Build-up mechanisms determining the topology of mutualistic networks

The frequency distribution of the number of interactions per species (i.e., degree distribution) within plant–animal mutualistic assemblages often decays as a power-law with an exponential truncation. Such a truncation suggests that there are ecological factors limiting the frequency of supergeneral...

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Detalles Bibliográficos
Autores: Guimarães, Paulo R., Machado, Glauco, Aguiar, Marcus A. M. de, Jordano, Pedro, Bascompte, Jordi, Pinheiro, Aluisio, Furtado dos Reis, Sergio
Tipo de recurso: artículo
Fecha de publicación:2007
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/38512
Acceso en línea:http://hdl.handle.net/10261/38512
Access Level:acceso abierto
Palabra clave:Complex networks
Forbidden links
Mutualisms
Plant–animal interactions
Pollination
Seed dispersal
Small networks
Species richness
Descripción
Sumario:The frequency distribution of the number of interactions per species (i.e., degree distribution) within plant–animal mutualistic assemblages often decays as a power-law with an exponential truncation. Such a truncation suggests that there are ecological factors limiting the frequency of supergeneralist species. However, it is not clear whether these patterns can emerge from intrinsic features of the interacting assemblages, such as differences between plant and animal species richness (richness ratio). Here, we show that high richness ratios often characterize plant–animal mutualisms. Then, we demonstrate that exponential truncations are expected in bipartite networks generated by a simple model that incorporates build-up mechanisms that lead to a high richness ratio. Our results provide a simple interpretation for the truncations commonly observed in the degree distributions of mutualistic networks that complements previous ones based on biological effects.