Livestock grazing is a major driver shaping the functioning and
stability of grasslands. Although previous studies have documented the
effect of grazing on grassland stability, whether this effect is
scale-dependent remains unclear. Here, we conducted a sheep-grazing
experiment in a temperate grassland to test grazing effects on biomass
stability across scales and organizational levels. We found that an
increase of grazing intensity increased species stability, but it
substantially decreased local ecosystem stability due to reduced
asynchronous dynamics among species. Moreover, grazing reduced ecosystem
stability at larger spatial scales, but to a lesser extent. By
decreasing biodiversity within and across communities, grazing impairs
the insurance effects of biodiversity and hence the up-scaling of
stability from species to ecosystem and further to larger scales. Our
study provides the first evidence for the context-dependence of grazing
effects on grassland stability via shaping biodiversity and contributes
to bridging fine-scale experiments and broad-scale ecosystem management.