Functionally explicit partitioning of plant β-diversity reveal soil fungal assembly in the subarctic tundra

Metabarcoding technologies for soil fungal DNA pools have enabled to capture the diversity of fungal community and the agreement of their beta-diversity with plant beta-diversity. However, processes underlying the synchrony of the aboveground-belowground biodiversity is still unclear. By using partitioning methods for plant beta-diversity, this study explored the process driving synchrony in tundra ecosystems, in which drastic vegetation shifts are observed with climate warming. Our methods based on Baselga's partitioning enabled the division of plant beta-diversity into two phenomena and three functional components. Correlation of fungal beta-diversity with the components of plant beta-diversity showed that the spatial replacement of fungi was promoted by plant species turnover, in particular, plant species turnover with functional exchange. In addition, spatial variety of graminoid or forbs species, rather than shrubs, enhanced fungal beta-diversity. These results suggest the importance of small-scale factors such as plant-fungal interactions or local environments modified by plants for the fungal community assemblage. The process-based understanding of community dynamics of plants and fungi allows us to predict the ongoing shrub encroachment in the Arctic region, which could weaken the aboveground-belowground synchrony.

Automated summary

By utilizing partitioning methods for plant beta-diversity, this study found that plant species turnover, particularly with functional exchange, drove the spatial replacement of fungi, while spatial variety of graminoid or forbs species enhanced fungal beta-diversity. These results suggest the significance of small-scale factors for the assemblage of fungal communities.