary Processes Shaping Postglacial Gene Pools of High-Altitude Forests: Evidence from the Endemic Eucalypts of Tasmania |
| title_sort | evolutionary processes shaping postglacial gene pools of high altitude forests evidence from the endemic eucalypts of tasmania |
| topic | hybridisation natural selection local adaptation chloroplast DNA microsatellite variation population genetics |
| url | https://www.mdpi.com/1999-4907/14/6/1072 |
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