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Abstract Environmental stress is increasing worldwide, yet we lack a clear picture of how stress disrupts the stability of microbial communities and the ecosystem services they provide. Here, we present the first evidence that naturally-occurring microbiomes display network properties characteristic of unstable communities when under persistent stress. By assessing changes in diversity and structure of soil microbiomes along 40 replicate stress gradients (elevation/water availability gradients) in the Florida scrub ecosystem, we show that: (1) prokaryotic and fungal diversity decline in high stress, and (2) two network properties of stable microbial communities—modularity and negative:positive cohesion—have a clear negative relationship with environmental stress, explaining 51–78% of their variation. Interestingly, pathogenic taxa/functional guilds decreased in relative abundance along the stress gradient, while oligotrophs and mutualists increased, suggesting that the shift in negative:positive cohesion could result from decreasing negative:positive biotic interactions consistent with the predictions of the Stress Gradient Hypothesis. Given the crucial role microbiomes play in ecosystem functions, our results suggest that, by limiting the compartmentalization of microbial associations and creating communities dominated by positive associations, increasing stress in the Anthropocene could destabilize microbiomes and undermine their ecosystem services.
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This content will become publicly available on June 19, 2026
Organic and inorganic fertilizers modulate the response of the soil microbiome to salinity stress
Salinity stress threatens soil microbiomes, a key driver of soil multifunctionality and health. This study employed high-throughput sequencing of 16S rRNA, PLFAs, multifunctionality index, and co-occurrence networks to gain a comprehensive understanding of the dynamic responses of soil microbiomes to salinity stress gradient (0, 0.4 and 1 mol NaCl). Additionally, we investigated how these responses are shaped by the addition of vermicompost and NPK fertilizer during short-term (2-h) and long-term (70-day) incubation periods. Salinity stress reduced bacterial and fungal phospholipid fatty acids (PLFA) concentrations in the short-term. Over the long-term, the microbial community evolved into a new pattern under salt stress, favoring the presence ofBacteriodota, a salt-tolerant phylum, while decreasing the relative abundance ofAcidobacteriotaandPlanctomycetota, which are more salt-sensitive. Furthermore, salinity decreased species richness by 11.33% and soil multifunctionality by 21.48% but increased microbial network complexity while decreasing its stability. Incorporating vermicompost increased bacterial and fungal PLFAs, enhanced bacterial diversity by 2.33%, promoted salt-tolerant bacteria, and increased the complexity and stability of the bacterial network. Conversely, the application of NPK fertilizer reduced bacterial richness, alpha diversity and soil multifunctionality by 14.52, 5.83, and 12.34%, respectively, further disrupting the microbial community and making resilience to salinity stress more challenging. Furthermore, NPK fertilization increased bacterial network complexity but decreased its stability. This study underscores the significance of employing vermicompost to improve the health of saline soils. Furthermore, it emphasizes the negative impacts of NPK fertilizer on soil microbial structure and function and hinder its recovery from salinity’s impacts.
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- Award ID(s):
- 2305456
- PAR ID:
- 10618866
- Publisher / Repository:
- Frontiers in Microbiology
- Date Published:
- Journal Name:
- Frontiers in Microbiology
- Volume:
- 16
- ISSN:
- 1664-302X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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