Grazing re-engineers grassland production via thermodynamic energy potential gradients

Grazing profoundly shapes grassland ecosystems, which are critical for global food security and carbon storage, yet a unifying theory to reconcile its contradictory roles as both a driver of degradation and a tool for sustainable production remains elusive. This impasse stems from a biomass-centric paradigm that fails to explain fundamental ecological dynamics. Here we propose and test a thermodynamic framework that reconceptualizes grasslands as a network of interconnected energy pumps (plant, animal, soil). Using data from a 20-year factorial experiment, we show that grazing actively re-engineers the ecosystem’s energetic architecture by forging a new landscape of energy potential gradients (EPGs), defined as the thermodynamic differences between pumps. Crucially, a unified path model reveals that these EPGs, not standing biomass, are the primary mechanistic drivers of plant, animal, and microbial production. Our findings offer a thermodynamic framework to help resolve long-standing paradoxes in grazing ecology and suggest a new, predictive paradigm for managing these vital ecosystems based on their underlying energetic state.