Arbuscular mycorrhizal fungal networks vary throughout the growing season and between successional stages

PLoS One. 2013 Dec 17;8(12):e83241. doi: 10.1371/journal.pone.0083241. eCollection 2013.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Ecosystem*
  • Extinction, Biological
  • Mycorrhizae / growth & development*
  • Plant Development*
  • Plants / microbiology*
  • Seasons*
  • Symbiosis*
  • Trees / growth & development
  • Trees / microbiology

Grant support

This research was funded by the Scottish Government Rural and Environment Research and Analysis Directorate (RESAS) Workpackage Themes one and three, by grants from Estonian Science Foundation (9050, 9157), targeted financing SF0180098s08), Centre National de la Recherche Scientifique and the European Regional Development Fund (Center of Excellence FIBIR).The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.