▪ Abstract Managed grazing covers more than 25% of the global land surface and has a larger geographic extent than any other form of land use. Grazing systems persist under marginal bioclimatic and edaphic conditions of different biomes, leading to the emergence of three regional syndromes inherent to global grazing: desertification, woody encroachment, and deforestation. These syndromes have widespread but differential effects on the structure, biogeochemistry, hydrology, and biosphere-atmosphere exchange of grazed ecosystems. In combination, these three syndromes represent a major component of global environmental change.

Summary: Leaf dark respiration (R_dark) is an important yet poorly quantified component of the global carbon cycle. Given this, we analyzed a new global database of R_dark and 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 R_dark. Area‐based R_dark at 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, R_dark at a standard T (25°C, R_dark²⁵) 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 R_dark²⁵ at a given photosynthetic capacity (V_cmax²⁵) or leaf nitrogen concentration ([N]) than species at warmer sites. R_dark²⁵ values at any given V_cmax²⁵ or [N] were higher in herbs than in woody plants. The results highlight variation in R_dark among species and across global gradients in T and aridity. In addition to their ecological significance, the results provide a framework for improving representation of R_dark in terrestrial biosphere models (TBMs) and associated land‐surface components of Earth system models (ESMs).

Significance: The state of California has a globally important economy and a population exceeding 38 million. The state relies on its forested watersheds to support numerous services, such as water provisioning, carbon storage, timber products, ecotourism, and recreation. However, secular changes in air temperature, combined with periodic and prolonged drought, pose a compounding challenge to forest health. Here we use new remote-sensing and modeling techniques to assess changes in the canopy water content of California’s forests from 2011 to 2015. Our resulting maps of progressive canopy water stress identify at-risk forest landscapes and watersheds at fine resolution, and offer geographically explicit information to support innovative forest management and policies in preparation for climate change.