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Danzey LM, Briceño VF, Cook AM, Nicotra AB, Peyre G, Rossetto M, Yap JYS, Leigh A. Environmental and Biogeographic Drivers behind Alpine Plant Thermal Tolerance and Genetic Variation. PLANTS (BASEL, SWITZERLAND) 2024; 13:1271. [PMID: 38732486 PMCID: PMC11085172 DOI: 10.3390/plants13091271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 04/26/2024] [Accepted: 04/30/2024] [Indexed: 05/13/2024]
Abstract
In alpine ecosystems, elevation broadly functions as a steep thermal gradient, with plant communities exposed to regular fluctuations in hot and cold temperatures. These conditions lead to selective filtering, potentially contributing to species-level variation in thermal tolerance and population-level genetic divergence. Few studies have explored the breadth of alpine plant thermal tolerances across a thermal gradient or the underlying genetic variation thereof. We measured photosystem heat (Tcrit-hot) and cold (Tcrit-cold) thresholds of ten Australian alpine species across elevation gradients and characterised their neutral genetic variation. To reveal the biogeographical drivers of present-day genetic signatures, we also reconstructed temporal changes in habitat suitability across potential distributional ranges. We found intraspecific variation in thermal thresholds, but this was not associated with elevation, nor underpinned by genetic differentiation on a local scale. Instead, regional population differentiation and considerable homozygosity within populations may, in part, be driven by distributional contractions, long-term persistence, and migrations following habitat suitability. Our habitat suitability models suggest that cool-climate-distributed alpine plants may be threatened by a warming climate. Yet, the observed wide thermal tolerances did not reflect this vulnerability. Conservation efforts should seek to understand variations in species-level thermal tolerance across alpine microclimates.
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Affiliation(s)
- Lisa M. Danzey
- School of Life Sciences, Faculty of Science, University of Technology Sydney, Broadway, NSW 2007, Australia;
| | - Verónica F. Briceño
- Research School of Biology, Australian National University, Canberra, ACT 2601, Australia; (V.F.B.); (A.B.N.)
| | - Alicia M. Cook
- School of Life Sciences, Faculty of Science, University of Technology Sydney, Broadway, NSW 2007, Australia;
| | - Adrienne B. Nicotra
- Research School of Biology, Australian National University, Canberra, ACT 2601, Australia; (V.F.B.); (A.B.N.)
| | - Gwendolyn Peyre
- Department of Civil and Environmental Engineering, University of the Andes, Bogota 111711, Colombia;
| | - Maurizio Rossetto
- Research Centre for Ecosystem Resilience, Australian Institute of Botanical Science, Royal Botanic Gardens Sydney, Sydney, NSW 2000, Australia; (M.R.); (J.-Y.S.Y.)
- Queensland Alliance of Agriculture and Food Innovation, University of Queensland, Brisbane, QLD 4072, Australia
| | - Jia-Yee S. Yap
- Research Centre for Ecosystem Resilience, Australian Institute of Botanical Science, Royal Botanic Gardens Sydney, Sydney, NSW 2000, Australia; (M.R.); (J.-Y.S.Y.)
- Queensland Alliance of Agriculture and Food Innovation, University of Queensland, Brisbane, QLD 4072, Australia
| | - Andrea Leigh
- Research School of Biology, Australian National University, Canberra, ACT 2601, Australia; (V.F.B.); (A.B.N.)
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Evans A, de Kort H, Brys R, Duffy KJ, Jersáková J, Kull T, Selosse MA, Tsiftsis S, Minasiewicz J, Jacquemyn H. Historical biogeography and local adaptation explain population genetic structure in a widespread terrestrial orchid. ANNALS OF BOTANY 2023; 131:623-634. [PMID: 36680796 PMCID: PMC10147325 DOI: 10.1093/aob/mcad010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Accepted: 01/11/2023] [Indexed: 05/20/2023]
Abstract
BACKGROUND AND AIMS Historical changes in environmental conditions and colonization-extinction dynamics have a direct impact on the genetic structure of plant populations. However, understanding how past environmental conditions influenced the evolution of species with high gene flow is challenging when signals for genetic isolation and adaptation are swamped by gene flow. We investigated the spatial distribution and genetic structure of the widespread terrestrial orchid Epipactis helleborine to identify glacial refugia, characterize postglacial population dynamics and assess its adaptive potential. METHODS Ecological niche modelling was used to locate possible glacial refugia and postglacial recolonization opportunities of E. helleborine. A large single-nucleotide polymorphism (SNP) dataset obtained through genotyping by sequencing was used to define population genetic diversity and structure and to identify sources of postglacial gene flow. Outlier analyses were used to elucidate how adaptation to the local environment contributed to population divergence. KEY RESULTS The distribution of climatically suitable areas was restricted during the Last Glacial Maximum to the Mediterranean, south-western Europe and small areas in the Alps and Carpathians. Within-population genetic diversity was high in E. helleborine (mean expected heterozygosity, 0.373 ± 0.006; observed heterozygosity, 0.571 ± 0.012; allelic richness, 1.387 ± 0.007). Italy and central Europe are likely to have acted as important genetic sources during postglacial recolonization. Adaptive SNPs were associated with temperature, elevation and precipitation. CONCLUSIONS Forests in the Mediterranean and Carpathians are likely to have acted as glacial refugia for Epipactis helleborine. Postglacial migration northwards and to higher elevations resulted in the dispersal and diversification of E. helleborine in central Europe and Italy, and to geographical isolation and divergent adaptation in Greek and Italian populations. Distinguishing adaptive from neutral genetic diversity allowed us to conclude that E. helleborine has a high adaptive potential to climate change and demonstrates that signals of adaptation and historical isolation can be identified even in species with high gene flow.
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Affiliation(s)
- Alexandra Evans
- Department of Biology, Plant Conservation and Population Biology, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Hanne de Kort
- Department of Biology, Plant Conservation and Population Biology, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Rein Brys
- Research Institute for Forest and Nature, Geraardsbergen, Belgium
| | - Karl J Duffy
- Department of Biology, University of Naples Federico II, Complesso Monte Sant’Angelo, Naples 80126, Italy
| | - Jana Jersáková
- Department of Biology of Ecosystems, Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Tiiu Kull
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, 5 Kreutzwaldi, 51014 Tartu, Estonia
| | - Marc-André Selosse
- Institut Systématique Evolution Biodiversité, Muséum national d’Histoire naturelle, CNRS, Sorbonne Université, Paris, France
- Department of Plant Taxonomy and Nature Conservation, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland
| | - Spyros Tsiftsis
- Department of Forest and Natural Environment Sciences, International Hellenic University, GR-66132, Drama, Greece
| | - Julita Minasiewicz
- Department of Plant Taxonomy and Nature Conservation, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland
| | - Hans Jacquemyn
- Department of Biology, Plant Conservation and Population Biology, Katholieke Universiteit Leuven, Leuven, Belgium
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Felkel S, Tremetsberger K, Moser D, Dohm JC, Himmelbauer H, Winkler M. Genome-environment associations along elevation gradients in two snowbed species of the North-Eastern Calcareous Alps. BMC PLANT BIOLOGY 2023; 23:203. [PMID: 37076814 PMCID: PMC10114330 DOI: 10.1186/s12870-023-04187-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 03/20/2023] [Indexed: 05/03/2023]
Abstract
BACKGROUND Anthropogenic climate change leads to increasing temperatures and altered precipitation and snowmelt patterns, especially in alpine ecosystems. To understand species' responses to climate change, assessment of genetic structure and diversity is crucial as the basis for the evaluation of migration patterns, genetic adaptation potential as well as the identification of adaptive alleles. RESULTS We studied genetic structure, diversity and genome-environment associations of two snowbed species endemic to the Eastern Alps with a large elevational range, Achillea clusiana Tausch and Campanula pulla L. Genotyping-by-sequencing was employed to assemble loci de novo, call variants and perform population genetic analyses. Populations of either species were distinguishable by mountain, and to some extent by elevation. We found evidence for gene flow between elevations. Results of genome-environment associations suggested similar selective pressures acting on both species, emanating mainly from precipitation and exposition rather than temperature. CONCLUSIONS Given their genetic structure and amount of gene flow among populations the two study species are suitable to serve as a model for genetic monitoring of climate change adaptation along an elevation gradient. Consequences of climate change will predominantly manifest via changes in precipitation and, thus, duration of snow cover in the snowbeds and indirectly via shrub encroachment accompanied by increasing shading of snowbeds at lower range margins. Assembling genomes of the study species and studying larger sample sizes and time series will be necessary to functionally characterize and validate the herein identified genomic loci putatively involved in adaptive processes.
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Affiliation(s)
- Sabine Felkel
- Institute of Computational Biology, Department of Biotechnology, University of Natural Resources and Life Sciences, Vienna, Vienna, 1190, Austria
| | - Karin Tremetsberger
- Institute of Botany, Department of Integrative Biology and Biodiversity Research, University of Natural Resources and Life Sciences, Vienna, Vienna, 1180, Austria
| | - Dietmar Moser
- Biodiversity Dynamics and Conservation Group, Department of Botany and Biodiversity Research, University of Vienna, Vienna, 1030, Austria
| | - Juliane C Dohm
- Institute of Computational Biology, Department of Biotechnology, University of Natural Resources and Life Sciences, Vienna, Vienna, 1190, Austria
| | - Heinz Himmelbauer
- Institute of Computational Biology, Department of Biotechnology, University of Natural Resources and Life Sciences, Vienna, Vienna, 1190, Austria
| | - Manuela Winkler
- GLORIA Coordination, Institute for Interdisciplinary Mountain Research, Austrian Academy of Sciences, Vienna, 1190, Austria.
- GLORIA Coordination, Institute of Botany, Department of Integrative Biology and Biodiversity Research, University of Natural Resources and Life Sciences, Vienna, Vienna, 1190, Austria.
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Chen SY, Huang CC, Cheng YT, Wang CC, Li CY, Lai IL, Hung KH. Effect of geographic isolation on genetic variation and population structure of Euphrasia nankotaizanensis, a threatened endemic alpine herb in Taiwan. Heliyon 2023; 9:e14228. [PMID: 36938387 PMCID: PMC10018478 DOI: 10.1016/j.heliyon.2023.e14228] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 02/21/2023] [Accepted: 02/27/2023] [Indexed: 03/07/2023] Open
Abstract
Euphrasia nankotaizanensis (Orobanchaceae) is a rare alpine herb that is endemic to Taiwan. Only four small populations remain in Xue, Nanhu, and Cilai Mountains of Taiwan. The distribution of alpine herbs is severely threatened by climate change, which influences genetic variation and population structure. In this study, we investigated the effects of the natural isolation of alpine habitats on the genetic diversity and geographic structure of populations of E. nankotaizanensis using chloroplast (cp) and nuclear DNA (nrDNA) markers. We found lower levels of genetic diversity in E. nankotaizanensis than in other alpine plants and little to no genetic variation within populations, which could be mainly attributed to the small population size and genetic drift. Only one nrDNA haplotype was present in each population. The lack of monophyly of the four populations in cpDNA probably resulted from lineage sorting or occasional long-distance seed dispersal. Phylogeographic analysis suggested that Nanhu Mountain was probably a refugium over the glacial maxima, agreeing with the potential refugia in central Taiwan. The STRUCTURE and AMOVA analyses revealed significant genetic differentiation in nrDNA among the mountains, which resulted from geographical isolation among these mountains. Estimates of the effective population size (Ne) and demography reflected lower Ne values and a recent population decline, probably implying a greater extinction risk for E. nankotaizanensis. We observed genetic depletion and considerable genetic differentiation among mountain populations, which should be considered in future conservation efforts for this species. In addition, this study provides important insights into the long-term potential of alpine herbs in Taiwan, which are useful for a better prediction of their responses to future climate change.
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Affiliation(s)
- Syuan-Yu Chen
- Graduate Institute of Bioresources, Pingtung University of Science and Technology, Pingtung, Taiwan
| | - Chi-Chun Huang
- Taiwan Endemic Species Research Institute, Nantou, Taiwan
| | - Yu-Tzu Cheng
- Department of Forestry, Pingtung University of Science and Technology, Pingtung, Taiwan
| | - Chih-Chiang Wang
- Department of Forestry, Pingtung University of Science and Technology, Pingtung, Taiwan
| | - Chiuan-Yu Li
- Taiwan Endemic Species Research Institute, Nantou, Taiwan
| | - I-Ling Lai
- Graduate Institute of Bioresources, Pingtung University of Science and Technology, Pingtung, Taiwan
- Biodiversity Research Center, National Pingtung University of Science and Technology, Pingtung, Taiwan
| | - Kuo-Hsiang Hung
- Graduate Institute of Bioresources, Pingtung University of Science and Technology, Pingtung, Taiwan
- Biodiversity Research Center, National Pingtung University of Science and Technology, Pingtung, Taiwan
- Corresponding author. Graduate Institute of Bioresources, Pingtung University of Science and Technology, Pingtung, Taiwan.
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