Beschreibung:
<jats:title>Abstract</jats:title><jats:p>Conifers growing at high elevations need to optimize their stomatal conductance (<jats:italic>g</jats:italic><jats:sub>s</jats:sub>) for maximizing photosynthetic yield while minimizing water loss under less favourable thermal conditions. Yet the ability of high‐elevation conifers to adjust their <jats:italic>g</jats:italic><jats:sub>s</jats:sub> sensitivity to environmental drivers remains largely unexplored.</jats:p><jats:p>We used 4 years of sap flow measurements to elucidate intraspecific and interspecific variability of <jats:italic>g</jats:italic><jats:sub>s</jats:sub> in <jats:styled-content style="fixed-case"><jats:italic>Larix decidua</jats:italic></jats:styled-content> Mill. and <jats:styled-content style="fixed-case"><jats:italic>Picea abies</jats:italic></jats:styled-content> (L.) Karst along an elevational gradient and contrasting soil moisture conditions. Site‐ and species‐specific <jats:italic>g</jats:italic><jats:sub>s</jats:sub> response to main environmental drivers were examined, including vapour pressure deficit, air temperature, solar irradiance, and soil water potential.</jats:p><jats:p>Our results indicate that maximum <jats:italic>g</jats:italic><jats:sub>s</jats:sub> of <jats:styled-content style="fixed-case"><jats:italic>L</jats:italic>. <jats:italic>decidua</jats:italic></jats:styled-content> is >2 times higher, shows a more plastic response to temperature, and down‐regulates <jats:italic>g</jats:italic><jats:sub>s</jats:sub> stronger during atmospheric drought compared to <jats:styled-content style="fixed-case"><jats:italic>P</jats:italic>. <jats:italic>abies</jats:italic></jats:styled-content>. These differences allow <jats:styled-content style="fixed-case"><jats:italic>L</jats:italic>. <jats:italic>decidua</jats:italic></jats:styled-content> to exert more efficient water use, adjust to site‐specific thermal conditions, and reduce water loss during drought episodes.</jats:p><jats:p>The stronger plasticity of <jats:italic>g</jats:italic><jats:sub>s</jats:sub> sensitivity to temperature and higher conductance of <jats:styled-content style="fixed-case"><jats:italic>L</jats:italic>. <jats:italic>decidua</jats:italic></jats:styled-content> compared to <jats:styled-content style="fixed-case"><jats:italic>P</jats:italic>. <jats:italic>abies</jats:italic></jats:styled-content> provide new insights into species‐specific water use strategies, which affect species' performance and should be considered when predicting terrestrial water dynamics under future climatic change.</jats:p>