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The Response of the Alpine Dwarf Shrub Salix herbacea to Altered Snowmelt Timing: Lessons from a Multi-Site Transplant Experiment.

Sedlacek J, Wheeler JA, Cortés AJ, Bossdorf O, Hoch G, Lexer C, Wipf S, Karrenberg S, van Kleunen M, Rixen C - PLoS ONE (2015)

Bottom Line: Longer phenological development times and smaller leaves were associated with reduced sexual reproduction on ridges.We found no home-site advantage in terms of sexual and clonal reproduction.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.

View Article: PubMed Central - PubMed

Affiliation: Ecology, Department of Biology, University of Konstanz, 78457, Konstanz, Germany.

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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Significant linear and quadratic selection gradients using a) a proxy for sexual reproductive fitness (flowering probability) and b) a proxy for clonal reproductive fitness (relative change in stem number from 2012 to 2013) of Salix herbacea turfs growing in ridge and snowbed microhabitat sites (panels).Turfs originating from ridges (R) are marked with solid lines and filled circles, turfs originating from snowbeds (S) with dashed lines and open circles.
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pone.0122395.g003: Significant linear and quadratic selection gradients using a) a proxy for sexual reproductive fitness (flowering probability) and b) a proxy for clonal reproductive fitness (relative change in stem number from 2012 to 2013) of Salix herbacea turfs growing in ridge and snowbed microhabitat sites (panels).Turfs originating from ridges (R) are marked with solid lines and filled circles, turfs originating from snowbeds (S) with dashed lines and open circles.

Mentions: Onset of leaf expansion and time from disappearance of snow to leaf expansion were significantly influenced by microhabitat of destination, with turfs in snowbeds expanding their leaves later and requiring less time for this after snowmelt relative to turfs on ridges (Table 1, Fig 1c). Both onset of and phenological development time to leaf expansion were not influenced by origin, but both were influenced by year and a year x destination interaction, due to a very early snowmelt in 2012. As other phenological stages were strongly correlated (see Methods), this suggests that both onset of the phenophase and the phenological development time are controlled by the destination environment in a similar way for plants originating from snowbeds and ridges, and thus respond plastically to environmental differences between the microhabitats. Selection gradient analysis showed that the relative change in stem number as a measure for clonal reproductive fitness, was highest with intermediate development time to leaf expansion in snowbed sites (Fig 3b, Table 2). The flowering probability increased with shorter development time to leaf expansion at ridge sites (Fig 3a, Table 2).


The Response of the Alpine Dwarf Shrub Salix herbacea to Altered Snowmelt Timing: Lessons from a Multi-Site Transplant Experiment.

Sedlacek J, Wheeler JA, Cortés AJ, Bossdorf O, Hoch G, Lexer C, Wipf S, Karrenberg S, van Kleunen M, Rixen C - PLoS ONE (2015)

Significant linear and quadratic selection gradients using a) a proxy for sexual reproductive fitness (flowering probability) and b) a proxy for clonal reproductive fitness (relative change in stem number from 2012 to 2013) of Salix herbacea turfs growing in ridge and snowbed microhabitat sites (panels).Turfs originating from ridges (R) are marked with solid lines and filled circles, turfs originating from snowbeds (S) with dashed lines and open circles.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4403918&req=5

pone.0122395.g003: Significant linear and quadratic selection gradients using a) a proxy for sexual reproductive fitness (flowering probability) and b) a proxy for clonal reproductive fitness (relative change in stem number from 2012 to 2013) of Salix herbacea turfs growing in ridge and snowbed microhabitat sites (panels).Turfs originating from ridges (R) are marked with solid lines and filled circles, turfs originating from snowbeds (S) with dashed lines and open circles.
Mentions: Onset of leaf expansion and time from disappearance of snow to leaf expansion were significantly influenced by microhabitat of destination, with turfs in snowbeds expanding their leaves later and requiring less time for this after snowmelt relative to turfs on ridges (Table 1, Fig 1c). Both onset of and phenological development time to leaf expansion were not influenced by origin, but both were influenced by year and a year x destination interaction, due to a very early snowmelt in 2012. As other phenological stages were strongly correlated (see Methods), this suggests that both onset of the phenophase and the phenological development time are controlled by the destination environment in a similar way for plants originating from snowbeds and ridges, and thus respond plastically to environmental differences between the microhabitats. Selection gradient analysis showed that the relative change in stem number as a measure for clonal reproductive fitness, was highest with intermediate development time to leaf expansion in snowbed sites (Fig 3b, Table 2). The flowering probability increased with shorter development time to leaf expansion at ridge sites (Fig 3a, Table 2).

Bottom Line: Longer phenological development times and smaller leaves were associated with reduced sexual reproduction on ridges.We found no home-site advantage in terms of sexual and clonal reproduction.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.

View Article: PubMed Central - PubMed

Affiliation: Ecology, Department of Biology, University of Konstanz, 78457, Konstanz, Germany.

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.

Show MeSH
Related in: MedlinePlus