Marta Baumane

Summary: Wetlands are crucial for biodiversity and climate change mitigation. Vast wetland areas have been lost through land‐use intensification. Thus, restoration efforts have gained attention globally. We assessed relationships between environmental conditions, aboveground and belowground plant traits and carbon cycling in restored wetlands in Denmark, both grazed and ungrazed, compared to a baseline in near‐natural wetlands. Wetland plant species strategy varied from acquisitive to conservative. More conservative species tended to have larger root diameters and higher percentages of root aerenchyma. However, at the community level, we found no evidence for differences in the suite of traits expressed in restored and near‐natural wetlands. Environmental and carbon cycling variables were not consistently different between restoration treatments. Average summer carbon fluxes were highly variable, but net ecosystem exchange was negative, indicating sequestration of CO ₂ . Groundwater level was the main driver of CO ₂ exchange in summer, with relatively dry sites tending to fix more carbon. Relationships between plant traits and carbon cycling were weak. Our results suggest that, for carbon cycling, plant community trait composition is less important than the abiotic environment, in particular, the water table depth. This shows that ecosystem functions can be restored, even in cases where plant biodiversity has not recovered.

Riparian Wetland conservation and restoration in Europe increasingly rely on nature-based solutions, yet biodiversity monitoring of their implementation remains fragmented across scales, methods and policy frameworks. This paper synthesises current approaches in wetland monitoring and proposes an integrated, adaptive framework linking long-term, system-orientated observation with short- to medium-term, intervention-focused restoration monitoring. Combining site-based surveys with standardised, multi-scale assessments enables differentiation of natural variability from human pressures, detection of tipping points in species sensitivity to climate pressures and evaluation of restoration outcomes under EU policies, such as the WFD, the Habitats and Birds Directives and the Nature Restoration Regulation. Besides conventional biodiversity monitoring, we highlight innovations that address critical monitoring gaps: artificial intelligence–supported remote sensing using satellites and unmanned aerial vehicles, sensor networks for near-real-time hydrological observations, environmental DNA metabarcoding and citizen-science approaches. Essential biodiversity variables and essential ecosystem-service variables are emphasised as integrative indicators that connect ecological integrity, ecosystem functioning and human well-being. Finally, we outline the enabling conditions for a harmonised European wetland monitoring architecture, supported by major environmental research infrastructures that provide long-term ecological data, advanced digital tools and integrated assessments essential for evidence-based, climate-resilient restoration. Highlights Riparian wetland conservation and restoration in Europe increasingly use nature-based solutions, but biodiversity monitoring remains fragmented across scales, methods and policies. Standardised, multi-scale assessments combined with site-based surveys help distinguish natural variability from human pressures. Integrated monitoring supports early detection of tipping points in species responses to climate change. Innovative monitoring tools are highlighted, including AI-supported remote sensing (satellites and UAVs), sensor networks, eDNA metabarcoding and citizen science. Major environmental research infrastructures are identified as key supports for long-term data, digital tools and evidence-based, climate-resilient restoration. The approach enables evaluation of restoration outcomes under key EU policies (WFD, Habitats and Birds Directives, Nature Restoration Regulation).

Measuring ecosystem gas fluxes is crucial to understanding the dynamics of ecosystem water and energy cycling. A common method to measure ecosystem gas fluxes (CO ₂ , CH ₄ , N ₂ O) and to compare experimental treatments is the use of closed‐loop chambers. However, the output data require extensive processing before analysis, making the workflow prone to bias and limiting comparability between studies. While there are various methods to process flux data, they lack reproducibility and automation. The fluxible R package provides a reproducible way to process raw gas concentration data from closed‐loop chambers into an analysis‐ready dataset of ecosystem gas fluxes. The processing steps include (1) separating the measurements, (2) fitting a linear, quadratic, or exponential model, (3) assessing the quality of the fit, (4) plotting the fluxes for visual inspection and (5) calculating the fluxes. In addition to reproducibility, fluxible focuses on homogeneity and automation in data processing, thus reducing the time investment for users while improving comparability across studies.

Questions: Alpine grasslands are affected by a range of global change drivers, including land‐use change, climate warming and pollution. How these drivers interact and affect plant functional communities is poorly understood. We used plant functional traits to test the single and interactive effects of warming, nitrogen addition and grazing on alpine grassland communities and assessed the importance of intraspecific trait variation. Location: Alpine and sub‐alpine grasslands in western Norway. Methods: For three years, we applied global change treatments to test the effects of warming with nitrogen addition, and warming with grazing at an alpine and sub‐alpine plant community. We measured six plant functional traits related to plant size and leaf economics, including intraspecific trait variation. Results: Our results show that warming and nitrogen addition shifted size‐related traits in plant communities towards taller plants with larger leaves, and more strongly in the alpine than in the sub‐alpine plant community. Warming also affected leaf economic traits, promoting faster traits in the alpine and slower traits in the sub‐alpine plant community. Grazing shifted communities to faster leaves (grazing tolerant ) in the sub‐alpine community and slower leaves (grazing avoidance ) in the alpine community. There were no interactive effects between the global change drivers. The relative contributions of species turnover and intraspecific trait variation to overall trait variation differed between origins of the two plant communities. Conclusions: We show that these global change drivers shift alpine and sub‐alpine plant communities in different directions, likely due to differences in resource availability. Our results support the need for site‐specific management strategies in these systems.

Agricultural intensification has led to the loss of most natural wetlands from human‐dominated landscapes but, in recent decades, wetland restoration has gained traction worldwide. Restoration of suitable habitat conditions is hampered by nutrient residues from decades of high‐input farming, by continued input of nutrients from surrounding farmland and by incomplete restoration of natural hydrology. We assessed the effect of wetland restoration and disturbance (grazing) on vascular plant and bryophyte diversity in restored wetlands in Denmark at plot and landscape scales. Compared to near‐natural wetlands, we found a lower species richness and community uniqueness in restored wetlands, but we also found that grazing had a positive effect on vascular plant richness in restored wetlands. The size of the local species pool, presence of near‐natural habitat prior to restoration and near‐natural restored hydrology all had positive effects on plant diversity, whereas high soil iron and nitrogen had negative effects. Synthesis and applications: Restoration of plant diversity in wetlands is challenging, but our results point to potential remedies: plan restoration areas near colonisation sources of the target biota, restore hydrology to near‐natural conditions, discontinue nutrient loads from surrounding arable land and restore near‐natural grazing regimes. Bryophytes may be particularly useful as indicators for successful restoration of wetlands.