Search

Seasonal regimes of stream temperatures are important for ecological health as well as for societal water use. Seasonal regimes can be captured in the annual temperature cycle (the mean temperature for each day of the year) or in summary statistics such as seasonal mean temperatures, the former of which is the focus of this work. The annual temperature cycle is often characterized as a sine function, which performs satisfactorily for most streams. However, the sine function is unable to capture major seasonal variations, particularly for colder, drier, and high‐elevation regions. Seasonal summary statistics are effective for classification but do not capture the full time series, preventing the use of lost time‐series information, and lack context for the comparison of trends, hindering distinction between different causes of similar seasonal trends. We propose an improved function called the “three‐sine model” to describe the stream annual temperature cycle with higher accuracy and demonstrate its use in two case studies. The three‐sine model uses a cosine function over the entire year coupled with two seasonal anomaly sine functions. The three‐sine model captures the stream annual temperature cycle with eight parameters, reveals distinct spatial trends, and outperforms the sinusoidal model for all elevations and 99% of streams. We conclude that this approach can support improved stream temperature analysis by capturing detailed seasonal trends in context. [ABSTRACT FROM AUTHOR]

The viromes of freshwater bodies are underexplored. The Picornavirales order, with 371 acknowledged species, is one of the most expansive and diverse groups of eukaryotic RNA viruses. In this study, we add 513 picorna-like viruses to the assemblage of more than 2000 unassigned picorna-like viruses. Our set of the aquatic Picornavirales virome of the Teltow Canal in Berlin, Germany, consists of 239 complete and 274 partial genomes. This urban freshwater body is characterized by the predominance of marna-like viruses (30.8%) and dicistro-like viruses (19.1%), whereas picornaviruses, iflaviruses, solinvi-like viruses, polycipi-like viruses, and nora-like viruses are considerably less prevalent. Caliciviruses and secoviruses were absent in our sample. Although presenting characteristic domains of Picornavirales, more than 100 viruses (20.8%) could not be assigned to any of the 9 Picornavirales families. Thirty-three viruses of the Marnaviridae—mostly locarna-like viruses—exhibit a monocistronic genome layout. Besides a wealth of novel virus sequences, viruses with peculiar features are reported. Among these is a clade of untypeable marna-like viruses with dicistronic genomes, but with the capsid protein-encoding open reading frame located at the 5′ part of their RNA. A virus with a similar genome layout but clustering with dicistroviruses was also observed. We further detected monocistronic viruses with a polymerase gene related to aparaviruses. The detection of Aichi virus and five novel posa-like viruses indicates a slight burden in municipal wastewater. [ABSTRACT FROM AUTHOR]

Numerous organic chemicals exist within aquatic environments, yet effectively screening and prioritizing them is a huge challenge. This study provides a comprehensive investigation into the ecological dynamics of the North Oconee River within Athens-Clarke County, Georgia, with a specific focus on the distribution of 33 identified compounds, including a prominent pesticide. The research, conducted in the riverine ecosystems proximal to the Firefly trail, employs advanced analytical techniques to elucidate potential contamination sources arising from agricultural and urban runoff. Intriguingly, the study reveals North Oconee River near the Firefly Trail as a notable site for heightened pesticide contamination, warranting a meticulous exploration of its origins. Furthermore, the investigation unveils the intricate microbial degradation processes of malathion within the North Oconee River, elucidating the pivotal role played by microbial activity in river water. The detection of degradant byproducts prompts the considerations of bioavailability and toxicity, associating potential implications for the river's overall ecological health. Ongoing research endeavors to precisely quantify environmental risks and unravel indigenous microbial degradation pathways, presenting pivotal contributions to the scientific community's understanding of complex riverine ecosystems. This research serves as a foundational piece in informing sustainable environmental management practices and emphasizes the urgency of comprehensive stewardship in safeguarding aquatic ecosystems. [ABSTRACT FROM AUTHOR]

Freshwater habitats display a high degree of heterogeneity in both space and time. This heterogeneity is a result of the hierarchical interplay of hydrology and geomorphology, producing the physical habitat template to which biological communities respond and interact. Thus, it follows that any effort to fully understand the complexity of these systems requires a spatial and temporal perspective of heterogeneity at multiple scales within a hierarchical framework. In this study we 1) test if fish assemblage structure differs between hydrogeomorphically distinct, off-channel patches of the Upper Mississippi River, USA, 2) identify which species are driving differences in assemblages between patch types and, 3) assess which hydrogeomorphic variables are associated with fish assemblages and if these are the same suite of variables responsible for the physical differentiation of patches. Different fish assemblages were associated with hydrogeomorphically distinct patches, importantly, sub-groups of backwaters. Species including the Bluegill Lepomis macrochirus Rafinesque, 1819, the Black Crappie Pomoxis nigromaculatus (Lesueur in Cuvier and Valenciennes, 1829), and the Gizzard Shad Dorosoma cepedianum (Lesueur, 1818) were influential in driving differences in assemblages. Fish assemblages did not respond to the same suite of hydrogeomorphic variables responsible for the physical character of patches, although there was some overlap. Instead, they responded to patch-scale characteristics and long-term hydrology and, in the case of backwaters, which navigation pool they were located in. We suggest that classification of hydrogeomorphic character across multiple spatio-temporal scales is critical. This classification should be done prior to sampling so patches can be targeted based on their physical character to draw out key habitat-assemblage relationships. We also contend that broad classification of habitats (e.g., floodplain lake vs backwater) may be too simplistic. Instead, individual characteristics defining the physical nature of a habitat need to be linked to biological responses across scales. A more nuanced understanding of these relationships is needed to improve restoration and management outcomes with respect to increasing or maintaining heterogeneity in the landscape. [ABSTRACT FROM AUTHOR]

Plant-infecting RNA viruses from 30 families and floating genera, as well as a great number of uncultured as yet-unclassified plant-associated viruses have been described. Even so, the plant RNA virosphere is still underexplored. RNA extracted from enriched virus particles of 50 L water samples from the Teltow Canal and the Havel River in Berlin, Germany, was sequenced using Illumina next-generation sequencing. Sequences were searched for plant viruses with BLAST and DIAMOND. Phylogenetic analyses were conducted with IQ-TREE 2. Altogether, 647 virus sequences greater than 1 kb were detected and further analyzed. These data revealed the presence of accepted and novel viruses related to Albetovirus, Alphaflexiviridae, Aspiviridae, Bromoviridae, Endornaviridae, Partitiviridae, Potyviridae, Solemoviridae, Tombusviridae and Virgaviridae. The vast majority of the sequences were novel and could not be taxonomically assigned. Several tombus- and endorna-like viruses make use of alternative translation tables that suggest unicellular green algae, ciliates, or diplomonades as their hosts. The identification of 27 albeto-like satellite viruses increases available sequence data five-fold. Sixteen new poty-like viruses align with other poty-like viruses in a link that combines the Astroviridae and Potyviridae families. Further, the identification of viruses with peptidase A6-like and peptidase A21-like capsid proteins suggests horizontal gene transfer in the evolution of these viruses. [ABSTRACT FROM AUTHOR]

The viromes of freshwater bodies are underexplored. The Picornavirales order, with 371 acknowledged species, is one of the most expansive and diverse groups of eukaryotic RNA viruses. In this study, we add 513 picorna-like viruses to the assemblage of more than 2000 unassigned picorna-like viruses. Our set of the aquatic Picornavirales virome of the Teltow Canal in Berlin, Germany, consists of 239 complete and 274 partial genomes. This urban freshwater body is characterized by the predominance of marna-like viruses (30.8%) and dicistro-like viruses (19.1%), whereas picornaviruses, iflaviruses, solinvi-like viruses, polycipi-like viruses, and nora-like viruses are considerably less prevalent. Caliciviruses and secoviruses were absent in our sample. Although presenting characteristic domains of Picornavirales, more than 100 viruses (20.8%) could not be assigned to any of the 9 Picornavirales families. Thirty-three viruses of the Marnaviridae—mostly locarna-like viruses—exhibit a monocistronic genome layout. Besides a wealth of novel virus sequences, viruses with peculiar features are reported. Among these is a clade of untypeable marna-like viruses with dicistronic genomes, but with the capsid protein-encoding open reading frame located at the 5′ part of their RNA. A virus with a similar genome layout but clustering with dicistroviruses was also observed. We further detected monocistronic viruses with a polymerase gene related to aparaviruses. The detection of Aichi virus and five novel posa-like viruses indicates a slight burden in municipal wastewater.

Timing of delivery of environmental water is essential for restoring and conserving riverine ecosystems. However, change in the timing of occurrence of streamflow and its implications on environmental water allocation and river ecosystems are often ignored in current environmental water research and management. We adopted the centre of timing approach to analyse the change in the occurrence of streamflow due to climate change (through a change in rainfall) and river operations (flow regulation and diversion) in the Goulburn-Broken catchment, Victoria, Australia. It was found that annual streamflow in the catchment declined by an average of 47%, while centre of timing increased by an average of 36%. These changes were 52% attributable to rainfall decline and 48% to river regulation. A decline in annual streamflow (35%) and an increase in centre of timing (21%) across the Goulburn River would be observed by 2050 as an impact of climate change. Current management efforts should be directed at reversing the change in centre of timing to support the sustainable management of riverine systems. The Goulburn-Broken catchment is typical of managed catchments in many areas of the world with forecast rainfall reduction, and the findings are likely to be widely applicable.

Plant-infecting RNA viruses from 30 families and floating genera, as well as a great number of uncultured as yet-unclassified plant-associated viruses have been described. Even so, the plant RNA virosphere is still underexplored. RNA extracted from enriched virus particles of 50 L water samples from the Teltow Canal and the Havel River in Berlin, Germany, was sequenced using Illumina next-generation sequencing. Sequences were searched for plant viruses with BLAST and DIAMOND. Phylogenetic analyses were conducted with IQ-TREE 2. Altogether, 647 virus sequences greater than 1 kb were detected and further analyzed. These data revealed the presence of accepted and novel viruses related to Albetovirus, Alphaflexiviridae, Aspiviridae, Bromoviridae, Endornaviridae, Partitiviridae, Potyviridae, Solemoviridae, Tombusviridae and Virgaviridae. The vast majority of the sequences were novel and could not be taxonomically assigned. Several tombus- and endorna-like viruses make use of alternative translation tables that suggest unicellular green algae, ciliates, or diplomonades as their hosts. The identification of 27 albeto-like satellite viruses increases available sequence data five-fold. Sixteen new poty-like viruses align with other poty-like viruses in a link that combines the Astroviridae and Potyviridae families. Further, the identification of viruses with peptidase A6-like and peptidase A21-like capsid proteins suggests horizontal gene transfer in the evolution of these viruses.

The materials added to the water from fish farms affect the water quality, as these are decomposed in the environment and may reduce the quality of the water so that it is not suitable for further use. Therefore, it is necessary to measure how water quality changes. The impact of the fish farms on the water in the Joobkhalleh River was investigated. Five sampling stations were selected before flowing into the farm, the outlet, and in 5, 8, and 10km after the farm, to be sampled 6 times in 2-month intervals in the spring 2015-winter 2015 period. DO (annual mean 9.0 mg/L), T (14.5˚C), pH (8.4), TDS (462mg/L), COD (8.1mg/L), [PO4]- (0.2mg/L), and [NO3] (1.3mg/L) did not show significant changes, while oxygen saturation, BOD (1.4mg/L), EC (711µS/cm), TSS (6.0mg/L), [NO2] (0.01mg/L), and [NH3] (0.13mg/L) differed significantly among the stations. Regression analysis proved a significant correlation between the increase with distance from the source for [NO2] (Pearson Correlation= 0.915), TDS (0.878), and EC (0.878). Comparison of the findings with water use criteria shows that most parameters were in the suitable range for aquaculture, except for the TDS, which was far out of the standard, and the ammonia which was slightly higher. Considering the effect of pH, these values for the annual average of ammonia and nitrite are considered toxic for fish farming. In conclusion, the annual average of ammonia and nitrite is toxic at the last point for fish farming due to the water pH; therefore, it is not appropriate to use the water for aquaculture development.

Inspired by calls for ecosystem service research on (in)equity and diverse cultural values, we designed a cross-cultural study to collect local, shared knowledge of riverine ecosystems and their perceived (in) equity within four Anglophone sites. Keywords: (In)Equity; Distributive justice; Riverine ecosystems; Qualitative research EN (In)Equity Distributive justice Riverine ecosystems Qualitative research 793 798 6 11/18/22 20220801 NES 220801 Introduction Since its inception, public perception and valuation have been key features of the ecosystem services framework (Millennium Ecosystem Assessment [27]). Metatheme 3: Ecosystem service distribution resulting from personal choice Many respondents (n = 69) identified access to ecosystem services as inequitably distributed, but provided personal choice as a central determinant of access to the riverine ecosystem (coded segments = 90). Metatheme 2: Socioeconomic status shapes inequity in ecosystem services Socioeconomic status was another factor widely perceived to influence equity in access to ecosystem services (coded segments = 102). [Extracted from the article]

Simple Summary: Competition and predation are the main factors shaping interspecific coexistence in wildlife communities. Species reappearance and introductions may alter these dynamics. The Eurasian beaver Castor fiber is a widespread species in Europe, and it is part of the diet of many birds and mammalian carnivores of all sizes. Additionally, competition with other herbivorous mammals at feeding sites could occur. For this reason, we computed the overlap of activity rhythms among the recently reappeared Eurasian beaver and its potential predators (red fox Vulpes vulpes and grey wolf Canis lupus) and competitors (coypu Myocastor coypus) in Central Italy. The beaver was confirmed as a mostly crepuscular species, avoiding the bright moonlight nights and the activity of its predators, which is potentially shaped by the behaviour of their main prey. Analyses of temporal partitioning and overlaps in activity rhythms are pivotal to shed light on interspecific coexistence between similar species or prey and predators. In this work, we assessed the overlap of activity rhythms between the Eurasian beaver Castor fiber and its potential competitors and predators through camera trapping in an area in Central Italy. Interspecific overlaps of temporal activity patterns were estimated for the beavers, potential predators (the red fox Vulpes vulpes and the grey wolf Canis lupus), and a potential competitor, the coypu Myocastor coypus. The beavers showed a mostly crepuscular behaviour. Although high temporal overlap was observed between the Eurasian beavers and the red foxes and grey wolves, the activity of the beavers did not overlap with that of the predators. Accordingly, the beavers were more active on the darkest nights, i.e., avoiding bright moonlight. [ABSTRACT FROM AUTHOR]

Rivers are important ecosystems, vital to the livelihoods of hundreds of millions of humans and other species. Despite their environmental, social, and economic importance, current use of rivers is unsustainable, due to a combination of solid waste and high levels of pollutants. Plastic materials are among the most predominant of such pollutants. Based on the need for additional research in this area, this study examines pressures put to rivers and explores trends related to riverine plastic pollution, with a focus on Asia. Apart from the bibliometric analysis, and relying on the collected information, examples describing the drivers of riverine plastic pollution in a sample of Asian countries are described, outlining the specific problem and its scope. Among some of the results obtained from it, mention can be made to the fact that much of the literature focuses on plastic pollution as a whole and less on one of its most significant ramifications, namely microplastics. Additionally, there is a need related to data availability on riverine plastic data and improving the understanding of transport mechanisms in relation to riverine plastic emission into the ocean. The results from this study illustrate the significance of the problems posed by plastic waste to Asian rivers and point out the fact that there are still significant gaps in respect of regulations and standards, which prevent improvements that are highlighted in this study. Based on the results of this bibliometric assessment, specific measures via which levels of riverine plastic pollution may be reduced are presented, bringing relevant new insights on this topic beyond the existing reviews. [ABSTRACT FROM AUTHOR]

To improve the understanding of the virome diversity of riverine ecosystems in metropolitan areas, a metagenome analysis was performed with water collected in June 2018 from the river Havel in Berlin, Germany. After enrichment of virus particles and RNA extraction, paired-end Illumina sequencing was conducted and assignment to virus groups and families was performed. This paper focuses on picorna-like viruses, the most diverse and abundant group of viruses with impact on human, animal, and environmental health. Here, we describe altogether 166 viral sequences ranging in size from 1 to 11.5 kb. The 71 almost complete genomes are comprised of one candidate iflavirus, one picornavirus, two polycipiviruses, 27 marnaviruses, 27 dicistro-like viruses, and 13 untypeable viruses. Many partial picorna-like virus sequences up to 10.2 kb were also investigated. The sequences of the Havel picorna-like viruses represent genomes of seven of eight so far known Picornavirales families. Detection of numerous distantly related dicistroviruses suggests the existence of additional, yet unexplored virus groups with dicistronic genomes, including few viruses with unusual genome layout. Of special interest is a clade of dicistronic viruses with capsid protein-encoding sequences at the 5′-end of the genome. Also, monocistronic viruses with similarity of their polymerase and capsid proteins to those of dicistroviruses are interesting. A second protein with NTP-binding site present in the polyprotein of solinviviruses and related viruses needs further attention. The results underline the importance to study the viromes of fluvial ecosystems. So far acknowledged marnaviruses have been isolated from marine organisms. However, the present study and available sequence data suggest that rivers and limnic habitats are relevant ecosystems with circulation of marnaviruses as well as a plethora of unknown picorna-like viruses. [ABSTRACT FROM AUTHOR]

To improve the understanding of the virome diversity of riverine ecosystems in metropolitan areas, a metagenome analysis was performed with water collected in June 2018 from the river Havel in Berlin, Germany. After enrichment of virus particles and RNA extraction, paired-end Illumina sequencing was conducted and assignment to virus groups and families was performed. This paper focuses on picorna-like viruses, the most diverse and abundant group of viruses with impact on human, animal, and environmental health. Here, we describe altogether 166 viral sequences ranging in size from 1 to 11.5 kb. The 71 almost complete genomes are comprised of one candidate iflavirus, one picornavirus, two polycipiviruses, 27 marnaviruses, 27 dicistro-like viruses, and 13 untypeable viruses. Many partial picorna-like virus sequences up to 10.2 kb were also investigated. The sequences of the Havel picorna-like viruses represent genomes of seven of eight so far known Picornavirales families. Detection of numerous distantly related dicistroviruses suggests the existence of additional, yet unexplored virus groups with dicistronic genomes, including few viruses with unusual genome layout. Of special interest is a clade of dicistronic viruses with capsid protein-encoding sequences at the 5′-end of the genome. Also, monocistronic viruses with similarity of their polymerase and capsid proteins to those of dicistroviruses are interesting. A second protein with NTP-binding site present in the polyprotein of solinviviruses and related viruses needs further attention. The results underline the importance to study the viromes of fluvial ecosystems. So far acknowledged marnaviruses have been isolated from marine organisms. However, the present study and available sequence data suggest that rivers and limnic habitats are relevant ecosystems with circulation of marnaviruses as well as a plethora of unknown picorna-like viruses.

Context: Understanding how spatial pattern changes with scale can provide insights into its relationship with ecological processes. In riverine landscapes, spatial pattern could scale differently from other well-studied landscapes because of their dendritic form. Objectives: The objectives of this study were (1) to assess how spatial pattern of hydrogeomorphic habitat patches (HGP) change with spatial extent, grain size, and thematic resolution, and (2) to quantify how spatial pattern in river networks varies across the contiguous United States (CONUS). Methods: We identified hydrogeomorphic patches in river networks located in different ecoclimatic domains. We then quantified spatial pattern within each river network using a suite of landscape metrics and investigated scaling relationships for each component of scale. We also assessed whether watershed area, river network length, and drainage density were related to spatial pattern among river networks and explored regional differences in the hydrologic, geomorphologic, and climatic variables that differentiate HGP types. Results: When predictable, scaling relationships within river networks followed either linear, logarithmic, or power functions. Among river networks, spatial pattern was related to total network length, catchment area and drainage density. Rarely were HGP types in different networks characterized by the same suite of hydrologic, geomorphologic and climatic variables. Conclusions: In riverine landscapes, there are a variety of relationships between spatial pattern and scale. The scaling functions we present can provide a concise description of scale dependency in these landscapes and improve our ability to synthesize information across scales. [ABSTRACT FROM AUTHOR]

As demand for water in the arid southwest increases, pressure is mounting on many aquatic and riparian species that rely on riverine habitat for survival. Some of these riverine areas are managed as private, state, or federal lands with differing levels of mandated protections; however, few efforts have explored the potential of filling gaps in riverine protection afforded by designation under the protection of the Wild and Scenic Rivers Act (WSRA) of 1968. Here, we examine how inclusion of eligible rivers, specifically the Nationwide Rivers Inventory (NRI), could fill gaps in protection for a species of high conservation need. A gap analysis overlapping the predicted species range with human disturbances and the level of protection identifies where sufficient protections for a species exist and where there are shortcomings, that is, gaps, potentially addressed by elevating NRI reaches to WSRA protection. This study uses the narrow‐headed garter snake as an indicator species for riverine ecosystem health of free‐flowing perennial reaches within the Arizona/New Mexico Mountains EPA Level III ecoregion. Over a quarter of NRI‐eligible reaches within the ecoregion are within the protection gap for the narrow‐headed garter snake. If designated Wild and Scenic, these reaches could offer needed protection for this species. [ABSTRACT FROM AUTHOR]

In food-productive river basins, ecosystems reliant on natural flows are affected by climate change and water removal. One such example is Australia's Murray-Darling Basin (MDB), to which the ecologically important black box tree Eucalyptus largiflorens (Myrtaceae) is unique. Little is known about its mineral nutrition and response to flooding. A field study conducted at Hattah Kulkyne National Park on the MDB examined nutrient and Al distribution in mature and young foliage of trees whose status varied with respect to the presence of surface floodwaters. Black box is also of interest due to emerging evidence of its capacity to accumulate high foliar salt concentrations. Here, cryo scanning electron microscopy alone (SEM), combined with energy dispersive spectroscopy (SEM-EDS) and X-ray fluorescence (XRF) spectroscopy were applied to evaluate leaf anatomy and elemental patterns at the cellular and whole-leaf levels. Variation in whole-leaf elemental levels across flooded and dry trees aligned with known nutritional fluctuations in this drought-tolerant species reliant on occasional infrequent flooding. The microprobe data provide evidence of drought tolerance by demonstrating that extended conditions of lack of water to trees do not elicit leaf anatomical changes nor changes to leaf cellular storage of these elements. Foliar Na concentrations of ~2000-6000 mg kg-1 DW were found co-localised with Cl in mesophyll and dermal cells of young and mature leaves, suggesting vacuolar salt disposal as a detoxification strategy. Black box, the iconic floodplain eucalypt unique to Australia's Murray-Darling Basin, is affected by anthropogenic activities, yet knowledge about its environmental interactions is limited. Little is understood of its adaptation to drier conditions well away from watercourses. This study revealed similar leaf structure and nutrient distribution in both flooded trees and those that received very little water, with indication of possible species-wide salt tolerance. Insights were gained into key aspects of black box tolerance of dry and saline conditions. [ABSTRACT FROM AUTHOR]

Analyses of temporal partitioning and overlaps in activity rhythms are pivotal to shed light on interspecific coexistence between similar species or prey and predators. In this work, we assessed the overlap of activity rhythms between the Eurasian beaver Castor fiber and its potential competitors and predators through camera trapping in an area in Central Italy. Interspecific overlaps of temporal activity patterns were estimated for the beavers, potential predators (the red fox Vulpes vulpes and the grey wolf Canis lupus), and a potential competitor, the coypu Myocastor coypus. The beavers showed a mostly crepuscular behaviour. Although high temporal overlap was observed between the Eurasian beavers and the red foxes and grey wolves, the activity of the beavers did not overlap with that of the predators. Accordingly, the beavers were more active on the darkest nights, i.e., avoiding bright moonlight.

Rivers are important ecosystems, vital to the livelihoods of hundreds of millions of humans and other species. Despite their environmental, social, and economic importance, current use of rivers is unsustainable, due to a combination of solid waste and high levels of pollutants. Plastic materials are among the most predominant of such pollutants. Based on the need for additional research in this area, this study examines pressures put to rivers and explores trends related to riverine plastic pollution, with a focus on Asia. Apart from the bibliometric analysis, and relying on the collected information, examples describing the drivers of riverine plastic pollution in a sample of Asian countries are described, outlining the specific problem and its scope. Among some of the results obtained from it, mention can be made to the fact that much of the literature focuses on plastic pollution as a whole and less on one of its most significant ramifications, namely microplastics. Additionally, there is a need related to data availability on riverine plastic data and improving the understanding of transport mechanisms in relation to riverine plastic emission into the ocean. The results from this study illustrate the significance of the problems posed by plastic waste to Asian rivers and point out the fact that there are still significant gaps in respect of regulations and standards, which prevent improvements that are highlighted in this study. Based on the results of this bibliometric assessment, specific measures via which levels of riverine plastic pollution may be reduced are presented, bringing relevant new insights on this topic beyond the existing reviews.

The presence of the Eurasian beaver Castor fiber L. has been recently confirmed with two separated populations in Tuscany (Central Italy) and probably represents the result of an unofficial release. In late spring and summer 2021, seven reliable records of Eurasian beaver have been collected in Umbria and other neighbouring regions, implying that the distribution of this large rodent is even wider than previously reported. In this short work, we updated the distribution of this protected species in Central Italy, by collecting and mapping all the confirmed occurrences. Beavers were proved to be present throughout the Tiber (Tevere) river basin in both provinces of Umbria, and another individual has been road-killed in the Marche region, near the border with Tuscany. Other single signs of presence occurred in Emilia Romagna and Latium. The only hair sample we were able to collect confirmed it as the Eurasian beaver species. No reliable evidence is available on the number of free-ranging beavers in Central Italy, and systematic monitoring is needed. Before any management and conservation action, further data are required concerning distribution range, potential origin, social perception, and the effects on the ecosystems. [ABSTRACT FROM AUTHOR]

Premise: Gesneria pauciflora is a rare, threatened plant in riparian forests. Periodic disturbances, expected in this habitat, could influence demographic dynamics on plant populations, yet their impact may not be the same across the watershed. We hypothesized that differences in disturbances between the main channel and tributaries may lead to spatial dissimilarities in population growth rate (λ), structure, and fecundity. Methods: In the Maricao River Watershed in Puerto Rico, 1277 plants were tagged and monitored for 1.5 years. Every 6 months, we measured plant size and recorded survival, fecundity, and appearance of seedlings. These variables were used in integral projection models to assess the population status of G. pauciflora. Results: Plants in the main channel were smaller but more likely to flower and fruit than those in the tributaries. Overall mortality was greater in the main channel and greater during the rainy season. At both sites, λ ranged from 0.9114 to 0.9865, and survival/growth of larger plants had a greater effect on λ (>0.90) regardless of site. Conclusions: Values for population growth rates suggest that G. pauciflora is declining across the watershed. Higher mortality rates in the main channel (more‐perturbed sites) might drive G. pauciflora to reproduce at smaller sizes, while tributaries (less‐perturbed sites) might be better for growth and lead to larger plant sizes. Extreme climatic events are expected to increase in the Caribbean and might decrease the population if the population is left unmanaged. Management strategies that reduce the time plants require to reach larger sizes might be necessary to increase λ, and reintroduction using cuttings might be a possible solution. [ABSTRACT FROM AUTHOR]

Abstract Floodplain soils across Central Elbe River (CER), Germany, vary considerably in potentially toxic element (PTE) content. However, there has never been a comprehensive study that links PTE levels with human health risk for children and adults. Our objective was to determine the contamination of 13 PTEs in 94 soil profiles along CER and assess the associated health risk via diverse indices for adults and children. Of 94 soil profiles, we measured soil properties and total content of arsenic, barium, chromium, copper, nickel, lead, rubidium, tin, strontium, vanadium, zinc, and zirconium using x-ray fluorescence spectrometer (XRF). We calculated the Contamination Factor and the Pollution Load Index (PLI), and assessed the health risk for male and female adults as well as for children. Topsoil median contents of Cr (84 mg kg−1), Cu (42), Ni (33), and Zn (195) exceeded the Precautionary Values for sandy soils according to the German Federal Soil Protection and Contaminated Sites Ordinance, while As, Pb, and V were 32, 73, and 77 mg kg−1, respectively. Median topsoil PLI was 1.73, indicating elevated multi-element contamination, with 90th percentile and maximum values being 3.20 and 4.31, respectively. All PTE concentrations were higher in top- compared to subsoils. Also at the 50th percentile the most enriched elements were Sn and As, followed by Zr and Rb, while in the 90th percentile Sn and As were followed by Zn, Pb and Cu. Median children's hazard index (HI) was higher than unity (HI = 2.27) and the 90th percentile was 5.53, indicating elevated health risk. Adult median HIs were 0.18 for male and 0.21 for female persons. Arsenic was found to be the primary contributor to total risk, accounting of 57.4% of HI in all three-person groupings, with Cr (17.3%) being the second, and V (10.2%) the third. Children's health is at dramatically higher risk than that of adults; also As, Cr, Pb, and V have a predominant role in contamination-related health risks. The presence of V, a less-expected element, among those of major risk contribution, reveals the necessity of monitoring areas at large scale. Our results demonstrate that our study may serve as a model for similar works studying multi-element-contaminated areas in future. Highlights • Tin had the highest enrichment in soil based on all studied contamination indices. • Tin was followed by As, Zn, Pb and Cu at 90th percentile. • Zirconium and Rb seem to originate from non-anthropogenic inputs. • Hazard Index for children was higher than unity, showing significant health risks. • Risk assessment indicated As as the predominant risk factor, followed by Cr, V, Pb. • The study is a model for works addressing contamination risks in extended areas. [ABSTRACT FROM AUTHOR]

Copyright of Revista Brasileira de Historia is the property of Associacao Nacional dos Professores Universitarios de Historia 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.)

[Display omitted] • Streamflow declined, and centre of timing increased due to rainfall decline and river regulation. • Inevitable effects of climate change and river regulation would reduce water availability. • Reduced water storage in lower parts of river systems would compromise ecosystems health. • Management should include reversing the change in centre of timing as a primary objective. Timing of delivery of environmental water is essential for restoring and conserving riverine ecosystems. However, change in the timing of occurrence of streamflow and its implications on environmental water allocation and river ecosystems are often ignored in current environmental water research and management. We adopted the centre of timing approach to analyse the change in the occurrence of streamflow due to climate change (through a change in rainfall) and river operations (flow regulation and diversion) in the Goulburn-Broken catchment, Victoria, Australia. It was found that annual streamflow in the catchment declined by an average of 47%, while centre of timing increased by an average of 36%. These changes were 52% attributable to rainfall decline and 48% to river regulation. A decline in annual streamflow (35%) and an increase in centre of timing (21%) across the Goulburn River would be observed by 2050 as an impact of climate change. Current management efforts should be directed at reversing the change in centre of timing to support the sustainable management of riverine systems. The Goulburn-Broken catchment is typical of managed catchments in many areas of the world with forecast rainfall reduction, and the findings are likely to be widely applicable. [ABSTRACT FROM AUTHOR]

A second order ordinary differential equations model (SODE) of a vegetated riverine ecosystem, amalgamating hydrological equations with ecological equations, is presented for the first time. After formulating plant production equations based on minimization of Medawar Growth Energy, hydrodynamical equations are introduced describing ideal water flow under a potential gradient and quadratic disapative terms, the latter due to vegetated drag from the plants deep rooted flexible stems. The drag coefficients are seen to depend on the plant biomass, and therefore, couple the 4 equations into an integrated whole indicated by the non-vanishing Berwald-Gauss curvature. Sediment impact on growth occurs via transport of clay in suspension, carrying minerals beneficial to the plants and is incorporated into the equations (SODE) via anholonomic frames and semi-symmetric connections. The set of constant total energy trajectories forms a Finslerian manifold with the Synge action-metric and their stability is studied. Several consequences are derived. In particular, it is proved that the hydrdynamical subsystem is unstable unless the elevation above sea level is an explicit function of both length along the riverbed and its orthoganal extent, the so-called wetted perimeter. [ABSTRACT FROM AUTHOR]

Past geological processes and climate change affected current species distributions and the genetic structure of riverine fauna. Western Gulf of Mexico coastal rivers harbour four mussel species within the genus Fusconaia (Bivalvia: Unionida). The distributions of these species are unclear owing to their indistinguishable shell morphologies. Using molecular phylogenetic and Fourier morphometric analyses, we examined phylogenetic relationships and morphological variation among the species and made inferences about the role of past geological and climatic factors in shaping the current genetic structure and distributions of these species in the region. Our results showed the presence of three Fusconaia species within the region: Fusconaia askewi, Fusconaia chunii and Fusconaia flava. We confirmed that Fusconaia lananensis is a junior synonym of F. askewi and that F. chunii is genetically distinct from F. askewi. The Trinity River has syntopic F. flava whose morphologies are indistinguishable from those of F. chunii. Divergence-time estimates matched major geological and climatic events in the region, where climate-driven river formations during the mid-Miocene to Pleistocene caused major diversification of Fusconaia species. Knowledge gained from the present study provides a better understanding of vicariant events that shaped current species distributions and helps to identify conservation priorities that apply to the Fusconaia species. [ABSTRACT FROM AUTHOR]

This work addresses multiple human stressors and their impacts on fish assemblages of the Drava and Mura rivers in southern Austria. The impacts of single and multiple human stressors on riverine fish assemblages in these basins were disentangled, based on an extensive dataset. Stressor configuration, i.e. various metrics of multiple stressors belonging to stressor groups hydrology, morphology, connectivity and water quality were investigated for the first time at river basin scale in Austria. As biological response variables, the Fish Index Austria (FIA) and its related single as well as the WFD biological- and total state were investigated. Stressor-response analysis shows divergent results, but a general trend of decreasing ecological integrity with increasing number of stressors and maximum stressor is observed. Fish metrics based on age structure, fish region index and biological status responded best to single stressors and/or their combinations. The knowledge gained in this work provides a basis for advanced investigations in Alpine river basins and beyond, supports WFD implementation and helps prioritizing further actions towards multi-stressor restoration- and management. [ABSTRACT FROM AUTHOR]

River regulation affects riparian systems world-wide and conservation and restoration efforts are essential to retain biodiversity, and the functioning and services of riverine ecosystems. Effects of regulation on plant species richness have been widely addressed, but the filtering effect of regulation on guilds has received less attention., We used a functional trait approach to identify adaptive plant strategies through regulation-tolerant traits and predict shifts of riparian vegetation communities in response to regulation. We analysed variation in functional diversity across gradients of hydrological alteration in northern Sweden in relation to modified timing and infrequent major floods, along with frequent short-term inundation., Functional richness was similar in all study sites, but species richness declined with increasing intensity of regulation, and the species lost were largely functionally redundant (i.e. co-existing species that have similar contribution to an ecosystem function). Guilds of species intolerant to waterlogging were particularly unsuccessful in most regulated sites as they were affected by hydropower dams which replace major fluvial disturbances with frequent short inundation events. We predict that this guild will disappear, with likely consequences for the entire riverine ecosystem., Synthesis and applications. We conclude that functional traits tolerant to waterlogging or submergence and lack of major fluvial disturbances were key to understanding our results. We suggest that the functional trait approach can be integrated with knowledge of other ecosystem components to provide an understanding of ecosystem function that can be used to guide fluvial ecosystem management. [ABSTRACT FROM AUTHOR]

Collembola were studied in a well-preserved riverine section of the Prut River in the Republic of Moldova. The study was focused on species diversity and habitat preferences of the particular species at two localities. Riparian habitats of the Prut River near Branişte included open river bank, forest belt and meadow, and the shore of Lake Costeşti-Stânca included meadow, pasture and shrub vegetation. In total 77 collembolan species were recorded, of which Neanura moldavica and Arrhopalites prutensis were endemic to Moldova. Comparative analyses showed a specific community composition at Branişte, with Anurida ellipsoides and Mesaphorura macrochaeta being abundant on the river bank and Hemisotoma thermophila in the meadow. In contrast, the forest plantation at the same locality was similar to the shrub-land in Costeşti, with the common species Mesaphorura critica, M. yosii, Deutonura albella and Isotomiella minor. Hygrophilous species preferred the habitats of the river section in Branişte, with quiet backwaters, to the artificial shoreline of the large lake. Species diversity was relatively high in the natural meadow and forest in Branişte and also in shrub-land on the lake shore. The present study documented relatively high collembolan species diversity at the shoreline and running water sections in the upper catchment area of the Prut River in Moldova that involve naturally valuable inundated habitats of Eastern Europe. [ABSTRACT FROM AUTHOR]

The aim of this study was to improve our understanding of seasonal variations and the effects of physicochemical conditions on the bacterioplankton communities in two small rivers, the Moo and Nakayachi Rivers in the Himi region of central Japan. These rivers are inhabited by unionid freshwater mussels, which are used for oviposition by the endangered Itasenpara bitterling ( Acheilognathus longipinnis). Water samples were collected every month between March 2011 and February 2012. Changes in bacterioplankton community structures were analysed using an approach that did not require cultivating the bacteria and involved PCR and denaturing gradient gel electrophoresis. The bacterioplankton community structures in the two rivers were similar in all seasons except winter. The bacterial sequences identified were dominated by typical freshwater Actinobacteria, Bacteroidetes, Cyanobacteria, α- Proteobacteria, and β- Proteobacteria bacterioplankton. Many β- Proteobacteria species were detected in all seasons, but Bacteroidetes species were dominant in the winter. The bacterioplankton community structures were affected by biochemical oxygen demand, chemical oxygen demand, chlorophyll-a concentration, water depth, and water temperature. These results provide a foundation for a more detailed understanding of the conditions that provide a suitable unionid habitat. [ABSTRACT FROM AUTHOR]

Freshwater ecosystems are impacted by a range of stressors arising from diverse human-caused land and water uses. Identifying the relative importance of single stressors and understanding how multiple stressors interact and jointly affect biology is crucial for River Basin Management. This study addressed multiple human-induced stressors and their effects on the aquatic flora and fauna based on data from standard WFD monitoring schemes. For altogether 1095 sites within a mountainous catchment, we used 12 stressor variables covering three different stressor groups: riparian land use, physical habitat quality and nutrient enrichment. Twenty-one biological metrics calculated from taxa lists of three organism groups (fish, benthic invertebrates and aquatic macrophytes) served as response variables. Stressor and response variables were subjected to Boosted Regression Tree (BRT) analysis to identify stressor hierarchy and stressor interactions and subsequently to Generalised Linear Regression Modelling (GLM) to quantify the stressors standardised effect size. Our results show that riverine habitat degradation was the dominant stressor group for the river fauna, notably the bed physical habitat structure. Overall, the explained variation in benthic invertebrate metrics was higher than it was in fish and macrophyte metrics. In particular, general integrative (aggregate) metrics such as % Ephemeroptera, Plecoptera and Trichoptera (EPT) taxa performed better than ecological traits (e.g. % feeding types). Overall, additive stressor effects dominated, while significant and meaningful stressor interactions were generally rare and weak. We concluded that given the type of stressor and ecological response variables addressed in this study, river basin managers do not need to bother much about complex stressor interactions, but can focus on the prevailing stressors according to the hierarchy identified. [ABSTRACT FROM AUTHOR]

An institutional framework and supporting water availability modelling capabilities are presented for integrating ecological needs into water resources management. Concepts illustrated by the Texas experience are relevant worldwide. Environmental flow standards with subsistence, base, in-bank pulse and over-bank flow components are established through a legislatively mandated process by stakeholder committees and science teams working in collaboration with government agencies. The flow standards incorporate ecosystem needs into water allocation and associated water availability modelling. Recognizing the complexities of defining and preserving environmental stream flows, expedited present action is combined with an adaptive management process for future improvements. [ABSTRACT FROM AUTHOR]

This work addresses human stressors and their impacts on fish assemblages at pan-European scale by analysing single and multiple stressors and their interactions. Based on an extensive dataset with 3105 fish sampling sites, patterns of stressors, their combination and nature of interactions, i.e. synergistic, antagonistic and additive were investigated. Geographical distribution and patterns of seven human stressor variables, belonging to four stressor groups (hydrological-, morphological-, water quality- and connectivity stressors), were examined, considering both single and multiple stressor combinations. To quantify the stressors' ecological impact, a set of 22 fish metrics for various fish assemblage types (headwaters, medium gradient rivers, lowland rivers and Mediterranean streams) was analysed by comparing their observed and expected response to different stressors, both acting individually and in combination. Overall, investigated fish sampling sites are affected by 15 different stressor combinations, including 4 stressors acting individually and 11 combinations of two or more stressors; up to 4 stressor groups per fish sampling site occur. Stressor-response analysis shows divergent results among different stressor categories, even though a general trend of decreasing ecological integrity with increasing stressor quantity can be observed. Fish metrics based on density of species ‘intolerant to water quality degradation’ and ‘intolerant to oxygen depletion” responded best to single and multiple stressors and their interactions. Interactions of stressors were additive (40%), synergistic (30%) or antagonistic (30%), emphasizing the importance to consider interactions in multi-stressor analyses. While antagonistic effects are only observed in headwaters and medium-gradient rivers, synergistic effects increase from headwaters over medium gradient rivers and Mediterranean streams to large lowland rivers. The knowledge gained in this work provides a basis for advanced investigations in European river basins and helps prioritizing further restoration and management actions. [ABSTRACT FROM AUTHOR]

Many management actions in aquatic ecosystems are directed at restoring or improving specific habitats to benefit fish populations. In the Grand Canyon reach of the Colorado River, experimental flow operations as part of the Glen Canyon Dam Adaptive Management Program have been designed to restore sandbars and associated backwater habitats. Backwaters can have warmer water temperatures than other habitats, and native fish, including the federally endangered humpback chub Gila cypha, are frequently observed in backwaters, leading to a common perception that this habitat is critical for juvenile native fish conservation. However, it is unknown how fish densities in backwaters compare with that in other habitats or what proportion of juvenile fish populations reside in backwaters. Here, we develop and fit multi-species hierarchical models to estimate habitat-specific abundances and densities of juvenile humpback chub, bluehead sucker Catostomus discobolus, flannelmouth sucker Catostomus latipinnis and speckled dace Rhinichthys osculus in a portion of the Colorado River. Densities of all four native fish were greatest in backwater habitats in 2009 and 2010. However, backwaters are rare and ephemeral habitats, so they contain only a small portion of the overall population. For example, the total abundance of juvenile humpback chub in this study was much higher in talus than in backwater habitats. Moreover, when we extrapolated relative densities based on estimates of backwater prevalence directly after a controlled flood, the majority of juvenile humpback chub were still found outside of backwaters. This suggests that the role of controlled floods in influencing native fish population trends may be limited in this section of the Colorado River. [ABSTRACT FROM AUTHOR]

Water temperature is a key variable affecting aquatic organisms. Understanding their response to elevated water temperatures is important for estimating upper thermal limits, and ultimately for assisting with setting defendable, biologically-relevant water temperature guidelines for lotic systems. Sublethal effects impacting on an individual organism or species may manifest at higher levels of the hierarchy, namely, populations, communities and entire ecosystems. Sublethal effects typically include those affecting an organism's physiology and metabolism (e.g. growth rates, secondary productivity, respiration); phenology (e.g. development time, voltinism, emergence); reproductive success and fitness (e.g. fecundity, rates and success of egg development and hatching); behaviour (e.g. migration, movement, drift); and broad-scale ecological effects (e.g. species richness, composition, density, distribution patterns). Sublethal effects are discussed with examples drawn from freshwater studies, in particular those focused on aquatic insects. Commonly-used methods, which vary from simple, cost-effective, laboratory-based methods to more elaborate, expensive, laboratory- and field-based studies, are assimilated to serve as a toolbox for future thermal research. Ultimately, the method adopted depends largely on the question(s) being asked and available resources. [ABSTRACT FROM AUTHOR]

Tiger beetles have been observed in many riverine ecosystems of Sri Lanka. However, current locations, species, distribution of species, habitat preferences and possible interactions between species are unknown. The present study intends to investigate these details and provide information that can be used in further studies. Tiger beetles are sampled from 15 riverine locations and examined for identification, body weight and body length. The riverine locations are analysed for locational, climatic and soil parameters and microhabitat details are recorded. Statistical analysis using One-Way Analysis of Variance and Tukey's pair comparison method of Minitab 16.0 statistical software package is conducted to compare the body sizes of species. Further, a statistical comparison between the climatic and soil parameters of the locations of Cylindera (Ifasina) labioaenea and that of other species are carried out. The study reveals five tiger beetle species Cylindera (Ifasina) labioaenea Horn, Cylindera (Ifasina) willeyi Horn, Cylindera (Ifasina) waterhousei Horn, Calomera cardoni Fleutiaux, Calomera angulata Fabricius, from the riverine ecosystems of Sri Lanka. Cylindera labioaenea is the most common species; C. willeyi and C. waterhousei are endemic to Sri Lanka. Cylindera labioaenea, C. willeyi and C. waterhousei are small, while Calomera cardoni and Calomera angulata are medium in size. Cylindera labioaenea is significantly smaller than C. willeyi and C. waterhousei, and resides in locations with significantly higher air temperatures, solar radiations and significantly lower relative humidity than the other two species. An optimal temperature range for the riverine tiger beetles is suggested and their preferences to soil moisture, soil temperature, soil colour and soil salinity are discussed. The occurrence of C. labioaenea as a single species population while the fact that other species co-exist may be due to a defensive strategy. [ABSTRACT FROM AUTHOR]

Habitat fragmentation and land use changes are causing major biodiversity losses. Connectivity of the landscape or environmental conditions alone can shape biodiversity patterns. In nature, however, local habitat characteristics are often intrinsically linked to a specific connectivity. Such a link is evident in riverine ecosystems, where hierarchical dendritic structures command related scaling on habitat capacity. We experimentally disentangled the effect of local habitat capacity (i.e., the patch size) and dendritic connectivity on biodiversity in aquatic microcosm metacommunities by suitably arranging patch sizes within river-like networks. Overall, more connected communities that occupy a central position in the network exhibited higher species richness, irrespective of patch size arrangement. High regional evenness in community composition was found only in landscapes preserving geomorphological scaling properties of patch sizes. In these landscapes, some of the rarer species sustained regionally more abundant populations better tracking their own niche requirements compared to landscapes with homogeneous patch size or landscapes with spatially uncorrelated patch size. Our analysis suggests that altering the natural link between dendritic connectivity and patch size strongly affects community composition and population persistence at multiple scales. The experimental results are demonstrating a principle that can be tested in theoretical metacommunity models and eventually be projected to real riverine ecosystems. [ABSTRACT FROM AUTHOR]

Micro-scale heterogeneity in water temperature was examined in 6 upland sites in the Western Cape, South Africa. Hourly water temperature data converted to daily data showed that greatest differences were apparent in daily maximum temperatures between shallow- and deep-water biotopes during the warmest period of the year. Pool depth affected water temperature with deeper pools creating a more stable thermal environment. Groundwater-dependency affected water temperature differences with less groundwater-dependent rivers exhibiting greater differences in daily maximum temperatures. The importance of maintaining instream and riparian habitat, including pools, undercut banks, marginal vegetation, and an intact hyporheos, is discussed, giving examples of organisms utilising such habitats as thermal refugia. Considerations when choosing an appropriate model to simulate water temperatures, including groundwater-dependency, temporal and spatial scale, and study objectives, are discussed. [ABSTRACT FROM AUTHOR]