Global patterns of genetic variation in plant species along vertical and horizontal gradients on mountains
TL;DR: Findings suggest that zoning by altitudes or ridges would be helpful for the conservation of tree populations with the onset of global warming and highlight the importance of phenotypic examinations in detecting altitudinal differences.
Abstract: Aim To understand global patterns of genetic variation in plant species on mountains and to consider the significance of mountains for the genetic structure and evolution of plant species. Location Global. Methods We review published studies. Results Genetic diversity within populations can vary along altitudinal gradients in one of four patterns. Eleven of 42 cited studies (26% of the total) found that populations at intermediate altitudes have greater diversity than populations at lower and higher altitudes. This is because the geographically central populations are under optimal environmental conditions, whereas the peripheral populations are in suboptimal situations. The second pattern, indicating that higher populations have less diversity than lower populations, was found in eight studies (19%). The third pattern, indicating that lower populations have lower diversity than higher populations, was found in 10 studies (24%). In 12 studies (29%), the intrapopulation genetic variation was found to be unaffected by altitude. Evidence of altitudinal differentiation was found in more than half of these studies, based on measurements of a range of variables including genome size, number of chromosomes or a range of loci using molecular markers. Furthermore, great variation has been found in phenotypes among populations at different altitudes in situ and in common garden experiments, even in cases where there was no associated variation in molecular composition. Mountains can be genetic barriers for species that are distributed at low elevations, but they can also provide pathways for species that occupy high-elevation habitats. [Correction added after publication 9 October 2007: ‘less diversity’ changed to ‘greater diversity’ in the second sentence of the Results section of the Abstract]. Main conclusions Genetic diversity within populations can vary along altitudinal gradients as a result of several factors. The results highlight the importance of phenotypic examinations in detecting altitudinal differences. The influence of mountain ridges on genetic differentiation varies depending, inter alia , on the elevation at which the species occurs. Based on these findings, zoning by altitudes or ridges would be helpful for the conservation of tree populations with the onset of global warming.
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01 Jan 2012
TL;DR: In this paper, the authors define criteria to define temperature regimes at treeline 4.1 The task 1.2 Previous works 2.2 Definitions and conventions 2.3 Limitation, stress and disturbance 2.4 Altitude-related and other environmental drivers 2.5 Treeline nomenclature 3.1 Treeline taxa 3.2 The summit syndrome and other treeline depressions 3.3 Mass elevation effect 3.4 Treeline elevation 3.5 Time matters 3.6 Forest structure near treeline4.6 Dry matter allocation in treeline trees 7
Abstract: 1. High elevation treelines 1.1 The task 1.2 Previous works 2. Definitions and conventions 2.1 The life form 'tree' 2.2 Lines and transitions 2.3 Limitation, stress and disturbance 2.4 Altitude-related and other environmental drivers 2.5 Treeline nomenclature 3. Treeline patterns 3.1 Treeline taxa 3.2 The summit syndrome and other treeline depressions 3.3 Mass elevation effect 3.4 Treeline elevation 3.5 Time matters 3.6 Forest structure near treeline 4. Treeline climate 4.1 Specific aspects of treeline climatology 4.2 Criteria to define temperature regimes at treeline 4.3 Treeline temperatures in different bioclimatic regions 4.4 Seedbed and branch temperatures 4.5 Whole forest temperatures 5. Global mountain statistics based on treeline elevation 5.1 Mountain geostatistics 5.2 Elevational belts 5.3 Global treeline ecotones 6. Structure and stature of treeline trees 6.1 Foliage properties 6.2 Wood properties 6.3 Bark properties 6.4 Root traits 6.5 Tree stature 6.6 Dry matter allocation in treeline trees 7. Growth and development 7.1 Tree growth near treeline 7.2 Xylogenesis at treeline 7.3 Apical growth dynamics 7.4 Root growth 7.5 Phenology at treeline 8. Evolutionary adjustments to life at treeline 8.1 Phylogenetic selection 8.2 Genotypic responses of growth and development 8.3 Genotypic responses of physiological traits 9. Reproduction, early life stages and tree demography 9.1 Amount and quality of seeds at high elevation 9.2 Germination, seedling and sapling stage 9.3 Tree demography at treeline 10. Freezing and other forms of stress 10.1 Stress at treeline in a fitness context 10.2 Mechanisms and principles of freezing resistance 10.3 Freezing resistance in treeline trees 10.4 Other forms of stress at treeline 11. Water, nutrient and carbon relations 11.1 Tree water relations during the growing season 11.2 Nutrient relations 11.3 Carbon relations 12. Treeline formation - currently, in the past and in the future 12.1 Causes of current treelines 12.2 Treelines in the recent past 12.3. Treelines in the distant past (Holocene) 12.4 Future treelines References Taxonomic index Subject index
656 citations
TL;DR: There is evidence that among-population differences in phenology were related to the annual temperature at the provenance sites for ash, beech, and oak, and evidence that significant altitudinal clines for growth were also revealed.
Abstract: The aim of the study was to determine whether there are genetic variations in growth and leaf phenology (flushing and senescence) among populations of six woody species (Abies alba Mill., Acer pseu...
296 citations
Cites background from "Global patterns of genetic variatio..."
...Because of the strong relationship between phenology and fitness, natural populations growing under contrasting temperature regimes are expected to undergo diversifying selection for dates of leaf unfolding and leaf senescence (Worrall 1983; Howe et al. 2003; Ohsawa and Ide 2008)....
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TL;DR: The 2007 European larch (Larix decidua Mill.) growing season was monitored along two elevational transects in the Lötschental valley in the Swiss Alps to provide new data on the timing and duration of basic growth processes and contributes to quantification of the impacts of global warming on tree growth and productivity.
Abstract: The 2007 European larch (Larix decidua Mill.) growing season was monitored along two elevational transects in the Lotschental valley in the Swiss Alps. Phenological observations and weekly microcore sampling of 28 larch trees were conducted between April and October 2007 at seven study sites regularly spaced from 1350 to 2150 m a.s.l. on northwest- and southeast-facing slopes. The developmental stages of nearly 75,000 individual cells assessed on 1200 thin sections were used to investigate the links between the trees' thermal regimes and growth phases including the beginning and ending of cell enlargement, wall thickening and maturation of the stem wood. Needles appeared approximately 3-4 weeks earlier than stem growth. The duration of ring formation lasted from mid-May to the end of October, with the length of the growing season decreasing along elevation from 137 to 101 days. The onset of the different growing seasons changed by 3-4 days per 100 m elevation; the ending of the growing season, however, appeared minimally related to altitude. If associated with the monitored altitudinal lapse rate of -0.5 degrees C per 100 m, these results translate into a lengthening of the growing season by approximately 7 days per degree Celsius. This study provides new data on the timing and duration of basic growth processes and contributes to quantification of the impacts of global warming on tree growth and productivity.
243 citations
Cites background from "Global patterns of genetic variatio..."
...A caveat to such projections is that observed growth timing is primarily forced by temperature changes along the transects (Ohsawa and Ide 2008)....
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TL;DR: The coexistence of genetic differentiation, gene flow and phenotypic plasticity along altitudinal gradients provides an adaptive potential for Festuca eskia to successfully adapt to climate change.
Abstract: Summary
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Alpine plant species are particularly vulnerable to climate change. Therefore, estimating the adaptive potential of alpine species is of vital importance for determining their future viability. In alpine plants, adaptive potential depends on (i) altitudinal genetic differentiation among populations, combined with gene flow along an altitudinal gradient; (ii) phenotypic plasticity for the traits under selection and (iii) co-gradient variation between genetic and environmental influences on these traits.
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The adaptive potential of Festuca eskia Ramond (Poaceae), a perennial alpine grass common in the Pyrenean Mountains, was examined in this study. A reciprocal transplant experiment involving 180 individuals along three altitudinal gradients (from 1500 to 2500 m) was established, and survival, functional and reproductive traits were recorded. In addition, four neutral sequence-tagged site and simple sequence repeat molecular markers were chosen to estimate gene flow among populations.
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Genetic differentiation attributable to selection was detected in all traits between populations along the altitudinal gradient despite the existence of restricted gene flow. For traits directly related to fitness, local altitudinal adaptation was clearly evident. The patterns of local adaptation suggested that selection patterns differed along an altitudinal gradient. Selection for reproductive output was predominant at low altitudes, whereas differential survivorship was observed at higher altitudes.
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Genetic differentiation with increasing altitude resulted in reduced plant stature and reproductive output but increased specific leaf area (SLA). This increased SLA at higher altitude is interpreted as a resource acquisition strategy.
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Phenotypic plasticity was seen in all traits at the population level. Evidence of co-gradient variation between genetic differentiation and plastic response was found for all traits except SLA, suggesting that adaptive phenotypic plasticity operates in F. eskia.
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Synthesis. Local adaptation occurs in F. eskia. It involves different adaptive traits according to the altitude. Such differentiation occurs at a small scale along altitudinal gradients despite the existence of gene flow and phenotypic plasticity. The coexistence of genetic differentiation, gene flow and phenotypic plasticity along altitudinal gradients provides an adaptive potential for F. eskia to successfully adapt to climate change.
231 citations
Cites background from "Global patterns of genetic variatio..."
...In their review, Ohsawa & Ide (2008) showed that four herbaceous species out of ten exhibit neutral genetic differentiation along altitudinal gradients....
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TL;DR: The links between climate change and some key issues in plant health, including tree mortality, changes in wildfire regimes, biological invasions and the role of genetic diversity for ecosystem resilience are summarized.
Abstract: Global change (climate change together with other worldwide anthropogenic processes such as increasing trade, air pollution and urbanization) will affect plant health at the genetic, individual, population and landscape level. Direct effects include ecosystem stress due to natural resources shortage or imbalance. Indirect effects include (i) an increased frequency of natural detrimental phenomena, (ii) an increased pressure due to already present pests and diseases, (iii) the introduction of new invasive species either as a result of an improved suitability of the climatic conditions or as a result of increased trade, and (iv) the human response to global change. In this review, we provide an overview of recent studies on terrestrial plant health in the presence of global change factors. We summarize the links between climate change and some key issues in plant health, including tree mortality, changes in wildfire regimes, biological invasions and the role of genetic diversity for ecosystem resilience. Prediction and management of global change effects are complicated by interactions between globalization, climate and invasive plants and/or pathogens. We summarize practical guidelines for landscape management and draw general conclusions from an expanding body of literature.
162 citations
Cites background from "Global patterns of genetic variatio..."
...Tree species genetic diversity in mountainous regions appears to be higher at intermediate altitudes, although exceptions to this pattern are present (Ohsawa & Ide, 2008)....
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...This finding is of relevance for future climate change, as low-lying regions are predicted to become suboptimal for many species, and as tree populations confined to mountain summits by their adaptation to cold climates are likely to dwindle or disappear (Ohsawa & Ide, 2008)....
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References
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TL;DR: In this article, a framework for the study of molecular variation within a single species is presented, where information on DNA haplotype divergence is incorporated into an analysis of variance format, derived from a matrix of squared-distances among all pairs of haplotypes.
Abstract: We present here a framework for the study of molecular variation within a single species. Information on DNA haplotype divergence is incorporated into an analysis of variance format, derived from a matrix of squared-distances among all pairs of haplotypes. This analysis of molecular variance (AMOVA) produces estimates of variance components and F-statistic analogs, designated here as phi-statistics, reflecting the correlation of haplotypic diversity at different levels of hierarchical subdivision. The method is flexible enough to accommodate several alternative input matrices, corresponding to different types of molecular data, as well as different types of evolutionary assumptions, without modifying the basic structure of the analysis. The significance of the variance components and phi-statistics is tested using a permutational approach, eliminating the normality assumption that is conventional for analysis of variance but inappropriate for molecular data. Application of AMOVA to human mitochondrial DNA haplotype data shows that population subdivisions are better resolved when some measure of molecular differences among haplotypes is introduced into the analysis. At the intraspecific level, however, the additional information provided by knowing the exact phylogenetic relations among haplotypes or by a nonlinear translation of restriction-site change into nucleotide diversity does not significantly modify the inferred population genetic structure. Monte Carlo studies show that site sampling does not fundamentally affect the significance of the molecular variance components. The AMOVA treatment is easily extended in several different directions and it constitutes a coherent and flexible framework for the statistical analysis of molecular data.
12,835 citations
Journal Article•
12,252 citations
TL;DR: Page 108, last line of text, for "P/P″" read "P′/ P″."
Abstract: Page 108, last line of text, for "P/P″" read "P′/P″."
Page 120, last line, for "δ v " read "δ y ."
Page 123, line 10, for "4Nn" read "4Nu."
Page 125, line 1, for "q" read "q."
Page 126, line 12, for "q" read "q."
Page 135, line 5 from bottom, for "y4Nsq" read "e4Nsq."
Page 141, lines 8
7,850 citations
TL;DR: The frequency of a given gene in a population may be modified by a number of conditions including recurrent mutation to and from it, migration, selection of various sorts and, far from least in importance, were chance variation.
4,833 citations
TL;DR: A Brooks parsimony analysis produced an unrooted area phylogram, showing that: (i) the northern regions were colonized generally from the Iberic and Balkanic refugia; and (ii) the Italian lineages were often isolated due to the presence of the Alpine barrier.
Abstract: The Quaternary cold periods in Europe are thought to have heavily influenced the amount and distribution of intraspecific genetic variation in both animals and plants. The phylogeographies of 10 taxa, including mammals (Ursus arctos, Sorex spp., Crocidura suaveolens, Arvicola spp.), amphibians (Triturus spp.), arthropods (Chorthippus parallelus), and plants (Abies alba, Picea abies, Fagus sylvatica, Quercus spp.), were analysed to elucidate general trends across Europe. Only a small degree of congruence was found amongst the phylogeographies of the 10 taxa, but the likely postglacial colonization routes exhibit some similarities. A Brooks parsimony analysis produced an unrooted area phylogram, showing that: (i) the northern regions were colonized generally from the Iberic and Balkanic refugia; and (ii) the Italian lineages were often isolated due to the presence of the Alpine barrier. The comparison of colonization routes highlighted four main suture-zones where lineages from the different refugia meet. Some of the intraspecific genetic distances among lineages indicated a prequaternary divergence that cannot be connected to any particular cold period, but are probably related mainly to the date of arrival of each taxon in the European continent. As a consequence, molecular genetics so far appears to be of limited use in dating Quaternary events.
2,855 citations
"Global patterns of genetic variatio..." refers background in this paper
...Indeed, much greater genetic diversity in the southern areas of the Alps than in recently colonized northern regions has been documented for several species in Italy (Taberlet et al., 1998)....
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...Cottrell et al. (2005) recently examined variation of chloroplast DNA in black poplar (Populus nigra) across Europe, and identified the presence of a specific haplotype throughout Italy and Austria which was almost entirely absent from France....
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...They found © 2007 The Authors Global Ecology and Biogeography, 17, 152–163, Journal compilation © 2007 Blackwell Publishing Ltd 159 that Italian lineages were often isolated due to the presence of the Alps as a barrier, suggesting that Italy has many endemic lineages....
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...Nevertheless, several lineages of some genera, such as Abies and Quercus, were able to cross even the Alps and to spread to the north, east and west (Taberlet et al., 1998)....
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...Reviewing previous reports, Taberlet et al. (1998) analysed the phylogeographies of several taxa in order to elucidate the amount and distribution of genetic variation across Europe....
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