Climatic and soil conditions jointly shape willow chemistry along elevational gradients

In a new study published in Plant, Cell & Environment, we investigated why willow chemistry changes along elevational gradients. Building on our previous work describing elevational shifts in phytochemical diversity, we asked which environmental factors drive these patterns and whether they extend beyond specialized defence chemistry. 

We studied four willow species growing between 950 and 2250 m in the Austrian Alps. We combined untargeted metabolomics with detailed data on climate, soil conditions, herbivory, and genetic variation. Harsher climates were associated with higher metabolite concentrations, particularly of salicinoids, but with lower flavonoid richness and lower structural diversity of the metabolome. Chemical differences among plants also generally increased towards higher elevations. Soil conditions contributed in a different way, particularly by shaping β-diversity of salicinoids. Importantly, similar responses were also detected in primary metabolites, showing that elevational changes extend beyond chemical defence. We found only weak genetic differentiation among populations from different elevations. This suggests that much of the observed chemical variation may reflect environmentally driven phenotypic plasticity rather than strong local genetic divergence. Such plasticity could help willows adjust their metabolomes as environmental conditions change, although high-elevation specialists may remain particularly vulnerable to future climate change. Together, our results move beyond describing elevational patterns and show that climate and soil affect different dimensions and components of willow metabolomes in distinct ways.

Renoult S. A.,  Mezzomo P., Leong J. V. ,  Sebek P., Panthee S. , Kukla J. , Nguyen P., Moos M. , Forrister D. L. , Wagner N. D. ,  Hörandl E., Koutecký P. ,  Sedio B. E.,  Frouz J., van Dam N. , and Volf  M. (2026) Climate Shapes Elevational Gradients in Concentration, Composition, and Functional Diversity of Willow Metabolomes. Plant, Cell & Environment 0: 1–16. https://doi.org/10.1111/pce.70775.