"Disentangling nestedness" disentangled

Analytical research indicates that the ‘nestedness’ of mutualistic networks facilitates the coexistence of species by minimizing the costs of competition relative to the benefits of facilitation. In contrast, James et al. recently argued that a more parsimonious explanation exists: the persistence of a community and its constituent species depends more on their having many interactions (high connectance and high degree, respectively) than for these interactions to be organized in any particular manner. Here we demonstrate that these conclusions are an unintended consequence of the fact that the methodology of ref. 2 directly changed the number of interactions of each species—and hence their expected persistence. When these changes are taken into account, we find a significant, positive relationship between nestedness and network persistence that reconfirms the importance of nestedness in mutualistic communities. There is a Reply to this Brief Communication Arising by James, A., Pitchford, J. W. & Plank, M. J. Nature 500, http://dx.doi.org/10.1038/nature12381 (2013).