Search Results (142)

Microplastic contamination in wetland ecosystems is an escalating environmental threat, compromising ecosystem services, biogeochemical cycling and biodiversity conservation. This study assessed the occurrence, distribution and physicochemical characteristics of microplastics in the Ramsar-designated Pallikaranai wetland, southern India. Six representative subsamples were collected from spatially distinct locations and analyzed using density separation, followed by polymer identification via Raman spectroscopy and energy-dispersive X-ray spectroscopy (EDS). Microplastics were ubiquitously detected across both sediment and water matrices, with significantly higher abundances in sediments, indicating their role as a major sink. The dominant polymer types, polyethylene (PE), polypropylene (PP) and polystyrene (PS), along with prevalent morphotypes such as fragments, fibers, beads and foams, reflect diverse and persistent anthropogenic inputs. The compositional profile strongly implicates mismanaged domestic and urban waste as the primary source. The widespread presence and accumulation of microplastics in this ecologically sensitive wetland raise concerns over potential impacts on trophic interactions, habitat quality and long-term ecosystem resilience. These findings underscore the urgent need for targeted waste management strategies, pollution mitigation frameworks and continuous monitoring to safeguard the ecological integrity of the Pallikaranai wetland and similar Ramsar-listed ecosystems. Full article

Floodplains are key components of inland river systems of Australia with floodplain vegetation playing important roles in habitat provision, nutrient cycling, and supporting strong cultural values. These vegetation communities are highly dynamic, particularly in response to flooding. However, decades of water development and highly managed water resources are linked to wetland habitat decline in this region. We explored patterns of vegetation response to flooding over twenty years at the Narran Lakes Ramsar site, a terminal floodplain wetland system in the northern Murray–Darling Basin, Australia. We collated data from previous monitoring efforts and resampled permanent plots for understorey vegetation structure and composition. Three flood events were surveyed over a 20-year period, with each event surveyed on two occasions first, following initial drawdown (minimal standing water) and a second survey under dry or drier conditions (~6 months after the recession of floodwaters). Overall, we observed a high diversity of native plant species (~110 species) in understorey communities across the wetland and high compositional turnover both between flood events and within years (i.e., paired surveys). Notably, vegetation cover, but not species richness, was greatest in the 2023 survey following the largest of the three flood events investigated. Understorey composition was strongly driven by inundation regimes, particularly the duration of recent inundation, and the number of wet and dry years prior. Large flood events are critical for supporting vegetation resilience in these systems, increasingly so under a drier climate and with stretched water resources. Continued long-term monitoring of vegetation through flood cycles at the Narran Lakes will be critical to understanding ecological responses to longer-term changes in climate and hydrology to inform adaptive water management and maintain the values of this Ramsar site. Full article

The Somyne lake-mire system is a unique wetland landscape complex in the Polissia region of Ukraine and forms part of the Rivne Nature Reserve. Its ecological importance is internationally recognised through its designation as the Ramsar wetland “Somyne Peatland Massif”. Effective conservation of this wetland requires an understanding of the factors controlling the functioning of the lake and its drainage basin, considered in this study as a lake-basin system (LBS). The aim of this study is to assess the geoecological condition of the Somyne LBS using the principles of landscape limnology and the basin approach. The research integrates morphological, morphometric, hydrological, landscape-metric, hydrochemical and geochemical analyses. These are complemented by bathymetric modelling, landscape mapping, and analysis of long-term meteorological observations. The results identify key natural and anthropogenic drivers shaping the functioning of the system, characterise the hydrochemical state of lake waters and the geochemical properties of bottom sediments, and describe the spatial distribution of bottom sediments and the bathymetric structure of the lake basin. A multivariate algorithm for the geoecological assessment of lake-basin systems is proposed, providing a framework for comparative analysis of small lakes in the Polissian lake region under climate change and increasing anthropogenic pressure. Full article

Seasonal tropical wetlands such as the Brazilian Pantanal are increasingly threatened by climate variability and extreme hydrological events, creating a need for robust monitoring tools that capture flood dynamics at high spatial and temporal resolution. This study used Sentinel-1 Synthetic Aperture Radar (SAR) imagery to map and monitor flooding in the northern Pantanal, a Ramsar site renowned for its wildlife, between 2017 and 2020. Ground Range Detected (GRD) VV-polarized scenes were preprocessed using radiometric terrain normalization and speckle filtering (Lee filter, 5 × 5 window) to improve the separability of water and non-water surfaces. Flooded areas were initially extracted with Otsu’s histogram thresholding and validated using high-resolution optical imagery (PlanetScope and Landsat-8). A supervised Random Forest classifier then refined land-cover discrimination into three classes (open water/flood, open land/vegetation, and others), achieving an overall accuracy of 97.70% on the independent testing dataset (n = 6622), while temporal consistency was supported by Cuiabá River hydrological data. The results revealed strong interannual variability in flood extent, with inundation covering 34.7% of the reserve in March 2017 compared with 0.75% in March 2020 and reaching a peak of 79.9% in April 2017. Overall, Sentinel-1 SAR effectively delineated open water and flood-affected surfaces under persistent cloud cover, demonstrating its value for complementing existing products such as MapBiomas, strengthening wetland management, and supporting scalable flood monitoring in other tropical flood-prone Ramsar sites. Full article

Wetlands are highly productive ecosystems that play a vital role in maintaining ecological balance. This study presents a geospatial assessment of the Harike Wetland, Punjab, using hyperspectral (PRISMA) and multispectral (Landsat series) satellite data to analyze its ecological structure and water dynamics. Six spectral indices—Normalized Difference Vegetation Index (NDVI), Normalized Dif-ference Aquatic Vegetation Index (NDAVI), Normalized Difference Water Index (NDWI), Modified NDWI (MNDWI), Floating Algal Index (FAI), and Algal Bloom Detection Index (ABDI)—were employed to map terrestrial agricultural cropland (paddy), aquatic vegetation and surface water. Threshold-based classification of index outputs was used to estimate the spatial extent of major land cover types. NDVI and NDAVI effectively captured vegetation patterns, while NDWI and MNDWI improved surface water delineation. Additionally, Z-spectral analysis was applied to extract and compare the reflectance profiles of agricultural cropland, open water, and algae, as well as built-up areas, enhancing spectral contrast and classification accuracy, particularly in spectrally mixed zones. The integration of index-based mapping with detailed spectral profiling demonstrates the advantage of combining multispectral and hyperspectral data for wetland monitoring and provides valuable insights to support wetland conservation and sustainable water management. Full article

Heavy metal pollution from mining activities and urban runoff poses a serious threat to public health and aquatic ecosystems in vulnerable communities around the Bolivia–Peru transboundary Lake Titicaca basin. This study evaluates the use of two abundant wetland plants—totora (Schoenoplectus californicus) and reed (Phragmites australis)—as low-cost, locally available biosorbents for the removal of dissolved iron (Fe²⁺) from the Pallina River, a major contaminant source to Cohana Bay. Monitoring data from Bolivia’s Ministry of Environment and Water (2019–2022) revealed Fe²⁺ concentrations exceeding the national legal limit (0.3 mg/L) by more than 20 times during the dry season. Laboratory experiments using synthetic Fe²⁺ solutions (20 mg/L) optimized biosorption conditions, identifying pH 5, 4–6 g/L biomass, fine particle size (0.15–0.212 mm), and a 3 h contact time as optimal. Both plants followed pseudo-second-order kinetics and Langmuir isotherms. Totora showed superior performance, achieving a maximum capacity of 7.8 mg/g compared to reed’s 2.9 mg/g. Continuous-flow column tests removed up to 95% of Fe²⁺ from synthetic water. When applied to real Pallina River water, totora achieved 50% Fe²⁺ removal despite reduced efficiency due to competing organic matter. The findings demonstrate the potential of totora-based biosorption as a scalable, nature-based solution for transboundary water management. The policy implications of this study are profound under the national and global water and wetland governance mechanisms and transboundary frameworks like the Binational Autonomous Authority of Lake Titicaca (ALT, est. 1996) and Ramsar Convention. Full article

Accurate delineation of stream networks in low-gradient wetlands remains challenging due to subtle topographic variation and dense vegetation cover. This study systematically evaluated 48 Unmanned Aerial Vehicle Light Detection and Ranging (UAV-LiDAR) processing workflows through 1128 pairwise comparisons to identify optimal approaches for mapping fine-scale channels in Japan’s Kushiro Wetland, a Ramsar-designated ecosystem. The workflows combined three ground filtering methods (Progressive Morphological Filter, Cloth Simulation Filter, Multiscale Curvature Classification), four interpolation techniques (Inverse Distance Weighting, Triangulated Irregular Network, Kriging, Multilevel B-spline Approximation), two sink-filling algorithms (Planchon & Darboux; Wang & Liu), and two flow direction models (D8, D-infinity). Performance was first assessed using pixel-based Intersection over Union (IoU) metrics to quantify inter-method consensus. Independent plausibility-based validation was then conducted using near-contemporaneous Sentinel-2 imagery. Although pairwise statistical analysis identified workflows that achieved high inter-method consensus (median IoU = 0.90), external validation demonstrated that the CSF-MBA-Planchon-D8 workflow provided the most realistic presentation of optically observable channel corridors (validation IoU ≈ 0.85). These findings reveal that high inter-method agreement does not necessarily imply accurate landscape representation; multiple workflows may converge on systematically biased solutions. Ground filtering exerted the strongest influence on pairwise consensus, whereas plausibility-based validation highlighted the importance of selecting workflow combinations that preserve subtle channel morphology. Sink-filling and flow direction choices exerted comparatively minor effects in this low-gradient setting. The proposed dual-validation framework provides methodological guidance for wetland restoration planning and highlights the necessity of external validation in LiDAR-derived hydrological feature extraction. Full article

Background/Objectives: Habitat degradation and fragmentation reduce population size, genetic diversity, and connectivity, increasing extinction risk in small and isolated populations. Coastal wetlands of northwestern Peru have undergone extensive anthropogenic modification, yet the genetic and ecological status of resident carnivore populations remains poorly documented. This study aimed to assess genetic diversity, relatedness, demographic signals, and diet composition of a Pampas cat (Leopardus garleppi) population inhabiting the Mangroves San Pedro de Vice (MSPV), a Ramsar-listed coastal wetland. Methods: We combined noninvasive fecal genotyping using eight nuclear microsatellite loci with vertebrate DNA metabarcoding. Scat samples were collected across three field seasons (2019–2021). Individual identification, genetic diversity metrics, genetic mark–recapture estimation of census size (Nc), effective population size (Ne), bottleneck tests, and relatedness analyses were performed to evaluate population status and kin structure. Dietary composition was characterized using metabarcoding and assessed for sex-specific differences. Results: Sixty-eight scats yielded multilocus genotypes for nine individuals (six males, three females). Genetic analyses revealed moderate diversity (mean allelic richness = 3.47; observed heterozygosity = 0.69; expected heterozygosity = 0.58) and evidence consistent with a recent genetic bottleneck. Genetic mark–recapture analyses estimated a small census size (Nc = 9; 95% CI: 7.0–9.0), while the effective population size was markedly low (Ne = 2.4; 95% CI: 1.5–7.4), yielding an Ne/Nc ratio of ~0.27. Multiple first-order kin dyads were detected, indicating strong local kin structure and limited external recruitment. Metabarcoding identified eight vertebrate prey species, with diet dominated by the native rodent Aegialomys xanthaeolus. No significant sex-specific differences in diet composition were detected. Conclusions: The MSPV Pampas cat population represents a small, kin-structured range-edge population showing signatures consistent with recent genetic erosion and restricted connectivity. These patterns align with isolation in a degraded coastal wetland landscape, highlighting the importance of habitat protection, prey resource conservation, and restoration of functional connectivity to support long-term population persistence. Full article

This study evaluates the costs and benefits of participatory forest management (PFM) versus non-participatory forest management based on the perceptions and involvement of local communities in the Kilombero Valley Ramsar site, Tanzania. The area hosts ecologically significant wetlands managed through different regimes: forests managed by local communities under PFM and protected areas controlled by national authorities. Using data collected through focus groups, key interviews, household surveys, and direct observations in two villages—Siginali (PFM) and Kilama (non-participatory)—this research explores perceptions of two different forest management approaches. The results revealed: (i) a generally low awareness and participation in forest management activities in both villages; (ii) restrictions on forest resource access, essential for local livelihoods, were common and often poorly accepted in the two villages; (iii) neither approach alleviates poverty, instead, strict regulations have worsened livelihoods by eliminating traditional income sources; (iv) forced participation in patrols and fire control was also noted as an unfair burden without direct compensation; and (v) the “fortress” model is perceived as more effective at improving forest health and stopping illegal activity due to stricter patrols. The study concludes that while PFM supports forest sustainability, it needs enhanced local engagement, benefit-sharing mechanisms, and complementary income-generating initiatives such as ecotourism to sustainably balance conservation and community welfare. Full article

The longest-standing international treaty for wetland and waterbird protection, the Ramsar Convention has resulted in the establishment of more than 2500 protected areas covering over 2.5 million square kilometers around the world. However, its measures are not legally binding, and its effectiveness as a tool for wildlife conservation has rarely been quantitatively assessed. In Benin, West Africa, breeding waterbirds are subjected to intense hunting and egg harvesting for both commercial and subsistence purposes. We quantified count data of waterbirds and eggs taken by local hunters and trappers to assess the effectiveness of the Ramsar Convention as a wildlife conservation tool in southeastern Benin. During the six-month period between May and October 2022, 64 people reported harvesting a total of 12,053 breeding waterbirds and 63,987 eggs, comprising eight species in three families in Ramsar site 1018. Birds most heavily targeted included Allen’s Gallinule (Porphyrio alleni), with 4187 breeding birds taken (~35% of all birds captured), and the White-faced Whistling Duck (Dendrocygna viduata), with 24,491 eggs taken (~38% of all eggs taken) over the course of a single breeding season. The Eurasian Moorhen (Gallinula chloropus) and Lesser Moorhen (Paragallinula angulata) were the third and fourth most targeted bird species, respectively, followed by the African Swamphen (Porphyrio madagascariensis), Black Crake (Zapornia flavirostra), African Jacana (Actophilornis africanus), and African Crake (Cecropsis egregia). Captured waterbirds were sold live at local markets, while eggs were eaten by hunters, except eggs containing chicks, which were discarded. Our findings show heavy persecution of waterbirds during their breeding season, when nesting birds are especially vulnerable to human predation, on a scale that is likely unprecedented and threatens to drive declines of targeted species in Benin. As local residents do not currently appear to recognize any deterrents to the uncontrolled hunting of breeding waterbirds or the collection of eggs in Ramsar site 1018, there is an urgent need to better leverage the Ramsar Convention to enforce conservation practices in this region. Full article

The Pantanos de Villa wetland, a protected Ramsar site in Lima, Peru, faces significant pressure from invasive species and urban pollution. This study provides a comprehensive evaluation of microhabitat use and trace-element bioaccumulation in the invasive crayfish Procambarus clarkii (Girard, 1852). We analyzed the physicochemical parameters of the microhabitat and measured the concentrations of macroelements (Na, Mg, P), trace metals (Cu, Zn, Al, Ni, Ti, Pb), and a metalloid (B) in water, sediment, and crayfish tissues (gill, hepatopancreas, and muscle) using ICP-OES. Additionally, we examined the growth pattern of P. clarkii through its length–weight relationships. A total of 171 individuals were recorded: 99 males and 72 females. Males were longer (13–15 cm), while females were heavier (18–21 g). Additionally, a positive correlation was observed in females between the size and weight of the hepatopancreas and abdominal muscle, whereas no significant link was found in males. Sediments had higher levels of the evaluated chemical elements, with Cu (28.26 mg kg⁻¹) and Zn (66.88 mg kg⁻¹) exceeding international quality guidelines, indicating a possible ecotoxicological risk. The significant negative correlation between dissolved oxygen and the abundance of P. clarkii suggests that higher D.O. is associated with less bioturbation and more predators, making the microhabitat less suitable for juveniles. We conclude that P. clarkii serves as an essential bioindicator and potential vector for the relocation of the trace in an urban wetland, highlighting the need for integrated management strategies to reduce the ecological impacts of this invasive species. Full article

African grasses deliberately introduced for cattle forage have become among the most destructive invaders of tropical wetlands globally, yet invasion mechanisms and management strategies remain poorly understood. We conducted field experiments examining competition dynamics between the invasive African grass Echinochloa pyramidalis and native wetland species in La Mancha, Mexico—a Ramsar site of international importance. Experiment 1 tested invasion potential within native Sagittaria lancifolia zones using four treatments: control, herbicide removal, E. pyramidalis transplant, and combined removal + transplant. Repeated-measures ANOVA showed significant treatment and time effects on invasion success, with vegetation removal facilitating invasion (relative importance value increasing from 0 to 149.4 ± 26.6 after 18 months) while transplants alone failed to establish (RIV < 7.0). Sagittaria maintained 35–48% biomass across treatments, demonstrating coexistence capacity. Experiment 2 examined natural invasion of the vegetation ecotone over 49 months. Mixed-effects models revealed that E. pyramidalis increased dominance in its zone (β = 9.98, z = 4.77, p < 0.001) but showed minimal expansion into the adjacent Sagittaria habitat, indicating propagule limitation rather than competitive exclusion as the invasion constraint. Sagittaria removal within E. pyramidalis zones significantly reduced invasion temporal increase (β = −6.44, z = −2.18, p = 0.030), suggesting biotic resistance. Results demonstrate that E. pyramidalis possesses invasion potential but requires disturbance to overcome establishment barriers. These findings support prevention-based management prioritizing disturbance limitation in intact wetlands and demonstrate that hydrological management maintaining permanent flooding (>30 cm depth) can effectively control established invasions by exploiting C4 photosynthetic limitations. Conservation implications for Mexican coastal wetlands—which lack legal protection equivalent to mangroves despite comparable ecosystem services—are discussed. These findings inform evidence-based management of African grass invasions in tropical wetlands worldwide. Full article

Wetlands are delicate ecosystems that host diverse species and face ongoing environmental stress. The “Carlos Anwandter” Ramsar Site in Valdivia, Chile, is the world’s main breeding ground for the black-necked swan, which strongly relies on the aquatic plant Egeria densa. This area has been impacted by anthropogenic activities that have increased particulate iron (Fe) and zinc (Zn) deposition. However, standard protocols for metal analysis encourage eliminating any particles on the plant’s surface, neglecting the contribution of deposited particulate contaminants. Appropriate sample treatment is therefore essential to quantify metal concentrations and the potential impact on herbivore species. This study aimed to evaluate how sample treatments and plant sectioning affect Fe and Zn concentrations in E. densa. Samples were collected from both the Ramsar site (Cruces River) and a control site (Calle-Calle River). Results showed that washing samples (both in the field and lab) significantly reduced reported metal concentrations, underscoring the importance of standardised sampling and pre-treatment protocols. Fe concentrations were notably higher at the Ramsar site (11,155 mg kg⁻¹) compared to the control (3783 mg kg⁻¹). The same is true for Zn (108 mg kg⁻¹ and 60 mg kg⁻¹, respectively). Over time, Fe concentrations remained stable, while Zn concentrations declined, suggesting a consistent Fe input and a decreasing Zn trend in the wetland. These findings are crucial for interpreting metal pollution and understanding spatial–temporal variability in aquatic plant contamination. Full article

Wetlands store large amounts of soil organic carbon stock (SOCS), making them crucial for global climate regulation. However, climate change, poor management, and weak protection policies threaten these stocks. To assess the contribution of different wetland types for national and international climate targets and to monitor the effectiveness of protection measures, additional research is required. Therefore, we assessed SOCS and disturbances from climate change, land use/land cover (LULC), and soil chemical composition in saline and eutrophic Ramsar sites in Serbia. Analyzing a total of 96 samples, we accounted for soil depth, reference soil group (RSG), and habitat/vegetation type. Mean SOCS in the saline site ranged from approximately 36 t·ha⁻¹ at 0–30 cm to 26 t·ha⁻¹ at 30–60 cm, whereas values were much higher for the eutrophic sites, ranging from 81 to 82 t·ha⁻¹ at 0–30 cm and 47–63 t·ha⁻¹ at 30–60 cm. Differences between groups for the whole soil columns (0–60 cm) were significant at the 0.1% level. While SOCS generally decreases with depth, it showed notable local variability, including occasional instances at deeper layers, indicating complex environmental and anthropogenic influences. Spatial mapping of soil chemistry parameters (pH, humus, P₂O₅, and K₂O) along with land use/land cover (LULC) data revealed nutrient dynamics influenced by agricultural activities. An analysis of regional climate data revealed temperature increases relative to the reference period of 1971–2000 by 0.5 °C for the decade 2001–2010 and of 1.5 °C for 2011–2020. Climate projections under the RCP4.5 and 8.5 scenarios predict further warming trends, as well as increased rainfall variability and drought risks. The results of our study contribute to quantifying the important, though variable, contribution of wetland sites to global climate regulation and show the influence of geogenic, pedogenic, and anthropogenic factors on SOCS. National policies should be adapted to safeguard these stocks and to limit negative effects from surrounding agricultural areas, as well as to develop strategies to cope with expected regional climate change effects. Full article

The interaction between freshwater and saline water in coastal wetlands generates an interface zone where vertical and horizontal salinity gradients develop. This interface has been investigated through geophysical, hydrochemical, and isotopic studies, which constitute useful tools that provide different types of information whose combined interpretation allows for a more comprehensive understanding of the processes associated with this interaction. This work assessed, through an integrated geophysical (electrical resistivity tomography), hydrochemical (major ions), and isotopic (δ²H, δ¹⁸O, and ²²²Rn) study, the freshwater–saline water interaction between marsh and dune environments in the Punta Rasa Natural Reserve (Argentina). Results show that salinity gradients occurring between dune and marsh environments are associated with fresh groundwater discharge and rainwater infiltration. Fresh groundwater discharge takes place in topographically elevated dunes, where freshwater lenses form. This discharge generates vertical and horizontal salinity gradients because the hydraulic gradient causes the interface to migrate with the groundwater flow. In low-relief dunes, lenses do not develop and the salinity gradient that develops within the interface due to rainwater infiltration is vertical. The findings clarify plant zonation linked to freshwater–saline water interfaces and provide environmental data to assess wetland resilience to climate-driven changes. Full article