Temporal variability of a single population can determine the vulnerability of communities to perturbations

Many aspects of global change affect the variability of species population densities, in terms of both the magnitude and pattern of density fluctuations. However, we have limited empirical understanding of the consequences of altered temporal variability of populations, independent of changes in their mean densities, for the structure and stability of natural communities and the responses of ecosystems to additional stressors. We used a field experiment to test the effects of altered temporal variability of a single consumer species on community structure and stability. Specifically, we manipulated the temporal variability of populations of a key grazer species on temperate rocky shores (Littorina littorea), independent of their mean densities, over 12 months and measured the responses of algal communities in terms of multiple measures of structure and stability. Further, we tested whether consumer variability determined the effects of an additional perturbation, elevated sedimentation,...