Biocrusts are associated with increased plant biomass and nutrition at seedling stage independently of root-associated fungal colonization

Havrilla, Caroline; Leslie, Alexander D.; Di Biase, Jacob L.; Barger, Nichole N.

Biocrusts are associated with increased plant biomass and nutrition at seedling stage independently of root-associated fungal colonization

2020

Havrilla, Caroline | Leslie, Alexander D. | Di Biase, Jacob L. | Barger, Nichole N.

AIMS: Plant-soil interactions are important drivers of plant productivity and community structure. Biocrusts – soil surface-dwelling biotic communities comprised of cyanobacteria, fungi, bryophytes, and/or lichens - are widespread in drylands globally. Biocrusts are described as “mantles of fertility” and have been shown to have facilitative, but species-specific effects on plant productivity. Yet, patterns and mechanisms underlying biocrust facilitation of plant productivity remain unclear. METHODS: Using mesocosms with bare soil versus biocrust cover we investigated the effects of biocrusts on plant biomass allocation, leaf chemistry and colonization by root-associated fungi. RESULTS: Plant responses to biocrust presence were species-specific. Overall, biocrusts were associated with increased plant biomass and/or leaf N concentrations in Elymus elymoides, Bouteloua gracilis and Zea mays. However, plants grown in biocrusts had lower root-associated fungal colonization compared to bare soils. CONCLUSIONS: Biocrusts were associated with increased plant biomass and leaf N. Yet, plant growth responses to biocrusts were not correlated with differences in root-associated fungal colonization between soil mesocosm types. Understanding species-specificity in biocrust facilitation of plant growth may have important implications for understanding plant community structure in dryland ecosystems.

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