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Wetland ecosystems are vital for both biodiversity and communities that depend on them. The Ligawasan Marsh in the southern part of the Philippines is one of the most threatened wetlands in the country. Apart from increasing anthropogenic development, wetlands have faced warfare-driven threats that have hindered research and conservation efforts in the area for many decades. Our study is the first to investigate the patterns of physicochemical parameters, patterns of land use cover, and the relationship between land use change and marshland environmental status. We also developed the Marshland Impact Area (MARia) index to assess the potential impact contributions of the surrounding towns. We found a strong negative correlation between dissolved oxygen (DO) and indicators of pollution such as biochemical oxygen demand (BOD), chemical oxygen demand (COD), and heavy metals. Interestingly, we observed elevated levels of phosphate and mercury at all sampling sites in the Ligawasan Marsh. Our landscape-level modelling showed that these elevated levels are associated with expanding croplands and urbanisation surrounding the marsh. We found that the potential impact contribution of cropland and urbanisation from surrounding towns of the Ligawasan Marsh varied significantly, suggesting the importance of implementing local policies to reduce land use change impacts. With the current yet remaims limited knowledge and beyond safe pollution levels in the Ligawasan Marsh, it is crucial to implement collaborative and science-based governance to integrate conservation initiatives with the priorities of global targets, such as the Kunming-Montreal Global Biodiversity Framework, for a comprehensive and sustainable approach to Ligawasan Marsh conservation. [ABSTRACT FROM AUTHOR]

ABSTRACT Freshwater biodiversity conservation has received substantial attention in the scientific literature and is finally being recognized in policy frameworks such as the Global Biodiversity Framework and its associated targets for 2030. This is important progress. Nonetheless, freshwater species continue to be confronted with high levels of imperilment and widespread ecosystem degradation. An Emergency Recovery Plan (ERP) proposed in 2020 comprises six measures intended to “bend the curve” of freshwater biodiversity loss, if they are widely adopted and adequately supported. We review evidence suggesting that the combined intensity of persistent and emerging threats to freshwater biodiversity has become so serious that current and projected efforts to preserve, protect and restore inland‐water ecosystems may be insufficient to avert substantial biodiversity losses in the coming decades. In particular, climate change, with its complex and harmful impacts, will frustrate attempts to prevent biodiversity losses from freshwater ecosystems already affected by multiple threats. Interactions among these threats will limit recovery of populations and exacerbate declines resulting in local or even global extinctions, especially among low‐viability populations in degraded or fragmented ecosystems. In addition to impediments represented by climate change, we identify several other areas where the absolute scarcity of fresh water, inadequate scientific information or predictive capacity, and a widespread failure to mitigate anthropogenic stressors, are liable to set limits on the recovery of freshwater biodiversity. Implementation of the ERP rapidly and at scale through many widely dispersed local actions focused on regions of high freshwater biodiversity and intense threat, together with an intensification of ex‐situ conservation efforts, will be necessary to preserve native freshwater biodiversity during an increasingly uncertain climatic future in which poorly understood, emergent and interacting threats have become more influential. But implementation of the ERP must be accompanied by measures that will improve water, energy and food security for humans – without further compromising the condition of freshwater ecosystems. Unfortunately, the inadequate political implementation of policies to arrest widely recognized environmental challenges such as climate change do not inspire confidence about the possible success of the ERP. In many parts of the world, the Anthropocene future seems certain to include extended periods with an absolute scarcity of uncontaminated surface runoff that will inevitably be appropriated by humans. Unless there is a step‐change in societal awareness of – and commitment to – the conservation of freshwater biodiversity, together with necessary actions to arrest climate change, implementation of established methods for protecting freshwater biodiversity may not bend the curve enough to prevent continued ecosystem degradation and species loss. [ABSTRACT FROM AUTHOR]

Freshwater biodiversity loss is accelerating globally, but humanity can change this trajectory through actions that enable recovery. To be successful, these actions require coordination and planning at a global scale. The Emergency Recovery Plan for global freshwater biodiversity aims to reduce the risk for freshwater biodiversity loss through six priority actions: (1) accelerate implementation of environmental flows; (2) improve water quality to sustain aquatic life; (3) protect and restore critical habitats; (4) manage exploitation of freshwater species and riverine aggregates; (5) prevent and control nonnative species invasions in freshwater habitats; and (6) safeguard and restore freshwater connectivity. These actions can be implemented using future-proofing approaches that anticipate future risks (e.g., emerging pollutants, new invaders, and synergistic effects) and minimize likely stressors to make conservation of freshwater biodiversity more resilient to climate change and other global environmental challenges. While uncertainty with respect to past observations is not a new concern for freshwater biodiversity, future-proofing has the distinction of accounting for the uncertainty of future conditions that have no historical baseline. The level of uncertainty with respect to future conditions is unprecedented. Future-proofing of the Emergency Recovery Plan for freshwater biodiversity will require anticipating future changes and developing and implementing actions to address those future changes. Here, we showcase future-proofing approaches likely to be successful using local case studies and examples. Ensuring that response options within the Emergency Recovery Plan are future-proofed will provide decision makers with science-informed choices, even in the face of uncertain and potentially new future conditions. We are at an inflection point for global freshwater biodiversity loss; learning from defeats and successes can support improved actions toward a sustainable future. [ABSTRACT FROM AUTHOR]

Myristica swamps are one of the world's unique freshwater ecosystems. In recent years there has been an increase in reports about their distribution along the Western Ghats. In this paper, we present a new distribution record for Myristica swamps in the northern part of the Western Ghats in Maharashtra. The Myristica swamp is located within the Bhalandeshwar Sacred Grove of Kumbral Bagwadi, Dodamarg Maharastra, India. This forms the second report from the state of Maharastra. Frequent field visits were made to study and document the floral assemblage and biodiversity in the swamp from November 2023 to January 2024. The swamp is dominated by Myristica magnifica Bedd. and is part of a sacred grove protected by villagers due to religious beliefs. The second discovery of a Myristica swamp with a gap of just six years points out to the potential existence of more swamps in the region. Therefore, systematic surveys are needed to document undocumented swamps in various areas. [ABSTRACT FROM AUTHOR]

As human-caused climate changes accelerate, California will experience hydrologic and temperature conditions different than any encountered in recorded history. How will these changes affect the state's freshwater ecosystems? Rivers, lakes, and wetlands are managed as a water resource, but they also support a complex web of life, ranging from bacteria, fungi, and algae to macrophytes, woody plants, invertebrates, fish, amphibians, reptiles, birds, and mammals. In much of the state, native freshwater organisms already struggle to survive massive water diversions and dams, deteriorating water quality, extensive land cover modification for agriculture and urban development, and invasions of exotic species. In the face of climate change, we need to expand efforts to recover degraded ecosystems and to protect the resilience, health, and viability of existing ecosystems. For this, more process-based understanding of river, lake, and wetlands ecosystems is needed to forecast how systems will respond to future climate change and to our interventions. This will require 1) expanding our ability to model mechanistically how freshwater biota and ecosystems respond to environmental change; 2) hypothesis-driven monitoring and field studies; 3) education and training to build research, practitioner, stewardship, and policy capabilities; and 4) developing tools and policies for building resilient ecosystems. A goals-driven, hypothesis-informed collaboration among tribes, state (and federal) agencies, nongovernmental organizations, academicians, and consultants is needed to accomplish these goals and to advance the skills and knowledge of the future workforce of practitioners, regulators, and researchers who must live with the climate changes that are already upon us and will intensify. [ABSTRACT FROM AUTHOR]

The protection of Chile's rivers is a matter of ongoing public and constitutional interest in the wake of Chile's failed 2019–2024 constitutional reforms. In this article we review and evaluate opportunities for greater legal protection and restoration of rivers in Chile. The legal analysis was complemented by a survey of social attitudes about river protection needs and several interviews with key experts and stakeholders, which found strong concern for enhanced river protection mechanisms in Chile. We conclude by outlining critical pathways towards durable legal protections for the future of Chile's rivers. [ABSTRACT FROM AUTHOR]

The present study recorded a total of 30 species of diving beetles (Dytiscidae) under 12 genera and 5 subfamilies from the central region of Kerala State, India, of which Copelatus neelumae, Hydaticus discindens, Hydaticus incertus, Sandracottus festivus, Hydrovatus picipennis, Hydroglyphus pendjabensis, Clypeodytes bufo, Microdytes cameroni cf., Laccophilus auropictus cf., Laccophilus elegans and Cybister tripunctatus lateralis are new records to Kerala. The genus Clypeodytes is a first report from Kerala. Hydrovatus picipennis and Hydaticus incertus are new reports from South India. Short diagnoses of the new records are provided. A checklist of 62 species of diving beetles of Kerala is furnished by compiling the 30 species from this study with previous relevant studies. The updated checklist has 11 additions. A brief account of habitat preference and co-existence among Dytiscidae and an identification key for 30 species of diving beetles from the study area is provided. [ABSTRACT FROM AUTHOR]

In a commercial fishery, some fish are classified as low-value, but their classification varies in different countries. The aim of this study was to determine the abundance, contribution, and dominance of low-value fish species, such as Abramis brama < 1000 g, Alburnus alburnus, Blicca bjoerkna, Gymnocephalus cernua, Perca fluviatilis < 100 g, Rutilus rutilus < 200 g, and Scardinius erythrophthalmus < 200 g, in 145 Polish lakes of different areas, depths, and trophic statuses situated in the northern and central parts of Poland in 2021. Perca fluviatilis and R. rutilus were the most frequent low-value species (100% and 99%, respectively). The contribution of all low-value fish to the total biomass of caught fish was relatively high, ranging from 37% in the mesotrophic lake to 100% in the eutrophic lake (mean of 77 ± 14%). Lakes in which the contribution of low-value species exceeded 90% were relatively numerous (24 lakes, 17% of the studied lakes). Among a total of about 437.5 thousand low-value fish, 261 thousand specimens (60%) had a body weight of below 10 g. All low-value fish species, except for P. fluviatilis and S. erythrophthalmus, were related to the studied environmental variables. The relative biomass of these species increased with increasing lake productivity, while it decreased with the increasing maximum and mean depth of the studied lakes. The high contribution of low-value fish to the total biomass in many lakes indicates the need for the constant monitoring of the abundance and structure of fish communities and the use of appropriate actions (biomanipulation and stocking with piscivorous fish species) to improve the ecological condition of lakes. [ABSTRACT FROM AUTHOR]

Abstract Wetland ecosystems are vital for both biodiversity and communities that depend on them. The Ligawasan Marsh in the southern part of the Philippines is one of the most threatened wetlands in the country. Apart from increasing anthropogenic development, wetlands have faced warfare-driven threats that have hindered research and conservation efforts in the area for many decades. Our study is the first to investigate the patterns of physicochemical parameters, patterns of land use cover, and the relationship between land use change and marshland environmental status. We also developed the Marshland Impact Area (MARia) index to assess the potential impact contributions of the surrounding towns. We found a strong negative correlation between dissolved oxygen (DO) and indicators of pollution such as biochemical oxygen demand (BOD), chemical oxygen demand (COD), and heavy metals. Interestingly, we observed elevated levels of phosphate and mercury at all sampling sites in the Ligawasan Marsh. Our landscape-level modelling showed that these elevated levels are associated with expanding croplands and urbanisation surrounding the marsh. We found that the potential impact contribution of cropland and urbanisation from surrounding towns of the Ligawasan Marsh varied significantly, suggesting the importance of implementing local policies to reduce land use change impacts. With the current yet remaims limited knowledge and beyond safe pollution levels in the Ligawasan Marsh, it is crucial to implement collaborative and science-based governance to integrate conservation initiatives with the priorities of global targets, such as the Kunming-Montreal Global Biodiversity Framework, for a comprehensive and sustainable approach to Ligawasan Marsh conservation.

Present study provides data of organochlorine pesticides (DDT, HCH) and polychlorinated biphenyls (28, 52, 155, 101, 118, 143, 153, 138, 180, 207 congener) content in six carp fish from Lake Khanka. Organochlorine compounds are found in all studied samples. HCHs isomers were dominant, constituting on average 70% of all pesticides detected. α-HCH content varied from 8 to 95%. Among DDTs, o,p’- and p,p’-DDE were predominant (on average 10–100 and 15–100%, respectively). PCBs content in all fish samples was primarily presented by low-chlorinated 28 and 52 congeners. Detected isomers evidence on the long-term pollution of Lake Khanka by persistent organic pollutants. Compare to southern China and Croatia, fish from Lake Khanka showed significantly higher levels of accumulation of HCH and lower levels of DDT and PCB. When comparing the data with the requirements of regulatory documents in Russia and China, no cases of exceeding maximum permissible concentrations were identified.

Mediterranean high-mountain lakes are being increasingly affected by strong Saharan dust deposition events. However, the ecological impacts of these severe atmospheric episodes remain largely unknown. We examined the effects of a strong Saharan dust intrusion to the Iberian Peninsula in 2022 on the physicochemical parameters and prokaryotic communities in sediments of nine high-mountain lakes of Sierra Nevada (Spain) located above 2800 m.a.s.l and in different orientations (north vs. south). A previous year (2021), with lower Saharan dust deposition with respect to 2022, was used for interannual comparisons. The strong dust deposition to the high-mountain lakes resulted in a significant increase in sediment nutrient availability which was linked to changes in the composition of prokaryotic communities. Decreases in alpha diversity and changes in beta diversity of prokaryotic communities were mainly observed in lakes located in the south compared to the north orientation likely because the former was more affected by the atmospheric dust deposition episode. Dust intrusion to the high-mountain lakes resulted in significant changes in the relative abundance of specific genera involved in important nutrient cycling processes such as phosphate solubilization, nitrogen fixation, nitrification, and denitrification. Saharan dust deposition also increased predicted microbial functionality in all lakes. Our findings show that severe atmospheric dust inputs to remote high-mountain lakes of Sierra Nevada can have significant biogeochemical and biodiversity consequences through changes in nutrient availability and prokaryotic communities in sediments of these freshwater ecosystems. This information contributes to understanding how Mediterranean high-mountain lakes of Sierra Nevada face strong intrusions of Saharan dust and their ecological consequences. [ABSTRACT FROM AUTHOR]

Microplastics (MPs, size ≤ 5 mm) have emerged as a significant worldwide concern, threatening marine and freshwater ecosystems, and the lack of MP detection technologies is notable. The main goal of this research is the development of a camera sensor for the detection of MPs and measuring their size and velocity while in motion. This study introduces a novel methodology involving computer vision and artificial intelligence (AI) for the detection of MPs. Three different camera systems, including fixed-focus 2D and autofocus (2D and 3D), were implemented and compared. A YOLOv5-based object detection model was used to detect MPs in the captured image. DeepSORT was then implemented for tracking MPs through consecutive images. In real-time testing in a laboratory flume setting, the precision in MP counting was found to be 97%, and during field testing in a local river, the precision was 96%. This study provides foundational insights into utilizing AI for detecting MPs in different environmental settings, contributing to more effective efforts and strategies for managing and mitigating MP pollution. [ABSTRACT FROM AUTHOR]

Riverine environments host diverse microbial communities, exhibiting distinctive assemblies at both microscopic and macroscopic levels. Despite the complexity of microbial life in rivers, the underlying factors that shape the community structure across different compartments remain elusive. Herein, we characterized microbial community composition of biofilm and planktonic (water column) compartments in five naturally saline inland streams and a freshwater stream to examine changes in microbial communities following salinization via sequencing of the microbial 16S rRNA gene. Significant differences in specific conductivity, oxidation–reduction potential, dissolved oxygen, and pH among the sampled streams were measured, as were significant differences in the microbial community composition between the planktonic and biofilm. The bacterial families Bacillaceae, Vicinamibacterceae, and Micrococcaceae were significantly more abundant in the biofilm compartment, while Methylophilaceae, Alcaligenaceae, Spirosomaceae, Burkholderiaceae, and Comamonadaceae were more abundant in the planktonic compartment. In addition, salinity (based on specific conductivity) influenced the microbial community composition in both compartments, with higher sensitivity of the planktonic compartment. Increases in the bacterial families Shewanellaceae, Marinomonadaceae, and Saccharospirillaceae or loss of Anaeromyxobacteraceae could be indicative of increased salinity within inland streams. Our results suggest that monitoring of microbial assemblages of freshwater ecosystems could be used as early warning signs of increased salinization levels. [ABSTRACT FROM AUTHOR]

Both the increasing salinity levels and the decline of submerged macrophytes represent growing concerns in global freshwater ecosystems, posing a threat to water quality and various aquatic organisms. However, there is a limited understanding of the interactive effects of salinity and submerged macrophytes on zooplankton and benthic Ostracoda in tropical zones. To address this knowledge gap, we conducted a controlled experiment spanning 6 months, comparing the biomass of zooplankton (including copepods, cladocerans, and rotifers) and benthic Ostracoda in mesocosms with three levels of salinity, at the presence or absence of submerged macrophytes. Our results showed that in tropical zones, both zooplankton and benthic Ostracoda biomass exhibited a noteworthy decrease in response to increasing salinity, but the presence of submerged macrophytes did not have a significant influence on the zooplankton biomass. However, the presence of submerged macrophytes had a positive effect on the benthic Ostracoda biomass. Interestingly, submerged macrophytes had a strong interaction with salinity on the Ostracoda biomass, which increased with macrophyte presence under intermediate salinity conditions (2 g/L). In summary, our study sheds light on the interplay between salinity, submerged macrophytes, and the biomass of zooplankton and benthic Ostracoda in tropical freshwater ecosystems. [ABSTRACT FROM AUTHOR]

Context: The prediction of freshwater quality is important for detecting pollution risks and assessing changes in freshwater ecosystems. As a high-precision interpolation method, Kriging was able to predict freshwater quality by using previously monitored data. However, how to select the key parameters, regression functions and correlation functions of Kriging method in the process of improving prediction accuracy is still a bottleneck. Aims: This study aims to propose an adaptive weighted-average Kriging (AWAK) method to further enhance the accuracy of freshwater-quality predictions. Methods: The AWAK method consists of four main steps. First, the key parameters influencing pollution indicators are selected by FPS method. Subsequently, six different Kriging candidate models are constructed by using regression and correlation functions with different characteristics. Then, an enhanced-likelihood function is used to determine the weights of the six Kriging candidate models. Finally, AWAK is built by weighted sum of these six Kriging models. Key results: The AWAK outperformed traditional Kriging in predicting pH and dissolved oxygen, significantly reducing prediction errors. Conclusions: By employing the AWAK method, this study successfully improved the accuracy of freshwater-quality predictions. Implications: The introduction of the AWAK provides an effective approach in the field of freshwater ecology. Freshwater-quality prediction is crucial for monitoring pollution risks and assessing changes in freshwater ecosystems. Whereas Kriging is a precise interpolation method for predicting freshwater quality, selecting key parameters, regression functions and correlation functions remains challenging. Therefore, this study proposed an adaptive weighted-average Kriging (AWAK) method that outperforms traditional Kriging in predicting pH and dissolved oxygen, reducing prediction errors significantly. Overall, AWAK improved freshwater-quality prediction and provided an effective approach in freshwater-ecology research. This article belongs to the collection Ecological Monitoring and Assessment of Freshwater Ecosystems. [ABSTRACT FROM AUTHOR]

Environmental flows (EFs), essential for upholding the ecological integrity of rivers and aquatic habitats, have been disrupted significantly by diverting water for agricultural, industrial and domestic uses. This underscores the imperative of implementing sustainable water resource management to harmonize agricultural and environmental needs. The study was conducted in the Indus River Basin (IRB), a region extensively transformed by human interventions. EFs were determined through various techniques, including the flow duration curve shifting method, flow duration curve analysis, low‐flow indices, the Tennant method, the Smakhtin approach, the Tessmann method and the Pastor method. Analysing the estimated EFs alongside downstream flows unveiled specific timeframes (days, months and seasons) of unmet EF requirements. To safeguard the downstream ecosystems, the following EFs were estimated for the respective locations: 880 m3/s (38% of the mean annual flow [MAF]) for the Indus River at Tarbela Dam, 412 m3/s (48% of the MAF) for the Jhelum at Mangla Dam, 425 m3/s (44% of the MAF) for the Chenab at Marala headworks, 389 m3/s (56% of MAF) for the Ravi at Balloki headworks, 184 m3/s (50% of MAF) for the Sutlej at Sulemanki headworks and 231 m3/s (38% of MAF) below Kotri Barrage. The study revealed that violations of EFs occurred 41%, 43%, 44% and 52% of the time during the study period for the Chenab at Marala headworks, the Ravi at Balloki headworks, the Sutlej at Sulemanki headworks and the Indus River at the Kotri Barrage, respectively. The results highlighted that the Chenab, Ravi and Sutlej rivers are particularly susceptible to vulnerability, as the estimated EFs were not consistently upheld in these rivers. These findings underscore the urgent need to take appropriate measures to ensure EFs are not violated, thus safeguarding the downstream ecosystems. [ABSTRACT FROM AUTHOR]

A novel assessment of the content of microplastics in the surface waters of Lake Khanka and its tributaries is performed. Collection, preparation, and analysis of samples were carried out in 2021‒2022. Five geographical sites were selected (the source of the Sungacha River, the mouth of the Spasovka River, the Vostochnyi cordon, the Ilistaya River, and the Komissarovka River) as areas most susceptible to pollution. Scanning spectrophotometry with an AIM-9000 SHIMADZU IR microscope detected the presence of microplastic particles (MPs) in all the water samples. The microplastics are predominantly of mixed and synthetic nature; the concentration varies depending on the season, amounting to 6–27 units/m3 in the spring–summer and 5–24 units/m3 in the autumn–winter sampling period. The detected microplastics are of mostly secondary origin and are overwhelmingly identified as fibers. Spectral analysis of the particles show that polyester and organic fibers are the most common types of microplastics. An increased concentration of microplastics is observed at the mouths of the Spasovka and Komissarovka rivers; in the area of the Vostochnyi cordon, which is located in the eastern coastal region of the lake on the territory of the Khanka Nature Reserve; and at the source of the Sungacha, the drainage river of Lake Khanka. It is concluded that the likely sources of microplastic pollution in Lake Khanka and rivers of its basin are runoff from wastewater treatment plants carried in by river flow, runoff from agricultural land, and precipitation and/or untreated wastewater. A comparative analysis of the surface waters of Lake Khanka, the Hai River (China), the Songhua River (China), and rivers of Japan and South Korea is performed. In all the considered water bodies, the predominant type of microplastics is fibers of synthetic origin. The average concentration of microplastics in Lake Khanka is found to be noticeably lower than in the other water bodies, with only that in the Hai River lower. [ABSTRACT FROM AUTHOR]

Cabomba caroliniana A. Gray, an ornamental submerged plant indigenous to tropical America, has been introduced to numerous countries in Europe, Asia, and Oceania, impacting native aquatic ecosystems. Given this species is a popular aquarium plant and widely traded, there is a high risk of introduction and invasion into other environments. In the current study the potential global geographic distribution of C. caroliniana was predicted under the effects of climate change and human influence in an optimisedMaxEntmodel. The model used rigorously screened occurrence records of C. caroliniana fromhydro informatic datasets and 20 associated influencing factors. The findings indicate that temperature and human-mediated activities significantly influenced the distribution of C. caroliniana. At present, C. caroliniana covers an area of approximately 1531×104 km² of appropriate habitat, especially in the south-eastern parts of South, central and North America, Southeast Asia, eastern Australia, and most of Europe. The suitable regions are anticipated to expand under future climate scenarios; however, the dynamics of the changes vary between different extents of climate change. For example, C. caroliniana is expected to expand to higher latitudes, following global temperature increases under SSP1-2.6 and SSP2-4.5 scenarios, however, intolerance to temperature extremes may mediate invasion at higher latitudes under future extreme climate scenarios, e.g., SSP5-8.5. Owing to the severe impacts its invasion causes, early warning and stringent border quarantine processes are required to guard against the introduction of C. caroliniana especially in the invasion hotspots such as, Peru, Italy, and South Korea. [ABSTRACT FROM AUTHOR]

The proximity of freshwater ecosystems to anthropogenic activities makes them one of the most threatened environments by plastic pollution in the form of microplastics (MPs). Therefore, it is crucial to identify the primary drivers of MP dynamics in rivers to enhance their management. This work analyzed the concentration of MPs in water and sediments and evaluated the influence of land use and its relationship with the main biotic indices employed to assess the water quality of rivers. This research was carried out in four different catchments, with three sampling points established in each river basin. The results revealed that MPs were ubiquitous across all locations, with concentrations ranging from 0.10 to 35.22 items m−3 in waters and from 26 to 643 items Kg−1 in sediments. The highest concentration of MPs both in water and sediments were found in the Lagares River (35.22 items m−3 and 643 items Kg−1), while the lowest concentrations were found in the Miñor River for water (0.10 items m−3) and Tea River for sediments (138 items Kg−1). Urbanization degree was identified as the primary driver of MP pollution in water, whereas population density correlated with sediment pollution levels. These findings explain the elevated MPs abundance in the more urbanized and populated Gafos and Lagares rivers compared to the relatively pristine Miñor and Tea rivers. Furthermore, the presence of MPs in sediments was found to negatively impact the most sensitive benthic macroinvertebrate taxa, as evidenced by lower values of the IASPT and EPT indices at sampling points with higher sediment MPs concentrations (Gafos and Lagares). [ABSTRACT FROM AUTHOR]

Multimetric indices play a pivotal role in assessing river ecological quality, aligning with the European Water Framework Directive (EU WFD) requirements. However, indices developed specifically for large rivers are uncommon. Our objective was to develop a fish-based tool specifically tailored to assess the ecological quality in Portuguese large rivers. Data were collected from seven sites in each of three Portuguese large rivers (Minho, Guadiana, and Tagus). Each site was classified using an environmental disturbance score, combining different pressure types, such as water chemistry, land use, and hydromorphological alterations. The Fish-based Multimetric Index for Portuguese Large Rivers (F-MMIP-LR) comprises four metrics: % native lithophilic individuals; % alien individuals; % migrant individuals; and % freshwater native individuals, representing compositional, reproductive, and migratory guilds. The index showed good performance in separating least- and most-disturbed sites. Least-disturbed sites were rated 'high' or 'good' by F-MMIP-LR, contrasting with no such classification for most-disturbed sites, highlighting index robustness. The three rivers presented a wide range of F-MMIP-LR values across the gradient of 'bad' to 'high', indicating that, on a large spatial extent, the biological condition was substantially altered. The F-MMIP-LR provides vital information for managers and decision-makers, guiding restoration efforts and strengthening conservation initiatives in line with the WFD. [ABSTRACT FROM AUTHOR]

The rapid deterioration of freshwater ecosystems, particularly rivers, has threatened many living organisms, including human beings. In order to comprehend and maintain the well-being of a river ecosystem, it is important to assess the spatial and temporal variations in its physico-chemical parameters. The aim of the present study was to examine spatial and temporal physico-chemical parameters of snow-fed River Poonch in the Northwest Himalayas from July 2021 to June 2023. In order to generate precise and reliable data, one-way ANOVA, Duncan's multiple range test, Pearson correlation, linear regression, principal component analysis (PCA) and cluster analysis (CA) were used to analyse a total of fifteen physico-chemical parameters of the river. Significant (p < 0.05) differences spatio-temporally in physico-chemical parameters were found through one-way ANOVA followed by Duncan's multiple range test. Pearson correlation revealed that majority of the examined physico-chemical parameters exhibited a robust positive association (r > 0.70) in most cases, apart from DO (r ≥ − 0.80). Linear regression indicated significant (p < 0.05) associations among various physico-chemical parameters, which were substantial both in nature and size, with a coefficient of determination (r2 > 0.70) in most of the cases. PCA showed that physico-chemical parameters such as AT, WT, EC, TDS, FCO2, TA, TH, NO2-N, NO3-N, TP, SO42− and F− were significant for the determination of qualitative characteristics of River Poonch. In CA, two distinct clusters, viz. Cluster-I consisting of Site-III, downstream site prone to pollution and Cluster-II consisting of Site-II and Site-I, mid and upstream sites, respectively, less prone to pollution were obtained. The results of the study revealed that the water quality parameters were found well within the recommended ranges, suggesting that they are conducive for the existence of inhabitant fish species, which influence the local economy of the region. [ABSTRACT FROM AUTHOR]

India boasts of a vast freshwater resource network (rivers, wetlands, and groundwater), which has unique ecological, social and economic values associated with it. Despite their importance for both people and biodiversity, its freshwater ecosystems (FWEs) are heavily impacted through multiple factors such as pollution, overexploitation, habitat loss/modification and climate change. India is also among the hotspots of water resource overuse that has caused a serious decline in freshwater availability.Given that healthy FWEs lie at the centre for supporting the country's ecology, health, economy, livelihoods and ultimately achieving multiple policy goals, it is crucial that holistic and focused efforts are made to protect, conserve, and restore all types of FWEs.We call for an urgent and a greater focus on implementing conservation actions for FWEs in India and suggest the following strategy to enhance focus on their conservation: (1) establishing a shared freshwater conservation vision at a national scale, (2) developing and including national freshwater conservation goals within global efforts, (3) conducting simultaneous conservation action planning at regional scales and (4) bridge planning to implementation gap by strengthening key enabling conditions: i) mainstream FWE conservation within key existing governance instruments, ii) secure sustainable conservation funding, iii) improve data access and knowledge translation; iv) create national awareness around importance of FWEs; v) facilitate collaboration among key actors. [ABSTRACT FROM AUTHOR]

Micro(nano)plastics (MNPs) are pervasive pollutants posing significant environmental and health risks. Selecting appropriate sentinel species to assess MNPs in terrestrial and aquatic environments involves considering factors such as species behavior, habitat, exposure pathways, and the feasibility of sampling. For these reasons, it was imperative to launch a virtual special issue (VSI) in Ecological Indicators. This editorial summarizes the contributions submitted to the VSI, which invited research on bioindicators of MNPs, including sampling protocols, monitoring strategies, and analytical methods, to advance our understanding and management of plastic pollution. The VSI received a total of 12 contributions from four countries, with a significant majority originating from Italy. To present the contributions, we have organized the sections into original articles and reviews. The original articles are further divided into sections on the occurrence of MNPs in biotic and abiotic compartments, the selection of bioindicators, and the effects and risk assessment of MPs. The reviews are categorized based on their focus on aquatic and terrestrial ecosystems. Future ecotoxicology studies should select bioindicators based on exposure to MNPs, conservation status, ecological roles, and human consumption.

Most studies assessing the combined effects of chemical and non-chemical stressors on aquatic ecosystems have been based on synchronous stressor applications. However, asynchronous exposure scenarios may be more common in nature, particularly for pulsed stressors such as heatwaves and pesticide concentration peaks. In this study, we investigated the single and combined effects of the insecticide chlorpyrifos (CPF) and a heatwave (HW) on a zooplankton community representative of a Mediterranean coastal wetland using synchronous (CPF+HW) and asynchronous (HW→CPF and CPF→HW) exposure scenarios. CPF was applied at a concentration of 0.8 µg/L (single pulse), and the HW was simulated by a temperature increase of 8°C above the control temperature (20°C) for 7 days in freshwater microcosms. The interaction between stressors in synchrony resulted in synergistic effects at the population level (Daphnia magna) and additive at the community level. The partial reduction of sensitive species resulted in an abundance increase of competing species that were more tolerant to the evaluated stressors (e.g. Moina sp.). The asynchronous exposure scenarios resulted in a similar abundance decline of sensitive populations as compared to the synchronous one; however, the timing of stressor resulted in different responses in the long term. In the HW→CPF treatment, the D. magna population recovered at least one month faster than in the CPF+HW treatment, probably due to survival selection and cross-tolerance mechanisms. In the CPF→HW treatment, the effects lasted longer than in the CPF+HW, and the population did not recover within the experimental period, most likely due to the energetic costs of detoxification and effects on internal damage recovery. The different timing and magnitude of indirect effects among the tested asynchronous scenarios resulted in more severe effects on the structure of the zooplankton community in the CPF→HW treatment. Our study highlights the relevance of considering the order of stressors to predict the long-term effects of chemicals and heatwaves both at the population and community levels.

IntroductionHabitat loss, as well as infectious diseases, have been suggested as the main causes for the worldwide decline of amphibian populations. Thus, the search for biotic indicators is a useful tool for mapping priority demands in disease management.AimsHere we analyzed the prevalence of two pathogens, Batrachochytrium dendrobatidis (Bd) and Ranavirus (Rv), in anuran communities in southern Brazil. We explored the relationship between the prevalence of Bd and landscape class and used an indicator-species and indicator-community approach to identify which species and communities have the potential to indicate the presence of Bd.MethodsWe used histological analyses to access Bd and PCR for Rv in tadpole communities.Key resultsOur data, based on 26 anuran communities, revealed high Bd prevalence but absence of Rv. Three species, of the 26 communities studied, were found to be Bd indicators, including endemic species from southern Brazil and Argentina. Additionally, the analysis with an indicator-community approach revealed that communities from larger forest areas are Bd indicators.ConclusionsAnalyses at the community level, which relate landscape to pathogens, provide unprecedented and highly relevant information for fragmented Atlantic Forest landscapes. Based on our results, we argue that even communities in larger forest patches (apparently well-preserved) are susceptible to Bd and deserve attention regarding the possibility of incidence of chytridiomycosis. Implications. From our results, we consider that the use of Bd-indicator species and Bd-indicator communities is a useful approach for conservation and could be used to evaluate the threatened status of species and for proposals for landscape management.

Abstract The rapid deterioration of freshwater ecosystems, particularly rivers, has threatened many living organisms, including human beings. In order to comprehend and maintain the well-being of a river ecosystem, it is important to assess the spatial and temporal variations in its physico-chemical parameters. The aim of the present study was to examine spatial and temporal physico-chemical parameters of snow-fed River Poonch in the Northwest Himalayas from July 2021 to June 2023. In order to generate precise and reliable data, one-way ANOVA, Duncan's multiple range test, Pearson correlation, linear regression, principal component analysis (PCA) and cluster analysis (CA) were used to analyse a total of fifteen physico-chemical parameters of the river. Significant (p 0.70) in most cases, apart from DO (r ≥ − 0.80). Linear regression indicated significant (p 0.70) in most of the cases. PCA showed that physico-chemical parameters such as AT, WT, EC, TDS, FCO2, TA, TH, NO2-N, NO3-N, TP, SO4 2− and F− were significant for the determination of qualitative characteristics of River Poonch. In CA, two distinct clusters, viz. Cluster-I consisting of Site-III, downstream site prone to pollution and Cluster-II consisting of Site-II and Site-I, mid and upstream sites, respectively, less prone to pollution were obtained. The results of the study revealed that the water quality parameters were found well within the recommended ranges, suggesting that they are conducive for the existence of inhabitant fish species, which influence the local economy of the region.

Community science models that complement formal scientific investigations are valuable tools for addressing gaps in knowledge and engaging the community. Freshwater quality monitoring and vulnerability assessment, for example, are essential for conserving freshwater ecosystems, but often suffer from limited resources. While municipal programs focus on priority areas, community based models can improve overall coverage both spatially and temporally. As an example of how community science initiatives centered on freshwater ecosystems enhance monitoring capacity, we present the case of the Young Naturalists Club (YNC) in Nova Scotia, Canada. The YNC’s Nature Guardians program involves youth aged 10–14 in water monitoring, restoration, and outreach activities within Shubie Park, in Dartmouth, Nova Scotia. Between 2018 and 2021 the Nature Guardians collected water monitoring data at multiple park locations, and shared findings with city authorities and the Atlantic Water Network. In response to high bacteria counts, and concerns over nutrient influxes, the group’s 2021–2023 restoration efforts have aimed to improve water quality, focusing on native plantings and outreach signage. This type of community-based monitoring offers several advantages, including local site selection based on community concerns, the potential for low-cost long-term monitoring, and community engagement. While a community-based monitoring model presents certain challenges including data standardization and verification, it offers a broader reach and can produce high-quality data when appropriat protocols are followed. This case underscores the potential of a community-based water quality monitoring approach and highlights the potential for community science to augment existing assessment structures, ultimately contributing to more resilient and sustainable freshwater ecosystems. [ABSTRACT FROM AUTHOR]

Copyright of Asian Journals of Ecotoxicology is the property of Gai Kan Bian Wei Hui and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Following several surveys of aquatic Coleoptera during 2013-2018 in northern Western Ghats, India, we hereby provide an illustrated checklist with modified keys to the species of families Dytiscidae, Gyrinidae, Noteridae, and Hydrophilidae. To date, we have collected 69 species of true water beetles, adding new occurrence records for two species to the fauna of the state. Keys are modified from the works of various authors. Distribution records are provided with district specific records for Maharashtra. Keys, species lists, and distribution records are based on our survey results. Species were identified following the works of various authors, and affirmed by dissecting male genitalia. Provided with keys are habitus images, images of male genitalia for 59 species, and digital drawings & scanning electron micrographs of taxonomically important structures wherever necessary. These surveys were conducted to revive the work on aquatic beetles that have been neglected for about 40 years, and to prepare a revised checklist. [ABSTRACT FROM AUTHOR]

Invasive species decimate entire ecosystems, outcompeting native organisms for resources. Four introduced carp species have been identified as invasive in the Great Lakes region with bighead and silver carp displaying the greatest potential for invasion of the Great Lakes. Currently, these two species have self-sustaining populations in the Mississippi River, and the edges of their ranges are near Lake Michigan and Lake Erie. Here we address the prolific spreading ability of carps, the potential impacts of a carp invasion in the Great Lakes and the effects they might have in the larger Great Lakes region. Through a systematic literature review, we found: 1) carp population locations present in the region and how these populations have shifted over time; 2) how carp management options in Illinois waterways have evolved over time; and 3) invasive carp have a large economic impact on the local Great Lakes region. Invasive carp populations continue to increase and negatively impact aquatic ecosystems. Various management methods, such as eDNA, acoustic deterrence, and others, have been effective in invasive carp management and show promise in preventing expansion. However, if not effectively managed, the economic impact of invasive carp will be substantial. [ABSTRACT FROM AUTHOR]

Freshwater ecosystems are among the most threatened worldwide. A great part of this threat comes from climate and land cover changes. This situation is specially worrying in areas and ecosystems that are highly relevant in terms of biodiversity but severely impacted by these two factors, such as water bodies in North Africa. Using water beetles as surrogates of freshwater biodiversity, we present a novel approach to identify priority basins for the preservation of freshwater biodiversity in Morocco, using Species Distribution Models to identify potential biodiversity hotspots under future climate change scenarios, and estimates of future Land Cover dynamics. The mountainous areas of the Rif and Prerif, Middle Atlas and northern Central Plateau areas, as well as some Atlantic coastal basins were identified as priority areas for water beetles conservation and will play a crucial role for the conservation of freshwater biodiversity. Indeed, these areas can act as a dead end for a number of African species in the future. However, most of these areas are poorly covered by the national protected areas network (i.e., protected area extent < 10%). In addition, our analyses revealed a general negative trend of the natural vegetation coverage in the study area, and an increase of non-irrigated cropland. Finally, we identified specific areas that need special attention because are priority for conservation but are expected to suffer intense land cover changes. These results, which consider not only biodiversity values, but also the potential threats driven by climate and land cover changes, can provide a solid scientific basis to policy-makers to define specific conservation measures to anticipate freshwater biodiversity loss in North Africa. [ABSTRACT FROM AUTHOR]

Seasonal changes in environmental conditions drive phenology, i.e., the annual timing of biological events ranging from the individual to the ecosystem. Phenological patterns and successional abundance cycles have been particularly well studied in temperate freshwater systems, showing strong and predictable synchrony with seasonal changes. However, seasonal successional changes in the abundance of parasites or their infection levels in aquatic hosts have not yet been shown to follow universal patterns. Here, using a compilation of several hundred estimates of spring-to-summer changes in infection by trematodes in their intermediate and definitive hosts, spanning multiple species and habitats, we test for general patterns of seasonal (temperature) driven changes in infection levels. The data include almost as many decreases in infection levels from spring to summer as there are increases, across different host types. Our results reveal that the magnitude of the spring-to-summer change in temperature had a weak positive effect on the concurrent change in prevalence of infection in first intermediate hosts, but no effect on the change in prevalence or abundance of infection in second intermediate or definitive hosts. This was true across habitat types and host taxa, indicating no universal effect of seasonal temperature increase on trematode infections. This surprising variation across systems suggests a predominance of idiosyncratic and species-specific responses in trematode infection levels, at odds with any clear phenological or successional pattern. We discuss possible reasons for the minimal and variable effect of seasonal temperature regimes, and emphasise the challenges this poses for predicting ecosystem responses to future climate change. [ABSTRACT FROM AUTHOR]

The metacommunity theory proposes that community structure and biodiversity are influenced by both local processes (such as environmental filtering) and regional processes (such as dispersal). Despite the extensive use of traditional bioassessments based on species‐environment relationships, the impact of dispersal processes on these assessments has been largely overlooked. This study aims to compare correlations between various bioassessment indices, including Shannon Weiner (H′), Biological Monitoring Working Party (BMWP), average score per taxon (ASPT), biotic index (BI), and EPT taxa index (EPT), based on macroinvertebrates collected from 147 sampling sites in a subtropical Chinese near‐natural catchment. Modified indices were calculated by removing species strongly influenced by dispersal processes to address the influence of dispersal processes. Their relationship with environmental factors was then compared to the original indices. The study employed random forest regression (RFR) to compare the explanatory power of environmental factors using the two sets of indices. The spearman rank correlation analysis was conducted to examine the correlation between indices and environmental factors. The river health assessment was performed based on both modified and original indices. The results reveal significant differences between original and modified indices (especially H′ and BI) providing a more accurate reflection of environmental conditions. Furthermore, the sensitivity of the different indices to various environmental factors varied, leading to differences in the bioassessment results between the modified and the original indices. Notably, original H′, BMWP, and ASPT overestimated the bioassessment results, whereas the original BI underestimated them. These findings offer valuable insights into bioassessment and river health assessment evaluation within the catchment and other interconnected freshwater ecosystems, such as lakes, reservoirs, and wetlands. Our study underscores the importance of assessing and mitigating the impact of dispersal processes on bioassessment to obtain a more precise representation of the status of freshwater ecosystems. [ABSTRACT FROM AUTHOR]

Climate change may lead to range shifts, and barriers to such displacements may result in extirpations from previously suitable habitats. This may be particularly important in freshwater ecosystems that are highly fragmented by anthropogenic obstacles, such as dams and other smaller in‐stream barriers. Conservation planning in freshwaters should consider the dynamic effects of climate change and the ability of species to cope with it. In this study, we developed a framework for incorporating climate‐driven dispersal barriers into conservation planning taking into account the medium and long‐term impacts of climate change and species with obligatory interactions. Given that freshwater mussels (Bivalvia: Unionida) are a group of highly threatened organisms dependent on fish hosts to complete their larval development and dispersal, we used Marxan to prioritize areas for their joint conservation in the Iberian Peninsula as a case study. We tested two connectivity scenarios between current and future habitats, (i) unlimited dispersal capacity and (ii) dispersal constrained by artificial barriers, and also identified priority translocation areas for species that were unable to disperse. Accounting for the effects of climate change on species distributions allowed the identification of long‐term conservation areas, but disregarding artificial barriers to dispersal may lead to unrealistic solutions. Integrating the location of barriers allowed the identification of priority areas that are more likely to be colonized in the future following climatic shifts, although this resulted in an additional loss of six to eight features (~5%–7%) compared to solutions without dispersal constraints. Between 173 and 357 artificial barriers (~1.6%–3.3%) will potentially block species dispersal to irreplaceable planning units. Where removal of artificial barriers is unfeasible, conservation translocations may additionally cover up to eight additional features that do not meet conservation targets due to dispersal constraints. This study highlights the challenge of identifying protected areas to safeguard biodiversity under climate change. [ABSTRACT FROM AUTHOR]

Little is known about microplastics (MPs) in adult frogs. We investigated MPs in adult Common River Frogs (Amietia delalandii) from Potchefstroom, South Africa. Five kinds of samples were analysed: natural water, water used to rinse the skin, skin, intestine, and the remainder of the body (corpus). Tissues were digested. Microplastics occurred in all frogs and sample types (1128 MPs counted). Fibres were the most prevalent MP. Fibre lengths were between 28 and 4300 μm, either polyester or polyvinyl alcohol. MPs in skin were likely derived from the ambient, and MPs in the corpus from translocation via the skin. Fibres in tissues were significantly shorter in larger frogs, a phenomenon we provisionally assign to in situ biodegradation. Microplastics in frogs can potentially be transferred through the food web to higher trophic levels. This study provides the first evidence of MPs in adult frog tissues and avenues for further investigations. [ABSTRACT FROM AUTHOR]

The Media Luna spring, Mexico, is the main reservoir of the endemic and endangered fish Ataeniobius toweri. In the last decades, the ecosystem has been modified by tourism, and the habitat has changed for this species. Therefore, for better conservation management of the natural fish population, it is necessary to understand its abundance status and suitable habitat conditions, in ecological and spatial scenarios, on a temporal scale. In the present study, we modeled A. toweri's ecological responses and spatial distribution for adult and juvenile life stages, in three summer periods (years 1999, 2009, and 2019). As habitat variables, we used water depth and underwater coverage. Ecological response curves were obtained from a Generalized Linear Model; distribution models were obtained with DOMAIN. In the modeling evaluation, for the Linear Regression Model, we obtained true statistical skills metric > 0.30 and, for DOMAIN, an area under the curve (AUC) > 0.70 with an AUC ratio > 1.00. In general, as the summer periods progressed, we found the highest probability of occurrence (P > 0.20) and distribution (P > 0.60) in areas with conditions of large coverage of underwater vegetation, in the first 1.5 m of depth, and near the shores of the spring. Also, the variations of relative abundance were always observed at sites with these habitat conditions. Thus, we concluded that our models had the performance to discern between suitable and unsuitable habitat conditions for A. toweri, and that areas with little or no anthropogenic pressure are more important for this species. [ABSTRACT FROM AUTHOR]

The Indus River dolphin (Platanista minor) is a severely threatened species of freshwater dolphin that occurs only in the lower Indus River system of Pakistan and India. The dolphin's range has declined by 80% since the 1870s, and total species abundance is estimated as approximately 2000 individuals.In 2007, a remnant population of Indus dolphins was discovered above Harike Barrage, in the Beas River in India, 600 km away from all other individuals of its species. This paper provides an overview of the conservation status of Indus dolphins in the Beas River, details the threats they face, and suggests priorities for their conservation and management.Between 2011 and 2022, 40 dolphin direct count surveys were conducted. Indus dolphins occur only in the lower third of the Beas River and reported counts have been from one to eight individuals. The data do not indicate an increase in abundance, and instead suggest a potential decrease; however, sightings of calves continue to be reported annually indicating reproduction is still taking place.Threats to the Beas River dolphin population include accidental entanglement in fishing gear, pollution, escapement downstream of Harike barrage, altered and depleted river flow regimes' and the effects of a very small population size. Urgent conservation measures are essential if this small, but important satellite population is to persist.Recommended management actions include the complete removal of fishing nets from dolphin habitat, reducing pollution, ensuring adequate river discharge to sustain aquatic ecology including dolphins, evaluating and monitoring dolphin movement through Harike barrage and into canals, and engaging riverside communities to protect dolphins. In addition, the possibility of conservation translocations to supplement this population with individuals from larger healthy populations elsewhere in the range of the species should be explored. [ABSTRACT FROM AUTHOR]

Urban Blue (like lakes, rivers and streams) and Green Areas (like parks or woods), UBGAs, provide natural areas within cities, potentially contributing to a better health and wellbeing (H&W) of citizens. However, if degraded these ecosystems pose a potential risk for human health. Understanding the role of UBGAs in citizens' health and wellbeing is crucial for developing sustainable cities under the One Health framework, particularly for vulnerable citizens like older adults, which hasn't been clearly demonstrated. To fill this gap and amplify existing evidence, we searched for studies published between 2011 and 2021 (WoS and PubMed). Our revision indicates that natural urban areas benefit older citizens H&W. The 174 studies selected were mostly from developed countries, addressing mainly urban green areas, like parks or forests (86%), while few were focused on urban blue areas (3%). Perceived health tends to increase in proportion and with the proximity to UBGAs. Larger UBGAs were positively associated with physical activity and negatively associated with depression. A higher Normalized Difference Vegetation Index was associated to lower mortality. Physical activity is often used a surrogate of physical health which may lead to several bias, as it doesn't distinguish the effect of degraded from health and biodiverse ecosystems on H&W. Most studies used indicators of quantity of UGBAs (e.g., size, number). Yet, it is crucial to also investigate the influence of quality aspects (i.e., ecological quality, biodiversity and conservation status), as the ecosystems health affects the supply of ecosystem services relevant for human health.

Amphibians are among the most endangered taxa worldwide, but little is known about how their disappearance can alter the functioning and structure of freshwater ecosystems, where they live as larval stages. This is particularly true for urodeles, which often are key predators in these ecosystems. The fire salamander (Salamandra salamandra) is a common predator in European fresh waters, but the species is declining due to habitat loss and the infection by fungal pathogens. We studied the consequences of fire salamander loss from three montane streams, by comparing two key ecosystem processes (periphyton accrual and leaf litter decomposition) and the structure of three communities (periphytic algae, aquatic hyphomycetes and invertebrates) using stream enclosures with and without salamander larvae. Salamander loss did not cause changes in invertebrate abundance or community structure, except for one stream where abundance increased in the absence of salamander larvae. However, salamander loss led to lower periphyton accrual, changes in algal community structure and slower leaf litter decomposition, with no associated changes in fungal communities or microbial decomposition. The changes observed may have been caused by release of salamander predatory pressure on invertebrates, which could have promoted their grazing on periphyton, in contrast to their preference for leaf shredding in the presence of salamander. Our study demonstrates an important role of salamander larvae in montane streams through top‐down control of lower trophic levels and thus in regulating key stream ecosystem processes. Our results highlight the need for improving protection measures for amphibians to prevent these alterations on ecosystem structure and function. [ABSTRACT FROM AUTHOR]

The introduction of non-native species causes a variety of negative ecological and economic-social impacts on aquatic ecosystems. One of the first studies conducted on these species was the study of their composition and abundance in recipient ecosystems. The present study aimed to investigate the distribution, composition, and abundance of non-native fishes in the lower Tigris basin in a fishing year from fall 2014 to summer 2015. To update and compare the information, the latest fishing situation in the fishing year 2022-2023 was also examined. In total, 31 species from 15 families, including eight non-native species were caught from the studied water bodies. According to the results, non-native species are widely spread to the most aquatic ecosystems of the studied area, among which tilapia, including the redbelly tilapia Coptodon zillii (Gervais, 1848) and the blue tilapia Oreochromis aureus (Steindachner, 1864) were the most abundant species. The redbelly tilapia showed the most distribution in the studied area. According to the local fishermen, the amount of catch in many areas of inland waters of Khuzestan province has decreased compared to 2014-2015, and their statements indicate that they are not satisfied with the state of fishing.

Harmful algal blooms (HABs) are a primary environmental concern, threatening freshwater ecosystems and public health and causing economic damages in the billions of dollars annually. These blooms, predominantly driven by phytoplankton species like cyanobacteria, thrive in nutrient-rich, warm, and low-wind environments. Because of the adverse impacts of HABs, this review examines various control methods, focusing on biological strategies as sustainable solutions. While effective in disrupting algal populations, traditional chemical and physical interventions carry ecological risks and can be resource-intensive. Biological control methods, including biomanipulation and using algicidal microorganisms such as Streptococcus thermophiles, Myxobacteria, and Lopharia spadicea, emerge as eco-friendly alternatives offering long-term benefits. Additionally, barley and rice straw application has demonstrated efficacy in curbing HAB growth. These biological approaches work by inhibiting algal proliferation, disrupting cellular structures, and fostering algal cell aggregation. Despite their advantages over conventional methods, biological controls face challenges, including intricate ecological interactions. This article delves into the latest biological techniques aimed at eradicating HABs, intending to diminish their frequency and reduce toxin levels in aquatic environments. While most research to date has been confined to laboratory settings, scaling these methods to field applications presents hurdles due to the variability and complexity of natural ecosystems. The review underscores the need for further research and development in this critical area of environmental science. [ABSTRACT FROM AUTHOR]

Aim: Over the last century, lakes all over the world have experienced significant eutrophication and become more susceptible to critical transitions. This has prompted a growing need to understand how community dynamics shift following ecological perturbations. This study aims to elucidate the present status, spatial patterns and determinants of biological diversity, and how they have changed in response to alterations driven by eutrophication. Location: Lakes of East China, mostly in the Yangtze River Basin. Taxa: Bacillariophyceae (163 species in 33 genres, see taxa names in Appendix S1). Methods: The environmental conditions of over 60 lakes were assessed based on parameters such as water quality, physical characteristics and biogeochemical constituents. Surface sediment samples and high‐resolution sediment records were collected to quantify the biodiversity of diatom communities, and principal component analysis (PCA) was used to determine the major environmental gradients. Meanwhile, linear regression, canonical correlation analysis and Mantel tests were used to quantify the correlations between variables. Results: Biodiversity metrics showed no distinct geographic patterns, although areas near large lakes showed comparatively high evenness. Smaller pairwise dissimilarities were observed among hypereutrophic lakes in comparison to lakes with a lower trophic status. The past century has witnessed a decrease in both pairwise dissimilarity and the standard deviation of evenness. A significant statistical association was found between dissimilarity and ionic concentration and composition in the surface sediment of lakes, rather than nutrient levels. Main Conclusions: Following regional eutrophication and human disturbance, a significant reduction in biodiversity differentiation was observed in lakes located in East China. Currently, the dominant factor in determining the beta diversity of diatom communities is geochemical conditions rather than nutrient concentrations. Long‐term stress caused by cultural eutrophication may also have altered the dominant determinant of regional biodiversity and diatom community dynamics. [ABSTRACT FROM AUTHOR]

The spread of non-native species is one of the outcomes of global change, threatening many native communities through predation and competition. Freshwater ecosystems are particularly affected by species turnover with non-native species. One species that has been established in Central Europe for many decades - or even a few centuries - is the amphipod crustacean Gammarus roeselii. Although G. roeselii is nowadays widespread in major river systems, there have been recent reports of its spread into smaller streams that are typically inhabited by the native species Gammarus fossarum. Due to their leaf shredding ability, G. fossarum takes up a key position in headwater streams. This raises the important question, to what extent G. roeselii can equivalently take over this function. To answer this question, we collected both species from nine different sites in a mid-mountain river system (Kinzig catchment, Hesse, Germany) and investigated their functional similarity using a combination of stable isotope analysis, gut content and functional morphology. The species hardly differed in morphological characteristics, only females showed differences in some traits. Gut content analysis indicated a broad dietary overlap, while stable isotopes showed a higher trophic position of G. roeselii. The observed functional overlap could intensify interspecific competition and allow the larger and more predaceous G. roeselii to replace G. fossarum in the future as a headwater keystone species. However, the differentiation in the stable isotopes also shows that co-existence can occur by occupying different trophic niches. Moreover, the wide range of inhabited sites and exploited resources demonstrate the omnivorous lifestyle of G. roeselii, which is likely to help the species succeed in rapidly changing environments. [ABSTRACT FROM AUTHOR]

External nutrient loading can cause large changes in freshwater ecosystems. Many local field and laboratory experiments have investigated ecological responses to nutrient addition. However, these findings are difficult to generalize, as the responses observed may depend on the local context and the resulting nutrient concentrations in the receiving water bodies. In this research, we combined and analysed data from 131 experimental studies containing 3054 treatment‐control abundance ratios to assess the responses of freshwater taxa along a gradient of elevated nutrient concentrations. We carried out a systematic literature search in order to identify studies that report the abundance of invertebrate, macrophyte, and fish taxa in relation to the addition of nitrogen, phosphorus, or both. Next, we established mixed‐effect meta‐regression models to relate the biotic responses to the concentration gradients of both nutrients. We quantified the responses based on various abundance‐based metrics. We found no responses to the mere addition of nutrients, apart from an overall increase of total invertebrate abundance. However, when we considered the gradients of N and P enrichment, we found responses to both nutrients for all abundance metrics. Abundance tended to increase at low levels of N enrichment, yet decreased at the high end of the concentration gradient (1–10 mg/L, depending on the P concentration). Responses to increasing P concentrations were mostly positive. For fish, we found too few data to perform a meaningful analysis. The results of our research highlight the need to consider the level of nutrient enrichment rather than the mere addition of nutrients in order to better understand broad‐scale responses of freshwater biota to eutrophication, as a key step to identify effective conservation strategies for freshwater ecosystems. [ABSTRACT FROM AUTHOR]

Mediterranean spring ecosystems are unique habitats at the interface between surface water and groundwater. These ecosystems support a remarkable array of biodiversity and provide important ecological functions and ecosystem services. Spring ecosystems are influenced by abiotic, biotic, and anthropogenic factors such as the lithology of their draining aquifers, their climate, and the land use of their recharge area, all of which affect the water chemistry of the aquifer and the spring discharges. One of the most relevant characteristics of spring ecosystems is the temporal stability of environmental conditions, including physicochemical features of the spring water, across seasons and years. This stability allows a wide range of species to benefit from these ecosystems (particularly during dry periods), fostering an unusually high number of endemic species. However, global change poses important threats to these freshwater ecosystems. Changes in temperature, evapotranspiration, and precipitation patterns can alter the water balance and chemistry of spring water. Eutrophication due to agricultural practices and emergent pollutants, such as pharmaceuticals, personal care products, and pesticides, is also a growing concern for the preservation of spring biodiversity. Here, we provide a synthesis of the main characteristics and functioning of Mediterranean spring ecosystems. We then describe their ecological value and biodiversity patterns and highlight the main risks these ecosystems face. Moreover, we identify existing knowledge gaps to guide future research in order to fully uncover the hidden biodiversity within these habitats and understand the main drivers that govern them. Finally, we provide a brief summary of recommended actions that should be taken to effectively manage and preserve Mediterranean spring ecosystems for future generations. Even though studies on Mediterranean spring ecosystems are still scarce, our review shows there are sufficient data to conclude that their future viability as functional ecosystems is under severe threat. [ABSTRACT FROM AUTHOR]

The introduction of non-native species causes a variety of negative ecological and economic-social impacts on aquatic ecosystems. One of the first studies conducted on these species was the study of their composition and abundance in recipient ecosystems. The present study aimed to investigate the distribution, composition, and abundance of non-native fishes in the lower Tigris basin in a fishing year from fall 2014 to summer 2015. To update and compare the information, the latest fishing situation in the fishing year 2022-2023 was also examined. In total, 31 species from 15 families, including eight non-native species were caught from the studied water bodies. According to the results, non-native species are widely spread to the most aquatic ecosystems of the studied area, among which tilapia, including the redbelly tilapia Coptodon zillii (Gervais, 1848) and the blue tilapia Oreochromis aureus (Steindachner, 1864) were the most abundant species. The redbelly tilapia showed the most distribution in the studied area. According to the local fishermen, the amount of catch in many areas of inland waters of Khuzestan province has decreased compared to 2014-2015, and their statements indicate that they are not satisfied with the state of fishing. [ABSTRACT FROM AUTHOR]

The research paper extensively covers the phenomenon of bioaccumulation, focusing on its impact in freshwater ecosystems, particularly on fish. It details how heavy metals like mercury, lead, cadmium, and arsenic, originating from industrial pollution, agricultural runoff, and atmospheric deposition, accumulate in fish tissues over time. The abstract highlights the adverse effects of such bioaccumulation on fish health, including reproduction issues, growth abnormalities, and organ damage. It also underscores the consequent risks to human health when these contaminated fish are consumed. The study emphasizes the importance of addressing heavy metal pollution in aquatic ecosystems through effective waste management, reduction of industrial discharges, sustainable agricultural practices, and regular monitoring of fish populations. This approach is crucial to manage and mitigate the risks of heavy metal bioaccumulation in freshwater fish, thereby protecting both aquatic life and human health. [ABSTRACT FROM AUTHOR]

Copyright of Natura Croatica is the property of Natura Croatica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)