Root oxygen governs dryland ecosystem stability

Roots are essential components of soil organisms and play pivotal roles in sustaining ecosystem stability. As drylands support over 38% of the global population and face unprecedented stability risks under anthropogenic warming, identifying the drivers of their stability is critical for early interventions to safeguard global food security. Divergent from the conventional view that higher soil biodiversity consistently enhances ecosystem stability—wherein ecosystem stability is typically linked to temporal scales, various properties, organizational structures and multiple thresholds—we present a new insight: root tissue oxygen elemental content (Root-O) indicates and drives dryland ecosystem stability. We integrated multiple approaches: satellite datasets (including global air temperature, soil biodiversity index, among others), field surveys (encompassing plant, soil, root and litter samples from multiple study sites in 2022), laboratory analyses (comprising elemental analyses of carbon, hydrogen, oxygen, and nitrogen across different sample properties), and global model simulations from the Sixth Coupled Model Intercomparison Project (CMIP6) were used to assess sensitive indicators driving threshold variations during 1950–2100. We find that Root-O explains more variation in dryland ecosystem stability than plant, litter, and soil properties. Under different Shared Socioeconomic Pathways (SSPs) scenarios, CMIP6 projections indicate that the dynamics of sensitive indicators driving threshold variations in relation to ecosystem stability will likely be governed by the pronounced Root-O by the end of 2100. The dependence of dryland ecosystem stability on Root-O dynamic mechanisms should be considered in “FeiTian” Ecological Security Grand Model to accurately predict ecological risk under changing environments.