Clinal variation in quantitative traits but not in evolutionary potential along elevational and latitudinal gradients in the widespread Anthyllis vulneraria

<p><strong>Premise of the study</strong></p> <p>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. </p> <p><strong>Methods </strong></p> <p>We studied quantitative traits of the widespread <em>Anthyllis vulneraria</em> 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.</p> <p><strong>Key results</strong></p> <p>Several traits showed similar clinal variation with elevation and latitude of origin. Higher Q_ST-values than F_ST-values in some traits indicated divergent selection. The same traits were subject to strongly diversifying selection among populations (high Q_ST) 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.</p> <p><strong>Conclusions </strong></p> <p>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.</p>