Arbuscular mycorrhizal fungi reduce the differences in competitiveness between dominant and subordinate plant species

Abstract

In grassland communities, plants can be classified as dominants or subordinates according to their relative abundances, but the factors controlling such distributions remain unclear. Here, we test whether the presence of the arbuscular mycorrhizal (AM) fungus Glomus intraradices affects the competitiveness of two dominant (Taraxacum officinale and Agrostis capillaris) and two subordinate species (Prunella vulgaris and Achillea millefolium). Plants were grown in pots in the presence or absence of the fungus, in monoculture and in mixtures of both species groups with two and four species. In the absence of G. intraradices, dominants were clearly more competitive than subordinates. In inoculated pots, the fungus acted towards the parasitic end of the mutualism-parasitism continuum and had an overall negative effect on the growth of the plant species. However, the negative effects of the AM fungus were more pronounced on dominant species reducing the differences in competitiveness between dominant and subordinate species. The effects of G. intraradices varied with species composition highlighting the importance of plant community to mediate the effects of AM fungi. Dominant species were negatively affected from the AM fungus in mixtures, while subordinates grew identically with and without the fungus. Therefore, our findings predict that the plant dominance hierarchy may flatten out when dominant species are more reduced than subordinate species in an unfavourable AM fungal relationship (parasitism).

Disentangling plant and soil microbial controls on carbon and nitrogen loss in grassland mesocosms

“…Thirdly, greater abundance of AMF in microbial communities from extensively managed grassland might have reduced the competitive ability of dominant species (Mariotte et al . ), thus increasing plant community diversity (Van der Heijden et al . ), while increasing the competitive ability of legumes (Scheublin, Van Logtestijn & Van der Heijden ; Sabais et al .…”

How Initial Composition Affects the Later Development? - A Secondary Successional Study in Differently Managed Agricultural Sites

“…They are very important determinants on the earlier successional phase by stabilizing perennial forb seedlings (Gange et al, 1993). It triggers this effect by reducing competition among species that facilitate coexistence in the critical phase of community development (Mariotte et al, 2013). Furthermore there are evidences showing that, not only the vegetation can change during succession, but simultaneously soil fungal community, suggesting a sensitive feed-back between plants and soil fungi ( Sikes et al, 2012, Cutler et al, 2014.…”

Arbuscular Mycorrhizal Diversity and Function in Grassland Ecosystems

“…subsecundus was reduced in the presence of Glomus cubense. These effects have been demonstrated in pot experiments where it has been suggested that less favourable AM fungi could reduce the dominance of some plant species in grassland (Mariotte et al 2013). In addition, seasonal changes in the composition of AM fungi in roots can occur (Santos et al 2006), and AM fungal diversity can be affected by plant species composition (Johnson et al 2004).…”