Multiple factors regulate resource use efficiency of Bothriochloa ischaemum ‐dominated community in arid and semi‐arid regions

Classical resource use efficiency (RUE) primarily quantifies productivity relative to resource uptake fluxes, while the capacity of long‐term soil resource pools to sustain ecosystem productivity remains understudied. We evaluated three ecosystem‐scale RUE indices (RUE C , RUE N , and RUE P ) representing net primary productivity per unit soil organic carbon, total nitrogen, and total phosphorus content in the Bothriochloa ischaemum ‐dominated grassland community across arid and semi‐arid China. Using piecewise structural equation modeling, we examined the influence of climate, soil, topography, biodiversity, and human activities. The results show divergent responses along moisture and elevation gradients. RUE C remains stable, RUE N increases moderately, while RUE P exhibits the strongest nonlinear rise with increasing moisture. RUE C and RUE N decline sharply above an elevation breakpoint, while RUE P increases markedly with elevation. Mean daily maximum air temperature of the warmest month is the dominant indicator, with positive effects on RUE C and RUE N but negative on RUE P . Climate and soil properties exert strong direct positive effects, whereas anthropogenic disturbance has consistent negative direct impacts. Climate and terrain also operate indirectly via soil mediation. These findings expand the classical RUE paradigm and inform sustainable management of arid and semi‐arid grasslands.