Interactions between communities of plants and arbuscular mycorrhizal (AM) fungi shape fundamental ecosystem properties. Experimental evidence suggests that compositional changes in plant and AM fungal communities should be correlated, but empirical data from natural ecosystems is scarce.

PhD student Lena Neuenkamp and co-authors fill this gap of knowledge with their recently published study in New Phytologist, where they clearly show that compositional changes of plant and AM fungal communities were correlated across three stages of grassland succession. The authors also reveal that strength of plant-AM fungal correlation weakened during succession following cessation of grassland management, which was brought about by changes in the proportion of plants exhibiting different AM status. Plant-AM fungal correlation was strong when the abundance of obligate AM plants was high, and declined as the proportion of facultative AM plants increased.

The findings of this study indicate that the extent to which plants rely on AM symbiosis can determine how tightly communities of plants and AM fungi are interlinked, regulating community assembly of both symbiotic partners. Further, the results of this study imply that restoration of ecosystems with obligate AM plant dominated vegetation, such as calcareous grasslands, might benefit from the re-introduction of local AM fungal communities, especially if the ecosystem is already heavily degraded.

Citation: Neuenkamp, L., Moora, M., Öpik, M., Davison, J., Gerz, M., Männistö, M., Jairus, T., Vasar, M. & Zobel, M. (2018). The role of plant mycorrhizal type and status in modulating the relationship between plant and arbuscular mycorrhizal fungal communities. New Phytologist, DOI: 10.1111/nph.14995 (link to full text)

Graphical abstract: Showing how the strength of correlation between plant and AM fungal communities in grasslands depends on the abundance of obligatory AM plants in the plant community. The higher is the abundance of obligatory AM plants, the stronger are plant and AM fungal communities related.

Abstract:

• Interactions between communities of plants and arbuscular mycorrhizal (AM) fungi shape fundamental ecosystem properties. Experimental evidence suggests that compositional changes in plant and AM fungal communities should be correlated, but empirical data from natural ecosystems are scarce. We investigated the dynamics of covariation between plant and AM fungal communities during three stages of grassland succession, and the biotic and abiotic factors shaping these dynamics.
• Plant communities were characterised using vegetation surveys. AM fungal communities were characterised by 454-sequencing of the small subunit rRNA gene and identification against the AM fungal reference database MaarjAM. AM fungal abundance was estimated using neutral-lipid fatty acids (NLFAs).
• Multivariate correlation analysis (Procrustes) revealed a significant relationship between plant and AM fungal community composition. The strength of plant–AM fungal correlation weakened during succession following cessation of grassland management, reflecting changes in the proportion of plants exhibiting different AM status. Plant–AM fungal correlation was strong when the abundance of obligate AM plants was high, and declined as the proportion of facultative AM plants increased.
• We conclude that the extent to which plants rely on AM symbiosis can determine how tightly communities of plants and AM fungi are interlinked, regulating community assembly of both symbiotic partners.