“Disentangling nestedness” disentangled

Arising from A. James, J. W. Pitchford & M. J. Plank 487, 227–230 (2012)10.1038/nature11214Analytical 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).

[1]  R. Guimerà,et al.  QUANTITATIVE PATTERNS IN THE STRUCTURE OF MODEL AND EMPIRICAL FOOD WEBS , 2004, q-bio/0401023.

[2]  Jordi Bascompte,et al.  The architecture of mutualistic networks minimizes competition and increases biodiversity , 2009, Nature.

[3]  A. Zuur,et al.  Mixed Effects Models and Extensions in Ecology with R , 2009 .

[4]  Richard J. Williams.  Biology, Methodology or Chance? The Degree Distributions of Bipartite Ecological Networks , 2011, PloS one.

[5]  J. W. Pitchford,et al.  ‘ ‘ Disentangling nestedness ’ ’ disentangled , .

[6]  Jordi Bascompte,et al.  Plant-Animal Mutualistic Networks: The Architecture of Biodiversity , 2007 .

[7]  Colin Fontaine,et al.  Stability of Ecological Communities and the Architecture of Mutualistic and Trophic Networks , 2010, Science.

[8]  Werner Ulrich,et al.  A consistent metric for nestedness analysis in ecological systems: reconciling concept and measurement , 2008 .

[9]  Stefano Allesina.  Ecology: The more the merrier , 2012, Nature.

[10]  J. Pitchford,et al.  Disentangling nestedness from models of ecological complexity , 2012, Nature.

[11]  Daniel B. Stouffer,et al.  Nestedness versus modularity in ecological networks: two sides of the same coin? , 2010, The Journal of animal ecology.

[12]  Jordi Bascompte,et al.  Non-random coextinctions in phylogenetically structured mutualistic networks , 2007, Nature.

[13]  Werner Ulrich,et al.  Statistical challenges in null model analysis , 2012 .

[14]  Serguei Saavedra,et al.  Strong contributors to network persistence are the most vulnerable to extinction , 2011, Nature.

[15]  J. Bascompte,et al.  Invariant properties in coevolutionary networks of plant-animal interactions , 2002 .

[16]  Stefano Allesina,et al.  The ghost of nestedness in ecological networks , 2013, Nature Communications.

[17]  Werner Ulrich,et al.  A consumer's guide to nestedness analysis , 2009 .

[18]  Carlos J. Melián,et al.  The nested assembly of plant–animal mutualistic networks , 2003, Proceedings of the National Academy of Sciences of the United States of America.