Macrophytes encompass a diverse array of submerged, emergent, and floating primary producers visible to the naked eye, including vascular plants, macroalgae, and bryophytes. Long regarded as ecological pillars of aquatic ecosystems, these plants perform an extraordinary range of functions: they stabilize sediments, oxygenate the water column, provide habitat and foraging grounds for fish, invertebrates, and amphibians, and drive nutrient cycling. Their ecophysiological adaptations—such as aerenchyma formation and radial oxygen loss that allow them to survive in waterlogged conditions—translate into ecosystem-level consequences that ripple through entire food webs, making them uniquely suited to serve as the biological foundation of nature-based restoration strategies.

The concept of nature-based solutions, formally introduced by the International Union for Conservation of Nature in the late 2000s and consolidated at the 2016 World Conservation Congress, defines actions to protect, sustainably manage, and restore natural or modified ecosystems that address societal challenges while simultaneously delivering human well-being and biodiversity benefits. Macrophytes have been quietly working within this framework for decades. Species such as the common reed Phragmites australis, cattails of the genus Typha, and water hyacinth Eichhornia crassipes have long been deployed in constructed and floating treatment wetlands to strip nutrients, metals, and organic pollutants from water. Recent research shows that the performance of these systems hinges on hydraulic retention time and plant functional traits: submerged species like Vallisneria spiralis and Ceratophyllum demersum enhance nitrification and phosphorus immobilization under moderate flows, while emergent species tolerate heavy metal loads and support microbial degradation of contaminants.

To assess the current state of knowledge, Bolpagni conducted a systematic search of literature published from 2020 onward across Scopus, Web of Science, and Google Scholar, screening more than 2,100 records and ultimately identifying 16 exemplary case studies in which macrophytes act as genuine restoration players rather than passive indicators of ecosystem condition. The studies spanned themes from nutrient legacy mitigation and biotic interactions to climate impacts and practical planting techniques. Across all cases, macrophyte-based interventions produced measurable improvements in habitat restoration, water quality, and biodiversity, with outcomes shaped primarily by light availability, nutrient loading, hydrology, and the remediation capacity of the plants themselves.

The mechanisms behind these successes are becoming increasingly well understood. By anchoring sediments, macrophytes reduce resuspension and turbidity, allowing more light to penetrate the water column and creating conditions favorable to further plant growth—a classic positive feedback loop. In shallow lakes studied in New Zealand, researchers emphasized that understanding macrophyte light and depth tolerances is essential for predicting restoration success. Danish lake studies have identified trophic thresholds beyond which macrophytes decline, with total phosphorus concentrations above roughly 0.13 to 0.20 milligrams per liter or total nitrogen above 1.2 to 2.0 milligrams per liter marking danger zones. Beyond light, macrophyte restoration increases dissolved oxygen, shifts microbial community composition, and enhances the microbial carbon pump, which can bolster aquatic carbon sequestration—a finding with profound implications for climate change adaptation.

The evidence for water quality gains is striking. One study of an urban shallow lake reported reductions exceeding 50 percent in nitrogen, phosphorus, and chlorophyll a following macrophyte restoration, alongside increases in recalcitrant dissolved organic matter. In a three-year study of a subtropical lake in China, submerged macrophyte restoration led to marked decreases in cyanobacteria and other algal taxa, with these changes negatively correlated with nutrient concentrations. Rooted plants also improve sediment chemistry: research on Vallisneria spiralis demonstrated that the species improves pore water conditions and increases potential nitrification in organically polluted sediments, effectively transforming contaminated substrates into more functional biological layers.

Success, however, is far from guaranteed, and the article is candid about the conditions that lead to failure. Restoration efforts falter when depth, turbidity, or shading limit light; when storms, waves, or dredging repeatedly disturb plantings; when invasive species or high grazing pressure suppress regrowth; or when propagule banks and genetic diversity are depleted. Perhaps most insidiously, short-term interventions without maintenance can backfire—when accumulated plant biomass is never harvested, nutrients released during decomposition can re-fertilize the very system the restoration was meant to save, triggering self-fertilization processes that undermine the entire effort. Modeling work based on the PCLake framework suggests that maintaining an optimal biomass window of roughly 5.5 kilograms of fresh weight per square meter, with substantial harvesting of about 80 percent during the decline period, can prevent this nutrient leakage.

Trade-offs are equally real. Biomass harvesting removes nutrients but demands significant labor and investment; floating and constructed wetlands must occupy considerable areas to be effective; and in some contexts, evapotranspiration from dense plant stands can reduce water volumes and accelerate the drying of colonized water bodies. Climatic extremes such as droughts and floods can disrupt restored systems in unpredictable ways. Quantitative operational thresholds are emerging to guide practitioners: in Chesapeake Bay, total suspended solids above 15 milligrams per liters signaled unfavorable conditions for submerged vegetation, while sediment organic matter contents above roughly 20 percent caused drastic growth reductions in even highly reactive species like Hydrilla verticillata and Myriophyllum spicatum.

To maximize effectiveness, the article proposes an operational framework for implementing macrophyte-based solutions, beginning with comprehensive pre-intervention assessments of nutrient loads, sediment phosphorus, light profiles, and hydrodynamics. It calls for climate-resilient design incorporating buffer zones and species redundancy, multifunctional approaches that combine submerged plantings with emergent buffers and floating wetlands, and careful attention to propagule banks and genetic diversity, prioritizing native species adapted to local stressors. Notably, mixing aquatic plant functional types appears to pay dividends: communities combining up to eight species across three functional groups form more stable stands, support clear-water states, reduce methane emissions through enhanced rhizosphere processes, and can outperform monocultures in nitrogen removal due to metabolic complementarity.

Ultimately, the synthesis signals a paradigm shift in freshwater restoration—away from short-term engineering fixes and toward system-level agendas grounded in adaptive management, stakeholder engagement, and long-term governance and financing. Success depends less on planting effort alone than on establishing the enabling conditions for recovery: reduced external nutrient loads, adequate light and hydrodynamic regimes, and sufficient propagule availability. As invasive taxa reshape freshwater communities in ways that may constitute nothing less than an ecological revolution, the stakes could hardly be higher. Macrophytes, the article concludes, should be recognized not only as vital targets of restoration but as essential tools for climate adaptation in the Anthropocene—living infrastructure already growing in the waters we are struggling to save.

Subject of Research: Macrophyte-based nature-based solutions for restoring freshwater ecosystems

Article Title: Macrophytes-based solutions as tools to halt the collapse of freshwater biodiversity, functions and benefits

Article References: Bolpagni, R. (2026). Macrophytes-based solutions as tools to halt the collapse of freshwater biodiversity, functions and benefits. Discover Ecology, 2(1), Article 8. https://doi.org/10.1007/s44396-026-00027-y

Image Credits: AI Generated

DOI: 10.1007/s44396-026-00027-y

Keywords: macrophytes, freshwater restoration, nature-based solutions, aquatic plants, eutrophication, water quality, biodiversity, shallow lakes, phytoremediation, ecosystem services, adaptive management, climate change