Can greater plant diversity help soil fungi resist drought?

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Biodiversity is known to affect ecosystem resistance, with implications for maintaining ecosystem functions and services under climate change. Compared with the many studies of above-ground vegetation, responses of below-ground communities to abiotic stresses across plant diversity gradients are often overlooked, leaving an important gap in ecosystem ecology.

The researchers conducted an integrative study to evaluate drought resistance in plant biomass, soil microbial communities and their associated functional profiles at different levels of plant diversity. In a three-year factorial manipulation experiment, they controlled plant species richness at 1, 2, 4 or 8 species and soil moisture under drought or non-drought conditions. They investigated plant biomass; soil bacterial and fungal diversity and community composition; soil glomalin; and five key soil enzymes.

Plant diversity significantly improved the resistance of soil fungal communities and microbial functional profiles characterized by soil glomalin and the five key enzymes. This was partly driven by plant diversity’s effects on the availability and accessibility of soil resources, such as soil moisture and organic matter. The increased resistance of fungal communities was also consistent with ecological insurance theory: diverse fungal communities at high plant diversity had a higher probability of containing taxa that adapt to drought.

In synthesis, the study provides empirical insights into how plant diversity regulates the drought resistance of above-ground vegetation and below-ground biota, with implications for understanding ecosystem responses to climate change and improving biodiversity conservation practices.