DOI: 10.5061/dryad.gxd2547tq
title: Clinal variation in quantitative traits but not in evolutionary potential along elevational and latitudinal gradients in the widespread Anthyllis vulneraria

description: Premise of the study Strong elevational and latitudinal gradients allow
 the study of genetic differentiation in response to similar environmental
 changes. However, it is uncertain whether the environmental changes along
 the two types of gradients result in similar genetically based changes in
 quantitative traits. Peripheral arctic and alpine populations are thought
 to have a lower evolutionary potential than more central ones. 
 Methods  We studied quantitative traits of the
 widespread Anthyllis vulneraria in a common garden. Plants
 originated from 20 populations along a 2000 m elevational gradient from
 the lowlands to the elevational limit of the species in the Alps, and from
 20 populations along a 2400 km latitudinal gradient from the centre of the
 distribution of the species in Central Europe to its northern
 distributional margin. Key results Several traits showed similar clinal
 variation with elevation and latitude of origin. Higher QST-values than
 FST-values in some traits indicated divergent selection. The same traits
 were subject to strongly diversifying selection among populations (high
 QST) and strong stabilising selection within populations (low
 evolvability). Genetic diversity of most quantitative traits and neutral
 molecular markers was only weakly correlated. Plasticity in response to
 benign conditions declined with both increasing elevation and latitude of
 origin, but the evolvability of most traits did not. Conclusions 
 The clinal variation suggests adaptive differentiation of quantitative
 traits along the two gradients. Our results indicate that the evolutionary
 potential of peripheral populations is not necessarily reduced. However,
 lower plasticity may threaten their survival under rapidly changing
 climatic conditions.
description: <strong><em>Sampling</em></strong>
 <strong><em>—</em></strong> We
 studied 20 populations of <em>Anthyllis vulneraria</em> along
 a 2400 km latitudinal gradient from the center of its distribution in
 Central Europe (46.4 °N) to its northern distribution limit in Scandinavia
 (68.1 °N) and 20 populations along three elevational gradients in the
 French, Swiss and Austrian Alps from 500 m to the elevational limit at
 2500 m a.s.l. (Fig. 1; Daco et al., 2021; Appendix S1, Table S1; see
 Supplemental Data with this article). The length of the two gradients was
 chosen to correspond to a change of 11.5 °C in annual mean
 temperature. In summer 2015, towards the end of the
 flowering period, we recorded at each site the elevation above sea level,
 latitude and longitude with a GPS (eTrex 20, Garmin Ltd.). We collected
 fruitheads from 20 plants/population along a 20 m transect and placed them
 in separate paper bags. To compare trait values in the field and in the
 common garden, for each mother plant we determined the height of the
 tallest flowering stem, the diameter of the rosette, the width of the
 terminal leaflet of the longest basal leaf, the number of stems with
 flowers (stems), and the number of flowerheads. In the laboratory, we
 extracted all healthy seeds (i.e. green and large) from the fruitheads of
 each mother plant. <strong><em>Cultivation
 in the common garden</em></strong>
 <strong><em>—</em></strong> In
 April 2016, ten seeds from each mother plant were scarified by rubbing
 them between sheets of sand paper, placed on moist filter paper in Petri
 dishes and kept at 20 °C in a greenhouse for germination. After five days,
 five seedlings (if available) per family (Appendix S1, Table S1) were
 planted into square pots of 11 cm x 11 cm x 12 cm filled with a 3:1
 mixture of low-nutrient soil (Substrat 1, Klasmann-Deilmann GmbH, Geeste,
 Germany) and sand. The plants were randomly placed outdoors in a common
 garden of the municipal park service of the city of Luxembourg. Plants
 were watered when necessary and re-randomized several times.
 <strong><em>Measurements of quantitative
 traits</em></strong>
 <strong><em>—</em></strong> In
 July 2016, we recorded which of the initially 3207 plants had survived and
 recorded the following traits for each plant: number of leaves, diameter
 of the rosettes, and the width of the terminal leaflet of the longest
 basal leaf. We measured leaf chlorophyll content with a chlorophyll meter
 (SPAD-502 Plus, Minolta, Osaka, Japan) and transformed the values into
 chlorophyll concentrations using the formula for total chlorophyll content
 given by Richardson et al. (2002). In June 2017, we recorded the following
 traits for the 1043 surviving plants: height of the tallest flowering
 stem, date of opening of the first flower (flowering onset), number of
 stems, total number of flowerheads and the number of flowerheads with open
 flowers. We collected the highest cauline leaf of each plant, placed those
 leaves between wet paper towels in labelled envelopes in plastic bags and
 stored them at 5 °C. On the next day, the leaves were weighed to determine
 their fresh weight, placed in separate paper envelopes, pressed, and dried
 with silica gel. We weighed the dried leaves and
 scanned them at a resolution of 300 x 300 dpi together with a length
 standard. With the program ImageJ v. 1.51j8 (Schneider et al. 2012) we
 measured the area of the cauline leaves and calculated specific leaf area
 (SLA) as the ratio between leaf area and dry mass. Leaf dry-matter content
 (LDMC) was calculated as the ratio between dry and fresh weight. As a
 proxy for flowering phenology we calculated the proportion of heads
 flowering per population as the ratio between the sum of flowerheads with
 open flowers and the total number of flowerheads. Survival was calculated
 as the number of plants that survived per population divided by the total
 number of seedlings planted per population.
 <strong><em>Pollination
 experiments</em></strong>
 <strong><em>—</em></strong> In
 June 2017, selfing-ability was tested on a subset of 223 plants from 27
 populations. On each plant, an immature flowerhead was selected. One
 flower per flowerhead was marked with a permanent marker and the
 flowerhead protected by a bag of fine nylon mesh (mesh size ca. 0.1 mm)
 against pollinators. Once the flowers had opened, each flower was either
 left as a control for autonomous self-pollination or hand-pollinated with
 pollen from the same flowerhead by using a toothpick to gently transfer
 pollen to the receptive stigma. In August of the same year, the marked
 flowers were collected and the presence of developed seeds was
 determined.
description: # Clinal variation in quantitative traits but not in evolutionary
 potential along elevational and latitudinal gradients in the widespread
 *Anthyllis vulneraria*
 [https://doi.org/10.5061/dryad.gxd2547tq](https://doi.org/10.5061/dryad.gxd2547tq) This dataset contains files with measurements of plants of *Anthyllis vulneraria* from different populations studied along elevational and latitudinal gradients and of plants grown in a common garden from seeds of the initially measured plants. This dataset contains 3 files: * Quanti_indiv.xlsx is a table with measurements of quantitative traits recorded from individual *A. vulneraria* plants of different origins grown in a common garden. * Quanti_pop.xlsx is a table with population means of measurements recorded on plants of different populations in their sites of origin and variables (e.g. latitude, longitude, ...) related to the field populations. * SelfingAbility.xlsx is a table with the results from a pollination experiment to test for selfing ability. ## Description of the data and file structure ### Quanti\_indiv.xlsx * PopulationName: Name of the population of origin * MotherNumber: Number of the mother plant sampled in each population * PlantNumber: Number of the plant obtained from seeds from each mother plant in each population * Gradient: Plant sampled in a population along the elevational or latitudinal gradient * No.ofLeaves: Count of leaves * RosetteDiameter: Diameter of the rosette (in cm) * LeafletWidth: Width of the longest leaflet (in cm) * ChlorophyllContent_Transformed: Chlorophyll content measured with a chlorophyll meter (SPAD-502 Plus, Minolta, Osaka, Japan) and then transformed into chlorophyll concentrations using the formula for total chlorophyll content given by Richardson et al. (2002) (in mg/m2) * Height: Height of the plant (in cm) * FloweringOnset_Days: Date of opening of the first flower (in days) * No.ofStems: Count of stems * No.ofFlowerheads: Count of flowerheads * No.ofOpenFlowerheads: Count of flowerheads with open flowers * SLA_CaulineLeaf: specific leaf area (SLA) of the highest cauline leaf calculated as the ratio between leaf area and dry mass (in cm2/g) * LDMC_CaulineLeaf: Leaf dry-matter content (LDMC) calculated as the ratio between dry and fresh weight (in %) * SurvivalUntilSecondSummer: if a plant survived (1=yes and 0=no) until the second set of measurements Empty cells represent not available measurements at the date of data collection (due to plants not having survived or the traits not being measurable). ### Quanti\_pop.xlsx * PopulationName: Name of the sampled population * Gradient: Population sampled along the elevational or latitudinal gradient * Elevation: Elevation at the site of origin of the population (in meters above sea level) * Latitude: Latitude at the site of origin of the population (in °N) * Longitude: Latitude at the site of origin of the population (in °E) * AnnualMeanTemperature: Annual mean temperatures for the site of origin (in °C) * uHe: molecular genetic diversity derived from microsatellite analyses * Height_MotherPlants: Height of the mother plant (in cm) * RosetteDiameter_MotherPlants: Diameter of the rosette of the mother plant (in cm) * LeafletWidth_MotherPlants: Width of the longest leaflet of the mother plant (in cm) * No.ofFlowerheads_MotherPlants: Count of flowerheads of the mother plant * No.ofStems_MotherPlants: Count of stems of the mother plant * SeedMass_MeanPerMotherPlants: Average of seed mass per mother plants (in mg) Empty cells represent not available measurements. ### SelfingAbility.xlsx * PopulationName: Name of the sampled population * Gradient: Population sampled along the elevational or latitudinal gradient * SumOfSeedsSet: sum of flowers per population that developed seeds * SumOfSeedsFailedToSet: sum of flowers per population that failed to developed seeds ## Sharing/Access information Data was derived from the following sources: * Annual mean temperatures for the sites of the *A. vulneraria* populations was derived from WorldClim-database v. 2.0 (Fick and Hijmans 2017) in a 30 arc-seconds resolution (1 km2).