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bioRxiv · 10.64898/2026.06.23.734103

Spatiotemporal differences in salmon nutrient inputs restructure functional and taxonomic fungal communities in riparian system

Polyakov, A. Y.·Larocque, A.·Lilleskov, E.·Mafune, K.·Vogt, K.·Vogt, D.·Berdahl, A.
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Abstract

O_LISpawning salmon transport marine-derived nutrients (MDN) into riparian forests, influencing soil, plant, and animal communities, yet their effects on fungal communities remain poorly understood. C_LIO_LIWe used DNA metabarcoding to examine fungal responses to three spatial patterns of salmon-derived nitrogen (N) in southwest Alaska: (i) patchy inputs from wildlife-deposited carcasses, (ii) a 21-year carcass relocation experiment, and (iii) natural N gradients with distance from streams. C_LIO_LIDecomposing carcasses increased saprotrophic fungal diversity, identifying taxa responsible for salmon carcass decomposition. Long-term carcass relocation reduced diversity of medium-distance fringe ectomycorrhizal fungi (EMF), whereas recent, patchy carcass inputs increased diversity of both medium-distance fringe and long-distance EMF--guilds often associated with low-nutrient environments. Along natural stream N gradients, EMF responses varied markedly within functional guilds and genera, revealing unexpected variation in N sensitivity among closely related taxa. C_LIO_LIPulsed, spatially heterogeneous nutrient inputs enhanced diversity of typically nitrophobic EMF, likely reflecting their capacity to maintain extensive mycelial networks, exploit nutrient hotspots, and mobilize organic N and phosphorus. The diversity of responses along natural N gradients suggests that mechanisms linking EMF traits to nutrient acquisition and tolerance remain unresolved. Our findings emphasize the importance of linking fungal community composition with functional attributes and nutrient dynamics. C_LI

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Polyakov, A. Y., Larocque, A., Lilleskov, E., Mafune, K., Vogt, K., Vogt, D., Berdahl, A.. 2026-06-25. Spatiotemporal differences in salmon nutrient inputs restructure functional and taxonomic fungal communities in riparian system. https://doi.org/10.64898/2026.06.23.734103

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