Global variability in leaf respiration in relation to climate, plant functional types and leaf traits

Leaf dark respiration (Rdₐᵣₖ) is an important yet poorly quantified component of the global carbon cycle. Given this, we analyzed a new global database of Rdₐᵣₖand associated leaf traits. Data for 899 species were compiled from 100 sites (from the Arctic to the tropics). Several woody and nonwoody plant functional types (PFTs) were represented. Mixed‐effects models were used to disentangle sources of variation in Rdₐᵣₖ. Area‐based Rdₐᵣₖat the prevailing average daily growth temperature (T) of each site increased only twofold from the Arctic to the tropics, despite a 20°C increase in growing T (8–28°C). By contrast, Rdₐᵣₖat a standard T (25°C, Rdₐᵣₖ²⁵) was threefold higher in the Arctic than in the tropics, and twofold higher at arid than at mesic sites. Species and PFTs at cold sites exhibited higher Rdₐᵣₖ²⁵at a given photosynthetic capacity (Vcₘₐₓ²⁵) or leaf nitrogen concentration ([N]) than species at warmer sites. Rdₐᵣₖ²⁵values at any given Vcₘₐₓ²⁵or [N] were higher in herbs than in woody plants. The results highlight variation in Rdₐᵣₖamong species and across global gradients in T and aridity. In addition to their ecological significance, the results provide a framework for improving representation of Rdₐᵣₖin terrestrial biosphere models (TBMs) and associated land‐surface components of Earth system models (ESMs).