Soil Fungi May Help in Shaping Global Gradient of Forest Diversity: Study

A new study reveals the role of soil fungi, particularly mycorrhizal fungi, in shaping the global gradient of forest diversity. Led by Camille Delavaux from ETH Zurich​, Department of Environmental Systems Science, Zurich, Switzerland, the research explores how these microbes influence the richness and distribution of tree species across latitudes. Contrary to prevailing theories that soil pathogens drive the diversity gradient, this study suggests that mycorrhizal fungi's interactions significantly impact forest composition.

Microbial Influences on Tree Diversity

The study unveils the significant influence of two major classes of mycorrhizal fungi—ectomycorrhizal and arbuscular—on tree survival and diversity. While both types enhance juvenile tree survival, the research notes a stronger effect from ectomycorrhizal fungi. These fungi encase plant roots, providing direct protection against pathogens, predominantly at higher latitudes. Their specialization in supporting a single tree species also contributes to their impact on diversity.

Conversely, arbuscular fungi, more prevalent near the equator, offer comparatively lesser protection against pathogens and display a lower tendency to specialize with specific tree species. This characteristic prompts the growth of diverse tree species in proximity.

Revising Diversity Paradigms

The research findings challenge prevailing notions, suggesting that both arbuscular and ectomycorrhizal fungi play roles in shaping global biodiversity in trees. This paradigm shift implies that biodiversity patterns in forests are not solely driven by antagonistic tree-pathogen relationships but also by symbiotic associations with soil fungi.

A Global Forest Science Collaboration

The study's success owes credit to the extensive network of forest plots managed by the Smithsonian Institution's Forest Global Earth Observatory (ForestGEO) Network. Leveraging data from 43 of its 77 global plots, including UMBC's campus plot, the research exemplifies collaborative efforts in the scientific community. UMBC's contribution, led by graduate student Anita Kraemer and Professor Matthew Baker, underscores the importance of collective resources for advancing scientific understanding.

Diverse Forests, Distinct Microbial Communities

UMBC's unique urban, temperate ForestGEO plots stand out for their distinct features. Established in 2012, these plots, supervised by Professor Erle Ellis and graduate student Jonathan Dandois, represent urban forests and harbor a mix of native and exotic species. The resulting high species diversity in these plots challenges traditional perceptions about temperate forests and fuels research on urban forest dynamics.

Unveiling Microbial Roles

The revelation of fungi's impact on global forest structure marks the initial steps in deciphering microbial contributions to biodiversity patterns. Dr. Delavaux's excitement for forthcoming research underscores the intent to link microbial genetic sequencing with tree census data across 30 plots, aiming to directly correlate the microbiome with plant community structure.