Fig. 1: Quantification of species contributions to multiple dimensions of ecological stability.

We quantified contributions of individual species to the various components of stability by comparing stability properties in plots from which species were removed (red lines) to those that experienced no species losses (blue lines). We measured stability responses to our experimentally imposed pulse perturbation (that is, resistance, reactivity, recovery time and resilience; see Table 1 for detailed description of stability measures and their quantification) by comparing perturbed (solid lines) to equivalent unperturbed (dotted lines) plots within species removal treatments. Because they do not require an explicit perturbation for their quantification, spatial and temporal variability were measured from unperturbed plots only. Where a dimension of stability was reduced (that is, the system was destabilized) in the absence of a species (red lines) compared to when it was present (blue lines), this implies that the species contributes positively to that dimension of stability, and vice versa. All stability measures were quantified separately from both total macroalgal biomass and assemblage structure as dimensions of, respectively, functional and compositional stability.