Thomas J. Valone and Nicholas A. Barber. 2008. An empirical evaluation of the insurance hypothesis in diversity–stability models. Ecology 89:522–531.

Appendix B. A figure showing the relationship between the scale of a study and the percentage of positive pairwise correlations observed for the Global Population Dynamics Database.

FIG. B1. The relationship between the scale of a study and the percentage of positive pairwise correlations observed for the Global Population Dynamics Database studies reviewed. The figure does not include the Alaskan raptor, Russian shrew, and Utah snake communities because it was impossible to determine the area studied.