Date for Variation in embolism resistance occurs within plant communities and differentiates plant biomes

<p>Embolism resistance determines when internal water transport fails during drought, yet how embolism resistance varies within and among plant communities has been difficult to characterize. We now know that earlier syntheses incorporated measurements influenced by potential artifacts, influencing our understanding of how embolism resistance drives ecological differentiation. Here, we assemble a global database of embolism resistance using community-level studies that employe methods not prone to open-vessel artifacts. With results spanning all major climatic zones, this dataset reveals three consistent patterns relating to drought tolerance. Communities with species with more resistant xylem tend to dominate in drier climates, whereas wetter biomes host communities with species with comparatively more vulnerable xylem. Safety margins between stomatal closure and hydraulic failure widen along the same climate gradient driven by increased embolism resistance, indicating that species from communities in arid environments are more buffered against drought. Finally, we find that stomatal closure point, defined by turgor loss point, has less variation than when embolism forms in the xylem, suggesting that stomatal safety margins are primarily determined by embolism resistance rather than stomatal closure point.</p>