Wetland ecological health is assessed using an indicator system that comprehensively considers aquatic environments, soil conditions, biological communities, and socioeconomic factors. In this study, the assessment unit basins and baseline wetland sections were established, and a Pressure-State-Response (PSR) framework comprising twelve indicators was applied to evaluate the ecological health of riverine wetlands. The assessment units were delineated as small watersheds at a spatial scale appropriate for riverine wetland management. In addition, alluvial zones were introduced as a geomorphic reference to delineate baseline wetland sections, defined as the potential wetland space against which human-induced degradation was assessed. The indicator grades may vary depending on the study area, and the state indicators were analyzed using three to five indicators per basin. The assessment results of 80 unit basins in the upper Geum River Basin, South Korea, revealed that one unit basin rated as Grade 1 (Very healthy), 29 unit basins as Grade 2 (Healthy), 47 unit basins as Grade 3 (Moderate), three as Grade 4 (Vulnerable), and none as Grade 5 (Highly vulnerable). Unit basins with higher population density, urbanization rate, and cultivated land ratio generally showed lower wetland ecological health grades. Unit basins adjacent to the mainstream tended to be relatively healthy whereas some tributary unit basins with high urbanization rates and pollution loads showed degraded ecological conditions. This study provides a scientific foundation for prioritizing restoration efforts and establishing sustainable wetland management and conservation policies.
Vegetation water-use efficiency (WUE) does not necessarily indicate improved ecosystem functioning under compound drought, because increases in WUE may result from stress-induced reductions in evapotranspiration rather than enhanced carbon uptake. Here, we develop a mechanism-constrained, scenario-based framework to diagnose WUE risk and prioritize ecological restoration across China. A previously trained XGBoost model based on multi-source remote-sensing and environmental data for 2000–2024 was used to simulate WUE responses under three levels of warm-dry climate perturbation and three vegetation-background conditions. Vapor pressure deficit (VPD) and soil moisture (SM) thresholds were integrated into the simulations to quantify compound threshold-crossing risk, ecological safety-boundary contraction, and risk-potential zoning. Although national mean WUE increased under all perturbation levels, the proportion of vegetation within the safe zone declined from 28.64% to 15.49%, while the high-risk area expanded from 31.40% to 44.28% as climate pressure intensified. Risk escalation was concentrated in northern arid and semi-arid regions, agro-pastoral transition zones, and parts of Northeast and North China, with additional exposure emerging in humid regions under severe perturbation. By combining risk intensity with restoration potential, the framework identified natural succession protection zones (46.10%), ecological function enhancement zones (33.42%), ecological degradation warning zones (11.55%), and priority intervention and restoration zones (8.94%). The results demonstrate that mean WUE alone may conceal emerging ecological vulnerability. The proposed framework provides a spatially explicit decision-support tool for distinguishing where restoration should be protected, enhanced, monitored, or actively prioritized, thereby supporting water-constrained ecological engineering and adaptive restoration planning under intensifying compound drought.
Organochlorine contamination by hexachlorocyclohexane (HCH) and chlorobenzenes (ClB), co-occurring with iron and manganese, poses persistent challenges for constructed wetland treatment systems. Microbial biofilms are central to pollutant attenuation, yet the responses of benthic diatoms and bacterial communities to such complex chemical gradients remain poorly understood. Biofilm communities were sampled on standardised fritted glass disc carriers (n = 15 per site, 25 days incubation) and natural substrates (n = 6 per site) at five sites spanning the biosorption/biodegradation (module C) and aerobic wetland (module D) compartments of a full-scale modular treatment system (Wetland+, Hájek, Czech Republic). Metabolic function (net primary production, community respiration), phototrophic biomass (chlorophyll-a), diatom assemblages (microscopy, Shannon diversity) and bacterial communities (16S rRNA amplicon sequencing) were characterised alongside hydrochemical and contaminant profiling. Biofilm metabolism was predominantly heterotrophic (NPP:CR < 1) at all sites, with strongest suppression at upstream sites where HCH (12.25–13.35 μg/L), ClB and Fe concentrations were highest. Chlorophyll-a and net primary production increased downstream as pollutant loads declined. Benthic diatoms dominated the phytobenthos throughout; 48 taxa across 21 genera were identified, with species richness increasing from 4 to 5 taxa at upstream sites to 23–24 at downstream sites. Key tolerant taxa included Achnanthidium minutissimum, Rhopalodia parallela and Nitzschia palea. Bacterial communities clustered distinctly by module: Parasediminibacterium and Rhodoferax dominated module C, while Rhodobacteraceae and diatom diversity increased in module D. Fritted glass carriers supported diatom assemblages comparable to, or richer than, natural substrates at most sites. These findings demonstrate a clear pollution-driven gradient in biofilm structure and function across the Wetland+ system. The integration of metabolic measurements, diatom assemblages and bacterial community profiling provides a robust framework for evaluating organochlorine remediation performance, supporting the use of standardised biofilm carriers for ecological monitoring in constructed wetlands.
Landslides, as complex geomorphological disturbances, deeply reshape landscapes and influence ecosystem dynamics by exposing new substrates, redistributing soil and organic matter, and altering hydrological and nutrient cycles. In this context, Soil and Water Bioengineering (SWBE) techniques represent an effective Nature-Based Solution (NBS) that combines mechanical slope stabilisation with ecological restoration. This study evaluated the ecological effectiveness of SWBE interventions for shallow landslide restoration within mountainous forest environments of Central Italy. An integrated assessment of soil physicochemical properties and biological indicators—herbaceous and tree vegetation, soil microorganisms, and soil fauna—was carried out across three sites: a restored landslide (SWBE), a naturally recovering landslide (natural), and an undisturbed reference site (control). Vegetation emerged as the most responsive indicator of recovery, with the restored site showing significantly higher alpha diversity than both the natural and control sites. Although different pedological conditions characterised the three study sites, microbial communities' metabolic diversity and soil fauna composition showed strong resilience, reaching values comparable to undisturbed conditions. Overall, SWBE restoration effectively paired slope stability with the native ecological processes, promoting the establishment of diverse and functionally relevant plant communities. These findings highlight the dual benefits of SWBE as a sustainable solution for erosion control, slope stabilisation and biodiversity enhancement. Finally, long-term multi-taxon monitoring is suggested to further clarify the trajectories of ecological succession and ecosystem functionality in restored mountain environments.
Nature-based solutions (NBS) provide sustainable alternatives to conventional activated sludge (CAS) systems for municipal wastewater treatment, yet comprehensive full-scale comparisons remain limited. This study evaluates the simultaneous long-term performance of three full-scale treatment systems operating in parallel and receiving the same influent: CAS system, a treatment wetland (TW), and a high-rate algal pond (HRAP). Performance was monitored over two growing periods, focusing on the removal of organic matter, suspended solids, and nutrients. Additionally, HRAP system was tested with varying hydraulic retention times (HRT) and biomass recycling strategies. Results indicate that while CAS system and TW provided consistent organic matter removal (97% and 89% BOD5 removal, respectively), HRAP efficiency was limited by insufficient separation of algal biomass from the effluent. HRAP achieved significantly higher ammonium‑nitrogen removal (86 ± 24%) than CAS and TW. Both HRAP and TW significantly reduced total phosphorus (53 ± 29% and 56 ± 26%, respectively). Operating the HRAP under prolonged retention times (35 days) and with biomass recycling demonstrated stable performance. Removal of suspended solids and BOD5 was significantly improved, reaching effluent concentrations of 39 ± 30 mg/L and 18 ± 9 mg/L, respectively; however, nutrient removal remained unchanged. The study confirms that while CAS is compact and efficient, HRAP and TW offer viable, low-energy alternatives with added benefits of resource recovery and lower environmental footprints. These findings support the integration of algal and wetland technologies into decentralised treatment schemes, contributing to circular economy goals in the water sector.
Two different interventional strategies have been developed for soil stabilization of unconsolidated soils in arid and semi-arid environments with the aim to curb wind-driven formation of fugitive dust: engineered biocrust restoration (EBR) and enzyme-induced carbonate precipitation (EICP). Pristine arid topsoil hosts microbial communities (biological soil crusts, or biocrusts) that naturally stabilize soil surfaces, greatly reducing wind and water erosion. EBR seeks to restore these communities where they are missing. EICP is a chemical intervention to generate an effective stabilizing topsoil crust through localized precipitation of a carbonate cement from enzyme-mediated ureolysis.Here we evaluated whether EBR and EICP can be implemented in tandem to combine their differential advantages, namely the self-regenerating, nature-like EBR with the fast action of EICP. The application of EICP on biocrust-covered soil resulted in the expected formation of a carbonate crusts, but also in the complete and immediate mortality of the biocrust. This could have resulted from toxicity of EICP reagents or reaction products, or from a subsequent deleterious effect of the newly formed carbonate crusts. We show that the presence of an EICP carbonate crust itself did not impede new biocrust development in the long term. By contrast, using cultures of the biocrust-forming cyanobacterium Microcoleus vaginatus, we show that the EICP reagent calcium chloride and the reaction by-product ammonium chloride were indeed irreversibly toxic when tested at concentrations typical of the field treatments. Additionally, urea (also an EICP reagent) had milder, bacteriostatic effects. Field experiments show that EICP toxicity decreases over time, in that biocrusts are able to recolonize previously treated areas, which we attribute to rainfall-driven leaching of toxic ions from the soils. We reproduced this phenomenon under controlled laboratory settings of simulated rainfall and successfully detoxified our soil, allowing biocrust re-establishment.We conclude that EICP and EBR can be applied synergistically, but only in this order, if allowing for a safe intervening period, dependent of rainfall, for natural dilution of EICP toxicants.
Coastal wetlands play a substantial role in regulating Earth's climate through exchanges of greenhouse gases (GHGs). Current European policies promote widespread coastal wetland restoration to reverse historical losses and ongoing pressures. However, substantial uncertainty remains regarding how carbon dioxide (CO2) and methane (CH4) fluxes respond to restoration across different coastal wetland types and whether these responses translate into net climate mitigation in terms of CO2 equivalents (CO2-eq). We measured simultaneous CO2 and CH4 fluxes using static chambers across four seasons at multiple locations spanning preserved, altered and restored sites within six European coastal wetlands of different ecological types. By comparing GHG exchanges and resulting CO2-eq balances across wetlands, we identified dominant biogeochemical drivers of CO2 and CH4 dynamics and assessed the climate mitigation potential of conservation and restoration actions. CO2 fluxes were primarily controlled by landscape-scale vegetation cover and inundation, whereas CH4 emissions responded to less evident changes in water quality, salinity and wetland hydrodynamics. Comparisons of CO2-eq balances between altered and restored sites showed that seagrass replantation was associated with significant mitigation potential under both 100-year and 20-year CH4 warming scenarios, while eutrophication reversal through improved water treatment was only significant under the 20-year scenario. In contrast, other restoration measures modified CO2 and CH4 fluxes in opposing directions, resulting in no significant net change in combined CO2-eq balances. Overall, our results demonstrate that climatic responses to coastal wetland restoration are both GHG-specific and wetland-type dependent, underscoring the need for tailored restoration strategies and robust, multi-GHG monitoring to detect and accurately quantify potential climatic benefits.
High-head hydropower dams fragment river corridors, yet conventional fishways are often impractical where dam height is large, reservoir levels fluctuate widely, and downstream hydraulics are highly complex. In this study, we developed and field-evaluated a tailwater-assisted fish collection and transportation system for a 270 m high hydropower dam on the lower Jinsha River, China. A three-dimensional hydrodynamic model was used to infer potential fish-approach corridors and aggregation areas downstream of the dam, and the facility was arranged near the tailrace outlets where rheophilic fishes were predicted to concentrate. The system integrates a fixed tailrace collection station with mobile collection buckets. The fixed station uses turbine tailwater as attraction flow and includes high-velocity and low-velocity entrances together with a low-velocity resting zone, enabling multi-depth and multi-velocity collection for species with different swimming abilities. Field operations in 2021 and 2022 yielded 30,368 and 33,931 fish, respectively, including all major target species and all minor target species across the two-year monitoring period. Collection performance was closely associated with hydropower operation. The best performance occurred when discharge through the tailrace tunnel adjacent to the fixed station was 500–1100 m3/s; lower discharge weakened local attraction, whereas higher discharge may have exceeded the hydraulic preferences or swimming capacity of some target species. These results show that operational tailwater can be used as an ecological guidance cue, providing a transferable trap-and-transport design for restoring fish passage at high-head dams.
Subtropical forests are among the most important ecosystems in Southern China, providing diverse ecological products and services crucial for sustaining resident welfare. However, existing research often lacks clarity regarding the current capacity of forests to supply these ecological products and their potential for future restoration. In this study, we introduced the Minimum Data Set (MDS) approach to develop an indicator system for assessing forest ecological product supply capacity (FEP). We measured and analyzed the spatial distribution patterns of the FEP in Longyan City. Furthermore, Similar Habitat Units (SHU) were employed to determine the upper potential limit of FEP, and the Geographic Self-Organizing Map (GeoSOM) algorithm was integrated to propose differentiated forest management recommendations. The results showed that the FEP index constructed using the MDS method demonstrated high reliability, showing a significant correlation coefficient of 0.758 with the total data set (TDS). The average FEP index was 0.436. Spatially, the FEP index decreases from the central mountainous areas outwards, exhibiting a significant positive spatial autocorrelation. The potential for the FEP index improvement ranges from 0 to 0.367, with high-potential areas located primarily in the northern part of the study region. The townships within the study area were classified into four distinct management zones to implement differentiated forest management strategies. This research provides a practical methodological framework for forest assessment, which is conducive to supporting long-term forest restoration monitoring and management practices in subtropical regions.
Ecological engineering in managed wetlands requires evidence that operational interventions can restructure habitat function, not merely alter physical conditions. We tested whether a small water-level drawdown could increase shallow-water accessibility for waterbirds in a managed saltpan wetland. Using a before–after–control–impact design, we evaluated a 7 cm drawdown in Yongan Wetland by integrating LiDAR-derived terrain modelling, calibrated water-level measurements, georeferenced waterbird observations, spatial analyses, and negative-binomial BACI models across two winter–spring periods. Weekly surveys recorded 72,434 individual waterbirds across manipulated and non-manipulated zones.The drawdown expanded shallow accessible habitat and reduced deeper underused zones in the manipulated area. Species richness increased from 72 to 103 species, and total abundance increased from 27,968 to 44,466 individuals, whereas the control zone showed no comparable increase. Spatial analyses indicated that waterbird use became more concentrated and temporally persistent in newly suitable areas. Primary BACI models detected positive period × treatment interactions for total abundance and for the two focal guilds most closely associated with shallow-water use.These results indicate that modest water-level adjustment can support biodiversity-oriented management when it restructures habitat accessibility. Terrain-informed hydrological manipulation offers a practical decision logic for evaluating ecological-engineering interventions in managed wetlands.
Coastal shelter forests are crucial, multi-functional ecosystems that provide a range of ecosystem services, serving as key nature-based solutions for climate change mitigation. China initiated the Coastal Protection Forest System Construction Program in the 1980s to stabilize coastlines, improve environmental quality, and enhance ecosystem services. However, the long-term benefits of the program for multiple ecosystem services have yet to be studied and remain unclear to policymakers. This study provides a systematic assessment of the coupling coordination between coastal shelter forests and ecosystem services from 2001 to 2022, followed by a dynamic impact analysis. Findings show that during this period, China's coastal shelter forests expanded by 6.33% (primarily in the Bohai Rim), with forest cover and stand age increasing by 47.69% and 99.53%, respectively, accompanied by an 88.47% rise in ecosystem services. Coupling coordination between coastal shelter forests and ecosystem services increased over time; however, its growth rate declined by 39.37% from 2016 to 2022, with pronounced decreases observed in the Pearl River Delta region. The development of coastal forests has substantially enhanced ecosystem services; however, these gains are being gradually offset by the combined pressures of climate change and human activities. Accordingly, we propose differentiated afforestation, nature-based periodic planning, and zoned forest management to mitigate the negative impacts of climate variability and human activities. This approach provides a practical guide for designing, implementing, and scaling future coastal forest programs.
