Papers

Studies of ecological networks (the web of interactions between species in a community) demonstrate an intricate link between a community’s structure and its long-term viability. It remains unclear, however, how much a community’s persistence depends on the identities of the species present, or how much the role played by each species varies as a function of the community in which it is found. We measured species’ roles by studying how species are embedded within the overall network and the subsequent dynamic implications. Using data from 32 empirical food webs, we find that species’ roles and dynamic importance are inherent species attributes and can be extrapolated across communities on the basis of taxonomic classification alone. Our results illustrate the variability of roles across species and communities and the relative importance of distinct species groups when attempting to conserve ecological communities.

In this paper we report our findings on the analysis of two large datasets representing the friendship structure of the well-known Facebook network. In particular, we discuss the quantitative assessment of the strength of weak ties Granovetter's theory, considering the problem from the perspective of the community structure of the network. We describe our findings providing some clues of the validity of this theory also for a large-scale online social network such as Facebook.