Scale-dependent effects of biodiversity and stability on marine ecosystem dynamics

The global biodiversity loss is causing abrupt shifts in the structure and functioning of ecosystems with severe ecological and socio-economic consequences. Therefore, improving our understanding of ecosystem dynamics and regime shifts, as well as the stabilizing role of biodiversity across multiple scales, is needed. Here, we investigate the temporal dynamics and stability of marine ecosystems using high-resolution monitoring data on fish species composition, abundances, and traits throughout European Seas. More specifically, we quantify and compare the direction and magnitude of community change at multiple spatial scales and levels of biological organization. Our results show less variability in community trajectories at larger spatial scales and higher levels of biological organization. The main underlying processes providing stability are statistical averaging arising from a larger pool of species, while at smaller spatial scales, stability emerges from functional complementarity channeled through the distribution of species traits within functional groups.