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- Sedlacek, Janosch, et al.
(författare)
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Evolutionary potential in the Alpine: trait heritabilities and performance variation of the dwarf willow Salix herbacea from different elevations and microhabitats
- 2016
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Ingår i: Ecology and Evolution. - : Wiley. - 2045-7758. ; 6:12, s. 3940-3952
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Tidskriftsartikel (refereegranskat)abstract
- Alpine ecosystems are seriously threatened by climate change. One of the key mechanisms by which plants can adapt to changing environmental conditions is through evolutionary change. However, we still know little about the evolutionary potential in wild populations of long-lived alpine plants. Here, we investigated heritabilities of phenological traits, leaf size, and performance traits in natural populations of the long-lived alpine dwarf shrub Salix herbacea using relatedness estimates inferred from SSR (Simple Sequence Repeat) markers. Salix herbacea occurs in early-and late-snowmelt microhabitats (ridges and snowbeds), and we assessed how performance consequences of phenological traits and leaf size differ between these microhabitats in order to infer potential for evolutionary responses. Salix herbacea showed low, but significant, heritabilities of leaf size, clonal and sexual reproduction, and moderate heritabilities of phenological traits. In both microhabitats, we found that larger leaves, longer intervals between snowmelt and leaf expansion, and longer GDD (growing-degree days) until leaf expansion resulted in a stronger increase in the number of stems (clonal reproduction). In snowbeds, clonal reproduction increased with a shorter GDD until flowering, while the opposite was found on ridges. Furthermore, the proportion of flowering stems increased with GDD until flowering in both microhabitats. Our results suggest that the presence of significant heritable variation in morphology and phenology might help S. herbacea to adapt to changing environmental conditions. However, it remains to be seen if the rate of such an evolutionary response can keep pace with the rapid rate of climate change.
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| 2. |
- Sedlacek, Janosch, et al.
(författare)
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The Response of the Alpine Dwarf Shrub Salix herbacea to Altered Snowmelt Timing : Lessons from a Multi-Site Transplant Experiment
- 2015
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 10:4
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Tidskriftsartikel (refereegranskat)abstract
- Climate change is altering spring snowmelt patterns in alpine and arctic ecosystems, and these changes may alter plant phenology, growth and reproduction. To predict how alpine plants respond to shifts in snowmelt timing, we need to understand trait plasticity, its effects on growth and reproduction, and the degree to which plants experience a home-site advantage. We tested how the common, long-lived dwarf shrub Salix herbacea responded to changing spring snowmelt time by reciprocally transplanting turfs of S. herbacea between early-exposure ridge and late-exposure snowbed microhabitats. After the transplant, we monitored phenological, morphological and fitness traits, as well as leaf damage, during two growing seasons. Salix herbacea leafed out earlier, but had a longer development time and produced smaller leaves on ridges relative to snowbeds. Longer phenological development times and smaller leaves were associated with reduced sexual reproduction on ridges. On snowbeds, larger leaves and intermediate development times were associated with increased clonal reproduction. Clonal and sexual reproduction showed no response to altered snowmelt time. We found no home-site advantage in terms of sexual and clonal reproduction. Leaf damage probability depended on snowmelt and thus exposure period, but had no short-term effect on fitness traits. We conclude that the studied populations of S. herbacea can respond to shifts in snowmelt by plastic changes in phenology and leaf size, while maintaining levels of clonal and sexual reproduction. The lack of a home-site advantage suggests that S. herbacea may not be adapted to different microhabitats. The studied populations are thus unlikely to react to climate change by rapid adaptation, but their responses will also not be constrained by small-scale local adaptation. In the short term, snowbed plants may persist due to high stem densities. However, in the long term, reduction in leaf size and flowering, a longer phenological development time and increased exposure to damage may decrease overall performance of S. herbacea under earlier snowmelt.
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| 3. |
- Wheeler, Julia A., et al.
(författare)
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The snow and the willows : earlier spring snowmelt reduces performance in the low-lying alpine shrub Salix herbacea
- 2016
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Ingår i: Journal of Ecology. - : Wiley. - 0022-0477 .- 1365-2745. ; 104:4, s. 1041-1050
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Tidskriftsartikel (refereegranskat)abstract
- Current changes in shrub abundance in alpine and arctic tundra ecosystems are primarily driven by climate change. However, while taller shrub communities are expanding, dwarf shrub communities show reductions under climate warming, and the mechanisms driving the latter (such as warming temperatures or accelerated spring snowmelt) may be complex. To determine and disentangle the response of a widespread arctic-alpine prostrate dwarf shrub to both climate warming and changes in snowmelt time, we investigated phenology, clonal and sexual reproduction, leaf size, wood tissue carbon balance and leaf damage in 480 patches of Salix herbacea, along its elevational and snowmelt microhabitat range over 3years in a space-for-time substitution. Earlier snowmelt was associated with longer phenological development periods, an increased likelihood of herbivory and fungal damage, lower stem density, smaller leaves and lower end-of-season wood reserve carbohydrates. Furthermore, while early snowmelt was associated with an increased proportion of flowering stems, the proportion of fruiting stems was not, as fruit set decreased significantly with earlier snowmelt. Warmer temperatures at lower elevations were associated with lower stem numbers and larger leaves.Synthesis. Our study indicates that phenology, fitness proxies and fungal/insect damage of the dwarf shrub S.herbacea are strongly influenced by snowmelt timing, and that earlier spring snowmelt reduced performance in S.herbacea. The likely mechanisms for many of the observed patterns are related to adverse temperature conditions in the early growing season. Reductions in clonal (stem number) and sexual reproduction (reduced fruit set) under earlier snowmelt, in addition to increasing damage probability, will likely lead to lower fitness and poorer performance, particularly in shrubs growing in early-exposure microhabitats. Further, we saw few concurrent benefits of higher temperatures for S.herbacea, particularly as warming was associated with lower clonal growth. As growing seasons become warmer and longer in arctic and alpine tundra ecosystems, early snowmelt is a critical mechanism reducing fitness and performance in a widespread dwarf shrub and may ultimately reduce dwarf shrub communities in tundra biomes.
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