Search Results (101)

The taxonomic composition and structure of invertebrate assemblages in five lakes from the Kulunda steppe, located in an arid region of southwestern Siberia (Russia), were studied. The lakes varied greatly in their total salinity (5 to 304 g L⁻¹) and carbonate alkalinity (0.03 to 4.03 mol-eq L⁻¹). The invertebrate fauna was characterized by low diversity. Only five taxa of macrozoobenthos and two taxa of planktonic invertebrates were identified. As water salinity increased, the taxonomic diversity of the studied lakes decreased, and at salinities > 276 g L⁻¹, monodominant assemblages were formed. The high numbers and biomass of aquatic organism provide a rich food supply for native and migratory waterfowl. The low taxonomic diversity of the invertebrate assemblages of the lakes makes them vulnerable to any negative external impact. The climate in the Kulunda steppe demonstrates a long-term aridization trend. If this continues in the future, then over time, this may lead to the gradual salinization of lakes and a further decrease in the taxonomic diversity of hydrobiological assemblages. This emphasizes the ecological importance of the studied territory and the necessity for its inclusion in the list of sites protected by the Ramsar Convention. Full article

The Sonora Estuarine Biocultural Corridor (CBES) is made up of six coastal wetlands with mangrove forest, internationally certified as Ramsar Sites. Four are part of indigenous territories whose inhabitants have serious development lags and low water security. Five are within one or more of six irrigation districts of national relevance. The objective is to learn about the socio-environmental problems of the CBES, focused on the issue of water, as well as community proposals for solutions. Intercultural, mixed methodology approach. Prospecting visits were carried out in the six estuaries of the CBES, and 84 semi-structured interviews were conducted with experts from all social sectors who know the problems of the CBES in three (out of six) estuaries associated with indigenous territories. The main problem is centered on the issue of water: they receive contaminated water from agroindustry, aquaculture, and the municipal service; the fresh water of the rivers is almost nil, rainfall has decreased while the heat increases, and marine and terrestrial biodiversity decreases. This affects the food and economic security of the local population and generates conflicts between the different productive activities. A multisectoral organization that integrates the six estuaries would improve community wellbeing and, in turn, climate resilience. Full article

Lake Chinchaycocha, Peru’s second-largest high-altitude lake and a Ramsar-designated wetland of international importance, is increasingly threatened by anthropogenic pollution and hydroclimatic shifts. This study integrates Sentinel-2 multispectral imagery with in situ water quality data from Peru’s National Water Observatory to assess spatiotemporal dynamics in 31 physicochemical parameters between 2018 and 2024. We evaluated 40 empirical algorithms developed globally for Sentinel-2 and tested their transferability to this ultraoligotrophic Andean system. The results revealed limited predictive accuracy, underscoring the need for localized calibration. Subsequently, we developed and validated site-specific models for ammoniacal nitrogen, electrical conductivity, major ions, and trace metals, achieving high predictive performance during the rainy season (R² up to 0.95). Notably, the study identifies consistent seasonal correlations—such as between total copper and ammoniacal nitrogen—and strong spectral responses in Band 1, linked to runoff dynamics. These findings highlight the potential of combining public monitoring data with remote sensing to enable scalable, cost-effective assessment of water quality in optically complex, high-Andean lakes. The study provides a replicable framework for integrating national datasets into operational monitoring and environmental policy. Full article

Aquatic fungi serve as core ecological engines in freshwater ecosystems, driving organic matter decomposition and energy flow to sustain environmental balance. Wetlands, with their distinct hydrological dynamics and nutrient-rich matrices, serve as critical habitats for these microorganisms. As an internationally designated Ramsar Site, Yunnan Dashanbao Black-Necked Crane National Nature Reserve in China not only sustains endangered black-necked cranes but also harbors a cryptic reservoir of aquatic fungi within its peat marshes and alpine lakes. This study employed high-throughput sequencing to characterize fungal diversity and community structure across 12 understudied wetland sites in the reserve, while analyzing key environmental parameters (dissolved oxygen, pH, total nitrogen, and total phosphorus). A total of 5829 fungal operational taxonomic units (OTUs) spanning 649 genera and 15 phyla were identified, with Tausonia (4.17%) and Cladosporium (1.89%) as dominant genera. Environmental correlations revealed 19 genera significantly linked to abiotic factors. FUNGuild functional profiling highlighted saprotrophs (organic decomposers) and pathogens as predominant trophic guilds. Saprotrophs exhibited strong associations with pH, total nitrogen, and phosphorus, whereas pathogens correlated primarily with pH. These findings unveil the hidden diversity and ecological roles of aquatic fungi in alpine wetlands, emphasizing their sensitivity to environmental gradients. By establishing baseline data on fungal community dynamics, this work advances the understanding of wetland microbial ecology and informs conservation strategies for Ramsar sites. Full article

In this study, the vegetation of the natural area of the Göksu Delta Special Environmental Protection Agency (SEPA), one of Turkey’s most important wetlands, is researched. The importance of this study in terms of contributing to environmental protection and land use planning studies reveals that this natural area, where rare ecosystems are found, has started to degrade and disappear under human influence. This study was conducted because the area is not only a designated RAMSAR wetland (a wetland site designated of international importance especially for the Waterfowl Habitat under the Ramsar Convention) but also includes nearby residential developments. With this study, the vegetation of the area was studied to determine the syntaxonomic units across different habitats. The natural area of Göksu Delta is divided into three main habitat groups: aquatic, sand dune, and halophytic. In the research, the Braun-Blanquet method was used. During the research in the Göksu Delta, 279 sample areas were surveyed. The data were analysed according to the fuzzy means cluster method. During the investigation, 29 associations were identified, and 16 of them are considered a new finding for science. These 29 associations can be classified as follows: aquatic vegetation is represented with four associations (three of them belong to Phragmito-Magnocaricetea and one of them belongs to Potametea classes), sand dune vegetation is represented with 12 associations (belonging to Ammophiletea Br.-Bl. & Tüxen ex Westhoff, Dijk, & Passchier 1946 class), and halophytic vegetation is represented with 13 associations (six of them belong to Salicornietea fruticosae Br.-Bl. & Tüxen ex A. & O. Bolòs 1950, six of them belong to Juncetea maritimi Br.-Bl. in Br.-Bl., Roussine & Nègre 1952, and one of them belong to Molinio-Juncetea Br.-Bl. (1931) 1947 classes). Three (Onopordum boissieri, Ambrosia maritima, and Chlamydophora tridentata) of the endemics and rare plants that were explored during the study were recorded as new alliance characteristics. Full article

A semi-empirical method for estimating actual evapotranspiration (ETa) based on ancillary and NDVI data, named NDVI-Cws, is currently being refined for improved applicability to wetlands. The investigation, in particular, addresses the case of semi-natural ecosystems where the impact of meteorological water stress (WS) is limited by groundwater resources. To adapt to this situation, the application of the NDVI-Cws method is preceded by a calibration phase based on spatially enhanced Land Surface Analysis Satellite Application Facility (LSA SAF) evapotranspiration products. This calibration is currently performed in the main wetlands of Tuscany (Central Italy) identified in the Ramsar Convention. The calibrated NDVI-Cws version is then applied to all regional Ramsar areas, yielding outputs that are first examined all over Tuscany. Next, the model estimates are quantitatively assessed versus ETa observations taken in a forest and a grassland Ramsar site. The results of these independent tests show the improvement achieved by the calibration phase with respect to the original model version. This supports the potential of the refined NDVI-Cws method to yield reasonably accurate daily ETa estimates for wetlands at a spatial resolution that is mainly dependent on the NDVI data used. Full article

Understanding the impact of climate change on waterbirds, particularly those of conservation concern, is essential for their long-term management and effective conservation. In arid regions such as North Africa, wetlands of international importance have been affected by severe drought events, but their impact on waterbirds is still not well understood. Here, we assess the population dynamics of four emblematic resident species (Aythya nyroca, Marmaronetta angustirostris, Oxyura leucocephala, and Porphyrio porphyrio porphyrio) in a North African Ramsar site (Garaet Hadj Tahar marsh, Northeast Algeria), and determine the climatic variables (temperature, precipitation, and drought index) that best predict the change in abundance in wintering and breeding seasons. We used a long-term survey of regular counts during the wintering and breeding seasons of 2002–2019. The temporal trend of waterbird abundance differed between species and seasons. Species showed different sensitivities to different climatic variables at different time windows preceding the wintering and breeding seasons. We found that the population dynamics of the endangered O. leucocephala in the wintering and breeding seasons were best predicted with the drought index, whereas those of P. p. porphyrio were best correlated with maximum temperature. Population dynamics during the wintering and breeding season of the two other species were best explained with either maximum temperature, precipitation, average temperature, or drought. Species responded differently to warming and drought. The most endangered species (O. leucocephala) showed population declines in drier years, whereas less threatened species (A. nyroca, M. angustirostris, and P. p. porphyrio) exhibited either positive or negative correlations. The observed temporal increase in vegetation cover was positively correlated with the wintering population size of O. leucocephala, as well as the breeding population size of P. p. porphyrio and M. angustirostris. These findings highlight the urgent need for climate-adaptive conservation strategies to sustain wetland biodiversity and ecosystem resilience in the face of increasing climate stressors, aligning with the global sustainability goals for biodiversity conservation and ecosystem management. Our results suggest that future increases in temperatures and drought severity might threaten endangered waterbirds and benefit more common species in the region. Full article

Coastal wetlands provide critical ecological services but are threatened by the human, climatic, and hydrological changes impacting these ecosystems. Several key ecosystem services and functions rely on aquatic macrophyte plant species. We integrate 10 years of seasonal monitoring data (2014–2024) and climatic and hydrological datasets to assess how environmental variability influences two dominant aquatic macrophytes—the invasive and non-indigenous Elodea densa Planch. Casp. (Hydrocharitaceae) and the native Schoenoplectus californicus (C.A.Mey.) Soják—in Chile’s first Ramsar site, Carlos Anwandter, and a Nature Sanctuary. We modeled suitable habitat areas using MaxEnt software with Landsat 8 spectral bands and indices as predictive layers. We found significant recent decreases in temperature, river flow, and water level, with a nonsignificant shift in precipitation. We also observed marked spatial and temporal fluctuations in areas with suitable habitat areas for both macrophytes. Stepwise regression analyses indicated that Elodea densa expanded with increasing temperature over time but declined with water level variability. Schoenoplectus californicus showed contrasting effects, declining with rising temperature and water levels but expanding with higher precipitation. These findings emphasize the complexity of coastal wetland ecosystems under environmental stress and climate change and the need for further research for the conservation and management of coastal wetlands along migratory flyways such as the Southeastern Pacific Flyway. Full article

The Ramsar Convention is a global endeavor for the protection of wetlands. However, there is limited research on its efficacy in safeguarding China’s wetlands. This study aims to identify differences within Chinese Ramsar sites and their surrounding areas over the past three decades. This assessment was conducted using extensive land cover maps created by ESA CCI (European Space Agency Climate Change Initiative) through the classification of remote sensing data using the LCCS (Land Cover Classification System) and other systems specified by the IPCC (Intergovernmental Panel on Climate Change), in addition to ecoregion maps. Three primary assessments were performed: detection of change in land covers, fragmentation using effective mesh size and driver analysis using a random forest classifier. The findings indicate significant land cover changes within both Ramsar sites and their surrounding areas. Tree cover and grasslands showed the largest decrease in land cover while flooded shrubs and herbaceous cover showed the largest increase within the Ramsar sites. In contrast, urban areas had the largest overall change in the surrounding areas, with twice the increase compared to the areas within the Ramsar sites. Most land cover changes within the Ramsar sites occurred closest to their boundaries where more human interactions occurred. It was also found that the fragmentation of flooded vegetation and water was also greater in areas surrounding the Ramsar sites in comparison to areas within the sites. This study also identified human activity as the primary driver of all observed changes, especially for wetlands. The differences observed indicate the effectiveness of Chinese Ramsar sites in wetlands protection and provide invaluable information for future strategic planning. Full article

The global degradation and loss of natural wetlands are increasingly threatening wetland-dependent taxa, particularly waterbirds, which are highly vulnerable to environmental changes. In response to these threats, an increasing number of waterbirds are relocating to surrounding satellite wetlands in search of compensatory habitats. However, how waterbirds utilize these satellite wetlands and respond to varying environmental variables remain poorly understood. In the winter of 2022–2023 and summer of 2023, we conducted surveys on waterbird assemblages in 49 satellite wetlands of different types (reservoirs, aquaculture ponds, paddy fields and natural ponds) surrounding Shengjin Lake, a Ramsar site, and analyzed the relationship between community metrics and environmental factors. Large numbers of waterbirds were recorded during both summer and winter, including several threatened and nationally protected species. Species richness and number of individuals varied significantly across wetland types, with aquaculture ponds supporting the highest number of species and individuals. These two metrics showed positive correlations with wetland areas and landscape connectivity in both seasons. Species richness was also positively correlated with habitat diversity in summer. The number of individuals was positively correlated with habitat diversity and negatively with distance to human settlements, but the pattern was in contrast to that in winter. The Shannon–Wiener diversity index displayed a similar pattern among wetland types in winter but did not in summer. We detected no effects of environmental factors on the diversity index. Species composition differed markedly between wetland types in both seasons, especially between reservoirs and aquaculture ponds. To safeguard waterbird communities in the middle and lower reaches of the Yangtze River, we recommend integrating surrounding satellite wetlands into the regional wetland network and reducing human disturbances, particularly during the winter months. Full article

Wetlands play a vital role in ecosystem sustainability by regulating atmospheric temperature and enhancing human comfort levels. This study aims to evaluate the temperature regulation function of the Nawabganj Wetland, Uttar Pradesh (India), a Ramsar site designated in January 2020, located in a semi-arid region vulnerable to increasing heat waves. The primary objective is to assess the wetland’s influence on microclimatic conditions and human thermal comfort across different seasons. Field surveys were conducted to collect temperature, humidity, wind speed, and vegetation data over three consecutive days in each season: 15–17 May 2019 (pre-monsoon), 12–14 August 2019 (monsoon), and 5–7 October 2019 (post-monsoon). The human comfort index was calculated using field data, while vegetation density and frequency were analyzed based on seasonal variations using the quadrant method. The results indicate that the wetland significantly contributes to local temperature reduction and improved comfort levels. Vegetation plays a crucial role in amplifying this cooling effect, particularly during summer when temperatures range from an average low of 23 °C to a high of 40 °C. In winter, temperatures vary between an average low of 6 °C and a high of 22 °C, with a consistently high humidity level of approximately 94%, further influencing microclimatic conditions. The extent of weed cover varied between 10% and 60% from December to May, reflecting seasonal fluctuations in water levels and wetland health. The study highlights the necessity of effective water and vegetation management, especially during summer, to sustain the wetland’s cooling capacity. Integrating wetland-based strategies into urban planning can enhance environmental sustainability, mitigate climate extremes, and improve human well-being in rapidly urbanizing regions. Full article

Shrimp farming has expanded over coastal areas in Mexico, particularly in the protected regions of Sonora and Sinaloa. Over the past 30 years, the economic activity associated with these farms has grown so much that the amount of shrimp produced in these ponds now exceeds that harvested from traditional shrimp fisheries. Establishing shrimp ponds has led to significant land changes. The construction of these ponds has fragmented local ecosystems, resulting in permanent alterations to areas such as floodplains, mangrove forests, and dunes, many of which are protected zones. This study aimed to investigate the long-term growth of shrimp farms from 1993 to 2022 and their impact on land-use changes in surrounding ecosystems, focusing on protected areas in the Sinaloa and Sonora coastal regions. We analyzed Landsat images using the Google Earth Engine platform. Our findings indicate that shrimp farm development over the past three decades has been extensive, with protected areas experiencing fragmentation and changes. Remote sensing and platforms like Google Earth Engine enable the effective monitoring of these spatiotemporal changes and their impacts, helping to identify the most affected areas. Full article

The study was conducted on the Obedska Bara Ramsar site at two localities, Krstonošića okno and canal Vok, to provide insight into fish community status by analysing fish biomass, biodiversity, and changes after restoration measures. A total of 685 fish samples were examined across four periods, from 2011 to 2023. Biodiversity index, relative biomass, and non-native species were analysed to evaluate the restoration measures’ influence. All parameters showed a negative trend until the restoration works were implemented, after which they increased. This study also provides recommendations to improve the site considering the Mission Restore our Ocean and Waters by 2030. Full article

Lakes are vital freshwater ecosystems that sustain biodiversity, support livelihoods, and drive socio-economic growth globally. However, they face escalating threats from anthropogenic activities, including urbanization, agricultural runoff, and pollution, which are exacerbated by climate change. Phewa Lake in Nepal was selected for this study due to its increasing rates of nutrient enrichment, sedimentation, and pollution. This study evaluated seasonal and spatial water quality variations within the lake by analyzing water samples from 30 sites during the pre-monsoon and post-monsoon seasons. Twenty physicochemical parameters, including the potential of hydrogen (pH), dissolved oxygen (DO), electrical conductivity (EC), and major ions, e.g., calcium (Ca²⁺), magnesium (Mg²⁺), sodium (Na⁺), potassium (K⁺), bicarbonate (HCO₃⁻), chloride (Cl⁻), sulfate (SO₄²⁻), nitrate (NO₃⁻), phosphate (PO₄³⁻), and ammonium (NH₄⁺), were measured. The average pH ranged from 8.06 (pre-monsoon) to 8.24 (post-monsoon), reflecting dilution from monsoon rains and increased carbonate runoff. Furthermore, the DO levels in Phewa Lake averaged 7.46 mg/L (pre-monsoon) and 8.62 mg/L (post-monsoon), with higher values observed post-monsoon due to rainfall-driven oxygenation. Nutrient concentrations were shown to be elevated, with the nitrate concentration reaching 2.31 mg/L during the pre-monsoon period, and the phosphate concentration peaking at 0.15 mg/L in the post-monsoon period, particularly near agricultural runoff zones. The dominant cations in the lake’s hydrochemistry were Ca²⁺ and Mg²⁺, while HCO₃⁻ was the primary anion, reflecting the influence of carbonate weathering. Cluster analysis identified the lake outlet as a high-pollution zone, with the total dissolved solids (TDS) reaching 108–135 mg/L. Additionally, Principal component analysis revealed agricultural runoff and sewage effluents as the main pollution sources. Seasonal dynamics highlighted monsoon-induced dilution and pre-monsoon pollution peaks. These findings underscore the need for targeted pollution control and eutrophication management. By aligning with the sustainable development goals (SDGs) relevant to clean water and climate action, this research provides a replicable framework for sustainable lake management that is applicable to freshwater ecosystems worldwide. Full article

A multi-proxy study of diatoms, palynofacies, and grain size was conducted on a 100 cm core from Arookutty, Vembanad wetland, Kerala, India, to reconstruct paleolimnological changes during the late Holocene, with a focus on natural versus anthropogenic influences. Four distinct depositional phases, from ca. 500 BCE to ca. 400 CE, were identified, aligning with the Roman Warm Period (RWP). The period from ca. 500 BCE to ca. 450 BCE shows high freshwater and marine planktic diatoms, augmented by silicoflagellates and terrestrial organic matter, with a low dinocyst presence, suggesting a dynamic aquatic environment. The period from ca. 450 BCE to ca. 350 BCE is marked by a high sand content, indicating significant runoff and terrestrial influx, along with increased freshwater and marine planktic diatoms and evidence of human activity in the area. Similarly, the period from ca. 350 BCE to ca. 50 CE is characterized by high sand content and strong anthropogenic influences, with a rise in silicoflagellates, pointing to rising sea levels and high monsoonal precipitation. The period from ca. 50 CE to ca. 400 CE initially shows a decrease in sand and an increase in mud, reflecting a weakening southwest monsoon, likely due to solar variations. However, from ca. 300 CE to ca. 400 CE, sand content rises again, accompanied by high terrestrial influx and dinocysts, while silicoflagellates diminish completely. Thus, despite the dominance of the RWP, the coastal region experienced an extended period of reduced monsoonal activity for a particular span. Full article