Spatial effects in mycorrhizal communities

Submitted by editor on 2 November 2015.Get the paper!

The symbiosis between plants and arbuscular mycorrhizal fungi (AMF) is a crucial interaction that mediates nutrient cycling in terrestrial ecosystems. It is hypothesized that this symbiosis was essential for the evolutionary radiation of terrestrial plants. Understanding how plant-AMF communities are structured is important for conservation and agricultural purposes. Furthermore, rapid declines of biodiversity and global changes threaten this symbiotic interaction and the ecosystem services it offers. The assembly of plant-AMF communities depends on several abiotic and biotic factors, however it is not clear how these factors affect the structure of plant-AMF communities. We can describe plant-AMF communities as networks of species interactions and previous research have shown that the structure of plant-AMF communities (using genetic samples) is highly structured (1,2).

An important characteristic of plant-AMF interactions is that they occur at a very fine spatial scale. But how is spatial structure affecting the assembly of plant-AMF networks? In our study: “Plant-mycorrhizal fungus co-occurrence network lacks substantial structure”, we used spatial data of plant and AMF species presence/absence to construct a plant-AMF co-occurrence network. We tested the importance of space and some environmental factors using three null models, from which only one considered spatial structure. We found that the null model considering spatial structure showed very few significant plant-AMF co-occurrences, while the other null models showed a highly structured co-occurrence network. Our study reveals that random encounters among plant-AMF and dispersal limitation could be important processes in the first step of the assembly of plant-AMF communities.

Francisco Encinas-Viso

References:

1) Montesinos-Navarro A, Segarra-Moragues JG, Valiente-Banuet A, Verdú M

(2012) The network structure of plant-arbuscular mycorrhizal fungi. New

Phytol 194: 536–547

2) Chagnon PL, Bradley RL, Klironomos JN. 2012. Using ecological network

theory to evaluate the causes and consequences of arbuscular mycorrhizal

community structure. New Phytologist 194: 307–312

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