Beyond species richness: Grazing and fertilisation shape temperate grassland stability through distinct diversity effects

Abstract Alterations in land use, particularly grazing and fertilisation, pose significant threats to the stability of grassland ecosystems. While biodiversity is often associated with ecosystem stability, the precise processes through which various disturbances impact diversity's effects remain incompletely understood. This investigation delves into the individual and combined impacts of grazing and fertilisation on the temporal stability of community productivity within a temperate meadow steppe. Additionally, the study examines the relationships between these practices, species diversity and specific stabilising effects, including the dominance, asynchrony, averaging and interaction stability effects. Through 9 years of field experimentation, it was discovered that grazing decreased community stability by reducing above‐ground biomass, while fertilisation partially offset this destabilising effect. Notably, changes in land use predominantly affected stability via their influence on stabilising effects, regardless of species diversity itself. Specifically, stability modifications induced by grazing were primarily related to the dominance effect, whereas those resulting from fertilisation were associated with the asynchrony effect. Moreover, the averaging effect and interaction stability together played a crucial role in driving stability shifts within various land‐use change scenarios. Bayesian structural equation modelling revealed that these stabilising effects exerted a substantial and positive influence on temporal stability. Synthesis . Our findings emphasise that grazing and fertilisation differentially regulate grassland stability via dominance and asynchrony pathways, respectively. More broadly, our work reveals that land use fundamentally reshapes the architecture of stability, demonstrating that stability is not maintained through a universal mechanism but through context‐dependent pathways shaped by specific environmental pressures. This research enhances the mechanistic understanding of diversity–stability relationships and offers valuable insights for tailored grassland management strategies, such as the integration of moderate nitrogen supplementation with grazing practices to optimise the productivity–stability trade‐offs.