Abstract

Embolism resistance is a key functional trait that limits plant survival under extreme drought, yet knowledge of variation in embolism resistance within and between plant communities remains limited. We determine embolism resistance within a North American forest community and place these results in the context of published community-level studies of embolism resistance. Our analysis suggests that significant vulnerability in hydraulic segmentation between leaves and stems is only observed in the most arid plant communities and that the key trait, hydraulic safety margin, is globally driven by variation in embolism resistance. Our results indicate that communities can vary broadly in embolism resistance, with those native to the most arid climates containing the most embolism-resistant species, but communities from areas of high water availability host species that span a range of embolism resistance. Considerable variation in embolism resistance within communities suggests that embolism resistance drives ecological differentiation across scales.