Limnological Review

20 pages, 7457 KB

Open AccessArticle

Evaluating a GIS-Based Multi-Criteria Decision Analysis Framework for Eutrophication Susceptibility in Lough Tay, Ireland

by Anja Batina

Limnol. Rev. 2026, 26(2), 17; https://doi.org/10.3390/limnolrev26020017 - 29 Apr 2026

Abstract

Freshwater ecosystems are increasingly threatened by eutrophication and other anthropogenic and climate-driven pressures that undermine ecological functioning and biodiversity. This study evaluates the transferability of a GIS-based multi-criteria decision analysis (GIS–MCDA) framework with Fuzzy Analytic Hierarchy Process (F-AHP), originally developed for a shallow [...] Read more.

Freshwater ecosystems are increasingly threatened by eutrophication and other anthropogenic and climate-driven pressures that undermine ecological functioning and biodiversity. This study evaluates the transferability of a GIS-based multi-criteria decision analysis (GIS–MCDA) framework with Fuzzy Analytic Hierarchy Process (F-AHP), originally developed for a shallow coastal lake, to a morphologically distinct deep upland lake (Lough Tay, Ireland). Monthly in situ measurements at a single monitoring point in 2024 were analysed together with meteorological variables using Spearman rank correlations. Because spatial interpolation of in-lake water quality parameters was not feasible, eutrophication susceptibility was mapped using four external spatial drivers: distance from water resources (River Cloghoge inflows), land-based nitrogen export potential, distance from environmental pollutants represented by the transportation network, and a wind exposure index derived from a DEM and wind-rose analysis. Criteria were standardized with fuzzy membership functions, weighted using F-AHP (consistency index 0.056), and aggregated using weighted linear combination at 25 m resolution. The resulting Eutrophication Susceptibility Index (ESI) ranged from 0.18 to 0.81, indicating generally moderate to good conditions, with higher ESI values concentrated in the northern lake sector near inflow zones. The results demonstrate that GIS–MCDA can be adapted to lakes with limited monitoring by relying on external drivers, providing a spatial proxy for susceptibility rather than measured trophic status. Full article

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28 pages, 1572 KB

Open AccessArticle

Assessment of Groundwater Quality in Some Regions of Kosovo Based on Physico-Chemical and Microbiological Parameters

by Florjana Zogaj, Tatjana Blazhevska, Fatbardh Sallaku, Rakesh Ranjan Thakur, Hazir Çadraku, Upaka Rathnayake, Debabrata Nandi, Vesna Knights, Gorica Pavlovska, Pajtim Bytyçi, Erinda Lika, Osman Fetoshi, Valentina Velkovski, Rozeta Hasalliu and Bojan Đurin

Limnol. Rev. 2026, 26(2), 16; https://doi.org/10.3390/limnolrev26020016 - 23 Apr 2026

Abstract

Physicochemical and microbiological parameters are important indicators of drinking water quality. This study assessed the quality of groundwater used for drinking in four regions of Kosovo at 16 locations using an integrated assessment framework that combined physicochemical, microbiological, and Water Quality Index (WQI) [...] Read more.

Physicochemical and microbiological parameters are important indicators of drinking water quality. This study assessed the quality of groundwater used for drinking in four regions of Kosovo at 16 locations using an integrated assessment framework that combined physicochemical, microbiological, and Water Quality Index (WQI) approaches. The results reveal substantial spatial variability in water quality. While most physicochemical parameters remained within recommended limits, elevated values of total dissolved solids (up to 2792.5 mg/L), electrical conductivity (up to 2768.5 µS/cm), nitrate (up to 60.75 mg/L), and phosphate (up to 0.875 mg/L) were observed at several locations, indicating localized hydrogeochemical and anthropogenic influences. Dissolved oxygen levels were generally low (0.68–5.49 mg/L), reflecting limited aeration conditions in groundwater systems. Microbiological analysis revealed critical contamination, with Escherichia coli concentrations up to 299.9 CFU/100 mL, and all sampling sites exceeded permissible limits, indicating widespread fecal pollution and rendering the groundwater unsafe for direct consumption. WQI assessment further confirmed this condition, where 93.75% of locations were classified as medium quality using the NSF-WQI method, whereas the WA-WQI method categorized 68.75% of samples as poor and 6.25% as very poor. The novelty of this study lies in the integrated evaluation of hydrogeochemical processes and microbiological contamination using dual WQI methods and multivariate statistical analysis, providing a comprehensive understanding of groundwater degradation pathways. The findings are significant for policymakers, environmental managers, and public health authorities, highlighting the urgent need for groundwater treatment, improved sanitation infrastructure, and sustainable water resource management strategies in vulnerable regions. Full article

(This article belongs to the Special Issue Freshwater Microbiology and Public Health)

37 pages, 8485 KB

Open AccessArticle

Geoecological Study of Lake and Basin Systems: An Applied Analysis of the Somyne Ramsar Wetland, Ukraine

by Ivan Kovalchuk, Vitalii Martyniuk, Vasyl Korbutiak, Ivan Zubkovych, Tetiana Pavlovska, Valentyna Stelmakh and Yaroslav Kurepa

Limnol. Rev. 2026, 26(2), 15; https://doi.org/10.3390/limnolrev26020015 - 17 Apr 2026

Abstract

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 [...] Read more.

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

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33 pages, 2506 KB

Open AccessArticle

Evaluation of the Trophic State of Lagoons and Reservoirs in High Andean Southern Peru

by Jose Alberto Calizaya-Anco, Yvonne Magalí Cutipa-Díaz, David Gonzalo Rubira-Otarola, Katia Aracely Denegri-Limache and Elmer Marcial Limache-Sandoval

Limnol. Rev. 2026, 26(2), 14; https://doi.org/10.3390/limnolrev26020014 - 14 Apr 2026

Abstract

High Andean lagoons in southern Peru have critical hydrological and ecological functions; however, long-term time series integrating trophic, integral quality, and metal contamination metrics to support adaptive management are lacking. A total of 1846 records (2015–2024) from four systems (3100–4600 m a.s.l.) were [...] Read more.

High Andean lagoons in southern Peru have critical hydrological and ecological functions; however, long-term time series integrating trophic, integral quality, and metal contamination metrics to support adaptive management are lacking. A total of 1846 records (2015–2024) from four systems (3100–4600 m a.s.l.) were analyzed using seven indices assessing trophic status (TSItsr, TRIX), general water quality (OWQI, WQIHA, CCME-WQI), and metal contamination (HPI, CD). Temporal trends were assessed using Mann–Kendall and Theil–Sen slope; spatial heterogeneity using Kruskal–Wallis and Dunn–Bonferroni comparisons; controlling factors using distance-based redundancy analysis (999 permutations); and functional typology using Ward’s hierarchical clustering on Z-standardized data. 93% of the series lacked monotonic trends (52/56 lagoon–stratum × index combinations), demonstrating high interannual stability; spatial variance was marked (ε² = 0.73 in CCME-WQI). Distance-based redundancy analysis (db-RDA) explained 24.6% of total variability, with lake identity as the dominant driver (~45%), followed by temporal change (~8%). Four functional archetypes emerged, including a metal-eutrophic hotspot (HPI ≈ 213; CD ≈ 19) and recovering reservoirs with intermediate water quality indicators. Joint thresholds (TSItsr ≥ 60 + HPI ≥ 100) establish early-warning criteria, with Paucarani (HPI = 213) approaching the critical domain where metal-driven stress may facilitate cyanobacterial dominance. Systems show temporal resilience but strong spatial divergence induced by local pressures. The proposed typology and thresholds provide an operational basis for early warnings and prioritization of remediation actions in high-mountain ecosystems subject to increasing anthropogenic stress. Full article

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18 pages, 3600 KB

Open AccessReview

Drivers of the Worldwide Distribution of Raphidiopsis raciborskii: Evidence from Experimental to Field Studies

by Florencia Soledad Alvarez Dalinger, Lucia Verónica Laureano, Liliana Beatriz Moraña, Claudia Nidia Borja, María Laura Sanchéz and Verónica Laura Lozano

Limnol. Rev. 2026, 26(2), 13; https://doi.org/10.3390/limnolrev26020013 - 12 Apr 2026

Abstract

Raphidiopsis raciborskii is one of the most widely reported cyanobacteria worldwide, responsible for dense blooms and cyanotoxin production. Classified as invasive, it has been documented across all continents except Antarctica. While its distribution has been extensively studied, abiotic factors have consistently emerged as [...] Read more.

Raphidiopsis raciborskii is one of the most widely reported cyanobacteria worldwide, responsible for dense blooms and cyanotoxin production. Classified as invasive, it has been documented across all continents except Antarctica. While its distribution has been extensively studied, abiotic factors have consistently emerged as the main determinants of its success, which are therefore the focus of the present study. The objective of the present review is to synthesize findings from both experimental and field-based studies to identify which are the key drivers of its dominance. In total, 30 abiotic factors were reported, reflecting the broad strategies of the species. Results show the temperature as a consistent universal factor (11–35 °C), while differences were found regarding nutrient dynamics. Particularly, nitrogen forms and N/P ratios predominated in field-based evidence, whereas photosynthetically active radiation was disproportionately emphasized within experimental studies under controlled conditions. Factors such as salinity and micronutrients, and synergistic interactions remain critically understudied, limiting predictive capacity under global change scenarios. Understanding which combinations of these drivers create favorable conditions is essential for anticipating bloom dynamics in order to establish management strategies for avoiding or mitigating the negative impact of them. Full article

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9 pages, 828 KB

Open AccessArticle

Confirmation of Species Identification and New Locations of Potamogeton nodosus Poir. in Biebrza National Park Region

by Steven Jacobs, Dimitri Van Pelt, Ignacy Kardel, Martijn Van Roie and Jonas Schoelynck

Limnol. Rev. 2026, 26(2), 12; https://doi.org/10.3390/limnolrev26020012 - 1 Apr 2026

Abstract

In 2013, plants tentatively identified as Potamogeton nodosus Poir. were discovered in the Biebrza River (NE Poland). In this study, the authors confirm the presence of P. nodosus by collecting new specimens at the original location and analyzing their microscopic characteristics, an essential [...] Read more.

In 2013, plants tentatively identified as Potamogeton nodosus Poir. were discovered in the Biebrza River (NE Poland). In this study, the authors confirm the presence of P. nodosus by collecting new specimens at the original location and analyzing their microscopic characteristics, an essential step due to significant overlap in macromorphological traits with the closely related P. × fluitans complex. Additionally, new occurrences of the species within Biebrza National Park are reported, and the possibility that its spread is linked to rising river water temperatures is discussed. The authors provide evidence of an increasing average water temperature in the Biebrza River and of a northbound expansion of P. nodosus in Europe. Given similar trends observed elsewhere in Northern Europe, it is likely that P. nodosus will continue to expand its range northward in response to ongoing climate change. Full article

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24 pages, 935 KB

Open AccessReview

Inventory of Metazoan Parasites Associated with Anostomids in South America

by Wallas Benevides Barbosa de Sousa, Maria Fernanda Barros Gouveia Diniz and Fabio Hideki Yamada

Limnol. Rev. 2026, 26(1), 11; https://doi.org/10.3390/limnolrev26010011 - 22 Mar 2026

Abstract

Anostomidae is one of the most diverse families within the order Characiformes and is widely distributed across the river basins of the Neotropical region. Anostomids are known to host a rich diversity of metazoan parasites, including ectoparasites, such as monopisthocotylans, and endoparasites, such [...] Read more.

Anostomidae is one of the most diverse families within the order Characiformes and is widely distributed across the river basins of the Neotropical region. Anostomids are known to host a rich diversity of metazoan parasites, including ectoparasites, such as monopisthocotylans, and endoparasites, such as nematodes, cestodes, and digeneans. The present study aims to develop an inventory of metazoan parasites recorded in fish of the Anostomidae family. A bibliographic review of metazoan parasite species in anostomids was conducted, using searches in different databases. This bibliographic review was complemented with information from books and book chapters on ictioparasitology. The data were compiled until January 2025. Based on the review, 191 taxa (126 are described at the species level and 65 were identified only to the genus level or higher taxonomic categories) of metazoan parasites associated with anostomid fishes were found. Monopisthocotyla and Nematoda were the taxonomic groups with the most parasitic associations at the species level, with 31 and 30 species, respectively. This study presents a comprehensive and updated inventory of metazoan parasites associated with fish from the family Anostomidae, covering over 170 years of research (1850–2025). This survey highlights the importance of anostomids as hosts for a rich parasitic fauna. Full article

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26 pages, 1097 KB

Open AccessReview

Public Health Risks of Pathogenic Bacteria in Freshwater Bodies: A Review of Quantitative Microbial Risk Assessment Approaches and Applications

by Manu Priya, Shvetambri Jasrotia and Akebe Luther King Abia

Limnol. Rev. 2026, 26(1), 10; https://doi.org/10.3390/limnolrev26010010 - 14 Mar 2026

Abstract

Freshwater ecosystems play an important role in human survival, ecosystem functioning, and biodiversity conservation, yet industrialisation and urbanisation dump over 80% of untreated sewage into them. This inadequate wastewater management leads to enteric pathogens like Escherichia coli, Salmonella, Shigella, Campylobacter [...] Read more.

Freshwater ecosystems play an important role in human survival, ecosystem functioning, and biodiversity conservation, yet industrialisation and urbanisation dump over 80% of untreated sewage into them. This inadequate wastewater management leads to enteric pathogens like Escherichia coli, Salmonella, Shigella, Campylobacter, Vibrio cholerae, Pseudomonas aeruginosa, and Legionella pneumophila that are responsible for a wide range of waterborne human diseases globally with extensive morbidity and mortality. The World Health Organization (WHO) estimates that at least 2 billion individuals drink water contaminated with pathogens, resulting in illnesses like cholera, dysentery, and diarrhoea, and approximately 50,000 diarrheal deaths annually. Classical epidemiology approaches are the basis for determining disease burden in public health, but they are limited in their capacity to predict future health risks. Quantitative microbial risk assessment (QMRA) addresses this by estimating the potential health risks of any exposure to microbial pathogens in any environment using four key elements, which include the identification of the microbial hazards, human exposure to the hazard through diverse activities, dose–response relationships, and the estimated risk of the infection. This review summarises information on freshwater pathogens, their occurrence, sources and health implications. The methodological approaches of QMRA in freshwater systems are reviewed with examples drawn from recreational activities, drinking water, and wastewater-impacted environments. Global QMRA studies indicate a wide range of infection risk estimates, reflecting differences in water sources, pathogens, and exposure conditions. Thus, QMRA is known to be a valuable public health tool for freshwater ecosystems, linking microbial contamination dynamics to health risk estimates that support proactive management and policy-relevant decision-making. Full article

(This article belongs to the Special Issue Freshwater Microbiology and Public Health)

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12 pages, 1344 KB

Open AccessArticle

Allelopathic Interference of the Cyanobacterium Raphidiopsis raciborskii Exudates on Photosynthetic Traits of Photosynthesizing Microorganisms

by Camila Nader, Maria Cecília Miotto, Carlos Yure B. Oliveira and Leonardo R. Rörig

Limnol. Rev. 2026, 26(1), 9; https://doi.org/10.3390/limnolrev26010009 - 13 Mar 2026

Abstract

Raphidiopsis raciborskii (formerly Cylindrospermopsis raciborskii) is a bloom-forming cyanobacterium that employs the production of toxins and other secondary metabolites as a competitive and allelopathic strategy. This study evaluated the effects of exudates from R. raciborskii cultivated under three nitrogen-to-phosphorus (N:P) ratios on [...] Read more.

Raphidiopsis raciborskii (formerly Cylindrospermopsis raciborskii) is a bloom-forming cyanobacterium that employs the production of toxins and other secondary metabolites as a competitive and allelopathic strategy. This study evaluated the effects of exudates from R. raciborskii cultivated under three nitrogen-to-phosphorus (N:P) ratios on the photosynthetic performance of Limnothrix sp. (cyanobacterium), Chlorella sp. (green algae), and Raphidocelis subcapitata (green algae), using pulse-amplitude-modulated (PAM) fluorometry. Rapid light curves (rETR) obtained under different N:P ratios and across the three target species exhibited similar response patterns. Likewise, effective quantum yield (ΦPSII), regulated (Y(NPQ)) and non-regulated (Y(NO)) energy dissipation showed comparable profiles among treatments after 24 h of exposure. Overall, the results of the present study indicate that, within the 24 h exposure period and based on the fluorescence parameters measured, exudates produced by R. raciborskii under the tested nutrient conditions did not cause measurable alterations in the photosynthetic performance of the three evaluated species. Full article

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13 pages, 3772 KB

Open AccessCommunication

Spatial Distribution and Composition of Solid Waste Pollution Along the Banks of the Amazon River, Brazil

by Gabriel dos Anjos Guimarães, Gysele Maria Morais Costa, Isreele Jussara de Azevedo Rodrigues, Manoel Henrique de Souza Neto, Gustavo Frigi Perotti, Bruno Sampaio Sant’Anna and Gustavo Yomar Hattori

Limnol. Rev. 2026, 26(1), 8; https://doi.org/10.3390/limnolrev26010008 - 5 Mar 2026

Abstract

Pollution from solid waste results mainly from improper disposal and inadequate waste management, causing environmental degradation and risks to human health. This study characterized solid waste pollution along the left bank of the Amazon River within the urban segment of Itacoatiara, Brazil. Eleven [...] Read more.

Pollution from solid waste results mainly from improper disposal and inadequate waste management, causing environmental degradation and risks to human health. This study characterized solid waste pollution along the left bank of the Amazon River within the urban segment of Itacoatiara, Brazil. Eleven sampling points were established across upstream, midstream and downstream sections. Solid waste was present at densities ranging from 0 to 0.65 items·m⁻², with a mean density of 0.15 ± 0.14 items·m⁻². Higher concentrations were observed in the midstream sections of the left bank (0.21 ± 0.16 items·m⁻²), and statistical analyses showed significant differences among sections. Plastics predominated among all materials (0.50 ± 0.60 items·m⁻²), and statistical analyses showed significant differences among the types of solid waste, with fragments mainly originating from bags, bottles, and fibers. Plastics were recorded in most sampling sections, with particularly high abundance in the midstream sections of the river (0.98 ± 0.80 items·m⁻²) and statistical analyses showed significant differences among sections and across material types. According to the general index and the clean coast index, sampling areas ranged from “clean” to “extremely dirty”, with midstream sections most impacted. The plastic abundance index indicated high plastic contamination, and hazardous waste was more frequent in the upstream and midstream sections. The environmental status index classified all sections as both “good” and “bad”, indicating compromised environmental quality and ecological integrity. These results show human pressure on the Amazon River banks and degraded environmental quality, supporting waste management policies, mitigation, monitoring, and environmental education to protect ecosystems and reduce risks to riverside communities. Full article

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14 pages, 3283 KB

Open AccessArticle

Growth of Chrysopogon zizanioides in Floating Treatment Wetlands with Different Substrates for the Remediation of an Urban River

by Luis Alfredo Hernández-Vásquez, Mauricio Rojas-Ascensión, Sergio Reyes Rosas, Rubén Daniel Hernández Cruz, Miguel Ángel Vega-Ortega, Gregorio Hernández-Salinas, Marco Antonio Benítez-Espíndola and Luis Carlos Sandoval Herazo

Limnol. Rev. 2026, 26(1), 7; https://doi.org/10.3390/limnolrev26010007 - 20 Feb 2026

Abstract

Urban river degradation demands remediation strategies that are both environmentally sustainable and technically feasible. This study evaluated the performance of Floating Treatment Wetlands (FTWs) vegetated with Chrysopogon zizanioides (vetiver) and incorporating four substrate configurations: leaf litter (LL), red volcanic rock (RVR), corn cobs [...] Read more.

Urban river degradation demands remediation strategies that are both environmentally sustainable and technically feasible. This study evaluated the performance of Floating Treatment Wetlands (FTWs) vegetated with Chrysopogon zizanioides (vetiver) and incorporating four substrate configurations: leaf litter (LL), red volcanic rock (RVR), corn cobs (CC), and a composite mixture of all three, for the rehabilitation of the “Paseo de Los Ahuehuetes” River in Veracruz, Mexico. Over a 182-day monitoring period, in situ water quality parameters and plant growth responses were systematically assessed. The results indicate that substrate selection is a decisive design factor governing the establishment and development of C. zizanioides in FTWs. Among the substrates tested, LL exhibited the most favorable performance, achieving the highest plant survival (82%), enhanced shoot elongation (71.5 ± 12.1 cm), greater root development (49.7 ± 10.0 cm), and the highest relative growth rate (0.028 g g⁻¹ d⁻¹), with statistically significant differences (p < 0.05) compared to CC. Additionally, localized improvements in water quality within the FTW zone were observed, including an increase in dissolved oxygen (2.07%) and a reduction in total dissolved solids (5.65%), likely associated with intensified rhizospheric processes. Overall, these findings identify leaf litter as a low-cost, locally available, and environmentally sustainable substrate that enhances vetiver establishment in FTWs. The study provides practical, evidence-based criteria for the design of nature-based phytoremediation systems aimed at the restoration of urban river ecosystems. Full article

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27 pages, 6788 KB

Open AccessArticle

From Expert-Based Evaluation to Data-Driven Modeling: Performance-Based Flood Susceptibility Mapping

by Mustafa Tanrıverdi and Tülay Erbesler Ayaşlıgil

Limnol. Rev. 2026, 26(1), 6; https://doi.org/10.3390/limnolrev26010006 - 18 Feb 2026

Abstract

Floods are natural disasters that cause significant socioeconomic and environmental losses in both urban and rural areas. Within the framework of spatial planning, precautionary measures against flood hazards can be developed using analytical approaches based on different modeling techniques. In this study, flood-prone [...] Read more.

Floods are natural disasters that cause significant socioeconomic and environmental losses in both urban and rural areas. Within the framework of spatial planning, precautionary measures against flood hazards can be developed using analytical approaches based on different modeling techniques. In this study, flood-prone areas in the Melen Basin, Türkiye, were identified and mapped using five statistical methods, namely Frequency Ratio (FR), Shannon Entropy (SE), Evidential Belief Function (EBF), and the hybrid models EBF–SE and EBF–FR. The analysis was conducted using a flood inventory and environmental datasets covering the period 2019–2024, including elevation, slope, aspect, land use, plan and profile curvature, drainage density, distance to river, curve number, long-term average precipitation, geological formation, soil depth, topographic wetness index, sediment transport, and stream power index. Model performances were evaluated using the Receiver Operating Characteristic (ROC) curve and the Area Under the Curve (AUC). The results indicate that the SE method achieved the highest predictive performance (AUC = 0.979), followed by FR (0.974), EBF–SE (0.972), EBF–FR (0.968), and EBF (0.966). According to the FR and SE models, elevation, lithology, and slope were identified as the most influential factors in flood occurrence. In the evaluation of the success index of the models, the following values were determined according to their size: EBF–SE (96.0), SE (94.4), EBF (91.8), FR (81.9), and EBF–FR (79.4). In the classification of flood sensitivity maps, Natural Breaks (Jenks) is the most successful method according to the success index. The findings demonstrate that data-driven and hybrid models can effectively support flood risk assessment and provide valuable input for land-use planning and flood risk management. Full article

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7 pages, 1130 KB

Open AccessPerspective

From Lakes in Poland to Global Water Security: A 25-Year Perspective from the Polish Limnological Society

by Włodzimierz Marszelewski, Piotr Rzymski and Piotr Klimaszyk

Limnol. Rev. 2026, 26(1), 5; https://doi.org/10.3390/limnolrev26010005 - 17 Feb 2026

Abstract

The designation of 2026 as the World Economic Forum’s Year of Water underscores the growing recognition of freshwater systems as critical to climate resilience, biodiversity conservation, and socio-economic stability. Coinciding with this global initiative, the Polish Limnological Society (PLS) marks its 25th anniversary, [...] Read more.

The designation of 2026 as the World Economic Forum’s Year of Water underscores the growing recognition of freshwater systems as critical to climate resilience, biodiversity conservation, and socio-economic stability. Coinciding with this global initiative, the Polish Limnological Society (PLS) marks its 25th anniversary, offering an opportunity to reflect on the evolving role of limnology in addressing contemporary environmental challenges. Founded in 2001, PLS has advanced integrative research on inland waters, fostered international scientific cooperation, supported scholarly publishing, and promoted societal engagement with freshwater issues. This Perspective highlights society’s contributions to understanding the natural and anthropogenic transformations of lakes and reservoirs, its commitment to open science and education, and its engagement in climate advocacy to address global water security. We argue that the experience of PLS illustrates how sustained, community-driven limnological science can inform policy, management, and public discourse, reinforcing the imperative to safeguard inland waters in an era of accelerating global change. Full article

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9 pages, 866 KB

Open AccessArticle

Hematological Values of Two Species of Amazonian Caimans, Caiman crocodilus and Melanosuchus niger

by Adriano Teixeira de Oliveira, Marcio Quara de Carvalho Santos, Jefferson Raphael Gonzaga de Lemos, Ariany Rabello da Silva Liebl, Maria Fernanda da Silva Gomes, Maiko Willas Soares Ribeiro, Rayana Melo Paixão, Suelen Miranda dos Santos, Adriene Nuzia de Almeida Carvalho, Cristiane Cunha Guimarães, João Paulo Ferreira Rufino, Lucas Maia Garcês, Caterina Faggio and Paulo Henrique Rocha Aride

Limnol. Rev. 2026, 26(1), 4; https://doi.org/10.3390/limnolrev26010004 - 6 Feb 2026

Abstract

Determining hematological values is essential to provide baseline health and condition data. We evaluated the hematological parameters of free-living individuals of Caiman crocodilus and Melanosuchus niger from the middle Negro River region of Brazil. We captured 18 C. crocodilus and 16 M. niger [...] Read more.

Determining hematological values is essential to provide baseline health and condition data. We evaluated the hematological parameters of free-living individuals of Caiman crocodilus and Melanosuchus niger from the middle Negro River region of Brazil. We captured 18 C. crocodilus and 16 M. niger. Blood was drawn using syringes containing 10% EDTA, and blood parameters were determined as previously described. The analyzed erythrocyte parameters were similar across the species, demonstrating that, despite their different sizes, they share similar strategies for oxygen absorption and transport in the blood. In the morphological analysis of blood cells, erythrocytes, erythroblasts, thrombocytes, lymphocytes, neutrophils, azurophils, heterophils, and basophils were found, and, in the quantification of leukocytes and thrombocytes, it was noted that lymphocytes are the central cells in the blood of the Amazonian caiman. In the plasma metabolite results, no significant differences were observed between glucose and total protein levels. Key physiological parameters were established to assess the health of C. crocodilus and M. niger, enabling the application of this information to sustainable captive production programs and helping to reduce pressure on wild populations. Full article

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9 pages, 2410 KB

Open AccessArticle

First Record of the Invasive Species Melanoides tuberculata (Müller, 1774) (Gastropoda: Thiaridae) in a Tourist Waterfall Complex in the State of Maranhão, Brazil

by Guilherme Silva Miranda, João Gustavo Mendes Rodrigues, Thamirys Borges Galdino, Marcia Regina da Silva Costa, Rafael Costa Leite and Thiago Ferreira Soares

Limnol. Rev. 2026, 26(1), 3; https://doi.org/10.3390/limnolrev26010003 - 6 Feb 2026

Abstract

Melanoides tuberculata is one of the world’s main invasive snail species; therefore, mapping its occurrence is essential for predicting its dispersion patterns and proposing control measures. This study aimed to map the occurrence of M. tuberculata and its associated parasites in a tourist [...] Read more.

Melanoides tuberculata is one of the world’s main invasive snail species; therefore, mapping its occurrence is essential for predicting its dispersion patterns and proposing control measures. This study aimed to map the occurrence of M. tuberculata and its associated parasites in a tourist waterfall complex located in Fortaleza dos Nogueiras, Southern Maranhão, Brazil. We collected snails over three months (July, August, and September 2025) in the Castanhão, Esmeralda, and Recanto das Águias waterfalls, and in the Panela stream, to estimate their reproductive stage and to assess the presence of parasites. We demonstrated for the first time the occurrence of M. tuberculata at all evaluated collection points. Morphological data of the shells suggested that the M. tuberculata populations were in the initial phase of their reproductive cycle; however, some specimens showed a complete reproductive stage. Additionally, we found M. tuberculata infected with trematode larvae that resembled the Gymnocephalus-type cercariae in the Castanhão waterfall and Panela stream. Therefore, we updated the distribution of M. tuberculata in Brazil and discussed the possible environmental and public health impacts of this species in the study area. Full article

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18 pages, 3379 KB

Open AccessArticle

Fish Communities and Management Challenges in Three Ageing Tropical Reservoirs in Southwestern Nigeria

by Olumide Temitope Julius, Francesco Zangaro, Roberto Massaro, Marco Rainò, Francesca Marcucci, Armando Cazzetta, Franca Sangiorgio, John Bunmi Olasunkanmi, Valeria Specchia, Oluwafemi Ojo Julius, Mahallelah Shauer, Alberto Basset and Maurizio Pinna

Limnol. Rev. 2026, 26(1), 2; https://doi.org/10.3390/limnolrev26010002 - 4 Jan 2026

Abstract

Three ageing reservoirs in Ekiti State, Nigeria (Ureje constructed in 1958, Egbe in 1982, and Ero in 1989), were comparatively assessed to evaluate fish assemblages and their conservation relevance. Despite the absence of formal fisheries governance, all three reservoirs supported temporally stable fish [...] Read more.

Three ageing reservoirs in Ekiti State, Nigeria (Ureje constructed in 1958, Egbe in 1982, and Ero in 1989), were comparatively assessed to evaluate fish assemblages and their conservation relevance. Despite the absence of formal fisheries governance, all three reservoirs supported temporally stable fish communities with low overall diversity. A core assemblage of six species dominated across sites, while species richness increased from seven species in the small urban Ureje reservoir to nine species in the larger and more rural Ero reservoir. Four native species that have become locally scarce in surrounding river systems (Heterotis niloticus, Parachanna obscura, Hepsetus odoe, and Hyperopisus bebe) persisted at low but consistent abundance. Aquatic environmental variables remained within suitable limits for freshwater fishes, and trophic structure appeared intact across the reservoirs. Catch density was substantially higher in the urban reservoir compared to the rural systems, reflecting spatial differences in fishing intensity. Overall, the findings demonstrate that small tropical reservoirs can function as important freshwater habitats that sustain fish biodiversity and fisheries production in modified landscapes. Full article

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12 pages, 3402 KB

Open AccessArticle

Assessment of Changes in the Size Structure of Ichthyofauna Based on Hydroacoustic Studies, and the Possibility of Assessing Changes in the Ecological State of Lakes on the Example of Lake Dejguny

by Andrzej Hutorowicz

Limnol. Rev. 2026, 26(1), 1; https://doi.org/10.3390/limnolrev26010001 - 30 Dec 2025

Abstract

The ecological status of lakes based on ichthyofauna, as defined by the Water Framework Directive, is assessed using intercalibrated methods. However, the methods adopted (in Poland, the Lake Fish Index LFI-EN method, based on results of one-off fishing with multi-mesh gillnets) are labor-intensive [...] Read more.

The ecological status of lakes based on ichthyofauna, as defined by the Water Framework Directive, is assessed using intercalibrated methods. However, the methods adopted (in Poland, the Lake Fish Index LFI-EN method, based on results of one-off fishing with multi-mesh gillnets) are labor-intensive and do not allow for frequent repeat testing. Therefore, the concept of a simple model describing changes in the relative number of single traces in the vertical profile (according to the TS target strength distribution) in a lake is presented, as well as an index (the sum of deviations from such a model), enabling quantification of the similarity of TS distributions in lakes with this model. Preliminary analyses were conducted on acoustic data collected in Lake Dejguny. This lake—the condition of which could be estimated based on historical data using the relationships between LFI and the degree of lake eutrophication (expressed by Carlson’s TSI)—was assessed as having a good status in 2006, whereas in 2021, (based on LFI-EN) it had a moderate status. The study tested the TS distribution model, calculated as the arithmetic mean of the relative number of single traces in 2 m-thick layers. It was also shown that the proposed indicator can effectively signal deterioration of ecological status—the sum of the absolute values of the TS distribution deviations in 2021 (moderate status) from the model was more than seven times greater than the sum of the deviations of the distributions from which the model was built (good status). The obtained results confirmed the hypothesis about the possibility of determining a characteristic distribution of single traces in the vertical profile when the lake was classified as being in good condition. Full article

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15 pages, 1290 KB

Open AccessArticle

Do Urban Trout Streams Have Higher Fish Community Diversity and Taxa Richness but Reduced Biotic Integrity Compared to Their Rural Counterparts? A Pilot Study

by Neal D. Mundahl

Limnol. Rev. 2025, 25(4), 55; https://doi.org/10.3390/limnolrev25040055 - 9 Dec 2025

Abstract

Urban streams are subjected to a variety of impacts from stormwater runoff, channelization, routing through culverts, and highly modified riparian zones, all of which can have negative effects on stream habitats and resident fish communities. Coldwater trout streams in urban areas may be [...] Read more.

Urban streams are subjected to a variety of impacts from stormwater runoff, channelization, routing through culverts, and highly modified riparian zones, all of which can have negative effects on stream habitats and resident fish communities. Coldwater trout streams in urban areas may be especially impacted due to their normally low fish diversity and the higher intolerance of those species to such factors as stream temperature, dissolved oxygen concentrations, and water chemistry. Fish communities were examined at two sites in each of four coldwater trout streams in southeastern Minnesota USA: one site within the residential/commercial areas of a city and one site outside of the city limits in rural (agricultural) areas. Fish were surveyed (all fish counted and identified) in representative 150 to 200 m sections at each stream site with a backpack electrofisher. Data were used to produce Simpson and Shannon diversity indices, taxa richness values, a coldwater index of biotic integrity (IBI) score and rating for each site, and an NMDS plot using fish communities to compare between urban and rural stream sections. Overall, fish representing 17 different species and 11 families were found at the sites examined. Brown trout (Salmo trutta) comprised 65% of the total catch and was the only species collected at every site. Average fish species richness was nearly three times higher at urban sites than at rural sites, and Simpson and Shannon diversities were also significantly (four to five times) higher at urban compared to rural sites. However, coldwater IBI scores were significantly higher at rural (average = 93, good rating) than at urban (average score = 59, a fair rating) sites, indicating better coldwater biotic integrity in rural stream sections. A NMDS plot indicated that fish communities at urban sites were more similar to one another than they were to rural site communities; separation between urban and rural sites was largely influenced by species exclusive to urban sites. Reduced biotic integrity and altered fish community composition in urban streams likely resulted from a combination of factors including modified stream habitat and hydrology, warmer water temperatures, and urban runoff. Full article

(This article belongs to the Special Issue Functional Ecology of Urban Streams)

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10 pages, 1024 KB

Open AccessArticle

Steroid Hormone Pollution and Life History Strategies of Freshwater Planarians and Snails in a Mesocosm Experiment

by Marcin Weselak and Anita Kaliszewicz

Limnol. Rev. 2025, 25(4), 54; https://doi.org/10.3390/limnolrev25040054 - 14 Nov 2025

Abstract

The problem of steroid hormones in the aquatic environment remains a current global research topic. These substances have a strong impact on biological processes, contributing to reductions in the populations of numerous fish and amphibian species. The impact of steroid hormones, especially the [...] Read more.

The problem of steroid hormones in the aquatic environment remains a current global research topic. These substances have a strong impact on biological processes, contributing to reductions in the populations of numerous fish and amphibian species. The impact of steroid hormones, especially the third-generation progestogens, on aquatic invertebrates is poorly understood. We aimed to determine whether desogestrel, progestogen of low androgenic activity, affects the reproduction and growth of the following freshwater invertebrates: snails of the species Melanoides tuberculata and the planarian Dugesia sp. We also tried to estimate the threshold concentrations of this substance at which significant changes in both the behavior and reproductive activity of the studied organisms are observed. In the mesocosm experiment, we performed three treatments with the following different concentrations of desogestrel: control 0 ng/L, medium 10 ng/L, and high 100 ng/L. The high hormone concentration significantly reduced the reproduction of both snails and planarians, despite their different life history strategies, compared to the control. Both planarians and snails showed a significantly lower abundance in the high concentration compared to the 10 ng/L treatment, indicating a threshold concentration > 10 ng/L. The impacts of steroid hormone pollution on aquatic organisms and the need for further research are discussed. Full article

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