Figure 2.

A theoretical framework for variability. Perturbations are characterised by their type, a statistical relationship between the direct effect of perturbations and the abundance of perturbed species. For a given type and fixed intensity, there remains a whole set of covariance structures of perturbations, that is various perturbation directions, that will be transformed by community dynamics into a whole set of community responses that is various covariance structures of species stationary time series. A sampling of those responses leads to a variability distribution, one for each perturbation type. Spanning all perturbation types leads to a family of variability distributions (in blue, green and red in the rightmost column).