Wetland Productivity Research Articles

Effects of Treated Effluent Discharge on Tree Growth and Water use in a Cypress Swamp

When municipal effluent is discharged into swamps, baldcypress trees (Taxodium distichum) generally respond with increased growth. This growth increase may be associated with increased transpiration (E), but if functional traits are also affected, they may modulate the response of E to environmental conditions such as atmospheric vapor pressure deficit (VPD). We measured tree growth and sap flux to assess water-use traits and daily E in mature baldcypress trees that received effluent discharge and compared them to nearby trees that did not receive effluent. Basal area increment and foliar N:P were higher in trees that received effluent. For any given tree size, E was 5.8 L day−1 higher in trees receiving effluent. Sap-flux-based whole-tree canopy conductance at the reference VPD of 1 kPa and its sensitivity to VPD were both positively related to foliar N:P, suggesting that effluent discharge shifted trees to higher water use when VPD was relatively low, but that water use was more sensitive to VPD. Our results suggest that when effluent discharge increases forested wetland productivity it can also increase E, but these effects may be diminished by high VPD.

Linking the Flow Regime of Papyrus‐Dominated Wetlands to Biologically Relevant Hydrologic Attributes

ABSTRACTThe dominant plant species in many African wetlands is Cyperus papyrus. Its adaptation to saturated and low‐oxygen conditions and its dense structure and height provide breeding and feeding grounds for unique flora and fauna. As a keystone species adapted to local hydrology, the flooding regime of papyrus offers the full range of hydrologic conditions and events essential to ecosystem health. However, no study has attempted to link papyrus wetlands' flow regimes to their biologically relevant hydrologic attributes. This study assesses hydrologic alterations of a papyrus wetland's flow regime due to rice irrigation. We develop a conceptual ecological model linking papyrus to hydrologic attributes to determine the consequences of changed environmental flow components (EFCs) on papyrus as a habitat. We find that agricultural water management considerably alters the magnitude, duration, timing and rate of change of EFCs, which could affect productivity (seed dispersal, germination and establishment; rhizome spreading; papyrus distribution across transects; and dispersal of floating mats) in papyrus wetlands. However, the effect on the papyrus wetlands' natural pulsed regime is negligible when the ratio of irrigated area to catchment area is no greater than 1:150. Overall, a better understanding of the threats of water diversion for agriculture is made by linking papyrus' flow regimes to biologically relevant hydrologic attributes. Knowledge of the roles of the various EFCs could provide opportunities for conserving and protecting papyrus wetlands, especially for systems at risk of altered flows.

Sulfate availability affect sulfate reduction pathways and methane consumption in freshwater wetland sediments

Methane (CH4) emissions from wetlands significantly contribute to global greenhouse gas fluxes, yet the mechanisms regulating CH4 production and oxidation in freshwater wetlands remain underexplored, particularly in the role of sulfate in the anaerobic oxidation of CH4. This study investigated the production, consumption, and release of CH4 in the sediments of the Qilihai wetland, focusing on the roles of hydrogenotrophic methanogenesis and sulfate dynamics across different seasons. CH4 concentrations ranged from 2.42 to 2290.52 μmol L⁻1, and δ13C–CH4 values became progressively more negative with depth, ranging from −87.37‰ to −57.18‰. Results indicate that hydrogenotrophic methanogenesis is the dominant pathway for CH4 production, particularly in sulfate-depleted environments, with CH4 concentrations in the sulfate-methane transition zone (SMTZ) strongly correlated with sulfate availability. Sulfate consumption through Sulfate Anaerobic Oxidation of Methane (SAOM) and Organoclastic Sulfate Reduction (OSR) demonstrated significant seasonal variation, with OSR accounting for up to 73% of sulfate consumption in the SMTZ. The SMTZ exhibited variations ranging from 2 to 40 cm in October, narrowing to 2–4 cm in July. These findings emphasize the complex interactions between sulfate availability, methanogenic pathways, and CH4 emissions in freshwater wetlands, highlighting the need for further research on sulfate dynamics and their implications for greenhouse gas emissions in the context of global climate change.

Environmental Factors Affecting Spatio-Temporal Distribution of Crop-Exploiting Species: Implications for Coexistence Between Agricultural Production and Avifauna Conservation in Wetlands

Bird communities in agroecosystems bring both ecosystem services (e.g., pollination) and disservices (e.g., crop exploitation) to farmers. However, in the proximity of wetland reserves, farmers disproportionately experience harvest yield loss due to large aggregation of bird species that can utilize various agricultural resources. This often results in negative human–wildlife interactions which lower conservation support among farmers. Knowledge about the distribution of avian species that negatively influence yields, and its environmental drivers is thus fundamental to reconcile crop production and bird conservation. This study aims to examine the spatio-temporal patterns in richness and abundance of bird species known to cause agricultural yield loss as well as species-specific distribution patterns for the six bird species that are most challenging for local farmers. In combination with interview surveys of local farmers (n = 367) and seasonal bird surveys (n = 720), we investigated distribution of crop-exploiting avian species in the Indawgyi wetland ecosystem in Myanmar. Our results showed high richness and abundance of crop-exploiting species in the water habitat across all seasons, with most challenging species exhibiting higher presence closer to these water sources. The crop phenology had positive effect on species richness and abundance during the growing season. The agricultural use of crop-exploiting species was season- and species-specific, where the presence probability in the agricultural habitat was higher in habitat generalists than wetland specialists. Therefore, we suggest improved management of natural wetland habitats (e.g., habitat restoration), sustainable coexistence mechanisms in farms close to water (e.g., bird-friendly rice farming and Ecolabel certification) to reduce avian impacts on the farming communities and, at the same time, to promote bird conservation in wetlands of international importance.

Unravelling CH4 and N2O dynamics in tidal wetlands using natural abundance isotopes and functional genes

Tidal wetlands are one of the major sources of CH4 and N2O in natural systems to the atmosphere; yet we still lack insights into the impact of their biogeochemical dynamics on the emissions of these greenhouse gases (GHGs). Here, we investigated the CH4 and N2O sources in four tidal wetlands ranging from freshwater to polyhaline with a focus on their production pathways. By using natural abundance isotopes and functional marker genes, we found that salinity level, sediment moisture content, quantity and quality of organic carbon (OC) and nutrients were major drivers of the wetland CH4 and N2O emissions. As the salinity levels decreased in the tidal wetlands, both the labile nature and concentration of nutrients and OC increased. These conditions favored methanogenesis as indicated in the abundance and expression of mcrA and the CH4 emissions from the freshwater wetland. Conversely, higher salinity depressed organic matter decomposition rates and microbial activities, causing much lower CH4 production in the saline wetlands. Isotope mapping revealed that denitrification contributed mainly to wetland N2O emissions (80–90%), reflected in the strong expression of denitrifier marker genes nirS, nirK, and nosZ and low nosZ:nir ratio. Nitrification played an important role in wetland N2O emissions at high NH4+ and low salinity levels. This condition was the case in the freshwater wetland – the strongest N2O emitter – where we found the highest NH4+ concentrations and the most abundant and expressed nitrifier marker genes amoA AOA and amoA AOB. Methanogen and denitrifier marker genes were more abundant and expressed at the surface layer compared to the subsurface layer, implying the presence of methane and denitrification paradoxes in the tidal wetlands. This study paves a way for the coupling of isotope and functional gene analyses to deeply explore GHG formation pathways and responsible microbial activities in dynamic wetland systems.

Designing a Business Model for Start-up Development of Downstream Wetland Products Based on Design Thinking

Abstract Wetland in South Kalimantan, especially swamp land, covers 6.07% of the land area. Wetland base products need to be accommodated in a start-up by providing a business design model accommodating many users. The research aimed at designing a business model accompanied by monetization to become a reliable start-up specifically for wetland commodities applying the concept of design thinking. The methodology began with conducting a needs analysis, determining an issue strategy, creating a demand design using the Analytical Network Process, establishing a Hierarchial Task Analysis for idea development and product design, conducting brainstorming, followed by further analysis until creating a Business Model applying five design thinking concepts, namely empathize, define, ideate, prototype and test. The application built based on the business model was named Hiyung Wonderful Wetland, Lambung Mangkurat University (HW2 ULM). Analysis of user needs included Admins, Innovators, Partners who were individual consumers/wholesalers, material providers and for monetization purposes. Entity Relationship Diagram (ERD) started from identifying to determine what entities used in the diagram, then determining the entities having relationships, followed by adding attributes and determining key attributes for each entity. After carrying out the empathize, define, ideate stages towards users, a prototype was produced with a wireframe design starting from the start page, registration, main page, consultation page, chat page schedule, pay page to forum page. The application of the Test concept was still being verified towards target validation. The visualization (UI) and Application part involves the user’s feelings when operating a digital product (UX) likewise with the back end having high security. User recommendations are that the HW2 ULM Prototype can be tested immediately to be eligible to obtain a license.

Mapping long-term Transformation of Wetlands and Annual Rainfall Variability in Madhubani District (1975-2022).

In addition to supporting a rich biodiversity, wetlands serve as ecosystems that connect aquatic and terrestrial settings. They also play a critical ecological role by providing essential supplies. According to the National Wetland Atlas (2010), Bihar has a total of 21,988 wetlands with a total area of 4,03,209 hectares. These wetlands exhibit great range of floral and faunal diversity with large number of endemic species. The present paper endeavors to map the natural wetlands of Madhubani district of North Bihar and assess their evolving hydro-physiographic characteristics. The study area is endowed with numerous small wetlands as it receives high average annual rainfall in Bihar. This study primarily emphasizes on identification of wetlands and their spatial-temporal assessment during the period 1975-2022 by utilizing datasets from various sources like topographical maps, satellite imageries, and other ancillary data. It uses geospatial tool like Arc Hydro and indices like Topographic Wetness Index (TWI) and Normalized Difference Wetness Index (NDWI) for identification and spatial-temporal assessment of wetlands during pre-monsoon and post-monsoon season. The study finds that despite being one of the rainiest districts of Bihar, the annual rainfall trends in Madhubani is decreasing. This has impacted upon the water quality, productivity, biodiversity and annual recharge of wetlands of Madhubani. Its entire geographic region has thus been significantly reduced as a result. Other important factors like accelerated anthropogenic intervention, land use changes and process of urbanization have contributed towards rapid transformation of floodplains of Madhubani District. These changes may affect future water potential of the region and thus threaten sustainability in the region.

Canopy Heterogeneity and Environmental Variability Drive Annual Budgets of Net Ecosystem Carbon Exchange in a Tidal Marsh

AbstractTidal salt marshes are important ecosystems in the global carbon cycle. Understanding their net carbon exchange with the atmosphere is required to accurately estimate their net ecosystem carbon budget (NECB). In this study, we present the interannual net ecosystem exchange (NEE) of CO2 derived from eddy covariance (EC) for a Spartina alterniflora salt marsh. We found interannual NEE could vary up to 3‐fold and range from −58.5 ± 11.3 to −222.9 ± 12.4 g C m−2 year−1 in 2016 and 2020, respectively. Further, we found that atmospheric CO2 fluxes were spatially dependent and varied across short distances. High biomass regions along tidal creek and estuary edges had up to 2‐fold higher annual NEE than lower biomass marsh interiors. In addition to the spatial variation of NEE, regions of the marsh represented by distinct canopy zonation responded to environmental drivers differently. Low elevation edges (with taller canopies) had a higher correlation with river discharge (R2 = 0.61), the main freshwater input into the system, while marsh interiors (with short canopies) were better correlated with in situ precipitation (R2 = 0.53). Lastly, we extrapolated interannual NEE to the wider marsh system, demonstrating the potential underestimation of annual NEE when not considering spatially explicit rates of NEE. Our work provides a basis for further research to understand the temporal and spatial dynamics of productivity in coastal wetlands, ecosystems which are at the forefront of experiencing climate change induced variability in precipitation, temperature, and sea level rise that have the potential to alter ecosystem productivity.

Ecological Regeneration of Wetland: Case Study of Kanwar Lake, Begusarai

The wetlands are the partially water-submerged environments that are highly productive, and support fauna and flora species in significant numbers that are dependent for their survival on the organic production of wetlands. Kanwar Lake is situated about 22 kilometers to the northwest of Begusarai. The Gandak River, a tributary of the Ganges, meanders across the area, creating the largest oxbow lake in Asia. It is a natural body of water that is significant on many different levels, including ecological, floral, faunal, geomorphological, and zoological. In 1989, the state government of Bihar designated Kanwar as a protected area for avian species. It has been considered a Ramsar site since 1987, but the wetland was not one of the 13 designated sites. In 1984, the lake’s area was 6,786 hectares (ha), but by 2004, it had shrunk to 6,043.825 ha. Only 2,032 hectares remained of the original lake area by 2012. Wealthy farmers and locals have rapidly colonized the lake bed. Lake biodiversity has declined as weeds have grown across the wetland. Widespread deforestation, overgrazing, unsustainable agricultural methods and over-exploitation of biomass for wood, fodder, and timber have stripped the land of its natural vegetative cover and exacerbated erosion. The research deals with the ecological study of the area and how urbanization has caused impacts on it. It focuses on how this has caused the deterioration of the lake and the measures for restoring the lake ecology, safeguarding the trend of urbanization. After analyzing the major key issues and analyzing the issues at the edge of the lake and around the Manjhaul, some of the major findings conclude that there is a need for stormwater management of the whole city, restoration of Kanwar wetland, and industrial control around the lake.

Waterfowl Eggshell Refines Palaeoenvironmental Reconstruction and Supports Multi-species Niche Construction at the Pleistocene-Holocene Transition in the Levant

Utilising multiple lines of evidence for palaeoenvironmental reconstruction improves our understanding of the past landscapes in which human populations interacted with other species. Illuminating such processes is key for a nuanced understanding of fundamental transitions in human history, such as the shift from hunting and gathering to farming, and allows us to move beyond simple deterministic interpretations of climate-driven innovation. Avifaunal remains provide detailed indications of complex multi-species interactions at the local scale. They allow us to infer relationships between human and non-human animals, but also to reconstruct their niche, because many bird species are sensitive to specific ecological conditions and will often relocate and change their breeding patterns. In this paper, we illustrate how novel evidence that waterfowl reproduced at Levantine wetlands, which we obtained through biomolecular archaeology, together with modern ornithological data reveals conditions of wetlands that are conducive for breeding waterfowl. By understanding the interplay between wetland productivity cycles and waterfowl ecology, we argue that human modifications to the environment could have promoted wetland productivity inviting waterfowl to remain year-round. Within this landscape of “mutual ecologies”, the feedback resulting from the agency of all species is involved in the construction of the human niche.

Application Of Nearest Neighbor Analysis Methods For The Distribution Of Small Storks (Egretta Garzetta) In The Mangrove Area North Sumatra

The penetrating waterbird on the east coast of North Sumatra is Egretta Garzetta. It is a kind of water bird that lives in water or parts of wetlands. The presence of waterbirds is an important indicator to evaluate the environmental quality and productivity of wetlands. Bird distribution patterns are needed to overcome problems related to habitat, such as food availability and population size. This study aims to apply themethod Nearest Neigbord Analysis to the distribution pattern of Egretta Garzetta in the Mangrove area of North Sumatra. This study uses a quantitative approach to the type of applied research (Applied Research). The type of data used in this research is secondary data. Analysis of the data in this study using Nearest Neighbor Analysis. The pattern of the spread of Egretta Garzetta in the Mangrove areas in North Sumatra have clumped pattern (clustered).The results from Nearest Neighbor Analysis show that the index value of the clustered distribution pattern can be caused by the abundance of food sources in a habitat.

Coupling coordination analysis of production, living, and ecological spaces in wetlands: A case study of Xianghai Wetland nature reserve, China

With the global alterations in ecological conditions and population growth, the study of production-living-ecological space (PLES) offers a new perspective in balancing land resource utilization with the sustainable development of society, economy, and environment. China has incorporated the optimization of PLES into its sustainable development strategy. However, research concerning the PLES functions within wetland ecosystems remains notably sparse. Wetlands, distinguished by their unique ecosystem, command a special place in the realm of production, living and ecology research. Their importance is multifaceted, stemming from their roles in ecology, economy, and socio-cultural dimensions, and further accentuated by their distinct geographical, climatic, and biodiversity attributes. In light of this, the Xianghai Wetland Nature Reserve in Jilin, China, was chosen as the focal point of this study to probe into the coupling coordination degree of its PLES functions. The study commenced with a thorough analysis of the changes in land use types from 2000 to 2020 using a land use transition matrix model. Following this, a customized land use function assessment framework called LUF-PLE was formulated, offering a quantitative assessment of the Xianghai wetland’s production, living, and ecological space functions and shedding light on their spatiotemporal dynamics. Finally, a coupling coordination degree model (CCDM) was employed to elucidate the evolution of the PLES functions of Xianghai wetlands. Key findings revealed that: (1) the Xianghai wetland’s PLES coupling coordination degree exhibited a pattern of decline, stabilizing post-2010, with the most pronounced dip observed between 2000–2010; (2) the coordination between production and living functions was notably subdued, whereas the coordination between production and ecological functions saw the steepest decline. In the future, a sustainable wetland development strategy should be formulated and implemented based on the observed trends in coupling coordination and the spatiotemporal differentiation of production-liveling-ecological functions in the local context. This research furnishes scientific substantiation and serves as a reference for the sustainable stewardship and preservation of wetlands.

Economic valuation of wetland products and services: A case study of Sone Beel, India

Economic valuation of wetland products and services: A case study of Sone Beel, India

Evaluation of Remote Sensing Products for Wetland Mapping in the Irtysh River Basin

As a transboundary river with rich and unique wetland types, the Irtysh River faces various challenges and threats from human activities and climate change, which affect area, type, and function of wetland. To accurately obtain information on the spatial and temporal distribution of wetlands in this basin, this study compares and evaluates the consistency and accuracy of a total of eleven remote sensing (RS) based land use/land cover (LULC), and wetland products. The information extraction effect of each RS product was examined through methods such as wetland area and type description, thematic map comparison, and similarity coefficient and Kappa coefficient calculations, which can reflect the wetland distribution characteristics and differences among the RS products in the Irtysh River Basin. The results show that although there is a consensus among the products in the major wetland distribution areas, there are still obvious deviations in detail depiction due to differences in factors such as data sources and methods. The products of Global 30 m Wetland Fine Classification Data (GWL_FCS30) and Global 30 m Land Cover Data (GLC_FCS30-2020) released by the Institute of Space and Astronautical Information Innovation (ISAI) of the Chinese Academy of Sciences (CAS) have a clear advantage in extracting spatial morphology features of wetlands due to the use of multi-source data, while the Esri Global 10 m Land Cover Data (ESRI_Global-LULC_10m) and products such as the global 10 m land cover data (FROM_GLC10_2017) from Tsinghua University have higher classification consistency. Moreover, data resolution, classification scheme design, and validation methods are key factors affecting the quality of wetland information extraction in the Irtysh River Basin. In practical terms, the findings of this study hold significant implications for informed decision-making in wetland conservation and management within the Irtysh River Basin. By advancing wetland monitoring technologies and addressing critical considerations in information extraction, this research effectively bridges the gap between remote sensing technology and practical applications, offering valuable insights for regional wetland protection efforts.

Grassland intensification effects cascade to alter multifunctionality of wetlands within metaecosystems

Sustainable agricultural intensification could improve ecosystem service multifunctionality, yet empirical evidence remains tenuous, especially regarding consequences for spatially coupled ecosystems connected by flows across ecosystem boundaries (i.e., metaecosystems). Here we aim to understand the effects of land-use intensification on multiple ecosystem services of spatially connected grasslands and wetlands, where management practices were applied to grasslands but not directly imposed to wetlands. We synthesize long-term datasets encompassing 53 physical, chemical, and biological indicators, comprising >11,000 field measurements. Our results reveal that intensification promotes high-quality forage and livestock production in both grasslands and wetlands, but at the expense of water quality regulation, methane mitigation, non-native species invasion resistance, and biodiversity. Land-use intensification weakens relationships among ecosystem services. The effects on grasslands cascade to alter multifunctionality of embedded natural wetlands within the metaecosystems to a similar extent. These results highlight the importance of considering spatial flows of resources and organisms when studying land-use intensification effects on metaecosystems as well as when designing grassland and wetland management practices to improve landscape multifunctionality.

Ecosystem carbon exchange across China's coastal wetlands: Spatial patterns, mechanisms, and magnitudes

Coastal wetlands are of great importance for global carbon cycle and climate mitigation because of their strong carbon uptake capacity. However, the national-scale ecosystem carbon exchange dynamics in coastal wetlands, including magnitudes, spatial patterns, and controlling mechanisms, remains poorly understood. In this study, we utilized eddy covariance measurements from China's coastal wetlands to quantify carbon fluxes, assess their spatial patterns, and explore the controlling mechanisms. Integrating climate, vegetation, and soil factors, we constructed a cascaded relationship network to reveal the potential controlling mechanisms of spatial variations in carbon fluxes. The results revealed that gross primary production (GPP) and ecosystem respiration (ER) were 1405 ± 656 (mean ± sd) gC m−2 yr−1and 893 ± 465, respectively. Net ecosystem production (NEP) in coastal wetlands (567 ± 348 gC m−2 yr−1) exceeded China's terrestrial and marine ecosystems by 2–8 times, highlighting their significant carbon sink capacity. The carbon sink capacity in mangroves was significantly higher than salt marsh, exhibiting a twofold difference in NEP. Spatially, carbon fluxes displayed negative correlations with latitude, indicating the influence of climate features. Although tropical climate zone exhibited significantly higher carbon fluxes than temperate zone, no differences were observed between subtropics zone with others due to the distribution of mixed plants and largest area. The structural equation model (SEM) showed that the climate factors, including temperature, precipitation, and net radiation indirectly promoted GPP and ER through regulating the physiological process of mangrove and salt marsh, as well as soil carbon production and consumption. The cascaded relationship of climate-vegetation-soil showed in SEM explained 71–85 % of the spatial variations in GPP and ER, and ultimately accounted for 85 % of NEP. The carbon consumption efficiency (ER/GPP) in coastal vegetations was of 0.6, lower than that of global and China's terrestrial ecosystems, suggesting their strong efficiency in carbon fixation in coastal wetlands. Lastly, the scenario simulation results implied the importance of coastal vegetation restoration on enhancing blue carbon benefits.

A perspective on how glyphosate and 2,4-D in wetlands may impact climate change

An increase in herbicide use is occurring due to a growing population and herbicide-resistant crops in agriculture, which has resulted in more herbicide tolerant target species. Glyphosate and 2,4-Dichlorophenoxyacetic acid (2,4-D) are two of the most commonly used herbicides worldwide and are more recently being used in combination in pre-mixed commercial formulas. Subsequently, herbicide contamination of wetlands will increase exposure of microorganisms to multiple chemical stressors. Methane is a potent greenhouse gas naturally emitted from wetlands, but herbicides may disrupt biogeochemical processes leading to an unbalanced methane cycle. We review the impacts of these herbicides on aquatic microbial communities from glyphosate-derived nutrient enrichment and 2,4-D inhibition of methane oxidation, and examine how these altered metabolic processes may lead to increased methane production in wetlands. The response of wetland ecosystems to herbicide contamination will vary across regions, in part due to the complexity of microbial communities, however, this perspective gives a glimpse into the potential global implications of continuing herbicide use on wetlands and demonstrates the importance for research on ecosystem-level co-stressors.

Impact of freshwater diversions on vegetation in coastal wetlands based on remote sensing derived vegetation index

There exist contrasting results on the impact of large-scale freshwater and sediment diversions on land gain/loss. To improve understanding on the efficacy of diversion projects in restoring coastal wetlands, we aim to evaluate the long-term impacts of diversion-altered salinity and water level on vegetation productivity in coastal wetlands. Two freshwater diversion projects Caernarvon and Davis Pond in Louisiana, U.S. and associated reference sites were selected for inclusion in this study. We implemented multi-level Bayesian models to evaluate 1) how vegetation productivity approximated by Landsat-derived Normalized Difference Vegetation Index (NDVI) in peak biomass season changed over time (pre- and post-construction and operation of the freshwater diversions), and 2) how peak-season NDVI responded to mean and variability of water level and salinity among a suite of factors that could affect vegetation productivity. Analysis showed difference in temporal trends of NDVI between the reference and diversion site for the Caernarvon project with a significant increase at the diversion site although NDVI negatively responded to diversion at the beginning. Diversion did not seem to negatively affect NDVI for the Davis Pond project and NDVI only marginally increased at the diversion site. For both projects, NDVI negatively responded to water level, while salinity negatively affected NDVI or showed quadratic relation with NDVI. At the Caernarvon diversion project, the negative impact of water level on NDVI was greater at the diversion site than at the reference site. At the Davis Pond project, it was the salinity that showed different impact between the diversion and reference site. The temporal increase of NDVI at the Caernarvon diversion site can be explained by the lower salinity driven by diversion. The quadratic relation between salinity and NDVI at the Davis Pond diversion project led to only marginal increase at the diversion site. This study provided uncertainty estimates in temporal trend of NDVI and the impact of two key abiotic drivers on NDVI. The improved understanding on vegetation productivity will help predict landscape change in response to freshwater diversions.

Wetland productivity determines trade-off between biodiversity support and greenhouse gas production.

Establishing wetlands for nutrient capture and biodiversity support may introduce trade-offs between environmentally beneficial functions and detrimental greenhouse gas emissions. Investigating the interaction of nutrient capture, primary production, greenhouse gas production and biodiversity support is imperative to understanding the overall function of wetlands and determining possible beneficial synergistic effects and trade-offs. Here, we present temporally replicated data from 17 wetlands in hemi-boreal Sweden. We explored the relationship between nutrient load, primary producing algae, production of methane and nitrous oxide, and emergence rates of chironomids to determine what factors affected each and how they related to each other. Chironomid emergence rates correlated positively with methane production and negatively with nitrous oxide production, where water temperature was the main driving factor. Increasing nutrient loads reduced methanogenesis through elevated nitrogen concentrations, while simultaneously enhancing nitrous oxide production. Nutrient loads only indirectly increased chironomid emergence rates through increased chlorophyll-a concentration, via increased phosphorus concentrations, with certain taxa and food preference functional groups benefitting from increased chlorophyll-a concentrations. However, water temperature seemed to be the main driving factor for chironomid emergence rates, community composition and diversity, as well as for greenhouse gas production. These findings increase our understanding of the governing relationships between biodiversity support and greenhouse gas production, and should inform future management when constructing wetlands.

Transformation of phosphorus forms and its regulation on phosphorus availability across differently degraded marsh soils

AbstractSoil phosphorus (P) is a vital nutrient that controls wetland productivity and ecological functions. However, the effects of soil P forms on P availability during wetland degradation are relatively unknown. We selected differently degraded marshes, including non‐degraded marsh (NDM), lightly degraded marsh (LDM), moderately degraded marsh (MDM), and heavily degraded marsh (HDM), to research the changes in soil P forms by sequential chemical extraction and its regulation on P availability in the Zoige Plateau, China. The results showed that compared with the 0–30 cm soil layers of NDM, the main changes in total P concentration were a significant increase of 31.6%–44.2% in LDM and MDM, and the available P concentration increased by 28.7%–76.2% in LDM and MDM but decreased by 4.0%–47.5% in HDM with a lower P activation coefficient. Marsh degradation increased the concentration of soil dicalcium phosphates, P occluded in iron hydroxides, and organic P from the entire profile by 46.7%–137.7%, 31.7%–49.3%, and 78.1%–82.1%, respectively, while it decreased that of iron oxide surface adsorbed P and apatite P by 17.2%–32.2% and 15.3%–27.8%, respectively. Soil available P was mainly related to organic P and P non‐occluded in iron oxide minerals, which might also be a non‐negligible direct source of available P. The transformation from apatite P to organic P was an important regulatory mechanism of P availability in soils during marsh degradation. This study revealed the transformation trajectory of soil P forms owing to soil desiccation accompanied by plant community changes and overgrazing during alpine marsh degradation, and the risk of P limitation in HDMs with low soil available P. For degraded marsh restoration, some measures for improving P availability should be implemented in the future, such as grazing exclusion and the application of organic fertilizer.