Irradiance, temperature and rainfall influence leaf dark respiration in woody plants: Evidence from comparisons across 20 sites

• Leaf dark respiration (R) is one of the most fundamental physiological processes in plants and is a major component of terrestrial CO₂ input to the atmosphere. Still, it is unclear how predictably species vary in R along broad climate gradients. • Data for R and other key leaf traits were compiled for 208 woody species from 20 sites around the world. We quantified relationships between R and site climate, and climate-related variation in relationships between R and other leaf traits. • Species at higher-irradiance sites had higher mean R at a given leaf N concentration, specific leaf area (SLA), photosynthetic capacity (A_mass) or leaf lifespan than species at lower-irradiance sites. Species at lower-rainfall sites had higher mean R at a given SLA or A_mass than species at higher-rainfall sites. On average, estimated field rates of R were higher at warmer sites, while no trend with site temperature was seen when R was adjusted to a standard measurement temperature. • Our findings should prove useful for modelling plant nutrient and carbon budgets, and for modelling vegetation shifts with climate change.