SFI Research Professor Jennifer A. Dunne, and collaborator R. J. Williams, building on prior work, compare levels of secondary extinctions in communities generated by four structural food-web models and a fifth null model in response to sequential primary species removals. They focused on various aspects of food-web structural integrity and how these relate to assumptions underlying different models, different species loss sequences, and simple measures of diversity and complexity. They find that hierarchical feeding, a fundamental characteristic of food-web structure, appears to impose a cost in terms of robustness and other aspects of structural integrity. However, exponential-type link distributions, also characteristic of more realistic models, generally confer greater robustness and decreased levels of web collapse are associated with increased diversity. See “Cascading Extinctions and Community Collapse in Model Food Webs” by J. A. Dunne and R. J. Williams, Philosophical Transactions of the Royal Society B-Biological Sciences 364(1524): 1711-1723.