Grazing-induced biodiversity loss impairs grassland ecosystem stability at multiple scales

Livestock grazing is a major driver shaping grassland biodiversity,
functioning, and stability. Whether grazing impacts on grassland
ecosystems are scale-dependent remains unclear. Here, we conducted a
sheep-grazing experiment in a temperate grassland to test grazing effects
on the temporal stability of productivity across scales. We found that
grazing increased species stability, but substantially decreased local
community stability due to reduced asynchronous dynamics among species
within communities. The negative effect of grazing on local community
stability propagated to reduce stability at larger spatial scales. By
decreasing biodiversity both within and across communities, grazing
reduced biological insurance effects and hence the up-scaling of stability
from species to communities and further to larger spatial scales. Our
study provides the first evidence for the scale-dependence of grazing
effects on grassland stability through biodiversity. We suggest that
ecosystem management should strive to maintain biodiversity across scales
to achieve sustainability of grassland ecosystem functions and services.