Unipartite and bipartite mycorrhizal networks of Abies religiosa forests: Incorporating network theory into applied ecology of conifer species and forest management

Abstract

Abies religiosa's forests are severely endangered as a result of climate change; to save this species and its biological interactions, population assisted migration is discussed in forest management, but not in the microbial ecology field. Our objectives were to analyze its mycorrhizal networks; and, with this data, to identify potential facilitator plants and it's most important mycorrhizal fungal links. This information could be used together in assisted migration programs to connect Abies religiosa saplings to their mycorrhizal network and improve their field establishment. We collected 47 rhizosphere samples from 19 plant species and sequenced their fungal ITS2 region by Illumina. In the whole fungal community, 464 species were mycorrhizal fungi with assigned guild (32%). In this subset, 85 fungi are arbuscular, 365 ectomycorrhizal and 14 from orchid-mycorriza. The Abies religiosa bipartite network is low nested and highly modular, and has a scale-free architecture. Besides Abies religiosa, the plants with the largest degree and the lowest average shortest path were Salix paradoxa, Muhlenbergia spp., and Baccharis conferta. The most important fungal nodes are species of Cortinarius, Genea, Rhodoscypha, Russula, and Tomentella. We suggest to evaluate the Abies' future establishment in the following scheme: in the first year reintroduce Muhlenbergia spp., and Baccharis conferta, in the second year Salix paradoxa, and in the third year–once the mycorrhizal network is reestablished– Abies religiosa' saplings in close proximity of these plants. This scheme is proposed using the data and network analyses of the present study.