Trait

Environmental gradient

Intraspecific competition

Photosynthesis

Habitat

Ecology

Programming language

Specific leaf area

Fagaceae

Twig

Pinaceae

Main stem

Pinus <genus>

Computer science

Xylem

Botany

Biology

New Phytologist

Trait variability in space and time allows plants to adjust to changing environmental conditions. However, we know little about how this variability is distributed and coordinated at different organizational levels. For six dominant tree species in northeastern Spain (three Fagaceae and three Pinaceae) we quantified the inter- and intraspecific variability of a set of traits along a water availability gradient. We measured leaf mass per area (LMA), leaf nitrogen (N) concentration, carbon isotope composition in leaves (δ13 C), stem wood density, the Huber value (Hv, the ratio of cross-sectional sapwood area to leaf area), sapwood-specific and leaf-specific stem hydraulic conductivity, vulnerability to xylem embolism (P50 ) and the turgor loss point (Ptlp ). Differences between families explained the largest amount of variability for most traits, although intraspecific variability was also relevant. Species occupying wetter sites showed higher N, P50 and Ptlp , and lower LMA, δ13 C and Hv. However, when trait relationships with water availability were assessed within species they held only for Hv and Ptlp . Overall, our results indicate that intraspecific adjustments along the water availability gradient relied primarily on changes in resource allocation between sapwood and leaf area and in leaf water relations.

Adjustments and coordination of hydraulic, leaf and stem traits along a water availability gradient