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Local adaptation and phenotypic plasticity can lead to environment-related morphological and genetic variations in freshwater fish. Studying the responses of fish to environmental changes is crucial to understand their vulnerability to human-induced changes. Here, we used a latitudinal gradient as a proxy for past and present environmental factors and tested its influences on both genetic and morphological patterns. We selected as a suitable biogeographic model, the barbels, which inhabit 17 Adriatic basins of the central-southern Italian Peninsula, and explored association among attributes from genetic, morphological, and environmental analyses. The analysis of the mitochondrial DNA control region evidenced a southward significant increase in the number of private haplotypes, supporting the isolation of the southernmost populations related to the Mio-Pleistocene events. In contrast, morphology was mainly affected by changes in the present environmental conditions. Particularly, the number of scales and fish coloration were clearly associated to latitude, and thus thermal and hydrological conditions. Other morphometric and functional traits varied under the selective pressure of other environmental factors like elevation and distance from headwater. These results highlight the sensitivity of barbels to climate changes, which can serve as a basis for future eco-evolutionary and conservation studies.

Instream hydraulics and riverbed substrate allow for the identification of mesohabitats, and contribute in shaping benthic macroinvertebrate assemblages. However, the role of different depositional conditions between mesohabitats in determining macroinvertebrate response to large sediment input still needs investigation. We studied the evolution of sediment deposits and benthic assemblages in two mesohabitats (a riffle and a glide) of an Alpine river affected by an extreme sediment input. Substrate and hydraulic characteristics were measured in each mesohabitat for 18 months after the sedimentation event. Benthic macroinvertebrates were sampled concurrently, and available pre-event data allowed for before/after comparison. We found evidence of a different response of benthic communities to siltation, associated to the physical structure of the mesohabitat they inhabit. Both substrate and macroinvertebrates were less impacted and recovered faster in the riffle than in the glide. Assemblages in the glide adjusted to the modified habitat through strong proliferation of sand tolerant and preferring families, resulting in higher density and lower diversity compared to the riffle. Our results could support the improvement of the impact assessment of sediment input events. This is particularly relevant given the current global warming, inducing the increase in frequency and intensity of severe rainfall events, and subsequent landslides.

Inland waters are important ecosystems for both their biodiversity and the services they provide to humans [...]

Climate change along with the increasing exploitation of water resources exacerbates low-flow periods, causing detrimental effects on riverine communities. The main mitigation measure currently adopted to counteract hydrological alterations induced by off-stream diversion is the release of minimum flows (MFs), even if within the European Union Water Framework Directive an upgrade towards ecological flows is urgently required to achieve good ecological status (GES). In this study, we investigated the temporal evolution of the benthic macroinvertebrate community in an Italian-regulated lowland river (Ticino River) to clarify the ecological effects of summer low flows, and we evaluated the current MFs in the perspective of meeting GES standard. Biomonitoring was carried out for four consecutive years (2019-2022), in a river site immediately below a large off-stream diversion. The four study years were characterized by different streamflow patterns, thus allowing us to compare the temporal trajectories of the community under different flow conditions. Moreover, the interruption of the low-flow periods due to overflow spilled by the upstream dam gave us the opportunity to assess the effects of experimental flow peaks. Contrary to the expectation, the macroinvertebrate assemblage kept almost unvaried across the years, showing great resistance and resilience to hydrological changes. Even in extraordinarily dry 2022, the community composition varied only slightly, with a reduction of mayflies and an increase of mollusks. However, a deterioration of the ecological status below GES standard was recorded that summer, indicating the need for an upgrading of the current MFs. This upgrade would include experimental flow peaks in critical periods, which act as intermediate disturbances, enhancing community richness, diversity, and overall quality, as well as compliance with a threshold of an index specifically developed for the hydrological pressure.

The global spread of multi-resistant pathogens responsible for infections, which cannot be treated with existing drugs such as antibiotics, is of particular concern. Antibiotics are becoming increasingly ineffective and drug resistance is leading to more difficult-to-treat infections, therefore, new bioactive compounds with antimicrobial activity are needed and new alternative sources should be found. Antimicrobial peptides (AMPs) are synthesized by processes typical of the innate immune system and are present in almost all organisms. Insects are extremely resistant to bacterial infections as they can produce a wide range of AMPs, providing an effective first line of defense. The AMPs produced by insects therefore represent a possible source of natural antimicrobial molecules. In this paper, the possibility of using plasma preparations from silkworm (Bombyx mori) larvae as a source of antimicrobials was evaluated. After simple purification steps, insect plasma was analyzed and tested on different Gram-positive and Gram-negative bacterial strains. The results obtained are encouraging as the assays on Escherichia coli and Enterobacter cloacae showed significant decrease in the growth of these Gram-negative bacteria. Similar results were obtained on Gram-positive bacteria, such as Micrococcus luteus and Bacillus subtilis, which showed strong susceptibility to the silkworm AMPs pool. In contrast, Staphylococcus aureus displayed high resistance to Bombyx mori plasma. Finally, the tested plasma formulations were assessed for possible storage not only at 4 °C, but also above room temperature. In conclusion, partially purified plasma from silkworm could be a promising source of AMPs which could be used in formulations for topical applications, without additional and expensive purification steps.

Drosophila suzukii, Spotted Wing Drosophila (SWD), is a serious economic issue for thin-skinned fruit farmers. The invasion of this dipteran is mainly counteracted by chemical control methods, however, it would be desirable to replace them with biological control. All assays were performed with Bacillus thuringiensis (Bt), Xenorhabdus nematophila (Xn), and Xn secretions, administered orally in single or combination, then larval lethality was assessed at different times. Gut damage caused by Bt and the influence on Xn into the hemocoelic cavity was also evaluated. In addition, the hemolymph cell population was analyzed after treatments. The data obtained show that the combined use of Bt plus Xn secretions on larvae, compared to single administration of bacteria, significantly improved the efficacy and reduced the time of treatments. The results confirm the destructive action of Bt on the gut of SWD larvae, and that Bt-induced alteration promotes the passage of Xn to the hemocoel cavity. Furthermore, hemocytes decrease after bioinsecticides treatments. Our study demonstrates that combining bioinsecticides can improve the efficacy of biocontrol and such combinations should be tested in greenhouse and in field in the near future.

As the global demand for renewable electricity grows, hydropower development of river basins increases across the world. Hydropeaking, i.e., streamflow alteration consisting of daily or subdaily rapid and marked discharge fluctuations, can affect river reaches below hydropower units. Environmental effects of hydropeaking include geomorphological alterations and possible modifications of the freshwater biota. Among affected instream communities, benthic macroinvertebrates are receiving increasing attention and the related scientific research has experienced significant progress in the last decade. In this context, this paper aims to summarize state-of-the-art methods for the assessment of hydropeaking impacts on benthic macroinvertebrate communities. The present review could support the proper design of monitoring plans aimed at assessing the ecological impacts of hydropeaking and the effects of possible mitigation strategies.

The Italian peninsula is a biodiversity hotspot, with its freshwater fish fauna characterized by high levels of local endemism. Two endemic fluvio‐lacustrine fishes of the genus Barbus (barbel, family Cyprinidae) have allopatric distributions in the Tyrrhenian and Adriatic basins of Italy. Barbus plebejus inhabits the mid‐ to northern Adriatic basins, while B. tyberinus is widespread in all central‐northern basins draining into the Tyrrhenian Sea. For basins in Southern Italy draining into the southern parts of these seas, there remains a knowledge gap on their barbel populations due to no previous genetic and morphological studies, despite their apparent biogeographic isolation. Correspondingly, this study quantified the presence and distribution of barbels in the Adriatic and Tyrrhenian basins of Southern Italy through genetic and morphological analyses of 197 fish sampled across eight populations. Testing of how local isolation has influenced the evolution and persistence of these populations was completed by examining sequence variation at two mitochondrial loci (cytochrome b and D‐loop) and performing geometric morphometric analyses of body shape, plus measuring 11 morphometric and meristic characters. Phylogenetic and morphological analyses revealed the presence of two genetically distinct lineages that differed significantly from adjacent B. tyberinus and B. plebejus populations. These two new taxa, here described as SI1 and SI2 Barbus lineages, are highly structured and reflect a complex mosaic biogeographic pattern that is strongly associated with the underlying hydrographical scenarios of the basins. The geographic isolation of these basins thus has high evolutionary importance that has to be considered for maintaining endemism., In Southern Italy, apparent biogeographic isolation may have influenced barbel evolutionary structure. Through genetic and morphological analyses, we quantified the presence and distribution of barbels in Southern Italy describing two new taxa, highly structured and reflecting a complex mosaic biogeographic pattern that is strongly associated with the underlying hydrographical scenarios of the basins.

In this work, we analysed the efficacy of different commercial bio-insecticides (Steinernema feltiae, Steinernema carpocapsae, Heterorhabditis bacteriophora and Bacillus thuringiensis) by valuating the mortality induced on two insect models, Galleria mellonella (Lepidoptera) and Sarcophaga africa (Diptera) after exposure to different temperatures (10, 20 and 30 °C). Moreover, we investigated the effects of temperature on the basal humoral immunity of the two target insects; particularly, phenoloxidase (PO) and lysozyme activity. Our results show that G. mellonella is susceptible to all bio-insecticides at all the examined temperatures, except when infected at 10 °C with S. carpocapsae and at 30 °C with S. feltiae and B. thuringiensis. S. africa is more susceptible at 30 °C to all bioinsecticides; whereas, when infected at 10 and 20 °C, H. bacteriophora is the most efficient. Temperature modulates PO activity of both G. mellonella and S. africa, otherwise variations in lysozyme activity is observed only in G. mellonella. Except for a possible correlation between the increased lysozyme activity and the delayed Bt efficacy recorded on G. mellonella at 30 °C, a different resistance to bio-insecticides at different temperatures does not seem to be associated to variations of the host basal immunity, probably due to immunoevasive and immunodepressive strategies of these entomopathogens.

Genetic introgression with native species is recognized as a detrimental impact resulting from biological invasions involving taxonomically similar invaders. Whilst the underlying genetic mechanisms are increasingly understood, the ecological consequences of introgression are relatively less studied, despite their utility for increasing knowledge on how invasion impacts can manifest. Here, the ecological consequences of genetic introgression from an invasive congener were tested using the endemic barbel populations of central Italy, where the invader was the European barbel Barbus barbus. Four populations of native Barbus species (B. plebejus and B. tyberinus) were studied: two purebred and two completely introgressed with alien B. barbus. Across the four populations, differences in their biological traits (growth, body condition and population demographic structure) and trophic ecology (gut content analysis and stable isotope analysis) were tested. While all populations had similar body condition and were dominated by fish up to 2 years of age, the introgressed fish had substantially greater lengths at the same age, with maximum lengths 410–460 mm in hybrids versus 340–360 mm in native purebred barbel. The population characterized by the highest number of introgressed B. barbus alleles (81%) had the largest trophic niche and a substantially lower trophic position than the other populations through their exploitation of a wider range of resources (e.g. small fishes and plants). These results attest that the genetic introgression of an invasive congener with native species can results in substantial ecological consequences, including potential cascading effects.

Invasions of alien fishes can result in considerable consequences for native biodiversity, including local extinctions of native species through genetic introgression. In Italy, the alien European barbel Barbus barbus was first detected in 1994. It has since undergone range expansion, raising conservation concerns on their impacts on endemic Barbus species, including Barbus plebejus and Barbus tyberinus. Here, the genetic and phenotypic consequences of B. barbus invasion in the Tyrrhenian and Adriatic basins of central Italy were assessed by comparing ‘invaded’ with ‘uninvaded’ river sections that remain free of B. barbus due to barriers preventing their upstream dispersal. In both basins, uninvaded sites were confirmed as B. barbus free, but the endemic populations had low genetic variability. In the invaded sections, haplotype and nucleotide diversity was relatively high, with introgression skewed towards B. barbus genes, with the barbel populations comprising of only 4% and 23% of pure B. tyberinus and B. plebejus respectively. Relatively high morphological differentiation was apparent between pure B. tyberinus and hybrid forms, whilst differences were less apparent between pure B. plebejus and their hybrid forms. Thus, the endemic Barbus species only persist in areas that remain free of invasive B. barbus, with this only due to river structures that impede their upstream movements. As these structures also limit the effective population size of the endemic species, conservation plans must reconcile B. barbus dispersal prevention with the need to increase the population connectivity of the endemics.

Non-native pests are often responsible for serious crop damage. Since Drosophila suzukii has invaded North America and Europe, the global production of soft, thin-skinned fruits has suffered severe losses. The control of this dipteran by pesticides, although commonly used, is not recommended because of the negative impact on the environment and human health. A possible alternative is the use of bio-insecticides, including Bacillus thuringiensis and entomopathogenic nematodes, such as Steinernema carpocapsae. These biological control agents have a fair effectiveness when used individually on D. suzukii, but both have limits related to different environmental, methodological, and physiological factors. In this work, we tested various concentrations of B. thuringiensis and S. carpocapsae to evaluate their efficacy on D. suzukii larvae, when administered individually or in combination by using agar traps. In the combined trials, we added the nematodes after 16 h or concurrently to the bacteria, and assessed larvae lethality from 16 to 48 h. The assays demonstrated a higher efficacy of the combined administration, both time-shifted and concurrent; the obtained data also showed a relevant decrease of the time needed to kill the larvae. Particularly, the maximum mortality rate, corresponding to 79% already at 16 h, was observed with the highest concentrations (0.564 µg/mL of B. thuringiensis and 8 × 102 IJs of S. carpocapsae) in the concurrent trials. This study, conducted by laboratory tests under controlled conditions, is a good starting point to develop a further application step through field studies for the control of D. suzukii.

Climate change can affect freshwater communities superimposing on other major stressors, such as water exploitation, with effects still poorly understood. The exacerbation of naturally-occurring periods of low flows has been reported as a major hydrological effect of water diversions, with severe impacts on river benthic macroinvertebrate communities. This study aimed at assessing long-term modifications of low-flow events in a large lowland Italian river possibly associated to climate change and the effects of these events, intensified by water withdrawals, on benthic macroinvertebrates. A 77-year dataset on daily discharge was thus analyzed through Mann-Kendall test and Sen’s method to investigate modifications of the main hydrological parameters. Moreover, macroinvertebrates were collected during the low-flow periods that occurred from 2010 to 2015 at three sites downstream of water withdrawals, representing three different conditions of hydrological impairment. After assessing possible differences in taxonomical and functional composition between sites and impairment conditions, redundancy analysis and ordinary least squares regression were performed to link benthos metrics to environmental (hydrological and physico-chemical) characteristics. An increase in the duration of the low-flow periods and reduced summer flows were detected on the long term, and the magnitude of low flows was significantly altered by water withdrawals. These hydrological features shaped both structural and functional characteristics of benthic assemblages, highlighting the need for a more environmentally-sustainable water resource management in the current context of climate change.

Two fluviolacustrine lineages (SI1 Barbus and SI2 Barbus) of the Barbus genus have been recently detected in the Apulia-Campania ichthyogeographic district (southern Italy). The aim of this study was to determine the taxonomic status of these lineages by comparing them with the two already-established Italian fluviolacustrine species Barbus plebejus and Barbus tyberinus through a more in-depth molecular and morphological investigation. Genetic analyses were performed on both mitochondrial (cytochrome b) and nuclear (growth hormone paralog 2) DNA markers, and morphological analyses were carried out on specific age classes and purebred populations. Molecular analyses detected four evolutionary lineages at the mitochondrial level, whereas the nuclear data set highlighted the strict evolutionary relation between B. plebejus sensu stricto and the new lineages, converged in the B. plebejus complex clade. The morphological analyses allowed us to discriminate SI1 Barbus and SI2 Barbus from both B. plebejus and B. tyberinus. The new taxa could be discriminated by the greatest maximum body height and the longest pre-orbital distance, respectively. Both the new lineages have longer ventral and pectoral fins than B. plebejus and B. tyberinus, a larger caudal fin than B. tyberinus and a lower number of scales along the lateral line than B. plebejus. Both molecular and morphological results suggested the two southern Italian lineages could be considered as distinct endemic species: the formal description of the new species Barbus samniticus sp. nov. (i.e., SI1 Barbus) and the revalidation of Barbus fucini Costa, 1853 (i.e., SI2 Barbus) were thus proposed, and, for both species, molecular and morphological diagnosis were provided.

Our study focused on quantifying the alterations of streamflow at a weir site due to the construction of a mini-hydropower plant in the Gurugoda Oya (Sri Lanka), and evaluating the spatial responses of benthic macroinvertebrates to altered flow regime. The HEC–HMS 3.5 model was applied to the Gurugoda Oya sub-catchment to generate streamflows for the time period 1991–2013. Pre-weir flows were compared to post-weir flows with 32 Indicators of Hydrologic Alteration using the range of variability approach (RVA). Concurrently, six study sites were established upstream and downstream of the weir, and benthic macroinvertebrates were sampled monthly from May to November 2013 (during the wet season). The key water physico-chemical parameters were also determined. RVA analysis showed that environmental flow was not maintained below the weir. The mean rate of non-attainment was ~ 45% suggesting a moderate level of hydrologic alteration. Benthic macroinvertebrate communities significantly differed between the study sites located above and below the weir, with a richness reduction due to water diversion. The spatial distribution of zoobenthic fauna was governed by water depth, dissolved oxygen content and volume flow rate. Our work provides first evidence on the effects of small hydropower on river ecosystem in a largely understudied region. Studies like this are important to setting-up adequate e-flows.

On August 2017, a massive rock slope failure triggered an extreme sedimentation event in a regulated Alpine river. Consequently, high sediment load affected the river for about 1 month, with sediment concentration peaking up to several hundred g/L, and overall sediment yield of 0.4–0.8 Mm³. The availability of sound pre‐event data concerning benthic macroinvertebrate assemblages gave us the opportunity to assess the impact of this unusually severe sediment disturbance through before/after comparison. Within 1 month from the event, all the monitored communities displayed low density, richness and diversity, with minimum values never recorded before, particularly at the most upstream investigated reach, and where riverbed aggradation was comparatively larger. Persisting riverbed alteration was also identified as a major determinant justifying the slow recovery observed during the year after the event. Overall, the high resilience of some taxa, suited to a baseline unnatural condition, allowed the fast recolonization of the investigated river reaches. However, the recovery of other taxa, more sensitive to sediment pressure, was slow or did not occur during the monitored year.

Monitoring of freshwaters allows the detection of the impacts of multiple anthropic uses and activities on aquatic ecosystems, and an eco-sustainable management of natural resources could limit these impacts. In this work, we highlighted two main issues affecting inland waters, referring to findings from the most inhabited Italian region (Lombardy, approximately 10 M inhabitants): the first issue is lake pollution by old generation pesticides, the second is river development for hydropower. In both cases, some management strategies reducing the anthropic impacts on freshwaters were discussed: organic farming and biocontrol as an alternative to diffuse pollution by agrochemicals; environmental flows and controlled sediment flushing operations to limit the hydropower impact on rivers. Although the two mentioned issues were discussed separately in this paper, the management of water resources should be carried out in a comprehensive way, accounting for the multiple impacts affecting freshwater ecosystems, including those related to the climate changes.

© 2019 Royal Swedish Academy of Sciences Italian freshwaters are highly biodiverse, with species present including the native fishes Barbus plebejus and Barbus tyberinus that are threatened by habitat alteration, fish stocking and invasive fishes, especially European barbel Barbus barbus. In central Italy, native fluvio-lacustrine barbels are mainly allopatric and so provide an excellent natural system to evaluate the permeability of the Apennine Mountains. Here, the morphologic and genetic distinctiveness was determined for 611 Barbus fishes collected along the Padany–Venetian (Adriatic basins; PV) and Tuscany–Latium (Tyrrhenian basins; TL) districts. Analyses of morphological traits and mitochondrial DNA sequence data explored the natural and anthropogenic factors that have shaped their distribution ranges. Over 100 alien B. barbus were recorded in the Tiber basin (TL district) and Metauro basin (PV district). Comparisons of genetic and morphometric data revealed that morphometric data could identify alien B. barbus from native Barbus, but could not differentiate between B. tyberinus and B. plebejus. Genetic analyses revealed ~50 D-loop mtDNA haplotypes and identified a distinct Barbus lineage present only in the Vomano River at the southern boundary of PV district. Demographic expansion and molecular variance analyses revealed a lack of geographic structuring across the sampling regions. While the contemporary B. plebejus distribution has been driven primarily by anthropogenic fish translocations, the dispersal of B. tyberinus has been via natural dispersion, including their crossing of the Apennine Mountains via temporary river connectivity. The results also revealed that the Barbus fishes of the mid-Adriatic region of Europe have a complex pattern of local endemism. To conserve these patterns of genetic uniqueness, especially in the mid-Adriatic basins, Barbus fishes should be managed by treating them as unique evolutionary units and ceasing translocations of all Barbus fishes between river basins.

Sediment flushing can tackle reservoirs siltation and improve sediment flux through dammed rivers. However, the increase of the sediment loading below the dam can trigger a suite of undesired ecological effects in the downstream river reaches. To limit these drawbacks, sediment flushing can be controlled, by jointly regulating the sediment concentration of the evacuated water and the streamflow in the downstream channel. In this paper, we report on ten controlled sediment flushing operations (CSFOs), carried out between 2006 and 2012 in the central Italian Alps, at four hydropower reservoirs. These CSFOs displayed specific common traits: (i) Limits were set by the local environmental authorities concerning the allowable suspended sediment concentration. (ii) Reservoirs were fully drawn-down, earth-moving equipment was used to dislodge sediment, and the downstream water discharge was increased, compared to baseflow, by operating upstream intakes. (iii) Abiotic and biotic measurements in selected downstream reaches (before, during, and after the CSFOs) represented an integral part of the operations. In contrast, significant differences characterize the hydropower facilities (elevation and storage of reservoirs, in particular) as well as the basic CSFOs parameters (i.e., season, duration, mass and grain-size of the evacuated sediment, suspended sediment concentration). The macroinvertebrate assemblages resulted noticeably impacted by the CSFOs. In the short term, a significant density drop was observed, slightly influenced by the extent of the perturbation. In contrast, the latter appeared to control the assemblages contraction in terms of richness, according to the different sensitivity to sediment stress of the different taxa. The time employed to recover pre-CSFO standard ranged from few months to just under one year, and the related patterns would seem mostly correlated to the flushing season and to further site specificities. The density of trout populations was impacted as well, thus suggesting the adoption of mitigating strategies as removal by electrofishing before, and repopulation after the CSFO. Most of the field sampling presented in this study was financed by the INTERREG Italy/ Switzerland project ECOIDRO (Water Use and Safeguard of Environment and Biodiversity in the River Basins of Adda, Mera, Poschiavino and Inn - ID 7630754). University of Insubria financed a PhD position (MLB) and a post-doc project (SQ) concerning CSFOs. This work was also supported from the Economy and Knowledge Department of the Catalan Government through the Consolidated Research Group Fluvial Dynamics Research Group - RIUS (2017 SGR 459), and within the CERCA Program.

This work aims to evaluate the effects of different environmental factors (i.e., geographical, chemical, and hydrological) on benthic diatoms at 34 sites located in 13 watercourses of northern Italy, and to highlight possible misclassifications of the ecological status of watercourses, sensu Water Framework Directive, related to the normative index currently adopted in Italy (ICMi). The analysis of both the taxonomical and functional composition of diatom communities confirmed the presence of differences in terms of taxonomical richness, diversity, and taxa assemblages, associated to the altitude and the geological characteristics of the investigated watercourses. Moreover, the data analysis revealed differences due to chemical and hydrological alterations. Specifically, our results showed a clear link among these environmental perturbations and the communities’ functional composition expressed through the use of ecological guilds. High abundance and richness of motile diatoms were detected in sites characterized by nutrient enrichment, while high abundance of low-profile diatoms was linked to hydrological alteration. In contrast, these anthropogenic perturbations were not detected by the ICMi, which ranked more than 90% of the analyzed samples in the highest quality class. This study stresses the need for a different approach in diatom data interpretation in order to achieve reliable information about the ecological status of watercourses.

Despite DDT and PCB having been banned for about 40 years, they are still detectable in the environment. In the present research we specifically investigated the trophic transfer of these organochlorine contaminants (OC) through a pelagic food web of a deep lake in Northern Italy (Lake Como) over time. Zooplankton and fish were sampled each season of a year and OC concentrations and the carbon and nitrogen isotopic ratios were measured. By using stable isotopes, the direct trophic relationship between pelagic zooplankton and zooplanktivorous fish was confirmed for Alosa agone only in summer. Based on this result, the biomagnification factor normalized on the trophic level (BMFTL) for organic contaminants was calculated. BMFTL values were within the range 0.9-1.9 for DDT isomers and 1.6-4.9 for some PCB congeners (PCB 95, PCB 101, PCB 149, PCB 153, PCB 138 - present both in zooplankton and in fish and representing >60% of the PCB contamination), confirming the biomagnification of these compounds in one of the two zooplanktivorous fish species of the lake. (C) 2018 Elsevier B.V. All rights reserved.

An eco-hydraulic survey of the highly regulated Adda River (northern Italy) was carried out to highlight the ecological implications of the current water management, including minimum flows (MFs) set as environmental protection measures. Macroinvertebrates, flows, and other main physico-chemical parameters were monitored from 2010 to 2012 at seven sites located in two river reaches characterized by different water abstraction schemes. In the upper part of the river, water is mainly diverted for hydro-power, and, in water-depleted reaches, discharges equalled MF for more than 100 days y-1, mainly during winter. In the downstream river reach, where irrigation use prevails, discharges were on average three times higher than in the upper part of the river, and flow values similar to MF were detected only for short periods during summer. The two resulting streamflow patterns seem to have shaped different benthic communities, superimposing to the natural downstream variation. The upper reach is characterized by univoltine taxa, while the lower reach by multivoltine taxa adapted to a more disturbed environment. Chironomidae, a well-known tolerant benthic family, dominated at a site affected by point-source pollution, which turned out to be another determinant of macroinvertebrate community. Despite these differences among sites in the benthic community structure, the current water management seems to allow, for all of the investigated river sites, the achievement of the good ecological status as defined by the local law set in accomplishment of the Water Framework Directive.

Water exploitation for hydropower and irrigation alters the natural hydrologic regime of rivers, and consequently instream biocenosis and ecological processes. The identification of management decisions able to protect freshwater ecosystems while maintaining important water uses is a crucial issue for both science and management. This study presents and compares water management schemes into two large Mediterranean river basins. Environmental issues linked to management are discussed taking into account different local features and the regulatory framework.

Background Although banned in many countries for decades, DDTs and PCBs still represent a global threat to food safety. As these contaminants are still present in aquatic ecosystems, fish can be an important contributor to their total dietary intake. Objectives Alosa agone specimens were sampled over a period of 10 years (from 2006 to 2015) to provide a representative overview of the DDT and PCB levels of Lago di Como, a deep Italian lake where a DDT input due to secondary sources was observed in recent years. The potential health risk from the consumption of both fresh and preserved fish was evaluated. Results While DDT levels have generally decreased during the monitored period, reaching quite stable levels, PCB concentrations were variable, with values exceeding, in some cases, the European Union limit for human consumption and enabling potential carcinogenic effects. However, typical local processing of this fish species markedly appeared to decrease these contaminant levels, thus making the fish product (called missoltino ) a safer food. Conclusions The results of this work highlighted the need of continuous biomonitoring of those contaminants considered a past issue along with the emergent ones.

Thermal alteration is one of the adverse effects of flow regulation sharpened in recent years due to climate changes. In this work, we characterize the thermal regime of a highly regulated river located in Northern Italy, which is the emissary of Lake Maggiore. The thermal characteristics of the study reach are influenced by the presence of two dams and by climate warming. In the 15-year monitored period (1999-2013) a significant increase of the mean annual river temperature (i.e., +1.8°C) was indeed recorded. Minimum and maximum water temperatures were detected in correspondence of low-flow periods in February and August, respectively. During August the temperature reached a maximum of 27°C, that is a value below the upper thermal limit of tolerance for most of the aquatic taxa collected in the study area. Moreover, the local presence of seeps and the interaction with groundwater play an important ecological role by guaranteeing patches of cool water to the aquatic communities. Nevertheless, the sensitive early life stages of fish species that spawn in spring/summer may be affected by the high summer temperatures and the expected future climate warming. The wider range of temperatures preferred by alien fish species could result into a competitive disadvantage for autochthonous species. The current minimum flows established by local laws as environmental flows appeared to be able to guarantee an acceptable thermal alteration in morphologically heterogeneous reaches where river/groundwater interaction occurred, at least within the current climatic conditions.

The present work focuses on evaluating the ecological effects of hydropower-induced streamflow alteration within four catchments in the central Italian Alps. Downstream from the water diversions, minimum flows are released as an environmental protection measure, ranging approximately from 5 to 10% of the mean annual natural flow estimated at the intake section. Benthic macroinvertebrates as well as daily averaged streamflow were monitored for five years at twenty regulated stream reaches, and possible relationships between benthos-based stream quality metrics and environmental variables were investigated. Despite the non-negligible inter-site differences in basic streamflow metrics, benthic macroinvertebrate communities were generally dominated by few highly resilient taxa. The highest level of diversity was detected at sites where upstream minimum flow exceedance is higher and further anthropogenic pressures (other than hydropower) are lower. However, according to the current Italian normative index, the ecological quality was good/high on average at all of the investigated reaches, thus complying the Water Framework Directive standards.

Sediment flushing may be effective to tackle the loss of reservoir storage as a result of siltation. When operationally possible, the impact of this practice on the downstream aquatic environment can be mitigated by limiting the sediment concentration of the discharged waters (controlled sediment flushing). However, this topic is poorly documented, and concerns arise when limits are discussed. We present the results of a 3-year field investigation concerning the controlled sediment flushing of a small reservoir on the Adda River, the main tributary of Lake Como—Italy. Two limits for suspended solid concentration (SSC) were adopted: 1.5 g L−1, as average value throughout the whole working day, and 3.0 g L−1, as alert threshold to adjust the ongoing activity. These constraints were essentially fulfilled in the course of the documented operations. The first year sediment flushing was more significant than the following year: 25 000 tons of fines below 2 mm in diameter were flushed in six non-consecutive days in summer 2010, while, one year earlier, 75 000 tons were flushed in 16 non-consecutive days. In the third year of investigation (2011), no sediment evacuation took place. The benthic macroinvertebrate and the fish communities were surveyed a short distance below the reservoir, that is, in the potentially more affected river reach. Clear pieces of evidence of environmental quality degradation were not detected; the adopted strategies can therefore be considered to be appropriate when planning sediment flushing management in comparable contexts. Copyright © 2014 John Wiley & Sons, Ltd.

pp'-Dichlorodiphenyl-dichloroethylene (pp'DDE), a metabolite of pp'-dichlorodiphenyl-trichloroethane poses a risk for many ecosystems in spite of the banning of the parent compound because of its persistence and bioaccum- ulability. Nevertheless, the knowledge of acute and chronic toxicity on aquatic organisms is still very poor. In the present study, Daphnia magna was exposed to varying concentrations of pp'DDE in water and through diet to determine both acute toxicity and potential for effects on reproduction and survivability. The 48 h IC50 was 5.08 l gL -1 (3.76-7.01 l gL -1 ). As pp'DDE concentration in water was not stable and the amount assumed by food cannot be established with certainty, the results of chronic toxicity tests were expressed as the concentration in the organism which caused a negative effect. Grazing activity was affected with a pp'DDE concentration in the organism of 24 ng mg -1 d.w., while the lowest observed effect con- centration for fecundity reduction was 109 ng mg -1 d.w.

This work reports on the downstream environmental effects of ten sediment flushing operations from four hydropower reservoirs in the Italian Alps. The sediment concentration of the sluiced water was controlled to mitigate the downstream impacts that were quantified through monitoring of benthic macroinvertebrates and brown trout (Salmo trutta trutta). Benthic communities were severely impaired by all of the monitored flushing operations, in terms of both density and richness, but they usually recovered to pre-flushing values within a year if the riverbed alteration due to sediment deposition was low. As expected, impacts on trout were heavier on juveniles. Evidences provided by the monitored flushing activities can support the planning phase of analogous operations at comparable sites.

Sediment flushing may be effective to preserve reservoir storage, but concerns arise about sustainability for downstream freshwater ecosystems. We report on the controlled flushing of approximately 110,000 tons of silt from a 120 Mm(3) reservoir on the Adda River, the main tributary of Lake Como, Italy. Technical constraints prevented flushing during high flows, and the operation had to be spread out over three consecutive years (2010-2012) and, for each year, over a rather long time span (40-50 days). To mitigate the downstream impact, the suspended sediment concentration (SSC) of the evacuated water was controlled by regulating the dislodging works inside the reservoir, increasing the streamflow in the regulated tributaries, and operating an instream settling basin. SSC and water flow as well as benthic macroinvertebrates and trout were monitored as far as 28 km below the reservoir. At the most upstream gauging station, SSC peaked up to 100 g/l and ranged from 3.5 to 8 g/l on average per each operation. Stream quality metrics based on macroinvertebrate data evidenced the impairment due to flushing; however, the benthic community showed high resilience, recovering to pre-flushing conditions in 6-9 months. Trout data were biased by stocking and sport fishing and were more difficult to be interpreted. The trout population wouldn't seem remarkably altered, even if a non-negligible impact could be deduced through pre/post-event sample comparison.

In conjunction with habitat loss and overfishing, pollution and parasitism are believed to be relevant causes of collapse of Anguilla, as these can affect eel swimming ability and the development of gonads and embryos. The present study investigated Persistent Organic Pollutant (POP) concentrations, infection levels of Anguillicoloides crassus, lipid content and gonad abnormalities in eels sampled in 2007-2008 in three Italian water bodies (Caprolace Lake, Lesina Lagoon and Tevere River) that vary in salinity, trophic condition, contamination level and fishing pressure. Our analysis revealed that low-to-moderate levels of contamination and parasitism were not associated with gonad abnormalities in Caprolace Lake and Lesina Lagoon. On the contrary, POP concentrations and abundances of swim bladder nematodes were remarkably high in eels from the heavily urbanized Tevere River and were associated with significant gonad and swim bladder alterations. Contamination and infestation levels were so high to potentially impair spawner successful migration and reproduction. POP concentrations in Tevere eels also exceeded levels considered safe for food consumption. Though marginally contaminated, eels from the oligotrophic Caprolace Lake were in critical health condition: their lipid reserve was so low as to be considered insufficient to sustain the energetic costs of the transoceanic migration. Lesina eel stock was the only one displaying relatively good quality but here spawner abundance is likely limited by overfishing. Our results suggest that multiple stressors may potentially affect eel reproductive success. More definitive studies are needed to assess whether health effects caused by these multiple stressors are additive, compensatory or synergistic.