Structural and functional loss in restored wetland ecosystems

Effectiveness assessment of China's coastal wetland ecological restoration: A meta-analysis

Due to the coastal wetland degradation caused by human activities and environmental changes, many coastal wetland restoration studies have been carried out in China to restore the degraded ecosystems, but it still lacks a comprehensive assessment of restoration effectiveness at national scale. In this study, a meta-analysis of 78 field studies was conducted to quantitatively assess the restoration effectiveness of biodiversity and ecosystem services in China's coastal wetlands. At the same time, we evaluated the impact factors such as ecosystem types, restoration methods and measures, and restoration time on restoration effectiveness. The results show that coastal wetland ecological restoration has improved the biodiversity and ecosystem services by 36.8 % and 38.2 % respectively within the time range reported in the research literature, but neither has returned to the level of natural ecosystems. Biodiversity recovery is significantly positively correlated with the recovery of ecosystem services, indicating the simultaneous recovery outcome. Compared with degraded wetlands, the effectiveness of passive restoration is better than that of active restoration. In the mangrove ecosystem, invasive species removal is the most effective among the restoration measures, and the restoration effectiveness of polyculture plantations is better than that of monoculture plantations. When time ranges from 0 to 20 years, the recovery level of coastal wetlands tends to increase with the extension of restoration time. However, when the restoration time is >20 years, the recovery level decreases, which may be related to the lack of maintenance and management measures in the later stage. Our study showcases the scientific evidence for future coastal wetland ecological restoration in China.

Ecological restoration and rewilding: two approaches with complementary goals?

As we enter the UN Decade on Ecosystem Restoration (2021-2030) and address the urgent need to protect and restore ecosystems and their ecological functions at large scales, rewilding has been brought into the limelight. Interest in this discipline is thus increasing, with a large number of conceptual scientific papers published in recent years. Increasing enthusiasm has led to discussions and debates in the scientific community about the differences between ecological restoration and rewilding. The main goal of this review is to compare and clarify the position of each field. Our results show that despite some differences (e.g. top-down versus bottom-up and functional versus taxonomic approaches) and notably with distinct goals - recovery of a defined historically determined target ecosystem versus recovery of natural processes with often no target endpoint - ecological restoration and rewilding have a common scope: the recovery of ecosystems following anthropogenic degradation. The goals of ecological restoration and rewilding have expanded with the progress of each field. However, it is unclear whether there is a paradigm shift with ecological restoration moving towards rewilding or vice versa. We underline the complementarity in time and in space of ecological restoration and rewilding. To conclude, we argue that reconciliation of these two fields of nature conservation to ensure complementarity could create a synergy to achieve their common scope.

Centennial loss of lake wetlands in the Yangtze Plain, China: Impacts of land use changes accompanied by hydrological connectivity loss

Humans have played a fundamental role in altering lake wetland ecosystems, necessitating the use of diverse data types to accurately quantify long-term changes, identify potential drivers, and establish a baseline status. We complied high-resolution historical topographic maps and Landsat imagery to assess the dynamics of the lake wetlands in the Yangtze Plain over the past century, with special attention to land use and hydrological connectivity changes. Results showed an overall loss of 45.6 % (∼11,859.5 km2) of the lake wetlands over the past century. The number of lakes larger than 10 km2 decreased from 149 to 100 due to lake dispersion, vanishing, and shrinkage. The extent of lake wetland loss was 3.8 times larger during the 1930s-1970s than that in the 1970s-1990s. Thereafter, the lake wetland area remained relatively stable, and a net increase was observed during the 2010s-2020s in the Yangtze Plain. The significant loss of lake wetland was predominately driven by agricultural activities and urban land expansion, accounting for 81.1 % and 4.9 % of the total losses, respectively. In addition, the changes in longitudinal and lateral hydrological connectivity further exacerbated the lake wetland changes across the Yangtze Plain through isolation between lakes and the Yangtze River and within the lakes. A total of 130 lakes have been isolated from the Yangtze River due to the construction of sluices and dykes throughout the Yangtze Plain, resulting in the decrease in the proportion of floodplain marsh from 28.3 % in the 1930s to 8.0 % in the 2020s. Furthermore, over 260 sub-lakes larger than 1 km2 (with a total area of 1276.4 km2) are experiencing a loss of connectivity with their parent lakes currently. This study could provide an improved historical baseline of lake wetland changes to guide the conservation planning to wetland protection and prioritization area in the Yangtze Plain.

Wetland habitats supporting waterbird diversity: Conservation perspective on biodiversity-ecosystem functioning relationship

Wetlands, as core habitats for supporting waterbird diversity, provide a variety of ecosystem services through diverse ecosystem functioning. Wetland degradation and wetland-habitat loss undermine the relationship between biodiversity-ecosystem functioning (BEF), affecting the diversity of habitats and waterbirds. The conservation of waterbird diversity is closely linked to the proper functioning of wetland ecosystems (nutrient cycling, energy storage, and productivity). Waterbirds have complex habitat preferences and sensitivities, which affect biotic interactions. By highlighting the importance of temporal and spatial scales guided by BEF, a habitat-waterbird conservation framework is presented (BEF relationships are described at three levels: habitat, primary producers, and waterbird diversity). We present a novel perspective on habitat conservation for waterbirds by incorporating research on the effects of biodiversity and ecosystem functioning to address the crucial challenges in global waterbird diversity loss, ecosystem degradation, and habitat conservation. Last, it is imperative to prioritize strategies of habitat protection with the incorporation of BEF for future waterbird conservation.

Rewilding soil and litter invertebrates and fungi increases decomposition rates and alters detritivore communities

Habitat degradation and associated reductions in ecosystem functions can be reversed by reintroducing or 'rewilding' keystone species. Rewilding projects have historically targeted restoration of processes such as grazing regimes or top-down predation effects. Few projects focus on restoring decomposition efficiency, despite the pivotal role decomposition plays in global carbon sequestration and nutrient cycling. Here, we tested whether rewilding entire communities of detritivorous invertebrates and fungi can improve litter decomposition efficiency and restore detritivore communities during ecological restoration. Rewilding was conducted by transplanting leaf litter and soil, including associated invertebrate and fungal communities from species-rich remnant sites into species-poor, and geographically isolated, revegetated farmland sites in a temperate woodland region of southeastern Australia. We compared communities in sites under the following treatments: remnant (conservation area and source of litter transplant), rewilded revegetation (revegetated farmland site with litter transplant) and control revegetation (revegetated site, no transplant). In one 'before' and three 'after' sampling periods, we measured litter decomposition and the abundance and diversity of detritivorous invertebrates and fungi. We quantified the effect of detritivores on the rate of litter decomposition using piecewise Structural Equation Modelling. Decomposition was significantly faster in rewilding sites than in both control and remnant areas and was largely driven by a greater abundance of invertebrate detritivores. Similarly, the abundance of invertebrate detritivores in rewilding revegetation sites exceeded the level of remnant communities, whereas there was little difference between control and remnant sites. In contrast, rewilding did not increase saprotrophic fungi relative abundance/diversity and there was no strong relationship between decomposition and fungal diversity. Our findings suggest the relatively simple act of transplanting leaf litter and soil can increase functional efficiency during restoration and alter community composition. Our methods may prove important across a range of contexts where other restoration methods have failed to restore ecosystem processes to pre-degradation levels.

The influence of management practices on plant diversity: a comparative study of three urban wetlands in an expanding city in eastern China

Rapid urbanization has drawn some aquatic environments into the urban texture from the outskirts of cities, and the composition and distribution of plant species in urban wetlands along the urban gradient have changed. Understanding the drivers of these changes will help in the conservation and utilization of urban wetlands. This study investigated the differences in plant diversity and associated influencing factors in three wetlands, Xixi wetland, Tongjian Lake wetland, and Qingshan Lake wetland, which are located in a core area, fringe area, and suburban area of Hangzhou City, respectively. The results showed that a total of 104 families, 254 genera, and 336 species of plants were recorded in the Xixi wetland; 179 species, 150 genera, and 74 families were found in the Qingshan Lake wetland; and 112 species, 96 genera, and 57 families were collected in the Tongjian Lake wetland. The main plant species and flora distribution of the three urban wetlands showed similarities. Indigenous spontaneous vegetation was highest in the Xixi wetland, while cultivated plant species were most abundant in the Tongjian Lake wetland. The introduction of cultivated plants decreased the distance attenuation effect of plant communities, which led to a certain degree of plant diversity convergence among the three wetlands. Eight endangered plants were preserved in the Xixi wetland by planting them in suitable habitats. Ellenberg's indicator values showed that the proportion of heliophilous plants was higher in the Qingshan Lake wetland, while the proportion of thermophilous plants and nitrogen-loving plants in the Tongjian Lake wetland was higher than in the other two wetlands. The importance of artificial interference factors affecting the differences in plant diversity was significantly higher than that of natural environmental factors in urban wetlands. The preservation of spontaneous plants and the introduction of cultivated plants had an importance of 25.73% and 25.38%, respectively. These were the main factors influencing the plant diversity of urban wetlands. The management mode that did not interfere with spontaneous vegetation and confined maintenance to cultivated plants in the Xixi wetland was beneficial for improving wetland plant diversity. Scientific plant reintroduction can also improve wetland plant diversity.

Natural and regenerated saltmarshes exhibit different bulk soil and aggregate-associated organic and inorganic carbon contents but similar total carbon contents

Saltmarshes are considered to be one of the planet's most efficient carbon sinks. The continued loss of saltmarshes and induced ecological consequences promoted their restoration worldwide. Previous efforts aimed to evaluate the success of restoration in terms of organic carbon accumulation, but inorganic carbon and carbon contents within soil aggregates, which are essential for making a comprehensive assessment of the carbon sink function, were rarely studied. To fill this gap, a range of metrics including bulk and aggregate-associated soil organic and inorganic carbon contents together with the soil's physical, chemical and microbiological parameters were measured to compare natural and a 15-year restoration effort in saltmarsh habitats within the Yellow River Delta region in eastern China. The results showed that regenerated saltmarsh exhibited significantly higher soil organic carbon (SOC) contents but significantly lower soil inorganic carbon contents, resulting in no notable change in total carbon contents between the regenerated and natural saltmarshes. SOC contents within the silt and clay fractions and their contribution to the bulk SOC contents were significantly lower in the regenerated saltmarsh than those in the natural ones (P < 0.05). In regenerated saltmarsh, significantly lower soil microbial biomass and distinct microbial community composition with reduced Gram-negative to Gram-positive bacteria ratios were observed compared to natural saltmarsh. These findings indicate the stability of SOC fraction and soil microbe-mediated carbon biogeochemical processes differed between naturally occurring and artificially regenerated saltmarshes. As interest in blue carbon programs gains global attention, further research on the generation and transformation processes of different carbon fractions during restoration are needed, which can be conducive to elucidating more details in coastal carbon cycling processes.

Land degradation neutrality: Testing the indicator in a temperate agricultural landscape

Land degradation directly affects around 25% of land globally, undermining progress on most of the UN Sustainable Development Goals (SDG), particularly target 15.3. To assess land degradation, SDG indicator 15.3.1 combines sub-indicators of productivity, soil carbon and land cover. Over 100 countries have set Land Degradation Neutrality (LDN) targets. Here, we demonstrate application of the indicator for a well-established agricultural landscape using the case study of Great Britain. We explore detection of degradation in such landscapes by: 1) transparently evaluating land cover transitions; 2) comparing assessments using global and national data; 3) identifying misleading trends; and 4) including extra sub-indicators for additional forms of degradation. Our results demonstrate significant impacts on the indicator both from the land cover transition evaluation and choice or availability of data. Critically, we identify a misleading improvement trend due to a trade-off between improvement detected by the productivity sub-indicator, and 30-year soil carbon loss trends in croplands (11% from 1978 to 2007). This carbon loss trend would not be identified without additional data from Countryside Survey (CS). Thus, without incorporating field survey data we risk overlooking the degradation of regulating and supporting ecosystem services (linked to soil carbon), in favour of signals from improving provisioning services (productivity sub-indicator). Relative importance of these services will vary between socioeconomic contexts. Including extra sub-indicators for erosion or critical load exceedance, as additional forms of degradation, produced a switch from net area improving (9%) to net area degraded (58%). CS data also identified additional degradation for soil health, including 44% arable soils exceeding bulk density thresholds and 35% of CS squares exceeding contamination thresholds for metals.

Soil organic carbon stocks increased across the tide-induced salinity transect in restored mangrove region

Blue carbon in mangrove ecosystems contributes significantly to the global carbon cycle. However, large uncertainties maintain in the soil organic carbon (SOC) storage throughout the tide-induced salinity and alkalinity transect in the mangrove restoration region in Southern China. Total 125 soil samples were obtained to detect the SOC content and physicochemical properties. The mean SOC content of each layer ranged from 6.82 to 7.86 g kg-1, while the SOC density ranged from 2.99 to 11.41 kg m-2, increasing with soil depths. From different land covers in the study region, the SOC content varied from 4.63 to 9.71 g kg-1, increasing across the salinity and alkalinity transect, while the SOC density fluctuated from 3.01 kg m-2 in mudflats to 10.05 kg m-2 in mangrove forests. SOC concentration was favorably linked with total nitrogen (r = 0.95), and total phosphorus (r = 0.74), and negatively correlated with Cl- (r = - 0.95), electrical conductivity (r = - 0.24), and total dissolved solids (r = - 0.08). There were significant logarithmic relationships between SOC content and the concentrations of clay (r = 0.76), fine silt (r = 0.81), medium silt (r = - 0.82), and coarse silt (r = - 0.78). The spatial patterns of SOC concentration were notably affected by soil texture, physicochemical properties, and land-cover type, providing essential reference for future investigations of blue carbon budget in restored mangrove forests.

Short-term responses of the soil microbiome and its environment indicate an uncertain future of restored peatland forests

Restoring peatland ecosystems involves significant uncertainty due to complex ecological and socio-economic feedbacks as well as alternative stable ecological states. The primary aim of this study was to investigate to what extent the natural functioning of drainage-affected peat soils can be restored, and to examine role of soil microbiota in this recovery process. To address these questions, a large-scale before-after-control-impact (BACI) experiment was conducted in drained peatland forests in Estonia. The restoration treatments included ditch closure and partial tree cutting to raise the water table and restore stand structure. Soil samples and environmental data were collected before and 3-4 years after the treatments; the samples were subjected to metabarcoding to assess fungal and bacterial communities and analysed for their chemical properties. The study revealed some indicators of a shift toward the reference state (natural mixotrophic bog-forests): the spatial heterogeneity in soil fungi and bacteria increased, as well as the relative abundance of saprotrophic fungi; while nitrogen content in the soil decreased significantly. However, a general stability of other physico-chemical properties (including pH remaining elevated by ca. one unit) and annual fluctuations in the microbiome suggested that soil recovery will remain incomplete and patchy for decades. The main implication is the necessity to manage hydrologically restored peatland forests while explicitly considering an uncertain future and diverse outcomes. This includes their continuous monitoring and the adoption of a precautionary approach to prevent further damage both to these ecosystems and to surrounding intact peatlands.

How does water diversion affect land use change and ecosystem service: A case study of Baiyangdian wetland, China

Baiyangdian wetland is the biggest plant-dominated shallow freshwater wetland in Huabei Plain, providing a wide range of ecosystem services. In the past few decades, the water scarcity and eco-environmental problems resulted from climate changes and human activities have become more and more serious. To relieve the pressure of water scarcity and ecological degradation, the government has implemented ecological water diversion projects (EWDPs) since 1992. In this study, land use and land cover change (LUCC) caused by EWDPs over three decades was analyzed to quantitatively assess the impact of EWDPs on ecosystem services. Coefficients of ecosystem service value (ESV) calculation were improved for regional ESV evaluation. The results showed that the area of construction, farmland and water increased by 6171, 2827, 1393 ha, respectively, and the total ESV increased by 8.04 × 108 CNY primarily due to the increase of regulating service with water area expansion. Redundancy analysis and socio-economic comprehensive analysis showed that EWDPs impacted water area and ESV with threshold and time effect. When the water diversion exceeded the threshold, the EWDPs affected the ESV through influencing LUCC; otherwise, the EWDPs affected the ESV through influencing net primary productivity or social-economic benefits. However, the impact of EWDPs on ESV gradually weakened as time passed, which could not keep sustainability. With the establishment of Xiong'an New Area in China and implementation of carbon neutrality policy, rational EWDPs will become crucial to achieve goals of ecological restoration.

Microbially mediated climate feedbacks from wetland ecosystems

Wetlands are crucial nodes in the carbon cycle, emitting approximately 20% of global CH4 while also sequestering 20%-30% of all soil carbon. Both greenhouse gas fluxes and carbon storage are driven by microbial communities in wetland soils. However, these key players are often overlooked or overly simplified in current global climate models. Here, we first integrate microbial metabolisms with biological, chemical, and physical processes occurring at scales from individual microbial cells to ecosystems. This conceptual scale-bridging framework guides the development of feedback loops describing how wetland-specific climate impacts (i.e., sea level rise in estuarine wetlands, droughts and floods in inland wetlands) will affect future climate trajectories. These feedback loops highlight knowledge gaps that need to be addressed to develop predictive models of future climates capturing microbial contributions. We propose a roadmap connecting environmental scientific disciplines to address these knowledge gaps and improve the representation of microbial processes in climate models. Together, this paves the way to understand how microbially mediated climate feedbacks from wetlands will impact future climate change.

Evidence-based target setting informs blue carbon strategies for nationally determined contributions

The magnitude and pace of global climate change demand ambitious and effective implementation of nationally determined contributions (NDCs). Nature-based solutions present an efficient approach to achieving mitigation, adaptation and resilience goals. Yet few nations have quantified the diverse benefits of nature-based solutions to evaluate and select ecosystem targets for their NDCs. Here we report on Belize's pursuit of innovative, evidence-based target setting by accounting for multiple benefits of blue carbon strategies. Through quantification of carbon storage and sequestration and optimization of co-benefits, we explore time-bound targets and prioritize locations for mangrove protection and restoration. We find increases in carbon benefits with larger mangrove investments, while fisheries, tourism and coastal risk-reduction co-benefits grow initially and then plateau. We identify locations, currently lacking protected status, where prioritizing blue carbon strategies would provide the greatest delivery of co-benefits to communities. These findings informed Belize's updated NDCs to include an additional 12,000 ha of mangrove protection and 4,000 ha of mangrove restoration, respectively, by 2030. Our study serves as an example for the more than 150 other countries that have the opportunity to enhance greenhouse gas sequestration and climate adaptation by incorporating blue carbon strategies that provide multiple societal benefits into their NDCs.

Vegetation changes over time in Prairie Pothole Region reference wetlands

Periodic assessments of reference condition wetlands are needed to determine changes over time; however, they are rarely conducted. The vegetation from past assessments, 1998 to 2004, was compared to 2016 assessments of 12 reference wetlands in the Missouri Coteau sub-ecoregion of the Prairie Pothole Region using nonmetric multidimensional scaling and permutational multivariate analysis of variance. Analyses indicated the vegetation in the 2016 assessments trended away from the abundance of native highly conservative species as found during the 1998 to 2004 assessments. Instead, the 2016 plant communities trended towards lower abundance of the same native conservative species and higher abundance of non-native species. Both the average coefficient of conservatism values and floristic quality index values significantly declined, supporting the interpretation that reference wetlands were moving towards plant communities with lower abundance of highly conservative species. The assumption that reference wetlands in the Prairie Pothole Region will change little over time is challenged by these findings. Vegetation in refence wetlands within the Prairie Pothole Region is no longer resembles past monitoring and is trending towards a distinct vegetation composition. Future management will need to consider the potential of reference wetlands' vegetation composition moving away from a historic baseline and how this may impact future wetland assessment, especially when vegetation is compared to reference conditions.

Comparison of GHG emissions from annual crops in rotation on drained temperate agricultural peatland with production of reed canary grass in paludiculture using an LCA approach

Drained peat soils contribute significantly to global human-caused CO₂ emissions and reducing peat degradation via rewetting is high on the political agenda. Ceasing agricultural activities on rewetted soils might lead to land owner resistance and high societal expenses to compensate farmers. Continued biomass production adapted for wet conditions on peat soils potentially minimizes these costs and helps supplying the growing demand for e.g. materials, fuels and feed. Here we used a life cycle assessment approach (cradle to farm gate) to investigate the greenhouse gas (GHG) emissions related to three cases by applying IPCC (Intergovernmental Panel on Climate Change) emission factors and specific site conditions at a bog and a fen site that represent widely distributed temperate peat soils. Besides soil emissions, upstream emissions from input, operational emissions and emission related to rewetting construction work were included. The analyzed systems were deeply drained cash cropping on agricultural bog (potatoes (Solanum tuberosum L.), spring barley (Hordeum vulgare L.) and oat (Avena sativa L.), permanent Reed canary grass (RCG) (Phalaris arundinacea L.) production on non-drained bog and permanent RCG production on shallow-drained fen. The annual mean water table depths (WTD) were -70, -38 (estimated) and -13 cm, respectively. Results showed estimated GHG emissions of 40.5, 26.1 and 20.6 Mg CO₂eq ha^-1, respectively, corresponding to a 35% GHG reduction for the non-drained bog case as compared to the drained bog case, despite that the obtained WTD due to ceased drainage did not adhere to the IPCC rewetting threshold of -30 cm. Emissions related to crop management represented 7, 14 and 19% of total emissions. In the RCG cultivation on fen case, the WTD were controlled primarily by the water table of the nearby stream and total GHG emissions were even lower as compared to the RCG production on the non-drained bog reflecting the difference in WTD. Rewetting projects need to include careful knowledge of the specific peat area to foresee the actual reduction potential.

Microbial Community Succession Along a Chronosequence in Constructed Salt Marsh Soils

In this study, we examined the succession of soil microbial communities across a chronosequence of newly constructed salt marshes constructed primarily of fine-grained dredge material, using 16S rRNA amplicon sequences. Alpha diversity in the subsurface horizons was initially low and increased to reference levels within 3 years of marsh construction, while alpha diversity in the newly accumulating organic matter-rich surface soils was initially high and remained unchanged. Microbial community succession was fastest in the surface horizon (~ 24 years to reference equivalency) and became progressively slower with depth in the subsurface horizons (~ 30-67 years). Random forest linear regression analysis was used to identify important taxa driving the trajectories toward reference conditions. In the parent material, putative sulfate-reducers (Desulfobacterota), methanogens (Crenarchaeota, especially Methanosaeta), and fermenters (Chloroflexi and Clostridia) increased over time, suggesting an enrichment of these metabolisms over time, similar to natural marshes. Concurrently in the surface soils, the relative abundances of putative methane-, methyl-, and sulfide oxidizers, especially among Gammaproteobacteria, increased over time, suggesting the co-development of sulfide and methane removal metabolisms in marsh soils. Finally, we observed that the surface soil communities at one of the marshes did not follow the trajectory of the others, exhibiting a greater relative abundance of anaerobic taxa. Uniquely in this dataset, this marsh was developing signs of excessive inundation stress in terms of vegetation coverage and soil geochemistry. Therefore, we suggest that soil microbial community structure may be effective bioindicators of salt marsh inundation and are worthy of further targeted investigation.

Agricultural land use regulates the fate of soil phosphorus fractions following the reclamation of wetlands

Over half of the Earth's wetlands have been reclaimed for agriculture, leading to significant soil P destabilization and leaching risks. To evaluate the effects of agricultural land use on soil P stability, we used sequential P extraction to investigate the long-term effects of wetland cultivation for rice and soybean on soil P fractions, including labile and moderately labile inorganic/organic P (LPi, LPo, MPi, and MPo), and stable P in Northeast China. The results showed that soybean cultivation decreased the total P by 35.9 %, whereas rice cultivation did not influence the total P content (p < 0.05). Both the soybean and rice cultivations significantly increased LPi (p < 0.05). Soybean cultivation significantly decreased the LPo and MPo compared to rice cultivation, and the latter increased MPi by 309.28 % compared with the reference wetlands (p < 0.05). Redundancy analysis indicated that pH, poorly crystalline Fe (Feca), crystalline Fe (Fec), and total organic carbon (TOC) explained similar variations in P fractions during soybean and rice cultivation (54.9 % and 49.7 %, respectively). Similarly, during soybean or rice cultivation, pH negatively influenced LPo and MPo, while Feca positively influenced MPi and LPi. Furthermore, TOC showed a positive role in LPo, and MPo, but a negative effect on LPi and MPi during rice cultivation. Hence, we concluded that the cultivation of soybean or rice create contrasting modifications to wetland soil P fractionation by altering TOC, Feca, Fec, and pH. Our study indicates that agricultural land use can regulate the fate of wetland soil P fractionation, with potential benefits to both i) P risk management in cultivated wetlands and ii) potential approaches for future wetland restoration.

Evolutionary game of stakeholders' behavioral strategies in wetland ecosystems from the vulnerability perspective

Wetland ecosystems have been seriously degraded by human activities and natural factors, and its restoration and coordinated development depend on long-term effective cooperation between the government and investors and providers. From the perspective of vulnerability of wetland ecosystem construction, this paper takes the government and investors, providers as the research object and propose a wetland ecosystem cooperation network, the article considers the "Matthew effect" of network connection and relationship cost, and uses the method of the evolutionary game on complex networks to construct the cooperative game model of wetland ecosystems. This research finds that (1) the vulnerability of wetland ecosystem varies greatly in different development stages, especially when the government subsidy coefficient for providers is reduced to 0.3, the vulnerability index is instead smaller.(2) The cooperative strategy adopted by investors can produce synergistic effect, which plays a major role in the healthy function of wetland ecosystem. (3) When the government subsidy coefficient for investors reaches 0.8, wetland ecosystem vulnerability shows a significant downward trend; when the provider loss coefficient reaches 0.8, wetland ecosystem vulnerability is significantly reduced and system stability is significantly enhanced. Thus, when the government actively promotes cooperation by adopting appropriate subsidies and regulation for investors and providers, the willingness of investors and providers to cooperate rapidly converges to 1, wetland ecosystem in vulnerability is at the lowest level. Finally, the findings combined with the numerical simulation analysis indicates that the importance of investors cooperating with the government in taking cooperative strategies actively, showing that stakeholder behavioral strategies can improve wetland ecosystem vulnerability. This paper provides a theoretical basis for the cooperation of wetland ecosystem stakeholders and a new direction for effectively reducing the vulnerability of wetland ecosystems and building efficient and benign wetland ecosystems in practice, which is of far-reaching significance for promoting wetland conservation management and an important reference value for wetland conservation planning, governance and improving the level of wetland conservation management.

Habitats generated by the restoration of coal mining subsidence land differentially alter the content and composition of soil organic carbon

The content and composition of soil organic carbon (SOC) can characterize soil carbon storage capacity, which varies significantly between habitats. Ecological restoration in coal mining subsidence land forms a variety of habitats, which are ideal to study the effects of habitats on SOC storage capacity. Based on the analysis of the content and composition of SOC in three habitats (farmland, wetland and lakeside grassland) generated by different restoration time of the farmland which was destroyed by coal mining subsidence, we found that farmland had the highest SOC storage capacity among the three habitats. Both dissolved organic carbon (DOC) and heavy fraction organic carbon (HFOC) exhibited higher concentrations in the farmland (20.29 mg/kg, 6.96 mg/g) than in the wetland (19.62 mg/kg, 2.47 mg/g) or lakeside grassland (5.68 mg/kg, 2.31 mg/g), and the concentrations increased significantly over time, owing to the higher content of nitrogen in the farmland. The wetland and lakeside grassland needed more time than the farmland to recover the SOC storage capacity. The findings illustrate that the SOC storage capacity of farmland destroyed by coal mining subsidence could be restored through ecological restoration and indicate that the recovery rate depends on the reconstructed habitat types, among which farmland shows great advantages mainly due to the nitrogen addition.

Setting Targets for Wetland Restoration to Mitigate Climate Change Effects on Watershed Hydrology

How much wetland we should protect or restore is not a simple question, such that conservation targets are often set according to political agendas, then standardized globally. However, given their key regulating hydrological functions, wetlands represent nature-based solutions to the anticipated, exacerbating effect of climate change on drought and flood events, which will vary at the regional scale. Here, we propose a science-based approach to establishing regional wetland restoration targets centered on their hydrological functions, using a case study on several sub-watersheds of a northern temperate basin in south-eastern Canada. We posit that restoration targets should minimally mitigate the negative effects of climate change on watershed hydrology, namely peak and low flows. We used a semi-distributed hydrological model, HYDROTEL, to perform a hydroclimatic assessment, including 47 climate projections over the 1979-2099 period, to test the effect of wetland restoration scenarios on peak and low flows. The results showed that hydrological responses to climate change varied among sub-watersheds (even at the scale of a relatively small region), and that, to mitigate these changes, increases in wetland coverage should be between 20% and up to 150%. At low restoration levels, increasing wetland coverage was more effective in attenuating floods than alleviating droughts. This study indicates that a no-net-loss policy is insufficient to maintain current hydrological cycles in the face of climate change; rather, a 'net gain' in wetland cover is needed.

Predicting water quality from geospatial lake, catchment, and buffer zone characteristics in temperate lowland lakes

Lakes provide essential ecosystem services and strongly influence landscape nutrient and carbon cycling. Therefore, monitoring water quality is essential for the management of element transport, biodiversity, and public goods in lakes. We investigated the ability of machine learning models to predict eight important water quality variables (alkalinity, pH, total phosphorus, total nitrogen, chlorophyll a, Secchi depth, color, and pCO₂) using monitoring data from 924 to 1054 lakes. The geospatial predictor variables comprise a wide range of potential drivers at the lake, buffer zone, and catchment level. We compared the performance of nine predictive models of varying complexity for each of the eight water quality variables. The best models (Random Forest and Support Vector Machine in six and two cases, respectively) generally performed well on the test set (R² = 0.28-0.60). Models were then used to predict water quality for all 180,377 mapped Danish lakes. Additionally, we trained models to predict each water quality variable by using the predictions we had generated for the remaining seven variables. This improved model performance (R² = 0.45-0.78). Overall, the uncovered relationships were in line with the findings of previous studies, e.g., total nitrogen was positively related to catchment agriculture and chlorophyll a, Secchi depth, and alkalinity were influenced by soil type and landscape history. Remarkably, buffer zone geomorphology (curvature, ruggedness, and elevation) had a strong influence on nutrients, chlorophyll a, and Secchi depth, e.g., curvature was positively related to nutrients and chlorophyll a and negatively to Secchi depth. Lake area was a strong predictor of multiple variables, especially its relationship with pH (positive), pCO₂ (negative), and color (negative). Our analysis shows that the combination of machine learning methods and geospatial data can be used to predict lake water quality and improve national upscaling of predictions related to nutrient and carbon cycling.

Rapid carbon accumulation at a saltmarsh restored by managed realignment exceeded carbon emitted in direct site construction

Increasing attention is being paid to the carbon sequestration and storage services provided by coastal blue carbon ecosystems such as saltmarshes. Sites restored by managed realignment, where existing sea walls are breached to reinstate tidal inundation to the land behind, have considerable potential to accumulate carbon through deposition of sediment brought in by the tide and burial of vegetation in the site. While this potential has been recognised, it is not yet a common motivating factor for saltmarsh restoration, partly due to uncertainties about the rate of carbon accumulation and how this balances against the greenhouse gases emitted during site construction. We use a combination of field measurements over four years and remote sensing to quantify carbon accumulation at a large managed realignment site, Steart Marshes, UK. Sediment accumulated rapidly at Steart Marshes (mean of 75 mm yr-1) and had a high carbon content (4.4% total carbon, 2.2% total organic carbon), resulting in carbon accumulation of 36.6 t ha-1 yr-1 total carbon (19.4 t ha-1 yr-1 total organic carbon). This rate of carbon accumulation is an order of magnitude higher than reported in many other restored saltmarshes, and is somewhat higher than values previously reported from another hypertidal system (Bay of Fundy, Canada). The estimated carbon emissions associated with the construction of the site were ~2-4% of the observed carbon accumulation during the study period, supporting the view that managed realignment projects in such settings may have significant carbon accumulation benefits. However, uncertainties such as the origin of carbon (allochthonous or autochthonous) and changes in gas fluxes need to be resolved to move towards a full carbon budget for saltmarsh restoration.

Restoring function: Positive responses of carbon and nitrogen to 20 years of hydrologic restoration in montane meadows

Montane meadows are highly productive ecosystems that contain high densities of soil carbon (C) and nitrogen (N). However, anthropogenic disturbances that have led to channel incision and disconnected floodplain hydrology have altered the C balance of many meadows, converting them from net C sinks to net sources of C to the atmosphere. Restoration efforts designed to reconnect floodplain hydrology may slow rates of soil C loss from degraded meadows and restore the conditions for C sequestration and N immobilization, yet questions remain about the long-term impact of such efforts. Here, we used a 22-year meadow restoration chronosequence to measure the decadal impact of hydrologic restoration on aboveground and belowground C and N stocks and concentrations. Increases in herbaceous vegetation biomass preceded changes in soil C stocks, with the largest gains occurring belowground. Root biomass (0-15 cm) increased at a rate of 270.3 g m^-2 year^-1 and soil C stocks (0-15 cm) increased by 232.9 g C m^-2 year^-1 across the chronosequence. Increases in soil C concentration (2.99 g C kg^-1 year^-1 ) were tightly coupled with increases in soil N concentration (0.21 g N kg^-1 year^-1 ) and soil C:N did not vary with time since restoration. Fourier transform infrared spectroscopy results showed that the fraction of labile aliphatic C-H and carboxylate C-O (COO) compounds in the soil increased with the age of restoration and were positively correlated with soil C and N concentrations. Our results demonstrate that restoration of floodplain hydrology in montane meadows has significant impacts on belowground C and N stocks, soil C and N concentration, and soil C chemistry within the first two decades following restoration.

Bird Communities and the Rehabilitation of Al Karaana Lagoons in Qatar

Qatar, a peninsular country in the Persian Gulf, is significant to avian species due to its location along the African–Eurasian Flyway, a key migratory path. Receiving untreated domestic and industrial liquid waste from Qatar in the past, Al Karaana Lagoons have since been reconstructed as an artificial wetland to address the growing environmental concern posed by contamination build-up. This study documents the changes in biodiversity at Al Karaana Lagoons following their environmental remediation. Data collected (2015 and 2017) by Ashghal (Public Works Authority) prior to project implementation was analyzed alongside data collected independently following project completion (2019–2021). There was a marked increase in bird biodiversity following remediation, including substantial use by migratory species and resident breeders. Further analysis of water quality data of the TSE (treated sewage effluent) ponds shows that they are eutrophic but still support substantial bird life. The project’s success demonstrates how reclaimed lands can provide important habitats to local and migratory birds and encourages similar restoration efforts in the future in both Qatar and elsewhere. We call for the continued monitoring of the site and the implementation of guidelines for the use of the site that balance human activities and habitat quality.

Vegetation zones as indicators of denitrification potential in salt marshes

Salt marsh vegetation zones shift in response to large-scale environmental changes such as sea-level rise (SLR) and restoration activities, but it is unclear if they are good indicators of soil nitrogen removal. Our goal was to characterize the relationship between denitrification potential and salt marsh vegetation zones in tidally restored and tidally unrestricted coastal marshes, and to use vegetation zones to extrapolate how SLR may influence high marsh denitrification at the landscape scale. We conducted denitrification enzyme activity assays on sediment collected from three vegetation zones expected to shift in distribution due to SLR and tidal flow restoration across 20 salt marshes in Connecticut, USA (n = 60 sampling plots) during the summer of 2017. We found lower denitrification potential in short-form Spartina alterniflora zones (mean, 95% CI: 4, 3-6 mg N h^-1  m^-2 ) than in S. patens (25, 15-36 mg N h^-1  m^-2 ) and Phragmites australis (56, 16-96 mg N h^-1  m^-2 ) zones. Vegetation zone was the single best predictor and explained 52% of the variation in denitrification potential; incorporating restoration status and soil characteristics (soil salinity, moisture, and ammonium) did not improve model fit. Because denitrification potential did not differ between tidally restored and unrestricted marshes, we suggest landscape-scale changes in denitrification after tidal restoration are likely to be associated with shifts in vegetation, rather than differences driven by restoration status. Sea-level-rise-induced hydrologic changes are widely observed to shift high marsh dominated by S. patens to short-form S. alterniflora. To explore the implications of this shift in dominant high marsh vegetation, we paired our measured mean denitrification potential rates with projections of high marsh loss from SLR. We found that, under low and medium SLR scenarios, predicted losses of denitrification potential due to replacement of S. patens by short-form S. alterniflora were substantially larger than losses due to reduced high marsh land area alone. Our results suggest that changes in vegetation zones can serve as landscape-scale predictors of the response of denitrification rates to rapid changes occurring in salt marshes.

Indictors of wetland health improve following small-scale ecological restoration on private land

Globally wetlands are imperilled and restoring these highly productive and biodiverse ecosystems is key to regaining their lost function and health. Much of the fertile, low-lying land that was historically wetland is now farmed, so privately-owned locations play critical roles in regaining space for wetlands. However, wetland restoration on private property is often small-scale and supported by minimal funding and expertise. Little is known about what these efforts achieve, and what contexts facilitate the greatest gains in wetland health. Using a paired plot design for 18 restored and 18 unrestored wetlands, we aimed to understand changes in wetland health following restoration on private property. We characterised plant and microbial communities and soil characteristics following wetland restoration and explored how environmental settings of restored wetlands related to the clustering of wetland health indicators. We found that all indicators of wetland health significantly increased following restoration except for the ratio of Gram negative to Gram positive bacteria. Restoration enhanced plant alpha and beta diversity, adding ~13 native plant species per plot. Soils in restored wetlands contained 20% more organic matter, and 25% more microbial biomass, which was driven by an increased abundance of fungi. Restoration reduced soil bulk density by 0.19 g^-1 cm³ and Olsen Phosphorus by 23%. These effects on soil physical characteristics and microbial communities were strongest in the wettest locations. Restored wetlands clustered into three main groups based on indicators of wetland health. Hydrological flow explained the clustering of wetlands, with riverine wetlands exhibiting greater indicators of recovery than depressional wetlands, suggesting that hydrological flow may influence post-restoration recovery. Overall, this study shows that small-scale wetland restoration on private land improved wetland health, providing evidence that it can be an effective use of marginal agricultural land.

Spatiotemporal Variability of Human Disturbance Impacts on Ecosystem Services in Mining Areas

Human activities pose significant impacts on ecosystem services (ESs) in mining areas, which will continually increase over time and space. However, the mechanism of ES change on spatiotemporal scales post-disturbance remains unclear, especially in the context of global climate change. Here, we conducted a global literature review on the impact of two of the most frequent disturbance factors (mining and restoration) on 27 different ESs, intending to synthesize the impacts of human disturbance on ESs in mining areas via a meta-analysis, and analyze the spatiotemporal variability of ESs after disturbance. We screened 3204 disturbance studies published on the Web of Science between 1950 and 2020 and reviewed 340 in detail. The results of independence test showed that human disturbance had a significant impact on ESs in the mining areas (p < 0.001). The impacts (positive and/or negative) caused by mining and restoration differed considerably among ESs (even on the same ESs). Additionally, spatiotemporal scales of human disturbance were significantly related to spatiotemporal scales of ES change (p < 0.001). We found that the positive and negative impacts of disturbances on ESs may be interconversion under specific spatiotemporal conditions. This seems to be associated with spatiotemporal variability, such as the temporal lag, spatial spillover, and cumulative spatiotemporal effects. Climate changes can lead to further spatiotemporal variability, which highlights the importance of understanding the changes in ESs post-disturbance on spatiotemporal scales. Our research presents recommendations for coping with the twofold pressure of climate change and spatiotemporal variability, to understand how ESs respond to human disturbance at spatiotemporal scales in the future, and manage disturbances to promote sustainable development in mining areas.

The Restoration of Degraded Lands by Local Communities and Indigenous Peoples

One of Earth's foremost ecological challenges is the degradation of land habitats. This degradation is often caused by deforestation and desertification resulting from the unsustainable management of natural resources. Land restoration seeks to reverse this trend and repair ecosystems to better health. Indigenous peoples and local communities have a key role in realizing long-term, sustainable land restoration. Local and indigenous communities often have intimate knowledge of the local ecosystems and an interest in preserving ecosystem services. Areas managed by indigenous peoples and local communities especially overlap with remaining intact ecosystems and suffer from less deforestation than unprotected areas. Here, we discuss how the knowledge and engagement of local communities can improve the management, implementation, and monitoring of habitat restoration. However, there are also challenges to land restoration, and scientists and policymakers that can align restoration outcomes with community benefits gained from environmental stewardship and knowledge, are more likely to achieve long-term sustainable restoration success.

Biodiversity Monitoring of a Riparian Wetland in a Mixed-Use Watershed in the Central Appalachians, USA, before Restoration

Wetland mitigation efforts have increased in numbers over the past two decades to combat wetland loss in the United States. Data regarding wetland function such as biodiversity are required to be collected 5–10 years after a project is complete; however, pre-restoration data that can inform the effectiveness of mitigation are often not collected. We conducted pre-restoration surveys on various taxa along or within Ruby Run, a tributary of Deckers Creek in north-central West Virginia, USA, from 2016 to 2020 to determine the baseline relative abundance and diversity within the stream and the associated riparian zone. In five years, we observed 237 species (154 plant, 58 bird, 13 fish, 6 small mammal, and 6 anuran) and 25 families of macroinvertebrates. Seasonal fluctuations in diversity were present, but mean diversity was relatively consistent among years across taxa, except in anurans, where there was a decrease each year. Wetland mitigation efforts should continue to be monitored for success using multiple taxa, because land use change can affect taxa in different ways, resulting in well-rounded assessments that can improve wetland management practices.

Spatial-temporal changes in the degradation of marshes over the past 67 years

Agricultural reclamation is widely regarded as a primary cause of marshes degradation. However, the process of marshes degradation on different geomorphology has rarely explored, which fail to explain the marshes degradation driven by natural restrictions in detail. The information deficiency unable propounded the targeted suggestions for the sustainable management of marshes. According to the development of China, we quantified the degradation rate of marshes on different geomorphic types from 1954 to 2020 in a typical transect in the Sanjiang Plain. The results indicated that (1) A total of 1633.92 km² of marshes reduced from 1954 to 2020. And 97% (1582.35 km²) of marshes were converted to crop cultivation. The process of marshes degradation had obvious historical stages characteristics. The marshes degradation rate showed a trend of increasing first and then decreasing. The most serious period was 1995-2005 (6.29%) which was approximately 35 times of the period of before the reform and opening up (1954-1976) a minimal shrunk period. (2) The background of geological tectonic decided the whole trends in marshes degradation process. The degradation occurred first and worst in the meco-scale recent slow ascent region, and then extended to substantially recent slow subsidence region and the small-amplitude recent slow ascent region. (3) Significant location characteristics of marshes degradation reflected in this research. The spatial location of marshes degradation on the sub-regions sequentially consisted of alluvial plain, lower terrace, high floodplain, micro-knoll, low floodplain, and depressions. (4) Most of the existing marshes of the sub-Sanjiang Plain distribution in the national reserves. This study provides important scientific information for restoration and conservation of marshes.

Ecological Service Value Tradeoffs: An Ecological Water Replenishment Model for the Jilin Momoge National Nature Reserve, China

Wetlands as an important ecosystem type have been damaged in recent years and restoration of wetland ecosystem functions through ecological water replenishment is one of the important ways. The present study involved the construction of a novel ecological water replenishment model for Jilin Momoge National Nature Reserve (JMNNR) using the interval two-stage stochastic programming (ITSP) method. Breaking down traditional economic models that often sacrifice environmental benefits, the model aims to replenish the ecological water in JMNNR, allocate the ecological water resources scientifically, restore the wetland function of the reserve, improve the functional area of the reserve, enhance the net carbon sequestration capacity of the reserve, and complete the reconstruction of the ecosystem, while considering the ecological service value (ESV) of the reserve to achieve a joint increase in the ecological and economic benefits. The ITSP model constructed in the present study overcame the limitation that the original project recommendation was a single recommended value, and the results are presented in the form of intervals to improve flexibility in decision making to allow the individuals responsible for under-taking decisions to bring focused adjustments according to the actual decision-making conditions and increase the selectivity of the decision-making scheme. The present report discusses the construction of an ITSP model for the ecological water replenishment of JMNNR in an attempt to effectively improve both economic benefits and ecosystem restoration of the reserve, achieve the reconstruction of the JMNNR ecosystem, and provide a selective decision space for the key decision-makers to formulate and optimize the project operation and the management plan. The use of the ITSP model as a pre-procedural basis for the implementation of the project and the simulation of the effects of the implementation of the project can effectively avoid the decision limitations that exist when carrying out the project directly. The ITSP model constructed in this paper can also be used as a theoretical guide for water replenishment projects in different areas of the world, and the model parameters can be reasonably adjusted to achieve better results when used according to the actual local conditions.

Wind drives fast changes of light climate in a large, shallow re-established lake

With ever greater frequency, wetlands and shallow lakes that had been diverted for agriculture are being re-established to reduce nutrient loss and greenhouse gas emission, as well as to increase biodiversity. Here, we investigate drivers of water column light attenuation (K_d) at multiple time scales and locations in Lake Fil, Denmark, during the first five years after its re-establishment in 2012. We found that K_d was generally high (overall mean: 3.4 m^-1), with resuspended sediment particles and colored dissolved organic matter being the main contributors. Using daily time series of light attenuation recorded at four stations, we used a generalized additive model to analyze the influence of wind speed and direction on K_d. This model explained a high proportion of the variation (R² = 0.62, RMSE = 0.74 m^-1, and MAE = 0.55 m^-1) and showed that higher wind speed increased K_d on the same day and, with smaller influence, on the next day. Furthermore, we found a significant influence of wind direction and an interaction between wind speed and wind direction, a combination that suggests that short-term variations in light climate depends on the interplay between wind direction and sources of particles. Wind from non-prevailing directions thus influence K_d more, as it can activate previously deposited particles. The maximum colonization depths of submerged vegetation occurred at ~2-6% of sub-surface light from 2014 to 2016 and peaked at 1.2 m in 2016. The fast, day-to-day variation of K_d in Lake Fil reveals the importance of wind on light climate and in turn biological elements such as phytoplankton and submerged macrophyte development in shallow lakes. The implications are essential for the prior planning and management of future lake re-establishment.

Consequences of above-ground invasion by non-native plants into restored vernal pools do not prompt same changes in below-ground processes

Given the frequent overlap between biological plant invasion and ecological restoration efforts it is important to investigate their interactions to sustain desirable plant communities and modify long-term legacies both above- and below-ground. To address this relationship, we used natural reference, invaded and created vernal pools in the Central Valley of California to examine potential changes in direct and indirect plant effects on soils associated with biological invasion and active restoration ecosystem disturbances. Our results showed that through a shift in vegetation composition and changes in the plant community tissue chemistry, invasion by non-native plant species has the potential to transform plant inputs to soils in vernal pool systems. In particular, we found that while invasive plant litter decomposition was driven by seasonal and interannual variability, associated with changes in precipitation, the overall decomposition rates for invasive litter was drastically lower than native species. This shift has important implications for long-term alterations in plant-based inputs to soils in an amplifying feedback to nutrient cycling. Moreover, these results were independent of historic active restoration efforts. Despite the consistent shift in plant litter decomposition rates and community composition, we did not detect associated shifts in below-ground function associated with invasion by non-native plants. Instead, soil C:N ratios and microbial biomass did not differ between invaded and naturally occurring reference pools but were reduced in the manipulated created pools independent of invasion levels. Our results suggest that while there is an observed invasive amplifying feedback above-ground this trajectory is not represented below-ground, and restoration legacies dominated 10 years after practices were applied. Restoration practices that limit invasive plant feedbacks and account for soil legacy recovery, therefore offer the best solution for disturbed ephemeral ecosystems.

Danish wetlands remained poor with plant species 17-years after restoration

For more than two decades, wetland restoration has been successfully applied in Denmark as a tool to protect watercourses from elevated nutrient inputs from agriculture, but little is known about how the flora and fauna respond to restoration. The main objective of this study was therefore to: (1) examine plant community characteristics in 10 wetland sites in the River Odense Kratholm catchment, restored between 2001 and 2011 by re-meandering the stream and disconnecting the tile drains, and (2) explore whether the effects of restoration on plant community characteristics change with the age of the restoration. Specifically, we hypothesised that plant community composition, species richness and diversity would improve with the age of the restoration and eventually approach the state of natural wetland vegetation. We found that the prevailing plant communities could be characterised as humid grasslands, moist fallow fields and improved grasslands, whereas the abundance of natural wetland plant communities (e.g., rich fens, fen-sedge beds and humid grasslands) was lower in both the recently restored as well as in older restored wetlands. Additionally, species richness and diversity did not seem to improve with the age of the restoration. We suggest that the continued high nutrient input at the restored sites in combination with restricted dispersal of wetland plant species may hamper the recovery of natural plant communities and that the sites therefore may stay botanically poor for many decades.

Seasonal variations in soil physicochemical properties and microbial community structure influenced by Spartina alterniflora invasion and Kandelia obovata restoration

Spartina alterniflora invasion has initiated one of the greatest changes to occur in coastal wetlands in China, and ecological replacement using mangrove species such as Kandelia obovata is an effective method for controlling these invasions. The effects of S. alterniflora invasions and subsequent K. obovata restorations on soil microbial community structures in different seasons are still not fully understood. In this study, soil samples were collected from six vegetation types (unvegetated mudflat, invasive S. alterniflora stands, one-/eight-/ten-year K. obovata restoration areas, and native mature K. obovata forests) in summer and winter. The variations in the soil microbial community structure between the vegetation types across two seasons were then characterized based on 16S rRNA gene sequencing, and the physicochemical properties that shaped the microbial communities were also determined. The invasion and restoration processes significantly influenced microbial community diversity, composition, and putative functions in different seasonal patterns. Microbial communities from a ten-year restoration area and a native mature K. obovata area shared more similarities than other areas. In both seasons, the key environmental factors driving microbial community included total carbon and nitrogen content, the ratio of carbon to nitrogen, and the soil pH. In addition, total sulfur and total phosphorus contents significantly contributed to structuring microbial communities in summer and winter, respectively. This study provides insights into microbial diversity, composition, and functional profiles in association with physicochemical impacts, with the aim of understanding microbial ecological functions during the invasion and restoration processes in wetland ecosystems.

Repeated large-scale mechanical treatment of invasive Typha under increasing water levels promotes floating mat formation and wetland methane emissions

Invasive species management typically aims to promote diversity and wildlife habitat, but little is known about how management techniques affect wetland carbon (C) dynamics. Since wetland C uptake is largely influenced by water levels and highly productive plants, the interplay of hydrologic extremes and invasive species is fundamental to understanding and managing these ecosystems. During a period of rapid water level rise in the Laurentian Great Lakes, we tested how mechanical treatment of invasive plant Typha × glauca shifts plant-mediated wetland C metrics. From 2015 to 2017, we implemented large-scale treatment plots (0.36-ha) of harvest (i.e., cut above water surface, removed biomass twice a season), crush (i.e., ran over biomass once mid-season with a tracked vehicle), and Typha-dominated controls. Treated Typha regrew with approximately half as much biomass as unmanipulated controls each year, and Typha production in control stands increased from 500 to 1500 g-dry mass m^-2 yr^-1 with rising water levels (~10 to 75 cm) across five years. Harvested stands had total in-situ methane (CH₄) flux rates twice as high as in controls, and this increase was likely via transport through cut stems because crushing did not change total CH₄ flux. In 2018, one year after final treatment implementation, crushed stands had greater surface water diffusive CH₄ flux rates than controls (measured using dissolved gas in water), likely due to anaerobic decomposition of flattened biomass. Legacy effects of treatments were evident in 2019; floating Typha mats were present only in harvested and crushed stands, with higher frequency in deeper water and a positive correlation with surface water diffusive CH₄ flux. Our study demonstrates that two mechanical treatments have differential effects on Typha structure and consequent wetland CH₄ emissions, suggesting that C-based responses and multi-year monitoring in variable water conditions are necessary to accurately assess how management impacts ecological function.

Can the native faunal communities be restored from removal of invasive plants in coastal ecosystems? A global meta-analysis

Coastal ecosystems worldwide are being threatened by invasive plants in the context of global changes. However, how invasive plants influence native faunal communities and whether native faunal communities can recover following the invader removals/controls across global coastal ecosystems are still poorly understood. Here, we present the first global meta-analysis to quantify the impacts of Spartina species invasions on coastal faunal communities and further to evaluate the outcomes of Spartina species removals on faunal community recovery based on 74 independent studies. We found that invasive Spartina species generally decreased the biodiversity (e.g., species richness), but increased coastal faunal abundance (e.g., individual number) and fitness (e.g., biomass), though the effect on abundance was insignificant. The pattern of influence was strongly dependent on habitat types, faunal taxa, trophic levels, and feeding types. Specifically, Spartina species invasion of mudflats caused greater impacts than invasion of vegetated habitats. Insects and birds at higher trophic levels were strongly affected by invasive Spartina, indicating that invasive plant effects can cascade upward along the food chain. Additionally, impacts of Spartina invasions were more obvious on food specialists such as herbivores and carnivores. Furthermore, our analyses revealed that invader removals were overall beneficial for native faunal communities to recover from the displacement caused by Spartina invasions, but this recovery process depended on specific removal measure and time. For example, the long-term waterlogging had strong negative impacts on faunal recovery, so it should not be encouraged. Our findings suggest that invasive plants could have contrasting effects on functional responses of native faunal communities. Although invasive plant removals could restore native faunal communities, future functional restorations of invaded ecosystems should take the legacy effects of invasive species on native communities into account. These findings provide insightful implications for future scientific controls of invasive species and ecosystem restoration under intensifying global changes.

The Potential of Satellite Remote Sensing Time Series to Uncover Wetland Phenology under Unique Challenges of Tidal Setting

While growth history of vegetation within upland systems is well studied, plant phenology within coastal tidal systems is less understood. Landscape-scale, satellite-derived indicators of plant greenness may not adequately represent seasonality of vegetation biomass and productivity within tidal wetlands due to limitations of cloud cover, satellite temporal frequency, and attenuation of plant signals by tidal flooding. However, understanding plant phenology is necessary to gain insight into aboveground biomass, photosynthetic activity, and carbon sequestration. In this study, we use a modeling approach to estimate plant greenness throughout a year in tidal wetlands located within the San Francisco Bay Area, USA. We used variables such as EVI history, temperature, and elevation to predict plant greenness on a 14-day timestep. We found this approach accurately estimated plant greenness, with larger error observed within more dynamic restored wetlands, particularly at early post-restoration stages. We also found modeled EVI can be used as an input variable into greenhouse gas models, allowing for an estimate of carbon sequestration and gross primary production. Our strategy can be further developed in future research by assessing restoration and management effects on wetland phenological dynamics and through incorporating the entire Sentinel-2 time series once it becomes available within Google Earth Engine.