In a groundbreaking meta-analysis published in Nature Communications, researchers have unveiled the profound impact of global nitrogen enrichment on terrestrial ecosystems, revealing that plant biodiversity is significantly more sensitive to nitrogen input than the diversity of soil bacterial and fungal communities. This comprehensive study synthesizes decades of experimental data to provide clarity on how anthropogenic nitrogen deposition, a byproduct of industrialization and intensive agriculture, disproportionately influences different layers of ecosystem complexity.
Nitrogen, an essential macronutrient for plant growth, forms the cornerstone of modern agricultural productivity. However, escalating rates of nitrogen fixation and atmospheric deposition have raised alarms about its cascading effects on ecological balance. Until now, the relative sensitivity of aboveground versus belowground biotic communities to nitrogen enrichment remained ambiguous. The present meta-analysis, involving data from hundreds of experimental sites worldwide, decisively concludes that plant diversity diminishes more sharply under increased nitrogen loads compared to the communities of soil microbes that underpin ecosystem function.
The research team, led by Song et al., meticulously compiled and analyzed over a thousand published studies, performing rigorous statistical synthesis to detect global patterns. Their methodological approach involved integrating data across diverse biomes, ranging from temperate forests and grasslands to tropical ecosystems, thereby capturing a comprehensive view of nitrogen’s ecological footprint. This holistic perspective allowed the authors to transcend local case studies and discern overarching trends with robust confidence.
One of the pivotal revelations from this meta-analysis is that nitrogen enrichment consistently suppresses plant species richness. Dominant plant species proliferate under high nitrogen availability, outcompeting less competitive species and driving homogenization of plant communities. Such a reduction in plant diversity negatively influences ecosystem resilience and functionality, as diverse plant assemblages are critical for maintaining nutrient cycling, habitat complexity, and overall ecosystem services.
Conversely, soil microbial diversity—particularly bacterial and fungal communities—displayed a more muted response to nitrogen enrichment. While some shifts in microbial community composition were evident, the overall richness and diversity metrics showed relative stability. This discrepancy suggests that soil microbes possess a greater functional redundancy or adaptive capacity to withstand nitrogen perturbations, potentially buffering certain ecosystem processes from nitrogen-induced disruption.
The study further dissects microbial community responses, noting that bacterial taxa involved in nitrogen cycling exhibited altered abundances, reflecting shifts in nitrogen availability and soil chemistry. Fungal communities, including mycorrhizal symbionts crucial for plant nutrient uptake, experienced nuanced changes in composition but not in total diversity. These differential responses underscore the complexity of soil ecosystems and the multifaceted ways through which nitrogen enrichment mediates belowground ecological networks.
Importantly, the authors highlight that the disproportionate impact on plant diversity has cascading repercussions for ecosystem stability in the face of global environmental change. Reduced plant diversity can impair ecosystem productivity, diminish habitat quality for fauna, and disrupt biogeochemical cycles. Therefore, nitrogen enrichment poses a threat not only to biodiversity but also to the sustainable provision of ecosystem services essential for human well-being.
The meta-analysis also explores the interactions between nitrogen enrichment and other global change drivers, such as climate warming and land-use intensification. These synergistic effects exacerbate the loss of plant diversity, suggesting that nitrogen deposition acts as a primary stressor that amplifies ecosystem vulnerability under multifactorial pressures. The authors urge that mitigation strategies prioritize nitrogen management to curb biodiversity loss and maintain ecosystem integrity globally.
Intriguingly, the study addresses temporal dynamics, revealing that the negative effects of nitrogen enrichment on plant diversity manifest rapidly and persist over long periods. This temporal persistence implies that once lost, plant species diversity may not readily recover even if nitrogen inputs are reduced, emphasizing the urgency of proactive intervention.
To unravel the mechanistic underpinnings of these patterns, the researchers delve into nutrient competition theory and soil chemistry alterations induced by nitrogen deposition. Excess nitrogen availability leads to soil acidification and nutrient imbalances, which favor fast-growing, nitrophilous plant species at the expense of others adapted to nutrient-poor conditions. These shifts in soil environment create selective pressures that shape plant community assembly and diversity outcomes.
From a methodological standpoint, this meta-analysis exemplifies the power of integrative data synthesis in ecology. By aggregating diverse studies, the authors overcome the limitations of individual experiments, such as site-specific factors and limited temporal scales. Their analytical framework incorporates advanced statistical models that account for heterogeneity and potential publication biases, ensuring robust and reliable conclusions.
The implications of these findings resonate beyond academic circles, calling for policy reforms targeting nitrogen emissions from agriculture, fossil fuel combustion, and industrial processes. Reducing reactive nitrogen inputs into the environment can mitigate biodiversity decline and promote ecosystem resilience. Additionally, restoration efforts should consider the sensitivity of plant communities to nitrogen when designing rehabilitation strategies.
Looking forward, the authors recommend further research to elucidate how different plant functional groups respond to nitrogen enrichment and how these changes influence ecosystem-level processes. Investigations into feedback mechanisms between plants, microbes, and soil chemistry under variable nitrogen regimes could deepen our understanding of ecosystem adaptability.
In sum, this study delivers a paradigm shift in ecological nitrogen research by demonstrating that the diversity of plants, the very architects of terrestrial ecosystems, suffers more acutely from global nitrogen enrichment than the hidden microbial custodians beneath the soil surface. Such insights compel a reevaluation of nitrogen management techniques worldwide, balancing the benefits of nitrogen for food production with the imperative to conserve biodiversity and ecosystem functioning.
With nitrogen deposition poised to increase in many regions due to continued anthropogenic activities, safeguarding plant diversity emerges as a critical environmental priority. This meta-analysis serves as an invaluable resource for ecologists, environmental managers, and policymakers striving to harmonize human development with Earth’s natural systems.
The integration of large-scale empirical evidence accentuates the urgency to advance sustainable agricultural practices, such as optimized fertilizer use and adoption of nitrogen-efficient cropping systems, which can minimize excess nitrogen release. Parallelly, enhancing green infrastructure and natural buffer zones may help intercept nitrogen before it reaches sensitive ecosystems.
Ultimately, the findings articulate a clarion call for global stewardship of nitrogen resources—acknowledging that the health of aboveground biodiversity holds profound implications for the resilience of the entire biosphere. Protecting plant diversity in the nitrogen-enriched Anthropocene will require concerted efforts rooted in sound science and effective governance.
Subject of Research: The differential impacts of global nitrogen enrichment on plant diversity versus soil bacterial and fungal diversity.
Article Title: Global nitrogen enrichment impacts plant diversity more than soil bacterial and fungal diversity: a meta-analysis.
Article References:
Song, Y., Kong, W., Wei, X. et al. Global nitrogen enrichment impacts plant diversity more than soil bacterial and fungal diversity: a meta-analysis. Nat Commun (2026). https://doi.org/10.1038/s41467-025-67815-0
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