DOI: 10.5061/dryad.5tb2rbp17
title: Pre-adaptation to climate change through topography-driven evolution of traits and their plasticity

description: 1. Climate change will increase the level of drought stress experienced by
 plant communities, but the spatial distribution of projected changes in
 dryness remains highly uncertain. Species can, to some extent, deal with
 climate uncertainty through natural variation in adaptive responses to
 environmental heterogeneity and predictability. Biodiversity conservation
 could thus target populations pre-adapted to climatic heterogeneity to
 anticipate climate uncertainty. Disentangling evolution of trait means vs.
 trait plasticity, however, requires a sampling design with genetic
 replicates grown under distinct environmental conditions. 2. Here, we
 applied three soil moisture treatments to genetic replicates of Fragaria
 vesca plants raised from seeds that were sampled in distinct topographical
 settings, to study adaptive trait and plasticity divergence in response to
 drought. 3. We demonstrate that various plant traits evolved along
 distinct topographical gradients. For example, populations on
 south-exposed slopes retained high levels of both flowering and runner
 formation under drought stress, while north-faced populations hardly
 flowered under reduced soil moisture levels. Aspect but not elevation was
 found to coincide with plant traits, suggesting that micro-environmental
 variation rather than general clines in elevation drive evolution in
 mountainous landscapes. Our results also indicate that traits and their
 plasticity can evolve independently in response to distinct topographical
 stressors. 4. Synthesis. We conclude that heterogeneous landscapes (i)
 harbor micro-refugia of adaptive genetic diversity that protect natural
 populations against environmental change, and (ii) represent invaluable
 sources of quantitative genetic variation that could support conservation
 where climate projections are inconclusive.
description: Phenotypic data were collected in a glasshouse, in which Fragaria
 vesca plants originating from 11 locations were subjected to three
 episodes of three soil moisture treatments. The phenotypic variables
 include dried above-ground biomass, specific leaf area (SLA), the total
 number of runners produced during the second episode soil moisture
 treatment (counted and cut each week), number of stomata, and total number
 of flowers during a third episode of soil moisture treatments.
 <b>SLA</b> was measured for the most representative leaf per
 plant (i.e. average in size), as the ratio of “leaf area / dried leaf
 mass”. Stomata were counted on nail polish leaf prints using a KEYENCE
 light microscope at 1000 x magnification. For three replicate counts per
 leaf print, median <b>stomatal density</b> instead of averages
 were used to minimize the impact of counting errors. We did not measure
 stomatal size because image quality was insufficient for accurate size
 estimates. To disconnect runner and flower formation from growth, we
 divided runner and flower numbers by biomass. Thus,
 <b>runnering</b> and <b>flowering</b> were
 expressed per unit dry biomass (g). As a proxy for potential maternal
 effects, dry above-ground biomass was measured during the first soil
 moisture treatment (<b>early growth</b>).
description: For each plant, the genotype, treatment, trait and topographical
 values are provided. Each plant has an ID representing the genotype, clone
 and treatment. For example, LC08_13 is genotype 8 from population LC,
 clone number 13, and is raised in wet conditions. Nheight represetns
 normalized height, and North_to_South represents orientation relative to
 the south (0=north, 180=south).