Wetlands are increasingly recognized as indispensable components in the global carbon cycle, serving as some of the Earth’s most carbon-dense ecosystems. Their significance in climate change mitigation efforts stems from their remarkable ability to sequester and store large amounts of soil carbon over prolonged periods. Despite this recognized importance, the role of plant diversity in influencing carbon storage within natural wetlands has remained somewhat enigmatic, particularly when contrasted with terrestrial ecosystems where plant diversity’s positive effect on soil carbon accumulation is well documented. A groundbreaking new study leverages extensive data from the US National Wetland Condition Assessment (NWCA) to unravel this complex interaction, highlighting the nuanced influence of plant traits on carbon dynamics in wetland soils.
The study comprehensively evaluates data from an impressive 1,268 natural wetland sites scattered across the United States, providing a robust framework to examine how both functional diversity and functional identity of plant communities impact soil carbon stocks. Functional diversity, defined as the range and value of species traits related to ecosystem function, has long been hypothesized to enhance soil carbon storage by promoting complementary resource use and increased biomass. However, the findings reveal a surprisingly minimal role for functional diversity in determining soil carbon levels within these wetlands, defying conventional ecological expectations.
One of the critical insights of this research is the identification of soil nutrient availability and the presence of non-native plants as moderating factors that weaken the potential positive influence of functional diversity on carbon storage. Elevated nutrient levels could disrupt the delicate balance within the wetland plant communities, potentially favoring fast-growing species that contribute less effectively to long-term soil carbon storage. Similarly, stress induced by invasive non-native plants appears to undermine functional diversity’s benefits, possibly by reducing the functional complementarity essential for maintaining high carbon inputs into the soil.
In stark contrast to the limited effects of functional diversity, the study illuminates the profound importance of functional identity—the dominant traits within the plant community—in promoting soil carbon sequestration. Specifically, wetlands characterized by the presence of large, slow-growing, and highly hydrophytic plants were found to consistently exhibit higher levels of carbon storage. These traits point to species adapted to wet environments with conservative growth strategies, which likely produce biomass that decomposes slowly and contributes to persistent soil organic matter accrual.
The relationship between these key plant traits and soil carbon storage is intricately linked to hydrological conditions and human impacts. The benefits of functional identity were most pronounced under conditions of elevated water levels and minimal anthropogenic disturbance. This finding underscores the critical role of hydric environments—wetlands with prolonged saturation—in fostering the slow decomposition and stabilization of organic carbon inputs. Conversely, high levels of human disturbance, such as drainage, land conversion, or pollution, can disrupt these processes and diminish the carbon sequestration potential of wetland ecosystems.
The implications of these findings extend beyond ecological theory and into practical conservation and restoration strategies aimed at climate change mitigation. By cultivating and preserving wetlands dominated by large, hydrophytic species with slow growth rates, land managers could enhance the carbon storage capacity of these ecosystems. This targeted approach emphasizes the quality and function of plant communities over mere species richness, shifting the focus toward trait-based conservation that optimally supports carbon sequestration.
In addition to species composition, this research highlights the importance of maintaining hydric conditions for wetland viability as carbon sinks. Restorative efforts that elevate or sustain water tables could maximize the carbon storage benefits by facilitating the growth of conservative hydrophytes and limiting aerobic decomposition. These hydrological interventions, combined with the strategic management of plant communities, present a powerful toolkit for ecosystem-based climate mitigation efforts.
While functional diversity’s role in wetland carbon dynamics appears limited, these findings do not dismiss its broader ecological importance, particularly in terrestrial environments. Instead, they call for a refined understanding that considers the distinct environmental context of wetlands. Unlike upland soils where diverse plant assemblages can increase biomass productivity and carbon inputs, wetlands rely more on specific plant traits adapted to saturated, anoxic conditions that slow decomposition and promote long-term carbon storage.
Furthermore, the research underscores the potential risks posed by invasive species and nutrient pollution in undermining the carbon storage function of wetlands. Invasive plants, often characterized by rapid growth and competitive displacement of native species, can alter community composition and ecosystem processes detrimentally. Nutrient enrichment from agricultural runoff or urban waste can accelerate microbial decomposition and reduce soil organic matter accumulation. Therefore, addressing these anthropogenic stressors is vital for maintaining and enhancing wetland carbon sequestration.
The authors’ approach, harnessing the vast and diverse data from the NWCA, exemplifies the power of large-scale ecological monitoring to elucidate complex ecosystem functions. By linking trait-based plant data with soil carbon measurements across a national gradient, this study sets a precedent for how integrated datasets can inform targeted biodiversity and ecosystem management policies.
Moreover, these findings contribute to the broader discourse on nature-based solutions for climate change by providing empirical evidence supporting trait-based vegetation management as a viable strategy. As global initiatives prioritize carbon sequestration in natural landscapes, the emphasis on selecting appropriate species with favorable traits becomes increasingly relevant to maximize ecological benefits.
In sum, this study marks a significant advancement in understanding how plant communities shape soil carbon storage in wetlands, revealing that the dominance of large, slow-growing hydrophytes under favorable hydrological conditions is key to maximizing carbon sequestration. The nuanced interplay between plant traits, hydrology, nutrient status, and human disturbance provides crucial insights for conservationists and policymakers aiming to harness wetland ecosystems in the fight against climate change.
Future research will benefit from exploring the mechanistic pathways through which these traits influence carbon stabilization, such as root morphology, litter chemistry, and microbial interactions under varying environmental contexts. Additionally, extending these findings to other wetland types and geographic regions will help generalize the principles identified.
Ultimately, this study affirms that not all biodiversity is created equal when it comes to carbon sequestration in wetlands. Prioritizing functional identity over mere diversity and safeguarding hydric conditions are essential steps for directing conservation efforts toward ecosystems that serve as robust, long-term carbon sinks. As the climate crisis intensifies, embracing such informed, trait-based approaches to wetland management offers a promising avenue for mitigating global carbon levels.
Subject of Research: The influence of trait-based plant diversity and composition on soil carbon storage in natural wetlands in the United States.
Article Title: Large slow-growing hydrophytes increase wetland carbon storage
Article References: Liu, H., Li, J., Wu, J. et al. Large slow-growing hydrophytes increase wetland carbon storage. Nat. Plants (2026). https://doi.org/10.1038/s41477-026-02221-y
Image Credits: AI Generated
DOI: https://doi.org/10.1038/s41477-026-02221-y
Tags: carbon density in wetland ecosystemsclimate change mitigation strategiesecological impact of wetland plantsfunctional diversity and soil carbonhydrophytes and carbon sequestrationnatural wetland sites researchplant diversity in wetlandsrole of plant traits in carbon storagesoil carbon dynamics in wetlandsUS National Wetland Condition Assessmentwetland carbon storagewetland ecosystems and climate
