QUERCUS ROBUR, Q. CERRIS AND Q. PETRAEA AS HOT SPOTS OF BIODIVERSITY

Abstract

Three different bipartite networks (pathogenic, ectomycorrhizal and galling insects) established by Quercus robur L., Q. cerris L. and Q. petraea (Matt.) Liebl. were merged in order to investigate the topological properties of the complex network, shading light on how biodiversity was organized through complex interactions. The complex network contains 290 species – 137 are pathogens (parasitic interaction), 72 are mycorrhizal fungi (mutualists) and 81 species of galling insects (herbivores). Most relevant network descriptors, connectivity, nestedness and modularity were analyzed. The main network and subnetworks displayed different behaviors in terms of topological properties, three of four networks showing significant modularity (galling insects network was marginally significant in what regards modularity). High connectivity and different degrees of nestedness characterized all networks. Clustering and Non Metric Multidimensional scaling refined the information provided by network analysis showing that networks occupy distant positions in ordination space and there are differences in terms of resemblance patterns.

Keywords

• biodiversity
• community assembly
• composite bipartite network
• modularity
• nestedness
• subnetworks