title: Arbuscular mycorrhizal fungal networks vary throughout the growing season and between successional stages.
abstract: To date, few analyses of mutualistic networks have investigated successional or seasonal dynamics. Combining interaction data from multiple time points likely creates an inaccurate picture of the structure of networks (because these networks are aggregated across time), which may negatively influence their application in ecosystem assessments and conservation. Using a replicated bipartite mutualistic network of arbuscular mycorrhizal (AM) fungal-plant associations, detected using large sample numbers of plants and AM fungi identified through molecular techniques, we test whether the properties of the network are temporally dynamic either between different successional stages or within the growing season. These questions have never been directly tested in the AM fungal-plant mutualism or the vast majority of other mutualisms. We demonstrate the following results: First, our examination of two different successional stages (young and old forest) demonstrated that succession increases the proportion of specialists within the community and decreases the number of interactions. Second, AM fungal-plant mutualism structure changed throughout the growing season as the number of links between partners increased. Third, we observed shifts in associations between AM fungal and plant species throughout the growing season, potentially reflecting changes in biotic and abiotic conditions. Thus, this analysis opens up two entirely new areas of research: 1) identifying what influences changes in plant-AM fungal associations in these networks, and 2) what aspects of temporal variation and succession are of general importance in structuring bipartite networks and plant-AM fungal communities.
authors.affiliation: Ecological Sciences, The James Hutton Institute, Dundee United Kingdom.
authors.forename: Alison Elizabeth
authors.initials: AE
authors.lastname: Bennett
authors.affiliation: Ecological Sciences, The James Hutton Institute, Dundee United Kingdom.
authors.forename: Tim John
authors.initials: TJ
authors.lastname: Daniell
authors.affiliation: Department of Botany, Institute of Ecology and Earth Sciences, University of Tartu, Tartu, Estonia.
authors.forename: Maarja
authors.initials: M
authors.lastname: Öpik
authors.affiliation: Department of Botany, Institute of Ecology and Earth Sciences, University of Tartu, Tartu, Estonia.
authors.forename: John
authors.initials: J
authors.lastname: Davison
authors.affiliation: Department of Botany, Institute of Ecology and Earth Sciences, University of Tartu, Tartu, Estonia.
authors.forename: Mari
authors.initials: M
authors.lastname: Moora
authors.affiliation: Department of Botany, Institute of Ecology and Earth Sciences, University of Tartu, Tartu, Estonia.
authors.forename: Martin
authors.initials: M
authors.lastname: Zobel
authors.affiliation: Muséum national d'Histoire naturelle (Département Systématique et Evolution), Paris, France.
authors.forename: Marc-André
authors.initials: MA
authors.lastname: Selosse
authors.affiliation: School of Biological, Biomedical and Environmental Sciences, University of Hull, Kingston upon Hull, United Kingdom.
authors.forename: Darren
authors.initials: D
authors.lastname: Evans
mesh_terms: D017753:Ecosystem; D053476:Extinction, Biological; D038821:Mycorrhizae / Q000254:growth & development*; D063245:Plant Development; D010944:Plants / Q000382:microbiology*; D012621:Seasons; D013559:Symbiosis; D014197:Trees / Q000254:growth & development / Q000382:microbiology