Search Results (93)

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

Wetland birds are undergoing severe population declines globally, primarily attributed to extensive wetland loss and degradation. The attributes of the landscape surrounding a focal locality, referred to as ‘landscape context’, have been shown to influence the diversity of wetland birds living in the given area. At a global scale, however, the landscape context effects on wetland birds have not been assessed. Here, we assessed the effect of landscape context on the richness of threatened bird species recorded in 334 inland Ramsar wetland sites across the globe. Generalized linear mixed models were used to quantify the relationship between the richness of these bird species and the landscape context of the Ramsar sites. Variation partitioning was used to quantify the independent explanatory power of landscape context for comparison between migratory and non-migratory species. The overall and independent explanatory power of landscape context for the global-scale richness pattern of threatened avifauna reached ca. 17% and 3%, respectively, with the scale of peak explanatory power being 5 times the area of a focal Ramsar site. The independent explanatory power of landscape context was significantly higher for migratory species (ca. 30%) than for non-migratory ones (ca. 3%). Among the landscape context metrics, wetland habitat loss and fragmentation were most strongly associated with the global-scale richness of threatened migrant species at Ramsar sites. Our results suggest that even at macroecological scales, landscape context contributes to shaping the richness pattern of threatened bird species, especially for migrants. These findings provide useful insight for managing landscapes surrounding Ramsar sites, in order to improve conservation effectiveness for wetland birds worldwide. Full article

Human activities and climate change increasingly threaten wetlands worldwide, yet their hydrochemical properties and water quality are often inadequately studied. This research focused on the Ghodaghodi Lake Complex (GLC) and associated lakes in Nepal, a Ramsar-listed site known for its biodiversity and ecological significance. The study was conducted to assess seasonal water quality, investigate the factors influencing hydrochemistry, and assess the lakes’ suitability for irrigation. Forty-nine water samples were collected from the GLC in pre-monsoon and post-monsoon periods. Nineteen physicochemical parameters, such as dissolved oxygen (DO), total dissolved solids (TDS), and major ions (calcium ‘Ca²⁺’, magnesium ‘Mg²⁺’, and bicarbonate ‘HCO₃⁻’), were analyzed using standard on-site and laboratory methods. Statistical methods, including analysis of variance (ANOVA), T-tests, and hydrochemical diagrams, e.g., Piper, were adopted to explore spatial and seasonal variations in water quality, revealing significant fluctuations in key hydrochemical indicators. Results showed marked seasonal differences, with pre-monsoon TDS levels averaging 143.1 mg/L compared to 78.9 mg/L post-monsoon, underscoring evaporation and dilution effects. The hydrochemical analysis identified Ca²⁺-HCO₃⁻ as the dominant water type, highlighting the influence of carbonate weathering on GLC’s water composition. Gibbs, mixing, and Piper diagram analysis supported these findings, confirming the predominance of HCO₃⁻, with Ca²⁺ and Mg²⁺ as the main cations. Additionally, sodium adsorption ratio (SAR) values were consistently below 1, confirming excellent irrigation quality. These findings provided critical data for policymakers and stakeholders, supporting sustainable wetland management and aligning with the United Nations’ Sustainable Development Goals relevant to environmental conservation, i.e., clean water and life on land. Full article

Chilika Lake, a RAMSAR site, is an environmentally and ecologically pivotal coastal lagoon in India facing significant emerging environmental challenges due to anthropogenic activities and natural processes. Traditional in situ water quality monitoring methods are often labor intensive and time consuming. This study presents a novel approach for ex situ water quality monitoring in Chilika Lake, located on the east coast of India, utilizing Google Earth Engine (GEE) and spectral indices, such as the Normalized Difference Turbidity Index (NDTI), Normalized Difference Chlorophyll Index (NDCI), and total suspended solids (TSS). The methodology involves the integration of multi-temporal satellite imagery and advanced spectral indices to assess key water quality parameters, such as turbidity, chlorophyll-a concentration, and suspended sediments. The NDTI value in Chilika Lake increased from 2019 to 2021, and the Automatic Water Extraction Index (AWEI) method estimated the TSS concentration. The results demonstrate the effectiveness of this approach in providing accurate and comprehensive water quality assessments, which are crucial for the sustainable management of Chilika Lake. Maps and visualization are presented using GIS software. This study can effectively detect floating algal blooms, identify pollution sources, and determine environmental changes over time. Developing intuitive dashboards and visualization tools can help stakeholders engage with data-driven insights, increase community participation in conservation, and identify pollution sources. Full article

The morphological aspects of urban growth on wetlands in Africa are under-researched. Using the Densu Delta Ramsar site in Accra, Ghana, as a case study, this paper analyses the morphological patterns and drivers of urban growth and its impact on wetlands. Data were obtained through remote-sensing, ground truthing, and limited key informant interviews. The analysis combined land use/land cover, building coverage and spatial autoregressive and ordinary least square regression techniques with the aid of ArcGIS version 10.8.2, QGIS version 3.34 and STATA version 17 software. The findings reveal that urban growth at the Ramsar site follows discernible spatial patterns consistent with the spreading pancake, village magnet, and ribbon development models. However, the primary force behind these patterns is growing demand for land to meet housing needs, aided by the failure of state institutions to perform their land use control and wetland protection functions. To achieve sustainable urban development, there is an urgent need to ensure effective wetland management by enforcing existing land use, development control, and wetland protection measures. This calls for the strengthening, resourcing, and closer collaboration of the relationships between the various state agencies responsible for urban planning and wetland management. There is also the need to engage and sensitise political leaders to increase their commitment to implementing wetland protection and pro-environmental policies. Full article

The long-term monitoring of wetland ecosystem functioning is critical because wetlands, which provide multiple services, can be affected by human activities and climate change. The aim of this study was to monitor wetland ecosystem functioning in the long term using the Landsat archive. Four contrasting, Ramsar wetlands were selected in boreal, temperate, arid, and tropical areas. First, the annual sum of the normalized difference vegetation index (NDVI-I) was calculated as an indicator of annual net primary productivity for the period 1984–2021 using the continuous change detection and classification (CCDC) algorithm. Next, the influence of the number of Landsat images and class of land use and land cover (LULC) on the accuracy of the CCDC was investigated. Finally, correlations between annual NDVI-I and climate were analyzed. The results revealed that NDVI-I accuracy was influenced mainly by the LULC class and to a lesser extent by the number of cloud-free Landsat observations. Infra- and inter-site variations in NDVI-I were high and showed an overall increasing trend. NDVI-I was positively correlated with the mean temperature. This study shows that this approach applied in contrasting sites is robust for the long-term monitoring of wetland ecosystem functioning and can be used to improve the implementation of international biodiversity conservation policies. Full article

This study evaluated the ingestion of microplastics (MP) by copepods in Terminos Lagoon (TL), a RAMSAR-listed site in the southern Gulf of Mexico. The evaluation was carried out in two contrasting seasons of 2022, as follows: the dry (April) and the rainy (October). Copepods were collected using a conical plankton net (mesh size of 200 μm). In the laboratory, a pool of all pelagic adult copepod taxa was picked, and the MP inside the organisms were extracted, classified, and photographed using traditional optical and scanning electron microscopy. A total of 268 MP particles were extracted from the interior of copepods; among them, 149 and 119 corresponded to the dry and rainy seasons, respectively. The ingestion rate in the dry season was 0.14, while in the rainy season, it was 0.11. In addition, fibers, plastic fragments, and microspheres with different colors (blue, red, black, green, transparent, and multicolored), sizes, forms (angular, round, triangular, and twisted), and textures were also detected. Fibers were the most abundant MP found in a proportion of more than 85%. In addition, in some sampling sites, microspheres were observed with high relative abundance values (80%). In some sites, fragments reach 20% of the total abundance. Significant differences were observed between the two seasons. The sites closest to the urban area adjacent to TL observed high diversity and abundance of MP. The higher abundance of MP in the dry season is due to lower river discharge, on the other hand. Thus, MP particles accumulate and become available for consumption by copepods. This is the first study that has revealed that the MP was ingested by the copepods in TL. Furthermore, this study provides a baseline information for future research on the abundance of MP in the Gulf of Mexico region. Full article

Ornamental gardens are probably the most important source of invasive alien plants. However, the role of roadside shrines as a source of alien plant introductions remains unexplored. Herein, we are reporting the cultivated alien flora of a roadside shrine (devoted to the ‘Difunta Correa’) in south-eastern Spain, while making a prior assessment of the risk of spreading in the surroundings. In an area of less than 50 m², up to 20 plant taxa were identified, with the vast majority of them being alien. Some of the observed alien taxa can be very problematic (e.g., Kalanchoe × houghtonii) and are even included in the Spanish catalogue of invasive species (such as Opuntia ficus-indica). Although the shrine is not affecting the local biodiversity yet (though a few taxa are showing the first signs of spread), it is located just 1 km away from a valuable protected area (included within the Natura 2000 network of the European Union and also recognized as a Ramsar site). Roadside shrines and similar places (e.g., memorials or calvaries) should be, thus, regarded as a potential source of alien plant introductions; thus, monitoring is recommended, particularly when close to protected areas. Full article

Dinoflagellates belonging to the genus Hematodinium are key parasites of marine crustaceans, primarily decapods. In this study, we document the first report of H. perezi Chatton & Poisson, 1930 on the African Atlantic coast. This is also the first parasite record in the invasive non-native Atlantic blue crab Callinectes sapidus Rathbun, 1896 in Morocco. Specimens of C. sapidus were sampled in winter 2023 from two Ramsar sites on the Moroccan Atlantic, namely Merja Zerga and Oualidia Lagoons, and were screened to detect the presence of parasites in their hemolymph. Based on staining fresh hemolymph smears, we did not detect Hematodinium in any of the 36 investigated individuals (20 and 16 from Merja Zerga and Oualidia Lagoons, respectively), probably due to methodological artifacts. The PCR-based method was revealed to be more accurate in diagnosing the Hematodinium parasite. It showed that at Merja Zerga Lagoon, 13 individuals of C. sapidus were infected by the parasite (prevalence: 65%) in comparison to four at Oualidia Lagoon (25%). Genetic analysis, based on the ITS1 rDNA gene from Hematodinium, confirmed the sequences as being those of Hematodinium perezi. Full article