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Biological invasions pose a major threat to biodiversity, ecosystem functioning, and human well-being. Non-native species can have severe ecological impacts that are transformative, affecting ecosystems across both short-term and long-term timescales. However, few studies have determined the temporal dynamics of impact between these scales, impeding future predictions as invasion rates continue to rise. Our study uses a meta-analytical approach to dissect the changing taxonomic and functional impacts of biological invasions on native macroinvertebrate populations and communities in freshwater ecosystems across Europe, using a recently collated European long-term time series spanning several decades. Our findings reveal a complex temporal pattern: while initial stages of invasions (i.e. five years after the first record of non-native species) often exhibited benign impacts on macroinvertebrate abundance, richness, or functional diversity, the long-term (i.e. the period following the early invasion) effects became predominantly negative. This pattern was consistent between taxonomic and functional metrics for impacts at both the population and species level, with taxonomic metrics initially positively affected by invasions and functional metrics being more stable before also declining. These results suggest that even initially benign or positively perceived impacts could be eventually superseded by negative consequences. Therefore, understanding the magnitude of invasion effects increasingly requires long-term studies spanning several years or decades to offer insights into effective conservation strategies prioritising immediate and future biodiversity protection efforts. These findings also highlight the importance of integrating multiple taxonomic, functional and temporal components to inform adaptive management approaches to mitigate the negative effects of current and future biological invasions., (© 2024 The Author(s). Global Change Biology published by John Wiley & Sons Ltd.)

Mediterranean high-mountain lakes are being increasingly affected by strong Saharan dust deposition events. However, the ecological impacts of these severe atmospheric episodes remain largely unknown. We examined the effects of a strong Saharan dust intrusion to the Iberian Peninsula in 2022 on the physicochemical parameters and prokaryotic communities in sediments of nine high-mountain lakes of Sierra Nevada (Spain) located above 2800 m.a.s.l and in different orientations (north vs. south). A previous year (2021), with lower Saharan dust deposition with respect to 2022, was used for interannual comparisons. The strong dust deposition to the high-mountain lakes resulted in a significant increase in sediment nutrient availability which was linked to changes in the composition of prokaryotic communities. Decreases in alpha diversity and changes in beta diversity of prokaryotic communities were mainly observed in lakes located in the south compared to the north orientation likely because the former was more affected by the atmospheric dust deposition episode. Dust intrusion to the high-mountain lakes resulted in significant changes in the relative abundance of specific genera involved in important nutrient cycling processes such as phosphate solubilization, nitrogen fixation, nitrification, and denitrification. Saharan dust deposition also increased predicted microbial functionality in all lakes. Our findings show that severe atmospheric dust inputs to remote high-mountain lakes of Sierra Nevada can have significant biogeochemical and biodiversity consequences through changes in nutrient availability and prokaryotic communities in sediments of these freshwater ecosystems. This information contributes to understanding how Mediterranean high-mountain lakes of Sierra Nevada face strong intrusions of Saharan dust and their ecological consequences., (© 2024. The Author(s).)

Land-use and land-cover transitions can affect biodiversity and ecosystem functioning in a myriad of ways, including how energy is transferred within food-webs. Size spectra (i.e. relationships between body size and biomass or abundance) provide a means to assess how food-webs respond to environmental stressors by depicting how energy is transferred from small to larger organisms. Here, we investigated changes in the size spectrum of aquatic macroinvertebrates along a broad land-use intensification gradient (from Atlantic Forest to mechanized agriculture) in 30 Brazilian streams. We expected to find a steeper size spectrum slope and lower total biomass in more disturbed streams due to higher energetic expenditure in physiologically stressful conditions, which has a disproportionate impact on large individuals. As expected, we found that more disturbed streams had fewer small organisms than pristine forest streams, but, surprisingly, they had shallower size spectrum slopes, which indicates that energy might be transferred more efficiently in disturbed streams. Disturbed streams were also less taxonomically diverse, suggesting that the potentially higher energy transfer in these webs might be channelled via a few efficient trophic links. However, because total biomass was higher in pristine streams, these sites still supported a greater number of larger organisms and longer food chains (i.e. larger size range). Our results indicate that land-use intensification decreases ecosystem stability and enhances vulnerability to population extinctions by reducing the possible energetic pathways while enhancing efficiency between the remaining food-web linkages. Our study represents a step forward in understanding how land-use intensification affects trophic interactions and ecosystem functioning in aquatic systems., (© 2023 John Wiley & Sons Ltd.)

Freshwater ecosystems face many threats in the form of reduced water quantity, poor water quality and the loss of biodiversity. As a result, aquatic biomonitoring tools are required to enable the evaluation of these critical changes. Currently, macroinvertebrate-based indices are globally the most widely used biomonitoring tools in fluvial ecosystems. However, very little is known about the potential effects of changes in taxonomic understanding (updating of classification and nomenclature) or the presence of new non-native species for biotic indices calculation. This is especially relevant given that errors, incorrect classification or exclusion of new/updated nomenclature may affect ecological status evaluations and have direct consequences for the management and conservation of freshwater systems. In this discussion paper the main constraints, challenges and implications of these issues are outlined and case studies from a range of European countries are discussed. However, similar challenges affect rivers and managers globally and will potentially be amplified further in the future. Bioassessment science needs to be open to improvements, and current tools and protocols need to be flexible so that they can be updated and revised rapidly to allow new scientific developments to be integrated. This discussion highlights specific examples and new ideas that may contribute to the future development of aquatic biomonitoring using macroinvertebrates and other faunal and floral groups in riverine ecosystems., (Copyright © 2019. Published by Elsevier B.V.)

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

Freshwater biodiversity faces a critical situation globally. Current efforts to protect and conserve India's freshwater biodiversity have been insufficient in light of emerging challenges. To address this, we propose 14 science-based and policy-backed recommendations aimed at achieving long-term protection of Indian freshwater ecosystems and biodiversity conservation goals. Managers of India's nodal agencies have expressed support for implementing these recommendations. The Wildlife Institute of India has recently launched a pioneering master's degree programme in freshwater ecology and instituted scholarships for local citizens known as 'Guardians of the Ganga', who are actively engaged in conserving biodiversity along the Ganga River under the auspices of the 'Biodiversity Conservation and Ganga Rejuvenation' project sponsored by the National Mission for Clean Ganga. These initiatives align closely with our proposed recommendations. Implementing these timely recommendations by policymakers is crucial to safeguarding India's freshwater biodiversity. [ABSTRACT FROM AUTHOR]

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

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

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

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Turkey has many ecological characteristics due to its geographical location, allowing it to have a rich biodiversity in freshwater ecosystems. This study was carried out on the Kızılırmak river, the longest river (1.355 km) in the country; it originates and empties into the sea within its borders. The Kızılırmak river serves various agricultural, industrial, drinking water-related, and recreational purposes and greatly contributes to the region's economy. This study aimed to determine the distribution of the river's macroinvertebrate fauna and evaluate the impact of environmental variables on species distribution. In addition, using species-based biodiversity indices such as the Biological Monitoring Working Party (BMWP), Average Score per Taxon (ASPT), the Shannon–Wiener index, and evenness analysis, spatial and temporal similarities and differences were determined. According to the results, the ten taxonomic groups in the Kızılırmak river belong to the following categories: Gastropoda (81.5%), Gammaridae (9.8%), Oligochaeta (6.2%) Chironomidae (2.1%), Hirudinea (0.3%), and various others (0.1%). The Shannon–Wiener and evenness indexes were 0.29–1.9 and 0.46–0.14, respectively. TR-BMWP scores are in the poor to very poor water quality classes, and the ASPT ranges from moderate to poor water quality. Correlation analysis between species and physicochemical parameters indicated that the benthic macroinvertebrate fauna diversity of the river is affected by natural and anthropogenic factors. [ABSTRACT FROM AUTHOR]

Biodiversity loss occurs much faster in the world's freshwaters than in the terrestrial or marine realms, yet worries have been expressed that freshwater systems are not given the same priority as 'land and oceans' in global environmental governance.The Intergovernmental Science–Policy Platform on Biodiversity and Ecosystem Services (IPBES) is mandated to provide the knowledge basis supporting international environmental agreements such as the Convention on Biological Diversity. To a large extent, the work of IPBES is dependent on voluntary contributions by independent experts from across the world.Here, I present an overview of the various ways in which freshwater experts can contribute to IPBES, ultimately to strengthen the representation of freshwater ecosystems in global environmental governance.Avenues to contribute include participating in the development of IPBES assessment reports that are adopted by the 139 member states, engaging in the external review process of IPBES products, filling in knowledge gaps as identified by IPBES assessment reports to inform upcoming assessments, implementing IPBES outcomes and recommendations in practice, and actively engaging with plenary meetings of government delegations to influence decisions.Actively supporting governments worldwide in making evidence‐based decisions can be intrinsically rewarding and offers several additional benefits. These benefits include the potential for enhanced professional reputation, given the authoritative nature of IPBES products; networking and collaboration opportunities with experts and stakeholders from around the world; and professional development through gaining experience in navigating the science–policy interface on biodiversity and ecosystem services.I conclude with a call to action. [ABSTRACT FROM AUTHOR]

Motivation: Aquatic insects comprise 64% of freshwater animal diversity and are widely used as bioindicators to assess water quality impairment and freshwater ecosystem health, as well as to test ecological hypotheses. Despite their importance, a comprehensive, global database of aquatic insect occurrences for mapping freshwater biodiversity in macroecological studies and applied freshwater research is missing. We aim to fill this gap and present the Global EPTO Database, which includes worldwide geo‐referenced aquatic insect occurrence records for four major taxa groups: Ephemeroptera, Plecoptera, Trichoptera and Odonata (EPTO). Main type of variables contained: A total of 8,368,467 occurrence records globally, of which 8,319,689 (99%) are publicly available. The records are attributed to the corresponding drainage basin and sub‐catchment based on the Hydrography90m dataset and are accompanied by the elevation value, the freshwater ecoregion and the protection status of their location. Spatial location and grain: The database covers the global extent, with 86% of the observation records having coordinates with at least four decimal digits (11.1 m precision at the equator) in the World Geodetic System 1984 (WGS84) coordinate reference system. Time period and grain: Sampling years span from 1951 to 2021. Ninety‐nine percent of the records have information on the year of the observation, 95% on the year and month, while 94% have a complete date. In the case of seven sub‐datasets, exact dates can be retrieved upon communication with the data contributors. Major taxa and level of measurement: Ephemeroptera, Plecoptera, Trichoptera and Odonata, standardized at the genus taxonomic level. We provide species names for 7,727,980 (93%) records without further taxonomic verification. Software format: The entire tab‐separated value (.csv) database can be downloaded and visualized at https://glowabio.org/project/epto%5fdatabase/. Fifty individual datasets are also available at https://fred.igb‐berlin.de, while six datasets have restricted access. For the latter, we share metadata and the contact details of the authors. [ABSTRACT FROM AUTHOR]

The exploration of biodiversity has predominantly been based on taxonomic measures, whereas functional diversity, a key component of biodiversity, is comparatively understudied. Therefore, studies simultaneously investigating patterns of taxonomic and functional diversity change in biological communities are of increasing interest.We collated high‐resolution macroinvertebrate and environmental data from 70 boreal headwater stream sites across three European countries (Germany, Finland, Sweden) to (1) investigate seasonal variation in taxonomic diversity, functional diversity, and redundancy, and (2) identify their potential drivers of spatial and seasonal variation.Seasonal changes in boreal macroinvertebrate taxonomic diversity were decoupled from changes in functional diversity. Seasonal shifts in environmental conditions, including acidity and nutrient variability, drove fluctuations in taxonomic diversity which were far more pronounced than those of functional diversity.Seasonal shifts in environmental conditions including variation in the quantity, quality, and state of organic carbon (dissolved vs particulate) facilitate an exchange of taxa, leading to taxonomically unique communities that exploit the pool of available seasonal resources. Thus, similar levels of functional diversity across seasons—even as taxonomic diversity changes—suggest limited differences in interspecific changes in community function, potentially indicating functional resistance rooted in redundancy.We highlight the spatial and seasonal discrepancies of freshwater communities, emphasising the need for both taxonomic and functional diversity patterns to be assessed in future biodiversity monitoring programmes. [ABSTRACT FROM AUTHOR]

Free‐flowing rivers (FFRs) are important surrogates for freshwater biodiversity as there are increasingly fewer rivers that reflect intact habitat and species diversity from source to sea. The status and changes in the ecological condition or protection of FFRs is not explicitly reported on in global biodiversity targets. Indices are proposed for reporting such changes to the Sustainable Development Goals (SDGs) 6 and 15, Aichi Target 11, and the post‐2020 global biodiversity framework.FFRs were identified at a countrywide scale in South Africa for protection, planning, monitoring, and assessing changes in their ecological condition and protection status. They were selected and prioritized using criteria co‐produced with national, provincial, and local river managers and policy makers. Given the high competition for water resources and the unlikely possibility for strictly protecting all FFRs, a subset of FFRs, termed 'flagship FFRs', was identified.Methods for reporting changes in the protection levels of prioritized FFRs at a countrywide scale were developed, which included indices of FFRs related to global targets: the loss of the extent of FFRs in a natural and largely natural ecological condition for SDG 6; changes in the connectivity of FFRs included in the post‐2020 global biodiversity framework targets; and changes in protection levels of FFRs for Aichi Target 11 and SDG 15.1.2.Flagship FFRs attracted targeted management initiatives and thus maintained their connectivity and ecological condition. This was not true when all FFRs were considered; in the broader set of FFRs, longitudinal fragmentation increased and ecological condition declined from 2011 to 2018.Considering the increasing pressures rivers are likely to experience from human and climate change impacts, particularly in semi‐arid to temperate environments, urgent prioritization and monitoring of FFRs is called for so that a targeted set of protection and management strategies can be applied. [ABSTRACT FROM AUTHOR]

Southern Vietnam, particularly the Mekong Delta, is popular in inland fish species diversity. In this study, fish species diversity across six stations from the estuary to the upstream of Cua Tieu River, which is situated in the Tien Giang province in Southern Vietnam, has been studied from January 2018 to June 2020. Altogether, 2088 specimens were collected and classified, and these belonged to 115 species, 98 genera, and 54 families of 15 orders that were recognized and identified. The names of species, genera, families, and orders are cited. In the total of 115 species, the Perch-like order (Perciformes) is the most diverse group, with 50 species (consist of 43.48% of total species). The catfish order (Siluriformes) is the second-most diverse group, consisting of 19 species (16.52% of total species). The carp order (Cypriniformes) consists of 8 species (6.96%), and the herring order (Clupeiformes) consists of 7 species (6.09%). Three orders of fishes, needle fish order (Beloniformes), Spiny eel order (Synbranchiformes), and flounder order (Pleuronectiformes), consist of 6 species (5.22%), and other orders consist of 1–3 species (0.87–2.61%). Among the 115 species recorded, 4 species were classified as vulnerable (VU) in the Red Data Book of Viet Nam (2007) (which is 3.48% of the total species collected). These are Elops saurus, Anodontostoma chacunda, Datnioides polota, and Toxotes chatareus. According to the IUCN Red list (2020), 1 species is endangered (EN) (0.87%), 1 species is vulnerable (VU) (0.87%), 3 species of fish are near threatened (NT) (2.61%), 6 species are data deficient (DD) (5.22%), and 58 species are least concern (LC) (50.43%). The result also recorded 41 fish as migratory species (26 freshwater species and 15 marine species), which is 35.65% of total species collected. Some migratory species are important and endemic species of the Mekong River, such as Bagarius yarrelli, Boesemania microlepis, Yasuhikotakia modesta, Cyclocheilos enoplos, Pangasianodon hypophthalmus, Pangasius conchophilus, Pangasius krempfi, Pangasius pleurotaenia, Phalacronotus bleekeri. [ABSTRACT FROM AUTHOR]

Investigating the influence of biodiversity on ecosystem functioning over environmental gradients is needed to anticipate ecosystem responses to global change. However, our understanding of the functional role of freshwater biodiversity, especially for microbes, is mainly based on manipulative experiments, where biodiversity and environmental variability are minimized. Here, we combined observational and manipulative experiments to analyse how fungal biodiversity responds to and mediates the impacts of drying on two key ecosystem processes: organic matter decomposition and fungal biomass accrual. Our observational data set consists of fungal biodiversity and ecosystem processes from 15 streams spanning a natural gradient of flow intermittence. Our manipulative design evaluates the responses of ecosystem processes to two fungal richness levels crossed with three levels of drying. For the observational experiment, we found that increasing the duration of drying reduced fungal species richness and caused compositional changes. Changes in species composition were driven by species turnover, suggesting resistance mechanisms to cope with drying. We also found that fungal richness had a positive effect on organic matter decomposition and fungal biomass accrual. Positive effects of fungal biodiversity were consistent when controlling for the effects of drying duration on richness by means of structural equation modelling. In addition, our results for the manipulative experiment showed that the positive effects of higher richness on both ecosystem processes were evident even when exposed to short or long simulated drying. Overall, our study suggests that maintaining high levels of biodiversity is crucial for maintaining functional freshwater ecosystems in response to ongoing and future environmental changes. [ABSTRACT FROM AUTHOR]

Freshwater ecosystems face multiple threats to their stability globally. Poyang Lake is the largest lake in China, but its habitat has been seriously degraded because of human activities and natural factors (e.g. climate change), resulting in a decline in freshwater biodiversity. Zooplankton are useful indicators of environmental stressors because they are sensitive to external perturbations. DNA metabarcoding is an approach that has gained significant traction by aiding ecosystem conservation and management. Here, the seasonal and spatial variability in the zooplankton diversity were analyzed in the Poyang Lake Basin using DNA metabarcoding. The results showed that the community structure of zooplankton exhibited significant seasonal and spatial variability using DNA metabarcoding, where the community structure was correlated with turbidity, water temperature, pH, total phosphorus, and chlorophyll‐a. These results indicated habitat variations affected by human activities and seasonal change could be the main driving factors for the variations of zooplankton community. This study also provides an important reference for the management of aquatic ecosystem health and conservation of aquatic biodiversity. [ABSTRACT FROM AUTHOR]

Abstract Freshwater ecosystems face multiple threats to their stability globally. Poyang Lake is the largest lake in China, but its habitat has been seriously degraded because of human activities and natural factors (e.g. climate change), resulting in a decline in freshwater biodiversity. Zooplankton are useful indicators of environmental stressors because they are sensitive to external perturbations. DNA metabarcoding is an approach that has gained significant traction by aiding ecosystem conservation and management. Here, the seasonal and spatial variability in the zooplankton diversity were analyzed in the Poyang Lake Basin using DNA metabarcoding. The results showed that the community structure of zooplankton exhibited significant seasonal and spatial variability using DNA metabarcoding, where the community structure was correlated with turbidity, water temperature, pH, total phosphorus, and chlorophyll‐a. These results indicated habitat variations affected by human activities and seasonal change could be the main driving factors for the variations of zooplankton community. This study also provides an important reference for the management of aquatic ecosystem health and conservation of aquatic biodiversity.

Aim: Ecological relationships between species richness and biomass production are increasingly thought to be pervasive across the globe. Yet, diversity–production relationships have not been explored extensively for freshwater fish communities even though fisheries production provides key services to humans. Our aim was to evaluate the diversity–production relationship of fish communities inhabiting freshwater streams across the Appalachian Mountain range and examine how diversity–production relationships varied across streams possessing different thermal signatures. Location: Our study area included 25 freshwater stream ecosystems spanning from Vermont to North Carolina in the United States. Twenty sites were located in Maryland south to Tennessee and North Carolina, while five additional higher latitude sites were sampled in Massachusetts and Vermont. Methods: We sampled the 25 study streams from June to September 2012 and collected fish population information to calculate biomass, species richness, the Shannon diversity index and annual production for each fish community. Linear mixed effects models were used to analyse the relationship between diversity indices and total community production. We also compared diversity and production relationships across other taxa. Results: Across all streams, community fish production, biomass and P/B ratios ranged from 0.15–6.79 g m−2 y−1, 0.61–0.73 g m−2 and 0.21–1.07 y−1, respectively. Species richness had a significant positive effect (p =.012) on community fish production, while accounting for the thermal signature of the streams as a random effect and other habitat covariates. The Shannon diversity index did not have a significant effect (p =.101) on community production. Main conclusions: The diversity–production relationship observed for stream fish communities was similar to other studies but demonstrated one of the highest slopes. Our results demonstrate that effects of biodiversity resonate to influence the production of fishes; thus, management of fisheries is more closely coupled to biodiversity than previously thought. [ABSTRACT FROM AUTHOR]

Urban areas in the Brazilian Amazon have grown at an unprecedented rate during the last years. About 90% of the wastewater produced by these urban areas are discharged untreated into Amazonian freshwater ecosystems, constituting a potential environmental pathway for pharmaceuticals and other chemicals consumed by modern societies (e.g. psychostimulants, personal-care products, hormones). The distribution of these chemicals into the Amazon River and their potential risks for freshwater biodiversity have not been evaluated so far. Here, we show the results of the largest chemical monitoring campaign conducted in the Amazon region. We assessed exposure patterns for 43 pharmaceuticals and other urban contaminants in 40 sampling sites distributed along the Amazon River, three major tributaries (Negro, Tapajós and Tocantins Rivers), and four large cities of the Brazilian Amazon (Manaus, Santarém, Macapá, Belém). We assessed risks for freshwater biodiversity using species sensitivity distributions and mixture toxicity approaches. We found that urban areas constitute important hot-spots for chemical contamination, with mixtures containing up to 40 different compounds and exposure concentrations reaching the world’s maxima for some of them. We show that chemical pollution can result in long-term effects for up to 50–80% of aquatic species next to urban areas. Moreover, we identified several ubiquitous compounds which can be used as tracers of anthropogenic pressure in the Amazon basin. We conclude that the chemical burden created by urbanization significantly contributes to a biodiversity loss in the region and should be further controlled.

• Peatlands, land use and lake cover control water color variation in boreal forest streams. • Lake cover and water color exert strong control on stream invertebrate communities. • The effects of lake cover and water color on stream invertebrates are independent. • Strongly lake-influenced streams might be better protected from browning. • The effects of browning are likely similar, irrespective of catchment lake cover. Browning of streams due to increased export of dissolved organic carbon (DOC) and iron has been observed in vast areas of the northern hemisphere with likely adverse ecological effects. Lake basins in stream catchments can moderate DOC export and influence stream communities, which complicates understanding of the effects of DOC. In this study, we explored the independent and interactive effects of water color (proxy for DOC and iron) and catchment lake cover on benthic macroinvertebrate communities in 94 medium-sized boreal forest streams. We first investigated the role of lake basins and other catchment characteristics in controlling water color. We then studied the effects of water color and catchment lake cover on macroinvertebrate community composition, biodiversity, and functional feeding traits. Water color correlated negatively with catchment lake cover, whereas the correlation with peatland cover and drainage intensity was positive. PERMANOVA and GLS analyses indicated that both color and catchment lake cover had a distinct independent effect on invertebrate community composition and community attributes, without significant interactions. Color had an independent negative effect on EPT (Ephemeroptera, Plecoptera, Trichoptera) taxa richness irrespective of lake cover. Increasing water color had negative effect on relative abundance of grazer, but no significant effect on shredder trait, while lake cover had a negative effect on both of the traits. Lake cover exhibited a negative influence on collector-gatherers, and a positive effect on filter feeders, while the predators were positively affected by both factors. The results highlight that water color influences the community structure of boreal stream ecosystems, and the effects are similar regardless of catchment lake cover. Mitigation measures should be emphasized, aimed at reducing DOC and iron runoff, in land use planning and river basin management. [Display omitted] [ABSTRACT FROM AUTHOR]

The role of multitrophic diversity in sustaining multiple functions simultaneously (multifunctionality) is still poorly understood in natural communities, especially in highly diverse aquatic ecosystems. Existing studies have focused on the effect of single trophic group on ecosystem function and on individual ecosystem functions, neglecting the fact that multiple trophic groups are needed to maintain ecosystem multifunctionality.Here, using a 16‐year database from tropical shallow lakes, we combined species richness of nine single trophic group into a unique measurement of multitrophic richness. We then investigated the influence of the richness within separate single trophic group and in a multitrophic context on ecosystem multifunctionality. We also investigated how removal of any single trophic group influence the effect of the multitrophic richness on multifunctionality; and how the interactions among multiple single trophic group affect multifunctionality.We showed that the multitrophic richness had a stronger positive effect on multifunctionality than the richness of single trophic group. The removal of each single trophic group decreased the effect of the multitrophic richness on multifunctionality. The larger predatory vertebrates and primary producers had stronger positive effects on multifunctionality, but the richness of basal trophic groups fuelled the large‐sized predators, thus indirectly contributing to increase multifunctionality.Our study highlights the need for preserving multiple trophic groups to sustain multifunctionality in highly diverse aquatic ecosystems; thus, trophic degradation of the ecosystems should strongly impair their functioning. A free Plain Language Summary can be found within the Supporting Information of this article. [ABSTRACT FROM AUTHOR]

Invasive species represent one of the primary threats to global biodiversity. Despite acknowledged implications for taxonomic properties of ecological communities following invasion, functional measures remain poorly understood.We examined the long‐term implications of invasion by a crayfish species, Pacifastacus leniusculus, on functional alpha and beta diversity properties of lotic macroinvertebrate communities in three English regions. The dataset comprised 477 samples collected predominantly between 1990 and 2013. Unlike many invasion studies, we employed before and after invasion comparisons, in association with control rivers not invaded by crayfish.Functional richness and divergence metrics displayed the strongest responses to invasion, highlighting that P. leniusculus may alter the range of functional niches and extreme trait values (likely reflecting resistance and resilience mechanisms) displayed by macroinvertebrate communities. Interestingly, in one region, biodiversity gains seen in control rivers were not mirrored in invaded rivers, potentially suggesting that invasion inhibited ecological improvements.Invasion by signal crayfish resulted in functional compositional changes in two of the three English regions studied, with these rivers yielding greater ecological differences between pre‐ and post‐invasion periods relative to control rivers. This change was primarily driven by higher nestedness values in invaded rivers, with communities containing functional subsets relative to control rivers. The third region demonstrated no functional compositional changes or alterations in functional beta diversity associated with invasion.Our findings indicated that in most instances, the functional properties of macroinvertebrate communities responded to crayfish invasion and may therefore represent a complementary means to monitor the ecological condition of lotic ecosystems. Given their spatial transferability, functional traits could provide a platform to guide regional management practices in the face of biological invasions. A free Plain Language Summary can be found within the Supporting Information of this article. [ABSTRACT FROM AUTHOR]

A multisource approach to assessing freshwater biodiversity reveals the first occurrence of the Asian freshwater snail Sinotaia cf. quadrata (Gastropoda, Viviparidae) in inland waters of the northern Iberian Peninsula (Spain) and southwestern France. We present a detailed characterization, combining morphological traits and molecular tools for a genetic identification, and illustration of the species and its ultrastructure, as well as key information regarding its reproductive biology and ecology at the new locations. We discuss the most plausible introduction pathways and vectors, its potential invasiveness and the subsequent impacts that it may generate in the receiving localities. Our preliminary results raise concerns about the threat of Sinotaia cf. quadrata to human health and ecosystem dynamics, since this species acts as an intermediate host for several parasite species. Finally, this study confirms once again the usefulness of an integrative taxonomical approach for shedding light on hidden biodiversity and the invasion of freshwater ecosystems. [ABSTRACT FROM AUTHOR]

Aquatic hyphomycetes are key microbial decomposers in freshwater that are capable of producing extracellular enzymes targeting complex molecules of leaf litter, thus, being crucial to nutrient cycling in these ecosystems. These fungi are also able to assimilate nutrients (e.g., nitrogen) from stream water, immobilizing these nutrients in the decomposing leaf litter and increasing its nutritional value for higher trophic levels. Evaluating the aquatic hyphomycete functional genetic diversity is, thus, pivotal to understanding the potential impacts of biodiversity loss on nutrient cycling in freshwater. In this work, the inter- and intraspecific taxonomic (ITS1-5.8S-ITS2 region) and functional (nitrate reductase gene) diversity of 40 aquatic hyphomycete strains, belonging to 23 species, was evaluated. A positive correlation was found between the taxonomic and nitrate reductase gene divergences. Interestingly, some cases challenged this trend: Dactylella cylindrospora (Orbiliomycetes) and Thelonectria rubi (Sordariomycetes), which were phylogenetically identical but highly divergent regarding the nitrate reductase gene; and Collembolispora barbata (incertae sedis) and Tetracladium apiense (Leotiomycetes), which exhibited moderate taxonomic divergence but no divergence in the nitrate reductase gene. Additionally, Tricladium chaetocladium (Leotiomycetes) strains were phylogenetically identical but displayed a degree of nitrate reductase gene divergence above the average for the interspecific level. Overall, both inter- and intraspecific functional diversity were observed among aquatic hyphomycetes.

Motivated by recent global initiatives for biodiversity conservation and restoration, this article reviews the gaps in our understanding of, and the challenges facing, freshwater macroinvertebrate biodiversity and conservation in tropical regions.This study revealed a lack of adequate taxonomic, phylogenetic, and ecological information for most macroinvertebrate groups, and consequently there are large‐scale knowledge gaps regarding the response of macroinvertebrate diversity to potential climate change and other human impacts in tropical regions.We propose ideas to reduce the impact of key drivers of declines in macroinvertebrate biodiversity, including habitat degradation and loss, hydrological alteration, overexploitation, invasive species, pollution, and the multiple impacts of climate change.The review also provides recommendations to enhance conservation planning in these systems (as well as providing clear management plans at local, regional, and national levels), integrated catchment management, the formulation of regulatory measures, the understanding of the determinants of macroinvertebrate diversity across multiple scales and taxonomic groups, and the collaboration between researchers and conservation professionals.It is suggested that the integrated use of macroinvertebrate biodiversity information in biomonitoring can improve ecosystem management. This goal can be facilitated in part by conservation psychology, marketing, and the use of the media and the Internet. [ABSTRACT FROM AUTHOR]

Anthropogenic activities have led to a global decline in biodiversity, and monitoring studies indicate that both insect communities and wetland ecosystems are particularly affected. However, there is a need for long‐term data (over centennial or millennial timescales) to better understand natural community dynamics and the processes that govern the observed trends. Chironomids (Insecta: Diptera: Chironomidae) are often the most abundant insects in lake ecosystems, sensitive to environmental change, and, because their larval exoskeleton head capsules preserve well in lake sediments, they provide a unique record of insect community dynamics through time. Here, we provide the results of a metadata analysis of chironomid diversity across a range of spatial and temporal scales. First, we analyse spatial trends in chironomid diversity using Northern Hemispheric data sets overall consisting of 837 lakes. Our results indicate that in most of our data sets, summer temperature (Tjul) is strongly associated with spatial trends in modern‐day chironomid diversity. We observe a strong increase in chironomid alpha diversity with increasing Tjul in regions with present‐day Tjul between 2.5 and 14°C. In some areas with Tjul > 14°C, chironomid diversity stabilizes or declines. Second, we demonstrate that the direction and amplitude of change in alpha diversity in a compilation of subfossil chironomid records spanning the last glacial–interglacial transition (~15,000–11,000 years ago) are similar to those observed in our modern data. A compilation of Holocene records shows that during phases when the amplitude of temperature change was small, site‐specific factors had a greater influence on the chironomid fauna obscuring the chironomid diversity–temperature relationship. Our results imply expected overall chironomid diversity increases in colder regions such as the Arctic under sustained global warming, but with complex and not necessarily predictable responses for individual sites. [ABSTRACT FROM AUTHOR]

• Urbanization has an overall negative effect on the diversity of macroinvertebrates. • This finding is based mainly on the study of lotic ecosystems. • Analyses show significant heterogeneity among case studies. • We identified knowledge gaps regarding studied habitats and concepts of diversity. • We provided recommendation for the future research. Understanding the effects of urbanization on the diversity of freshwater macroinvertebrates is an important topic of biodiversity research and has direct conservation relevance. The absence of evidence-based systematic overviews on this topic motivated us to perform meta-analyses and to synthetize the present state of knowledge. We observed significant heterogeneity among individual case studies, reporting negative, neutral and positive effects. As expected, urbanization had an overall negative effect on the diversity of freshwater macroinvertebrates. These results are based mainly on the study of lotic (stream and river) ecosystems because there are insufficient data available for lentic (pond and lake) ecosystems. Compared to individual case studies, the present review reports an evidence-based synthesis for the first time. We identified knowledge gaps regarding case studies reporting the effects of urbanization on pond and lake ecosystems, case studies examining the phylogenetic and functional facets of biodiversity, as well case studies investigating the effect of urbanization on the beta diversity component of macroinvertebrate communities. The identification of these knowledge gaps allowed us to make recommendations for future research: (1) report results on specific taxonomic groups and not only the entire macroinvertebrate community, (2) study the impacts of urbanization on macroinvertebrate diversity in different habitat types and understudied continents, (3) focus on the functional and phylogenetic facets of diversity and (4) examine community differentiation (e.g. beta diversity) in urban freshwater ecosystems. Our results also suggested that the analysis of diversity- environment relationships is crucial for developing macroinvertebrate indicators especially in the increasingly urbanized world. [ABSTRACT FROM AUTHOR]

Public support for biodiversity conservation is shaped by people's values and their knowledge, beliefs, and attitudes toward the environment. We conducted the first multinational representative survey of the general public's perceptions of river fish biodiversity in France, Germany, Norway, and Sweden. For the online survey, 1000 respondents per country were randomly selected from large panels following country‐specific quotas set on age, gender, and educational level. Questions covered people's level of knowledge, beliefs, values, and attitudes toward river fish, environmental threats, and conservation measures. We found that the public had limited knowledge of freshwater fishes. Two non‐native species, rainbow trout (Oncorhynchus mykiss) and brook trout (Salvelinus fontinalis), were widely perceived as native, whereas native Atlantic salmon (Salmo salar) was mostly classified as native in Scandinavia and largely as non‐native in central Europe. These results suggest an extinction of experience paralleling the extirpation or decline of salmon stocks in countries such as Germany and France. Respondents thought pollution was the dominant threat to riverine fish biodiversity. In reality, habitat loss, dams, and the spread of non‐native fishes are equally important. Despite limited biological knowledge, respondents from all countries held an overwhelmingly proecological worldview, supported conservation stocking, and appreciated native fishes, although only a minority interacted with them directly. Differences among the 4 countries related to several conservation issues. For example, threats to biodiversity stemming from aquaculture were perceived as more prevalent in Norway compared with the other 3 countries. Promoting fish conservation based on charismatic species and use values of fishes may work well in countries with a strong economic and cultural link to the freshwater environment, such as Norway. In countries where people rather abstractly care for nature, focusing conservation messaging on broader ecosystem traits and non‐use values of fishes is likely to win more support. Article impact statement: Promoting river fishes as part of healthy ecosystems fits public perceptions better than use‐value, charismatic‐nature, or threat‐specific messages. [ABSTRACT FROM AUTHOR]

Abstract: Globally, offset schemes have emerged in many statutory frameworks relating to development activities, with the aim of balancing biodiversity conservation and development. Although the theory and use of biodiversity offsets in terrestrial environments is broadly documented, little attention has been paid to offsets in stream ecosystems. Here we examine the application of offset schemes to stream ecosystems and explore whether they suffer similar shortcomings to those of offset schemes focused on terrestrial biodiversity. To challenge the applicability of offsets further, we discuss typical trajectories of urban expansion and their cascading physical, chemical and biological impacts on stream ecosystems. We argue that the highly connected nature of stream ecosystems and urban drainage networks can transfer impacts of urbanization across wide areas, complicating the notion of like‐for‐like exchange and the prospect of effectively mitigating biodiversity loss. Instead, we identify in‐catchment options for stormwater control, which can avoid or minimize the impacts of development on downstream ecosystems, while presenting additional public and private benefits. We describe the underlying principles of these alternatives, some of the challenges associated with their uptake, and policy initiatives being trialed to facilitate adoption. In conclusion, we argue that stronger policies to avoid and minimize the impacts of urbanization provide better prospects for protecting downstream ecosystems, and can additionally, stimulate economic opportunities and improve urban liveability. [ABSTRACT FROM AUTHOR]

Freshwater ecosystems and associated habitats harbor incredible biodiversity. They offer various ecosystem services and sustain human livelihoods. However, due to increasing developmental pressure and rising water demand, these systems are under huge threat. As a result, many aquatic species are feared to become extinct in near future. Quantifying the patterns of aquatic species diversity and composition of river systems is urgently required. With this interest, we studied four river systems in the Western Ghats region, documenting the pattern of fish diversity and identifying the factors that influence fish species richness. Maintaining undisturbed streams and river basins, especially headwater regions is crucial for sustaining freshwater biodiversity in the tropical river ecosystems. [ABSTRACT FROM AUTHOR]

Se hace una revisión de la información taxonómica de las algas dulceacuícolas de Chile, particularmente referida a la diversidad expresada como riqueza específica de los grupos de algas que han sido citados para el país, exceptuando al grupo de las diatomeas o Bacillariophyceae. El análisis comprende desde las primeras citas bibliográficas a un análisis de la información existente. Se entrega un inventario de los géneros y especies citados por clase de algas, los tipos de comunidades, los cuerpos de aguas más estudiados, y se describen también algunas contribuciones que han significado un aporte al conocimiento taxonómico y florístico de estos grupos de algas. Gran parte de la información taxonómica ha derivado de estudios que en la mayoría de los casos tuvieron objetivos más ecológicos o limnológicos. Como consecuencia de lo anterior, lo que se conoce de la flora algal de los ambientes acuáticos continentales de Chile representa una subestimación de la riqueza específica. Actualmente, no existen en el país especialistas o grupos de especialistas que prioricen los objetivos taxonómicos en la investigación de ambientes acuáticos continentales, por las dificultades que se tienen para la obtención de recursos que financien estas investigaciones, o la escasa formación de especialistas a nivel de postgrados.This paper is a review of taxonomical information of freshwater algae of Chile, particularly referred to diversity expressed as specific richness of the algal groups cited for the country, except for the diatoms group or Bacillariophyceae. The analysis comprises the first bibliographical citations and an analysis of current information on algal biodiversity. An inventory has been given for the genera and species cited per algal class, the types of communities, the most studied water bodies, and are also described some contributions which have provided a support for the taxonomic and floristic knowledge of these algal groups. Great part of taxonomical information have derived from the studies which in the majority of the cases had most ecological and limnological objectives. Consequently, what it is known on the algal flora of continental aquatic environments of Chile represents an underestimation for the specific richness. At present, it does not exist in the country specialists or specialist groups preceding in time the taxonomic objectives in the continental aquatic environments, for the difficulties found to obtain funding resources for investigations or specialists formation at a postgraduate level. In the same way with the great majority of organism groups.

Biodiversity is declining world-wide with detrimental effects on ecosystems. However, we lack a quantitative understanding of the shape of the relationship between microbial biodiversity and ecosystem function ( BEF). This limits our understanding of how microbial diversity depletion can impact key functions for human well-being, including pollutant detoxification., Three independent microcosm experiments were conducted to evaluate the direction (i.e. positive, negative or null) and the shape of the relationships between bacterial diversity and both broad (i.e. microbial respiration) and specialized (i.e. toxin degradation) functions in five Australian and two UK freshwater ecosystems using next-generation sequencing platforms., Reduced bacterial diversity, even after accounting for biomass, caused a decrease in broad (i.e. cumulative microbial respiration) and specialized (biodegradation of two important toxins) functions in all cases. Unlike the positive but decelerating BEF relationship observed most frequently in plants and animals, most evaluated functional measurements were related to bacterial diversity in a non-redundant fashion (e.g. exponentially and/or linearly)., Synthesis. Our results suggest that there is a lack of functional redundancy in the relationship between bacterial diversity and ecosystem functioning; thus, the consequences of declining microbial diversity on ecosystem functioning and human welfare have likely been considerably underestimated. [ABSTRACT FROM AUTHOR]