Plant functional traits offer a mechanistic framework for understanding how plant communities respond to environmental change and shape ecosystem functioning. However, despite rapid advances over the past decades, the role of functional traits in driving wetland ecosystem functioning remains less well understood than in terrestrial systems, thereby limiting effective wetland conservation and restoration. In this review, we synthesize existing evidence on how plant functional traits and functional diversity influence key wetland ecosystem functioning, such as productivity, carbon cycling and nutrient cycling. We find that functional traits are key regulators of ecosystem functioning; therefore, targeted restoration should prioritize species with specific traits. We also call for coordinated actions across local and landscape scales to manage potential trade-offs among restoration objectives and enhance ecosystem multifunctionality. Clarifying the roles of functional diversity and wetland-specific flooding-adaptive traits in driving ecosystem functioning is identified as an important focus for future work. Moreover, a deeper understanding of how functional traits and diversity regulate wetland ecosystem functioning requires more manipulative experiments. This review highlights the role of plant traits in mechanistically linking vegetation dynamics to ecosystem functioning in wetlands.

Anthropogenic global change profoundly affects terrestrial ecosystem structure and function, creating an urgent and persistent need to accurately predict future ecosystem states. Field-based manipulative experiments provide critical mechanistic insights into these impacts but are inherently limited in spatio-temporal scope. Conversely, process-based models can extrapolate to broader scales but often contain simplified or unrealistic mechanisms that lead to uncertain projections. Data-model integration has emerged as an essential approach to bridging this gap, testing model assumptions against empirical evidence and guiding experimental design via model-based hypotheses. This review synthesized progress in integrating manipulative experiments with process-based models across three key global change drivers: elevated CO₂, climate change (warming and altered rainfall) and nutrient manipulation. We demonstrated how this integration reduced key uncertainties in processes such as photosynthesis, carbon-nutrient coupling and soil biogeochemistry, whilst exposing persistent gaps in plant hydraulics, microbial dynamics and multifactorial stresses. These advances were most pronounced in representing CO₂ fertilization effects, including improved stomatal optimization theory, dynamic carbon allocation schemes and coupled carbon-nitrogen-phosphorus cycling. By contrast, its application to warming, rainfall change and multi-nutrient interactions remained underdeveloped. To catalyze future progress, we propose specific strategies to foster a more synergistic cycle of knowledge co-production. These include prioritizing the quantification of mechanism-specific data to develop dynamic model formulations, systematically using multi-site experimental networks to benchmark and refine model processes across scales, and strategically employing models to design targeted experiments. Ultimately, these strategies are indispensable for developing more realistic models and achieving predictive understanding of ecosystem responses to global change.

Tropospheric ozone (O₃) is a major air pollutant that threatens wheat production. However, the mechanisms underlying cultivar-specific responses remain unclear, particularly how stomatal traits and leaf structural characteristics contribute to differences in O₃ sensitivity among cultivars. A field experiment was conducted using 13 winter wheat (Triticum aestivum L.) cultivars exposed to ambient (A-O₃) or elevated (E-O₃, 1.5 times A-O₃) O₃ treatment in a Free-Air O₃-Concentration Enrichment system (O₃-FACE). Elevated O₃ significantly increased stomatal density on both adaxial and abaxial leaf surfaces, with a stronger response on the adaxial side, indicating independent regulation between surfaces. At the anthesis stage, stomatal and pore width significantly increased under E-O₃, whereas their length was not affected. Elevated O₃ significantly reduced adaxial epidermal thickness, abaxial epidermal thickness, mesophyll tissue thickness, and total leaf thickness during grain filling, with significant O₃ × cultivar interactions for all traits except abaxial epidermal thickness. Cultivars were classified into sensitive, intermediate, and tolerant groups. Sensitive cultivars exhibited significant reductions in leaf structure, whereas tolerant cultivars largely maintained or even enhanced structural integrity. Overall, cultivar sensitivity to O₃ was not directly associated with stomatal traits but rather with the ability to preserve leaf anatomy. These findings suggest that maintaining flag leaf structure is critical for improving wheat resilience to rising O₃ levels.