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Nanoparticles are man-made materials defined as materials smaller than 100 nm in at least one dimension. Titanium oxide nanoparticles are of great interest because of their extensive use in self-care products. There is a lack of nanotoxicological studies of TiO2 NPs in benthic organisms to have evidence about the effects of these pollutants in freshwater ecosystems. Atya lanipes is a scraper/filter that can provide a good nanotoxicological model. This study aims to determine how the TiO2 NPs can develop a toxic effect in the larvae of the Atya lanipes shrimp and to document lethal and sublethal effects after acute exposures to TiO2 NP suspensions of: 0.0, 1.0, 10.0, 50.0, 100.0, and 150.0 mg/L. The results show that early exposure to TiO2 NPs in Atya lanipes creates an increase in mortality at 48 and 72 h exposures, hypoactivity in movements, and morphological changes, such as less pigmentation and the presence of edema in exposed larvae. In conclusion, TiO2 NPs are toxic contaminants in the larval stage of the Atya lanipes. It is necessary to regulate these nanoparticles for purposes of the conservation of aquatic biodiversity, especially for freshwater shrimp larvae and likely many other larvae of filter-feeding species.

Active environmental DNA (eDNA) surveillance through species-specific amplification has shown increased sensitivity in the detection of non-indigenous species (NIS) compared to traditional approaches. When many NIS are of interest, however, active surveillance decreases in cost- and time-efficiency. Passive surveillance through eDNA metabarcoding takes advantage of the complex DNA signal in environmental samples and facilitates the simultaneous detection of multiple species. While passive eDNA surveillance has previously detected NIS, comparative studies are essential to determine the ability of eDNA metabarcoding to accurately describe the range of invasion for multiple NIS versus alternative approaches. Here, we surveyed twelve sites, covering nine rivers across Belarus for NIS with three different techniques, i.e. an ichthyological, hydrobiological and eDNA survey, whereby DNA was extracted from 500 ml surface water samples and amplified with two 16S rDNA primer assays targeting the fish and macroinvertebrate biodiversity. Nine non-indigenous fish and ten non-indigenous benthic macroinvertebrates were detected by traditional surveys, while seven NISeDNA signals were picked up, including four fish, one aquatic and two benthic macroinvertebrates. Passive eDNA surveillance extended the range of invasion further north for two invasive fish and identified a new NIS for Belarus, the freshwater jellyfish Craspedacusta sowerbii. False-negative detections for the eDNA survey might be attributed to: (i) preferential amplification of aquatic over benthic macroinvertebrates from surface water samples and (ii) an incomplete reference database. The evidence provided in this study recommends the implementation of both molecular-based and traditional approaches to maximise the probability of early detection of non-native organisms.

The urbanization of riverine landscapes is an increasing threat to river ecosystems. However, it is unclear which metrics can best assess the response of macroinvertebrates to the conversion of forested lands to urban and agricultural lands. The main goal of this study is to examine whether trait-based approaches are more sensitive than taxonomic approaches in distinguishing macroinvertebrate responses to different land use types in a highly urbanized area of northern China. Results based on 14 environmental variables showed a significant difference across a human-induced environmental gradient. The results showed that no significant differences were observed in terms of taxonomic diversity indices between the different land use types. Functional evenness (FEve) and Rao’s quadratic entropy decreased with the increase in urban area caused by the intensification of human activity, demonstrating that functional diversity is more sensitive than taxonomic diversity in discriminating between different land use types. In addition, the results based on RLQ (physical–chemical variables (R), macroinvertebrate taxa (L), and species traits (Q)) and fourth-corner analyses indicated that the trait states of bi- or multivoltine, high dispersal capacity, and not-streamlined body shape were much higher in the agricultural area and positively related to farmland percentage. Taxa with large body size were dominant in urban areas and were positively correlated with EC. Overall, the observed responses of traits to environmental variables suggest that trait-based approaches should be incorporated into land use management for river restoration.

Aquatic contamination can settle into sediments, where it complexes with organic matter and becomes bioavailable. The resulting bioaccumulation of these contaminants by benthic fauna poses a serious threat due to the potential for trophic transfer. This paper offers an insight into the heterogenous accumulation behavior of different elements, and the consequences for ecological risk. In this study, we present field quantification of sediment-associated bioaccumulation factors (BAFS) in freshwater benthic macroinvertebrates. 17 elements were quantified using ICP-MS in sediment and Asellus aquaticus and Gammarus sp. samples. Previously published reports of contaminant concentrations in freshwater and marine sediments and benthic fauna were likewise analyzed to provide a complementary picture of bioaccumulation across contaminants and taxa. We demonstrate that the BAFS correlates strongly with the thiophilicity of the elemental contaminants, as defined by (Kepp, 2016), for all strata examined. These findings support the hypothesis that thiol-mediated processes, such as that of metallothionein, play a larger role in bioaccumulation than typically afforded. In conclusion, we demonstrate the potential for the thiophilic scale to act as a predictor of accumulation potential.

Previously, using plankton tows, and emergence and settlement traps, we documented persistent widespread nocturnal emergence, and planktonic redistribution, of benthic macroinvertebrates along the coral reef–seagrass interface at two geographically separated locations. We also documented that emergence intensity varies with distance from the reef, leading us to hypothesize that the spatial pattern of emergence is determined by the foraging patterns of nocturnally active, bottom-feeding, mid-level consumers (mainly grunts). In this second study, we coupled those previously published data with nocturnal fish surveys concurrently conducted along belt transects placed at the same locations as the emergence trap collections, and a controlled laboratory experiment, to test this hypothesis. The results of these analyses find that variability in the density of nocturnally active, bottom-feeding fish is strongly positively correlated with emergence intensity, regardless of site or season. Results from the laboratory experiments show that nocturnal invertebrate emergence is significantly higher in the presence of one bottom-feeding fish (the blue-striped grunt Haemulon sciurus) than in microcosms that do not contain this predator. Overall, this study shows that such processes may explain how benthic prey can avoid capture by nocturnally active, bottom-feeding predators and persist in the predator-rich seagrass habitats that surround coral reefs in the Florida Keys National Marine Sanctuary. This study also points out the need to consider nocturnal processes when studying seagrass biodiversity in a predator-rich environment.

Acid rain alters freshwater pH and ion composition, preventing organisms from performing essential bodily functions causing mortality. Macroinvertebrate communities in acidified streams are characterized by species loss in response to physiological stress and altered food quality resulting from the degradation of microbial (e.g., fungi on leaves) communities. Although freshwater acidification in the U.S. is lessening following reduced industrial emissions, little is known about macroinvertebrate recovery. Often, biotic recovery is assessed by looking at changes to what taxa and how many individuals are present in the community (e.g., richness, density). While providing a metric for change, changes in "who" is there (i.e., richness) doesn't necessarily tell us changes in "what" they are doing (i.e., function). The relationship between diversity and function requires linking a "who" to their "what" with direct measurements or as indicated by their traits. Traits are attributes of an organism that aggregate biological, morphological, and behavioral information and may relate to their success in a particular environment. For example, taxa that cannot survive with stream drying (not desiccation resistant) may only be found in streams with permanent water. Trait-based taxonomic metrics could bridge "who" and "what" and expand the impact of stream recovery assessments. My objective was to assess trends over time in water chemistry and macroinvertebrate taxonomic and trait richness and density following reduced industrial emissions. To do so, I studied two long-term data sets from Shenandoah National Park to assess trends in water chemistry and macroinvertebrate taxa and trait composition over a 30-year period to identify taxa and traits that are sensitive to acidification. I also measured how much biomass macroinvertebrates produced in a year (i.e., secondary production) in two streams (1 acidified; 1 not acidified) to determine taxa and traits that are functionally sensitive to acidification. I used these structural and functional measures of sensitivity to determine if changes in trait richness or density predict changes in the function of that trait (e.g., secondary production). Changes over time show that streams have some recovery from acid rain with increasing stream pH and a greater number of taxa and traits present in the community. Changes in taxa were greater than changes in traits over time. While this result was expected as multiple taxa make up each trait category, it may also suggest minimal or delayed functional recovery over time. Still, macroinvertebrate secondary production indicated that function did differ with differences in acidification. Therefore, observed small changes in traits over time mirror prior studies that found other variables, such as competition for food or space, delay or inhibit macroinvertebrates from returning to the recovering streams. Additionally, there were similarities between traits changing over time and the secondary production of traits that differed between more and less acidified streams. Taxa characterized by long life spans and large body size (e.g., semivoltine, long adult life, slow seasonal development) appeared to be the most sensitive to changes in acidification. These findings suggest that some compositional attributes, like taxonomic or trait richness, may predict functional changes measured as secondary production while others, such as density, do not. Master of Science in Life Sciences Acid rain causes the acidification of freshwater stream water observed as decreased stream pH and decreased ability of watershed soils to neutralize or "soak up" acidic inputs before they enter the stream. These changes in stream water chemistry inhibit the ability of aquatic animals to perform essential bodily functions resulting in mortality. The total number of aquatic insect taxa and total number of individuals in the community have been found to decrease in response to acidification. Although freshwater acidification is lessening following reduced industrial emissions, little is known about if and how aquatic insects can recover. Often, aquatic insect recovery is assessed through looking at changes to what taxa and how many individuals are present in the community. While providing a metric for change, changes in "who" is there (i.e., richness) doesn't necessarily tell us changes in "what" they are doing (i.e., function). The relationship between diversity and function requires linking a "who" to their "what". This is often done by assessing changes in the taxa present but also looking at how the composition of traits associated with those taxa also change. Traits or taxa-specific characteristics aggregate biological, morphological, and behavioral information and may relate to their ability to live in a given environment. For example, taxa that rely on filtering and consuming fine particles may only be found in faster flowing streams where they function to remove fine particulates. Trait-based assessments could link "who" and "what" to expand our understanding of how stream ecosystems change with a stressor. My objective was to assess recovery of streams in Shenandoah National Park following reduced industrial emissions. To do so, I studied two long-term (1987-2017) data sets from to assess trends in water chemistry and macroinvertebrate taxa and traits. This enabled me to determine "who" is changing in these streams over time. I also measured how much insect biomass s produced in a year (i.e., secondary production) in two streams (1 more acidic; 1 less acidic) to determine what taxa and traits alter "what" (e.g., secondary production) they are doing. I found that long-term trends indicate some recovery from acid rain with improving water quality and an increased number of insect taxa and traits present in the community over time. Changes in insect taxa were greater than changes in their traits suggesting that stream acidification did not greatly alter "what" the insects are doing greatly to begin with or that recovery may be delayed. In contrast, my secondary production study showed that "what" macroinvertebrates are doing does differ in more or less acidic streams. Therefore, our observed minimal changes in traits over time suggest that other variables, such as competition for food or space, delay or inhibit macroinvertebrates from returning to the recovering streams. Additionally, there were similarities between traits changing over time and traits that were different in the more or less acidic streams. Taxa characterized by long life spans and large body size (e.g., semivoltine, long adult life, slow seasonal development) appeared to be the most affected by differences or changes in stream water acidity. These findings suggest that changes in "who" can predict changes in "what" to some degree though static metrics of abundance do not always reflect the function of the taxa or community.

Background Urban areas are often built along large rivers and surrounded by agricultural land. This may lead to small tributary streams that have agricultural headwaters and urbanized lower reaches. Our study objectives assessed are as follows: (1) landscape, geomorphic, and water quality variables that best explained variation in aquatic communities and their integrity in a stream system following this agricultural-to-urban land use gradient; (2) ways this land use gradient caused aquatic communities to differ from what would be expected for an idealized natural stream or other longitudinal gradients; and (3) whether the impacts of this land use gradient on aquatic communities would grow larger in a downstream direction through the agricultural and urban developments. Our study area was an impaired coldwater stream in Michigan, USA. Results Many factors structured the biological communities along the agricultural-to-urban land use gradient. Instream woody debris had the strongest relationship with EPT (Ephemeroptera, Plecoptera, and Trichoptera) abundance and richness and were most common in the lower, urbanized watershed. Fine streambed substrate had the strongest relationship with Diptera taxa and surface air breather macroinvertebrates and was dominant in agricultural headwaters. Fish community assemblage was influenced largely by stream flow and temperature regimes, while poor fish community integrity in lower urban reaches could be impacted by geomorphology and episodic urban pollution events. Scraping macroinvertebrates were most abundant in deforested, first-order agricultural headwaters, while EPT macroinvertebrate richness was the highest downstream of agricultural areas within the urban zone that had extensive forest buffers. Conclusion Environmental variables and aquatic communities would often not conform with what we would expect from an idealized natural stream. EPT richness improved downstream of agricultural areas. This shows promise for the recovery of aquatic systems using well-planned management in watersheds with this agricultural-to-urban land use pattern. Small patches of forest can be the key to conserving aquatic biodiversity in urbanized landscapes. These findings are valuable to an international audience of researchers and water resource managers who study stream systems following this common agricultural-to-urban land use gradient, the ecological communities of which may not conform with what is generally known about land use impacts to streams.

Land use and climate change are driving widespread modifications to the biodiverse and functionally unique headwaters of rivers. In temperate and boreal regions, many headwaters drain peatlands where land management and climate change can cause significant soil erosion and peat deposition in rivers. However, effects of peat deposition in river ecosystems remain poorly understood. We provide two lines of evidence—derived from sediment deposition gradients in experimental mesocosms (0–7.5 g/m2) and headwaters (0.82–9.67 g/m2)—for the adverse impact of peat deposition on invertebrate community biodiversity. We found a consistent negative effect of sediment deposition across both the experiment and survey; at the community level, decreases in density (1956 to 56 individuals per m2 in headwaters; mean 823 ± 129 (SE) to 288 ± 115 individuals per m2 in mesocosms) and richness (mean 12 ± 1 to 6 ± 2 taxa in mesocosms) were observed. Sedimentation increased beta diversity amongst experimental replicates and headwaters, reflecting increasing stochasticity amongst tolerant groups in sedimented habitats. With increasing sedimentation, the density of the most common species, Leuctra inermis, declined from 290 ± 60 to 70 ± 30 individuals/m2 on average in mesocosms and >800 individuals/m2 to 0 in the field survey. Traits analysis of mesocosm assemblages suggested biodiversity loss was driven by decreasing abundance of invertebrates with trait combinations sensitive to sedimentation (longer life cycles, active aquatic dispersal of larvae, fixed aquatic eggs, shredding feeding habit). Functional diversity metrics reinforced the idea of more stochastic community assembly under higher sedimentation rates. While mesocosm assemblages showed some compositional differences to surveyed headwaters, ecological responses were consistent across these spatial scales. Our results suggest short‐term, small‐scale stressor experiments can inform understanding of “real‐world” peatland river ecosystems. As climate change and land‐use change are expected to enhance peatland erosion, significant alterations to invertebrate biodiversity can be expected where these eroded soils are deposited in rivers., Land use and climate change are driving widespread modifications to the biodiverse and functionally unique headwaters of rivers. In temperate and boreal regions, many headwaters drain peatlands where land management and climate change can cause significant soil erosion and peat deposition in rivers. We provide two lines of evidence—derived from sediment deposition gradients in experimental mesocosms and headwaters—for the adverse impact of peat deposition on invertebrate community biodiversity.

Rivers host a wealth of biodiversity and play critical ecological functions, so monitoring their environmental status and tracking its changes has paramount importance for appropriate management. Although some biological groups, and especially benthic macroinvertebrates, are employed routinely to achieve this goal, the quest for bioindicators of river quality is far from over, because finding further suitable organisms may improve indication performances and inform habitat management. Using organisms that are at risk for bioindication also fulfills the goal of providing important information for the conservation of the taxon (or taxa) used for bioindication. Bats are a diverse, threatened mammal group whose characteristics make them potentially suitable bioindicators in many ecosystem types, but research in this field is still limited. In this study, set in Central and Southern Italy, we hypothesize that assemblages of foraging bats will respond to environmental status and quality of riverine ecosystems and that therefore bats may serve as effective bioindicators. We established the environmental status of 50 sampling sites selected along 10 rivers using two indices officially adopted in the country, i.e. the STAR_ICMi (evaluating water quality from macrobenthic invertebrate assemblages) and the fluvial functionality index (Indice di Funzionalita Fluviale, IFF), which incorporates several biotic and abiotic components and represents a functional indicator of river ecosystem health. At the sampling sites, we also recorded bat activity with operator-independent real-time bat recorders and classified bat passes to species or phonic groups. We examined 167,371 macroinvertebrates and 55,157 bat passes, corresponding to 15 species or phonic groups. The activity of Miniopterus schreibersii/Pipistrellus pygmaeus and Myotis daubentonii/capaccinii declined with increasing values of STAR_ICMi and IFF, while the activity of Nyctalus/Eptesicus serotinus increased with both indices. The activity of P. kuhlii also declined as IFF values increased, while we observed the opposite for Pipistrellus pipistrellus, Myotis emarginatus, Myotis nattereri and Barbastella barbastellus. Pooling together species whose activity respectively increased or decreased as the values of quality indices increased improved indication performances by strengthening statistical significance. Our work constitutes a significant step towards the use of bats as bioindicators in river ecosystems as we show that differences in bat activity may reveal changes in environmental conditions and may thus demonstrate the effects of habitat alteration on the river biota. We highlight that locally adapted bat populations may show differences in foraging behaviour and food preferences; hence our findings warrant confirmation from other regions. Further constraints are given by the variable degree of taxonomic resolution achieved in bat sound analysis, which may represent an issue especially in species-rich bat assemblages such as those of southern Europe.

ContextStructural and functional connectivity, as subconcepts of landscape connectivity, are key factors in biodiversity conservation and management. Previous studies have focused on the consequences of connectivity for populations of terrestrial organisms, which may not be appropriate for aquatic organisms.ObjectivesAs landscape connectivity critically affects the potential value of ponds for biodiversity, here we used diving beetles (Dytiscidae), an indicator taxon of wetland biodiversity, to investigate how structural connectivity affects functional connectivity to aquatic invertebrates in an urban landscape.MethodsWe assessed pairwise similarities of dytiscid community, i.e. the variation of species composition between clustered and isolated ponds in the Helsinki Metropolitan Area, Finland. We investigated how dytiscid community similarity is affected by Euclidean distances between ponds, as an indicator of structural connectivity.ResultsWe found that clustered ponds shared more species than isolated ponds. Dytiscid species community similarity responded negatively to increasing Euclidean distance between ponds. Effectively dispersing species were widely distributed across the landscape, while poor dispersers were scarcely distributed in the same landscape.ConclusionsStructural connectivity determines which species are able to disperse successfully, with poor dispersers restricted to well-connected ponds. The different responses of effective dispersers and poor dispersers to the same structural connectivity indicate that functional connectivity determines species composition. We recommend providing well-connected aquatic habitats in urban landscapes and the implementation of measures to reduce isolation of wetland assemblages. Even clustered ponds need dispersal from other habitats to ensure their contribution to urban biodiversity.

Benthic macroinvertebrates Functional Feeding Group (FFG) have been used to determine aquatic assemblage dynamics and as a biomonitoring tool. The main goals of this study were to assess the effects of stream variables on the abundance and richness of FFGs and evaluate ecosystem attributes (FFG ratios) as a tool to assess ecological conditions of Atlantic Rainforest streams. We sampled 146 sites with different impairment conditions in Rio de Janeiro, Brazil. Richness was significantly different among impairment conditions for all FFGs. Mixed-effect models show that aquatic macroinvertebrate FFGs differed in their responses to abiotic variables for abundance and richness. Also, they were reduced in the impaired sites when compared to intermediate and reference sites. The FFG ratio indicated significant differences along the impairment gradient. The FFG ratio analysis was shown to be a fast and cheap tool that can be used for monitoring aquatic ecosystems in the Atlantic Forest biome. However, further studies are required to calibrate the method specifically for the Atlantic Forest region. Resumo: Os Grupos Funcionais de Alimentação (GFA) são utilizados para determinar a dinâmica da comunidade de macroinvertebrados bentônicos e como uma ferramenta de biomonitoramento. Os principais objetivos deste estudo foram: avaliar os efeitos de variáveis de riacho na abundância e riqueza de GFAs e os atributos do ecossistema (razão GFA) como uma ferramenta para avaliar as condições ecológicas dos córregos da Mata Atlântica. Foram amostrados 146 locais com diferentes condições de impacto no Rio de Janeiro, Brasil. A riqueza foi significativamente diferente com as condições de impacto entre todos os GFA. Os modelos de efeito misto mostraram que os GFA diferiam em suas respostas às variáveis abióticas quanto à abundância e riqueza. Além disso, eles diferem nas áreas impactadas quando comparados as áreas intermediária e de referência. A razão de GFA encontrou diferenças significativas ao longo do gradiente de impacto. A análise da razão de GFA evidenciou-se uma ferramenta rápida e barata, com potencial para ser utilizada no monitoramento de ecossistemas aquáticos no bioma Mata Atlântica. No entanto, mais estudos serão necessários para calibrar o método especificamente para a região da Mata Atlântica.

The use of reference conditions is essential to the monitoring and management of aquatic ecosystems. We examined existing and potential reference sites through historical data, maps, and field data collected from river sites in KwaZulu-Natal (KZN), South Africa. In our study, we applied nine criteria that best reflect the characteristics of South African rivers on 24 a priori selected reference sites. These nine criteria comprised of catchment conditions (flow modification and natural landscape) and site-specific attributes (water quality, human disturbance, river channel, water abstraction, riparian vegetation, riparian zone modification, and instream habitat quality). The a priori selected reference sites were subjected to validation using multivariate methods, such as analysis of similarities (ANOSIM), similarity percentages (SIMPER), and non-parametric multidimensional scaling (MDS) based on the macroinvertebrate fauna by applying a SASS5 threshold considered to be an indicator of undisturbed sites in South African rivers. We identified differences in the macroinvertebrate assemblages of the reference conditions for each river group based on their ecoregions, geomorphology and seasonal variations. Ecoregions and river geomorphology were better in the grouping of sites with similar reference conditions than the seasons. Our findings indicated that all of the selected sites could be considered as valid reference sites; however, caution should be taken in applying this method to lowland rivers because of their noticeable seasonal variability and habitat instability which tend to alter their reference states. We recommend that a type-specific reference condition be developed for lowland rivers. Also, statistical validation of reference conditions should be a continuous process in river biomonitoring.

The deep-sea biome (> 200 m depth) is the world’s last great wilderness, covering more than 65% of the earth’s surface. Due to rapid technological advances, deep-sea environments are becoming more accessible to scientific research and ocean exploration around the world and, in recent years, this is also true for the Galapagos Islands. Deep-sea habitats cover the largest proportion of Galapagos Marine Reserve (GMR), yet to date, no comprehensive baseline exists on the biodiversity of the benthic fauna associated with volcanic seafloor formations within this region. Closing this knowledge gap is essential to provide information for decision-making for the management of marine resources within the GMR and assessing any potential changes in biodiversity resulting from climate-driven alterations that deep-sea environments are expected to experience. In 2015, the Charles Darwin Foundation’s Seamounts of the GMR Research Project, together with the Galapagos National Park Directorate (GNPD) and Ocean Exploration Trust (OET), conducted a joint expedition on board the EV Nautilus. Using Remotely operated vehicles (ROVs), the aim of the expedition was to characterise the geological formations and biological communities present on seamounts, lava flows and other deep-sea habitats (> 200 m) within the GMR. We provide the first comprehensive image inventory for the phylum Arthropoda from 260 to 3400 m of depth within the GMR. Past studies on deep-sea macroinvertebrates in the GMR have been limited to voucher samples collected from dredging (restricted to soft bottom environments) or by submersibles (only allowing limited biological sampling). The image inventory, presented here, is based on high-definition video transects conducted by the Hercules ROV on board the EV Nautilus. Images of macroinvertebrate morphospecies were captured, catalogued and identified, thus providing the first known image inventory of in-situ macroinvertebrate species from the deep-sea region of the GMR. We present 32 distinct morphospecies occurrences within the class Malacostraca and order Decapoda. We also report 17 different families, three species that are new records to the GMR, in-situ images of two new species to science recently described and one possible new squat lobster, as well as interesting behavioural observations.

Global climate change threatens the integrity of freshwater ecosystems across the globe. At higher latitudes these ecosystems are experiencing the highest rates of temperature increase related to climate change. Freshwater invertebrate communities are important sources of food for fishes and bioindicators helping us understand the health of entire ecosystems. Our research is part of a larger experiment which aims to artificially warm an arctic lake by 2-4 ⁰C, to try and determine the impact of rising temperatures on lake food webs and ecosystem function. Our objectives were to calculate benthic macroinvertebrate densities in two arctic lakes, Fog1 and Fog3 (one control and one reference), compare between these lakes as a function of abiotic and biotic differences, and assess whether these macroinvertebrate densities have responded to increases in lake warming. Using standard protocols, we analyzed benthic samples from 2016-2019 taken using an Ekman dredge from lake depths between 0-4 meters. We classified each taxon into four main groups: Diptera, Mollusca, zooplankton, and other aquatic macroinvertebrates and calculated the densities of each group (number/m2). Densities varied greatly from year to year, ranging from 609 organisms/meter2 to 20,391 organisms/ meter2. We observed a very large increase in “other aquatic macroinvertebrates” group in Fog1 (warmed lake) in 2018, comprised mostly of Hydracarina (mites) and including some unique Trichopterans and Annelids. While the densities of benthic macroinvertebrates ranged greatly across lakes and years, we did not observe a definitive trend in response to experimental warming (some groups increased one year but decreased the next and vice versa). In future work, we will explore the metabolic preferences of those taxonomic groups that may have responded to warming, as well as potential top down (e.g., fish predation) pressures on benthic macroinvertebrates.

This study was carried out to identify the relations between macroinvertebrate communities and river basin specific (RBS) pollutants in the Danube River. The investigation was performed at 68 sites along 2,500 km of the Danube. Forward selection (FS), canonical correspondence analyses (CCA), the Spearman correlation coefficient (SC) and BIO-ENV analysis (to detect synergistic effects) were used to identify the relations between the macroinvertebrate dataset and selected biological metrics with RBS pollutants. Of the 20 analysed pollutants (preselected based on NORMAN network methodology), seven (2,4-dinitrophenol, chloroxuron, bromacil, dimefuron, amoxicillin, bentazon and fluoranthene) were found to significantly correlate with macroinvertebrate communities. BIO-ENV analysis revealed 3 subsets of environmental variables that were in high correlation with the biota resemblance matrix, consisting mainly of a combination of the above-mentioned pollutants. Our results indicate that there are significant correlations between chemical determinants and aquatic biota. Moreover, this study contributes to the validation of the methodology used for prioritization of RBS pollutants proposed by the NORMAN network.

Agarophyton vermiculophyllum (formally known as Gracilaria vermiculophylla) is an invasive, bloom-forming, marine macroalga originating from Japan. A. vermiculophyllum has invaded estuaries along both eastern and western coasts of North America, the Atlantic coast of Europe, and the northwest African coastline. A. vermiculophyllum can be found on intertidal mudflats, which are soft-sediment environments, usually without rooted vegetation. In many estuaries A. vermiculophyllum is now the dominant, or only macroalga on mudflats. This species affects mudflat ecosystems by increasing the abundance, and in some cases diversity of epifauna. Whether these community differences lead to ecosystem-scale effects in food webs, or biomass, has not been investigated. Additionally, the generality of epifaunal community changes across abiotic gradients is not well understood. The goal of this dissertation was to understand the drivers of A. vermiculophyllum spatial distribution and its effect on mudflat trophic structure across abiotic gradients. A > 900 km2 dynamic coastal seascape across which mudflats varied in elevation, topographic complexity, wave exposure, and water residence time was used for a study system. To understand the role of geomorphology for mudflat producers and consumers I developed a novel index variable describing topographic variability on mudflats. I investigated the effect of A. vermiculophyllum on primary producers, macroinvertebrates, and shorebirds across a gradient of topographic variability. Through behavioral observations, large-scale manipulations, surveys and models, I found community-level changes caused by A. vermiculophyllum were decoupled from ecosystem-scale biomass changes. Shorebird communities partitioned mudflats based on the distribution of A. vermiculophyllum, with species preferring or avoiding macroalgal habitat based on their foraging mode specialization. However, the biomass of benthic microalgae, macroinvertebrates, and shorebirds, as well as the individual body sizes of the macroinvertebrate and shorebird communities, did not change when mudflats were colonized with A. vermiculophyllum. Mudflat topography explained A. vermiculophyllum spatial distribution, and the abundance and body size distribution of macroinvertebrates and shorebirds. Once accounting for mudflat topography and sediment characteristics, effects of A. vermiculophyllum for mudflat consumer biomass were not evident. This may have been due to compensatory changes in community body size distribution of invertebrates and birds driven by topography and sediment characteristics. Highly invasive species do not always have ecosystem-level effects, and while monitoring and more experimentation are certainly required, it appears for now that Agarophyton vermiculophyllum may be one of these cases.

We tested the response of several different water quality metrics at 6 sites along a 4-km alternating forest (canopied) and floodplain (non-canopied) reach of the East Branch of the Black River, an undisturbed northern Lower Michigan trout stream, during summer 2015. Physicochemical parameters were unchanged between sites and reflected an undisturbed continuum. In-stream woody debris was higher at the forest sites, whereas relative canopy cover and sunlight intensity were higher at the floodplain sites. Both benthic macroinvertebrates and adult caddisflies exhibited greater species richness and a higher abundance of shredders at the forest sites, and a higher abundance of scrapers at the floodplain sites. Fish specimen abundance, species richness, and percentage of trout were not different between sites, and instead all increased throughout the summer. Community respiration was unchanged between the single tested floodplain site and the forest sites upstream and downstream of it. Gross primary production and net daily metabolism were higher at the floodplain site, leading to stream autotrophy. This result was also obtained when tested in summer 2017. Our results support the idea that terrestrial habitat changes can singularly affect the fundamental ecological functioning of an undisturbed stream, primarily due to deviations in sunlight penetration and allochthonous input. Moreover, the short distances between sites with alternating results indicate the dynamic and serially discontinuous state of natural rivers.

Macroinvertebrates are globally acclaimed as essential tools for biological monitoring in freshwater ecosystems. The essence of this study was to establish bioindicators for Agbede wetlands located in Edo- North in southern Nigeria. Both lotic (stations 1–3) and lentic (stations 4–7) water bodies were sampled between December 2012 and May 2014. Standard methods were applied for macroinvertebrates collection from the littoral habitats. The results of physicochemical parameters indicated that; flow velocity influenced the lotic environments, while temperature, electrical conductivity and turbidity mostly influenced the lentic water bodies. Three major pollution indicator groups were realised across the ecotypes and they are; the pollution sensitive (Ephemeroptera, Coleoptera and Trichoptera), the facultative (Anisoptera, Zygoptera and Decapoda) and the pollution tolerant groups (aquatic snail, Oligochaete and Leech). Pollution tolerant group was preponderance across the study stations but was significantly predominant in the lentic stations, especially during the dry seasons (November to March). The performance of pollution tolerance index (PTI) model, biodiversity indices and Multivariate analyses; all showed high taxa abundance, species composition and diversity across the stations. Similarly, PTI model revealed moderate water quality particularly in the lentic stations (values between 17 and 18) indicating healthy ecosystems, which was also proven by the biodiversity indices. The implication of this work is that, it will remain a comprehensive guide on biomonitoring programmes of the water bodies and the catchment areas as the water bodies are not in a bad quality.

Macroinvertebrate surveys are commonly used for assessing the health of freshwater systems around the world. Traditionally, surveying involves morphologically identifying the families, and sometimes genera, present in samples. Biological indices, derived from taxonomic lists, provide convenient ways to summarise community data and may be fairly insensitive to species-level changes in community compositions. In recent years, molecular techniques for identifying taxa have become increasingly popular and metabarcoding approaches that offer the ability to identify species from mixtures of whole animals (bulk-samples) or from environmental samples have gained much attention. However, generating accurate species lists from metabarcode data is challenging and can be impacted by sample type, choice of primers, community composition within samples, and the availability of reference sequences. This study compares the performance of molecular data extracted from bulk-samples against morphological data in calculating two biological indices (the Stream Invertebrate Grade Number Average Level 2 (SIGNAL2), which is calculated from family-level data, and a genus-level equivalent of this index, SIGNAL_SG) and one biological metric (taxon richness). Further, molecular indices and metrics derived from global, local or mixed reference DNA libraries and with varying degrees of filtering processes applied to them, are compared with respect to the strength of their relationships with morphological indices and metrics. Molecularly derived SIGNAL2 and SIGNAL_SG scores correlated strongly with morphologically derived scores, and were strongest when using a reference library containing a mix of local and global data. Molecularly derived richness metrics were moderately correlated with morphological taxa richness; however, the strongest correlations were observed when taxa that could not be assigned SIGNAL grades were omitted from analyses. This study highlights the utility of using molecular data as an objective and sensitive alternative to traditional freshwater biological assessment using macroinvertebrates.

Coastal wetlands are heterogeneous systems with multiple inputs and complex interactions within local food webs. Interpreting such complexity is limited by incomplete knowledge of trophic interactions among organisms. Although widely recognized as secondary consumers and predators of intertidal macroinvertebrates, shorebirds can also consume lower-trophic-level food sources, and frequently forage in adjacent supratidal habitats. To ascertain potential trophic links between overwintering shorebirds and alternative non-standard food sources, we collected carbon and nitrogen stable isotope data of shorebirds and benthic organisms from 4 coastal wetlands along the Eastern Atlantic: Tejo Estuary, Portugal; Sidi-Moussa, Morocco; Banc d'Arguin, Mauritania; and Bijagós Archipelago, Guinea-Bissau. Using dual-isotope Bayesian mixing models, we evaluated the relative importance of intertidal benthic macroinvertebrates and 3 other potential food sources (biofilm and seagrass rhizomes from intertidal areas, and saltpan macroinvertebrates) in the diet of wintering shorebirds. Although intertidal macroinvertebrates form the main part of most shorebird species' diet, our data revealed that supratidal saltpans can contribute to >30% of the biomass ingested by several shorebird species. Seagrass rhizomes represented >10% of the diet of several species in Banc d'Arguin and in Sidi Moussa. Little stint Calidris minuta appears to consume biofilm on all 3 wetlands where they were sampled, which is the first time biofilm consumption by shorebirds has been detected along the East Atlantic Flyway. Empirical evidence for generalized consumption of alternative food sources by intertidal avian predators show the greater complexity and food web connectivity in and of intertidal habitats, and also with the surrounding habitats.

Naturally stressed ecosystems hold a unique fraction of biodiversity. However, they have been largely ignored in biomonitoring and conservation programmes, such as the EU Water Framework Directive, while global change pressures are threatening their singular values. Here we present a framework to classify and evaluate the ecological quality of naturally stressed rivers along a water salinity gradient. We gathered datasets, including aquatic macroinvertebrate assemblages and environmental information, for 243 river locations across the western Mediterranean to: a) gauge the role of natural stressors (salinity) in driving aquatic community richness and composition; b) make river classifications by encompassing the wide range of environmental and biological variation exhibited by Mediterranean rivers; c) provide effective biomonitoring metrics of ecological quality for saline rivers. Our results showed that water salinity played a pivotal role in explaining the community richness and compositional changes in rivers, even when considering other key and commonly used descriptors, such as elevation, climate or lithology. Both environmental and biologically-based classifications included seven river types: three types of freshwater perennial rivers, one freshwater intermittent river type and three new saline river types. These new saline types were not included in previous classifications. Their validation by independent datasets showed that the saline and freshwater river types represented differentiable macroinvertebrate assemblages at family and species levels. Biomonitoring metrics based on the abundance of indicator taxa of each saline river type provided a much better assessment of the ecological quality of saline rivers than other widely used biological metrics and indices. Here we demonstrate that considering natural stressors, such as water salinity, is essential to design effective and accurate biomonitoring programmes for rivers and to preserve their unique biodiversity., CG-C and PA are supported by “Juan de la Cierva-Formación” research contracts (funded by the Ministry of Economy and Competitiveness - MINECO, Spain, FJCI-2015-25785 and FJCI-2014-20581, respectively). Saline river surveys were funded by the Ministry of Science and Innovation (Spain) through R&D&I Projects BOS2002-00702 (JV) and CGL2006-04159/BOS (AM).

Aquatic ecosystems are affected by multiple environmental stressors across spatial and temporal scales. Yet the nature of stressor interactions and stressor-response relationships is still poorly understood. This hampers the selection of appropriate restoration measures. Hence, there is a need to understand how ecosystems respond to multiple stressors and to unravel the combined effects of the individual stressors \ud on the ecological status of waterbodies. Models may be used to relate responses of ecosystems to environmental changes as well as to restoration measures and thus provide valuable tools for water management. Therefore, we aimed to develop and test a Bayesian Network (BN) for simulating the responses of stream macroinvertebrates to multiple stressors. Although the predictive performance may be further improved, the developed model was shown to be suitable for scenario analyses. For the selected lowland streams, an increase in macroinvertebrate-based ecological quality (EQR) was predicted for scenarios where the streams were relieved from single and multiple stressors. Especially a combination of measures increasing flow velocity and enhancing the cover of coarse particulate organic matter showed a significant increase in EQR compared to current conditions. The use of BNs was shown to be a promising avenue for scenario analyses in stream restoration management. BNs have the capacity for clear visual \ud communication of model dependencies and the uncertainty associated with input data and results and allow the combination of multiple types of knowledge about stressor-effect relations. Still, to make predictions more robust, a deeper understanding of stressor interactions is required to parametrize model relations. Also, sufficient training data should be available for the water type of interest. Yet, the \ud application of BNs may now already help to unravel the contribution of individual stressors to the combined effect on the ecological quality of water bodies, which in turn may aid the selection of appropriate restoration measures that lead to the desired improvements in macroinvertebrate-based ecological quality.

Although freshwater ecosystems support a disproportionately large number of species, decision-support tools for prioritizing protected area efforts have mostly been implemented in marine and terrestrial environments. Systematic conservation planners rely on surrogate metrics to represent unsampled elements of biodiversity, yet few studies have considered the potential benefits associated with prioritizing multiple dimensions of freshwater biodiversity across multiple organism groups. In this study, we first evaluated relationships among patterns of taxonomic richness, functional diversity, functional redundancy, and biotic integrity for freshwater fish and benthic macroinvertebrate communities in the Congaree Biosphere Region, South Carolina, USA. We then used the decision-support tool Marxan to explore a potential trade-off between the number of organism groups sampled (i.e., taxonomic extent) and the multidimensional nature of biodiversity. Our central findings indicated that the processes driving patterns of taxonomic and functional diversity among organism groups were complementary, with direct implications for the evaluation of surrogate performance. Our results also suggest that within-taxa variation among measures of taxonomic and functional diversity may be more important to consider than the taxonomic representation of multiple organism groups. That is, we may be able to enhance the efficiency of conservation planning efforts by using available datasets in a more comprehensive way, as surrogate performance was largely mediated by the variation among metrics. Through the continued development of functional trait databases, we may be able to enhance the efficiency of data collection efforts and promote the timely and sustainable development of conservation strategies.

Metacommunity ecology highlights the importance of integrating simultaneously environmental filtering and spatial processes, such as mass effects and dispersal limitation, into investigation of community assembly. However, few studies to date have tried to examine mass effects and dispersal limitation as independent ecological mechanisms along with environmental filtering in shaping biological communities in river networks. We examined the relative importance of three factor groups, i.e., environmental variables, within-river spatial factors (indicative of mass effects) and basin identity (referring to dispersal limitation) on a macroinvertebrate metacommunity and nine trait-based deconstructed sub-metacommunities from seven subtropical rivers. We applied redundancy analysis and variance partitioning to reveal the pure and shared effects of the three groups of factors on community variation. Environmental filtering, mass effects and dispersal limitation were all significant mechanisms affecting variation in macroinvertebrate communities, but their relative importance depended on biological traits. Environmental filtering explained more of the variation in the whole metacommunity, tolerant taxa and macroinvertebrate groups with weak dispersal ability (i.e., aquatic dispersal, aerial passive dispersal and large body size). In contrast, mass effects accounted for more variation in the communities of intolerant taxa and macroinvertebrate groups with strong dispersal ability (i.e., aerial active dispersal mode and medium body size). Dispersal limitation was more influential for sub-communities of moderately tolerant taxa and large-sized taxa. Our study highlights that simultaneously accounting for different spatial processes and using a trait-based approach are essential to improve our understanding of community assembly in river networks.

Ecological restoration is becoming increasingly widespread to compensate for wetland loss worldwide. However, most post-restoration studies fail to establish whether the restored wetlands replace or complement natural wetlands for communities of aquatic organisms such as macroinvertebrates. During two consecutive hydroperiods (ca 6 months each), we studied the macroinvertebrate communities in 32 new temporary ponds created during a restoration 6–7 years previously in Doñana, SW Spain, and compared them with ten natural temporary sites nearby. We compared results for two dominant groups of active dispersers (Coleoptera and Hemiptera) and for the whole aquatic macroinvertebrate community (a mix of active and passive dispersers) to shed light on the role of dispersal constraints during ecosystem recovery. We also compared the ranks of new ponds and reference sites in nested matrices to assess whether communities in new ponds are impoverished subsets of communities in reference sites. Because of their young age, newly created ponds were predicted to have less stable communities over the two study years than reference sites, and to have lower species diversity for the whole community but not for active dispersers. On the other hand, communities in new ponds were predicted to approach the taxonomic composition of reference sites as time went on. New ponds differed in environmental conditions (particularly less emergent vegetation cover and lower chlorophyll concentration) from reference sites, but their invertebrate richness and diversity matched those in reference sites and invertebrate abundance was even higher. Richness and diversity increased in the second hydroperiod in new ponds, but not in reference sites. Significant differences in community composition occurred between new ponds and reference sites, but were largely explained by their environmental differences. As succession progressed within a hydroperiod, communities in new ponds were first dominated by large branchiopods, then by active dispersers such as Chironomidae and Coleoptera, then finally by halotolerant taxa such as the beetle Ochthebius viridis fallaciosus. Communities in new ponds were not impoverished subsets of those in reference sites, and communities in new and reference ponds diverged towards the end of the hydroperiods. We conclude that new temporary ponds can provide diverse and complementary habitats important for maintaining macroinvertebrate diversity at the regional scale.

The objective of the investigation was to analyze of benthic macroinvertebrates biodiversity of Cunas river by means of environmental indicators. Three sampling sectors were defined two contrasting periods. The anthropic pressures evaluation was carried out by means of DBO5 determination contributed by waste water. Water samples were collected for nitrate, phosphate and fecal coliform determination. The measured indicators in situ were: dissolved oxygen, dissolved total solids, conductivity, temperature, pH and turbidity. The benthic macroinvertebrate samples were collected using a Surber net with 250 µm wire netting opening. The anthropic pressure results on the benthic macroinvertebrates were: fish farming waste water DBO5 mean 7.70 mg/L, from livestock activity 869 mg/L and from urban activity 428.3 mg/L. The physicochemical and bacteriological indicator results showed significant differences for conductivity, temperature and dissolved total solids. Four phyla, seven classes, 12 orders and 26 benthic macroinvertebrate families were identified. It is concluded that waste water discharge from livestock and urban activities are significant anthropic pressures on benthic macroinvertebrate biodiversity. The water quality physicochemical and bacteriological indicators, determined according to sector and time sampling are in the ECA range for highland river water. The richness, abundance and benthic macroinvertebrate diversity, according to the sector and time sampling, presented significant differences. El objetivo de la investigación fue analizar el estado de la biodiversidad de macroinvertebrados bentónicos del río Cunas mediante indicadores ambientales. Se definieron tres sectores de muestreo en dos épocas contrastantes. La valoración de las presiones antrópicas se realizó mediante la determinación de la carga de DBO5 aportada por aguas residuales. Se colectaron muestras de agua para la determinación de nitratos, fosfatos y coliformes termotolerantes. Los indicadores medidos in situ fueron: oxígeno disuelto, sólidos totales disueltos, conductividad, temperatura, pH y turbidez. Las muestras de macroinvertebrados bentónicos se colectaron utilizando una red Surber con malla de 250 µm de abertura. Los resultados de la presión antrópica sobre los macroinvertebrados bentónicos fueron: media de DBO5 de aguas residuales de la actividad piscícola 7,70 mg/L, de la actividad pecuaria 869 mg/L y de la actividad urbana 428,3 mg/L. Los resultados de los indicadores físico-químicos y bacteriológicos mostraron diferencias significativas para la conductividad, temperatura y sólidos totales disueltos. Se identificaron cuatro phyla, siete clases, 12 órdenes y 26 familias de macroinvertebrados bentónicos. Se concluye que las descargas de aguas residuales de las actividades pecuaria y urbana son presiones antrópicas significativas sobre la biodiversidad de macroinvertebrados bentónicos. Los indicadores fisicoquímicos y bacteriológicos de la calidad del agua determinados, según sector y época de muestreo, están en el rango de los ECA para agua de ríos de la sierra. La riqueza, abundancia y diversidad de macroinvertebrados bentónicos, según sector y época de muestreo, presentaron diferencias significativas.

The Water Framework Directive introduced in Europe major changes to improve the management of water resources. This study aims to highlight some of the potential implications of its implementation for lake water monitoring in Italy. A Life+ project was launched to plan the first monitoring of lake macroinvertebrates standardized at the national level. Quantile regression analysis was used to explain different metrics of diversity describing macroinvertebrate communities in response to twenty-one variables representing chemical, physical and morphological characteristics of the environment. Nine lakes located in two Italian regions (Piedmont and Sardinia) were analyzed covering a wide trophic spectrum, from oligotrophy to hyper-eutrophy. The lakes were sampled following the national standardized protocol with samples covering the three recognized lake zones: littoral, sublittoral, profundal. The studied lakes had high chemical variability with conductivity ranging between 53 and 561 μS/cm, pH between 6.5 and 9.1, and alkalinity between 14 and 398 mg/l. The bottom sediments were characterized by fine sand (range 51–99%), followed by silt (1–35%) and clay (0–28%). When the Lake Habitat Survey was also applied to these lakes, its synthetic indices (LHMS, Lake Habitat Modification Score and LHQA, Lake Habitat Quality Assessment) produced higher values in natural lakes (mean values ± SD: LHMS = 26 ± 7, LHQA = 57 ± 3) than in the reservoirs (LHMS = 22 ± 4, LHQA = 52 ± 6). In all lakes, macroinvertebrates mainly consisted of chironomids and oligochaetes characterized by relative abundances up to 80% and >90%, respectively. Using quantile regression to evaluate limiting responses, only two variables, namely sampling depth and oxygen percent saturation (oxygen content), resulted the ones that best explained all the analyzed metrics of diversity of the macroinvertebrate communities. Depth and oxygen were then used to suggest synthetic models describing the various metrics of potential community diversity. These models can help the environmental agencies responsible for monitoring at the national level in distinguishing entire lakes or part of them with high biodiversity from those in altered conditions and then address remediation efforts toward the water bodies with the most critical conditions. Such approach could also be used to optimize the sampling procedures for the application of the Benthic Quality Index for lakes currently adopted at national level.

The impacts of stream disturbance caused by pleasured boat, and differences in seasonality on benthic macroinvertebrate communities, were evaluated in Lijiang River, China, October 2009 and April 2010. The environmental characteristic differed significantly between affected conditions and unaffected conditions. In wet period, the water temperature, conductivity and salinity after disturbance was significantly (p

Made available in DSpace on 2020-12-12T01:06:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-03-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Academy of Finland Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Reliable biological assessments are essential to answer ecological and management questions but require well-designed studies and representative sample sizes. However, large sampling effort is rarely possible, because it demands large financial resources and time, restricting the number of sites sampled, the duration of the study and the sampling effort at each site. In this context, we need methods and protocols allowing cost-effective surveys that would, consequently, increase the knowledge about how biodiversity is distributed in space and time. Here, we assessed the minimal sampling effort required to correctly estimate the assemblage structure of stream insects sampled in near-pristine boreal and subtropical regions. We used five methods grouped into two different approaches. The first approach consisted of the removal of individuals 1) randomly or 2) based on a count threshold. The second approach consisted of simplification in terms of 1) sequential removal from rare to common species; 2) sequential removal from common to rare species; and 3) random species removal. The reliability of the methods was assessed using Procrustes analysis, which indicated the correlation between a reduced matrix (after removal of individuals or species) and the complete matrix. In many cases, we found a strong relationship between ordination patterns derived from presence/absence data (the extreme count threshold of a single individual) and those patterns derived from abundance data. Also, major multivariate patterns derived from the complete data matrices were retained even after the random removal of more than half of the individuals. Procrustes correlation was generally high (>0.8), even with the removal of 50% of the species. Removal of common species produced lower correlation than removal of rare species, indicating higher importance of the former to estimate resemblance between assemblages. Thus, we conclude that sampling designs can be optimized by reducing the sampling effort at a site. We recommend that such efforts saved should be redirected to increase the number of sites studied and the duration of the studies, which is essential to encompass larger spatial, temporal and environmental extents, and increase our knowledge of biodiversity. Programa de Pós-Graduação em Ecologia e Evolução Universidade Federal de Goiás Departamento de Ecologia Universidade Federal de Goiás Finnish Environment Institute Freshwater Centre Department of Geosciences and Geography University of Helsinki, PO Box 64 Departamento de Botânica e Ecologia Universidade Federal do Mato Grosso Instituto de Biociências Universidade Estadual Paulista UNESP, Rio Claro Instituto de Ciências Biológicas Universidade Federal do Rio Grande Department of Biological and Environmental Science University of Jyväskylä, P.O. Box 35 Instituto de Biociências Universidade Estadual Paulista UNESP, Rio Claro FAPESP: 2013/50424-1 Academy of Finland: 273557 Academy of Finland: 273560 CNPq: 304314/2014-5 CNPq: 307587/2017-7 CNPq: 307961/2017-6

The importance of parasites as both members of biological communities and structuring agents of host communities has been increasingly emphasized. Yet parasites of aquatic macroinvertebrates and the environmental factors regulating their richness and abundance remain poorly studied. Here, we quantified parasite richness and abundance within 12 genera of odonate naiads and opportunistically sampled four additional orders of aquatic macroinvertebrates from 35 freshwater ponds in the San Francisco Bay Area of California, U.S.A. We also tested the relative contributions of host‐ and habitat‐level factors in driving patterns of infection abundance for the most commonly encountered parasite (the trematode Haematoloechus sp.) in nymphal damselflies and dragonflies using hierarchical generalized linear mixed models. Over the course of two years, we quantified the presence and intensity of parasites from 1612 individuals. We identified six parasite taxa: two digenetic trematodes, one larval nematode, one larval acanthocephalan, one gregarine, and a mite, for which the highest infection prevalence (39%) occurred in the damselfly genus, Ishnura sp. Based on the hierarchical analysis of Haematoloechus sp. occurrence, infection prevalence and abundance were associated predominantly with site‐level factors, including definitive host (frog) presence, nymphal odonate density, water pH, and conductivity. In addition, host suborder interacted with the presence of fishes, such that damselflies had higher infection rates in sites with fish relative to those without, whereas the opposite was true for dragonfly nymphs. These findings offer insights into the potential interaction between host‐ and site‐level factors in shaping parasite populations within macroinvertebrate taxa.

(1) Background: Strategies aimed at managing freshwater eutrophication should be based on practices that consider cropland invertebrates, climatic change, and soil nutrient cycling. Specifically, detritivores play a crucial role in the biogeochemical processes of soil through their consumptive and burrowing activities. Here, we evaluated the effectiveness of increasing detritivore abundance as a strategy for nutrient management under varied rainfall. (2) Methods: We manipulated soil macroinvertebrate abundance and rainfall amount in an agricultural mesocosms. We then measured the phosphorus, nitrogen, and carbon levels within the soil, corn, invertebrates, and soil solution. (3) Results: Increasing detritivore abundance in our soil significantly increased corn biomass by 2.49 g (p &lt, 0.001), reduced weed growth by 18.2% (p &lt, 0.001), and decreased soil solution nitrogen and total organic carbon (p &lt, 0.05) and volume by 31.03 mL (p &lt, 0.001). Detritivore abundance also displayed a significant interaction effect with rainfall treatment to influence soil total P (p = 0.0019), total N (p &lt, 0.001), and total C (p = 0.0146). (4) Conclusions: Soil detritivores play an important role in soil nutrient cycling and soil health. Incorporating soil macroinvertebrate abundance into management strategies for agricultural soil may increase soil health of agroecosystems, preserve freshwater ecosystems, and protect the valuable services they both provide for humans.

The ‘home-field advantage’ (HFA) hypothesis states that litter decomposes faster in its ‘home’ habitat, i.e., in the same habitat as the plant species from which it was derived than it does ‘away’ from its home, i.e., in the habitat of a different plant species. However, studies pertaining to HFA in aquatic ecosystems are relatively few. One area not well-studied is whether the presence of living plants has an effect on the HFA of aquatic macrophyte decomposition in a eutrophic lake. Here, we conducted reciprocal litter transplanting experiments, coupled with removal of living plants, between a dominant submerged macrophyte (Myriophyllum spicatum) and a floating-leaved macrophyte (Trapa natans) in a eutrophic urban lake in China, for 50 days. Test plots were created at sites by removing the dominant macrophytes from their ‘home’ habitats to test the effect of living plants on decomposition rates and HFA effect. The water chemistry of the two sites was not significantly different. The initial litter qualities were significantly higher in M. spicatum than in T. natans. The decomposition rates of T. natans were significantly greater in both the control and test plots in its ‘home’ habitat, indicating a positive HFA effect, while the decomposition rates of M. spicatum were significantly greater in the ‘away’ habitat compared to its ‘home’ habitat in all treatments, indicating a home-field disadvantage effect. The removal of living plants had a noticeable effect on the abundance of associated-macroinvertebrates, but had an inconsistent effect on decomposition rates providing conflicting evidence for HFA. In total, 10 macroinvertebrate taxa from four functional feeding groups (FFGs) were collected during the experiment. Compared to macroinvertebrate communities, microbial activities showed less correlation with decomposition rates. Our results provide evidence to suggest that decomposition-based HFA is dependent upon litter quality, habitat, and their interactions in a eutrophic urban lake.

Songklanakarin Journal of Science and Technology, 40, 6, 1265-1270

Regional studies of biotic communities are important for characterising their normal spatial and temporal variation, but there are few such studies of tropical streams. This paper describes changes in invertebrate communities in Yuccabine Creek, a seasonal upland rainforest stream in tropical Australia, over three-year and decadal periods. Invertebrate abundance, richness and evenness were temporally stable, except after major drying or wet-season flows, from which they recovered quickly, however, three wet seasons contrasted in abundance patterns. Species’ responses to flood or drought varied depending on life-histories and habitat dynamics. Communities showed contrasts between wet, early-dry and late-dry seasons, with different characteristic species. Current velocity, leaf litter and substratum particle size were the main environmental correlates with species abundances and multivariate scores. Between-decade contrasts were due to antecedent rainfall and loss of canopy cover. Trophic composition varied seasonally, driven by abundances of predators and detritivores. Yuccabine Creek differs from comparable temperate streams in its high diversity of invertebrates, continual recruitment and spring-dominated continual leaf fall, and from some other tropical streams in its seasonal flow regime. Interpretation of invertebrate metrics in these streams needs to account for historical, antecedent and current conditions, but biannual samples would adequately characterise the fauna.

Streamflow variability is a major determinant of basin-scale distributions of benthic invertebrates. Here we present a novel procedure based on a probabilistic approach aiming at a spatially explicit quantitative assessment of benthic invertebrate abundance as derived from near-bed flow variability. Although the proposed approach neglects ecological determinants other than hydraulic ones, it is nevertheless relevant in view of its implications on the predictability of basin-scale patterns of organisms. In the present context, aquatic invertebrates are considered, given that they are widely employed as sensitive indicators of fluvial ecosystem health and human-induced perturbations. Moving from the analytical characterization of site-specific probability distribution functions of streamflow and bottom shear stress, we achieve a spatial extension to an entire stream network. Bottom shear stress distributions, coupled with habitat suitability curves derived from field studies, are used to produce maps of invertebrate suitability to shear stress conditions. Therefore, the proposed framework allows one to inspect the possible impacts on river ecology of human-induced perturbations of streamflow variability. We apply this framework to an Austrian river network for which rainfall and streamflow time series, river network hydraulic properties, and local information on invertebrate abundance for a limited number of sites are available. A comparison between observed species density versus modeled suitability to shear stress is also presented. Although the proposed strategy focuses on a single controlling factor and thus represents an ecological minimal model, it allows derivation of important implications for water resource management and fluvial ecosystem protection. Key Points Hydrologic variability is a major control of invertebrate habitat suitability New analytical basin-scale approach for pdfs of ecohydrological key features Austrian river basin used for ecohydrological data-model comparison

Propsilocerus akamusi (Diptera: Chironomidae) is a dominant macroinvertebrate species in many eutrophic lakes in subtropical and temperate zones. P. akamusi larvae can migrate deep into the sediment (>30 cm) during summer where is no oxygen. However, to our knowledge, the specific adaptive tactics of its tube-dwelling life (>30 cm) and underlying mechanisms why this species is favored by nutrient-rich lakes remain limited. With the understanding above-mentioned issues, we can provide important information for the development of sensitive biomonitoring. We examined monthly morphological dynamics and physiological adaptations of P. akamusi to anoxic conditions, and environmental relationships of the species abundance in a subtropical eutrophic lake. Results of our experiments indicated that this species presented extremely low fuel consumption at a state of estivation when the larvae dwelt in deep sediment, and conducted anaerobic respiration, with ethanol as a major metabolite, to withstand long term anoxic conditions. Additionally, in our field study, the abundance of P. akamusi correlated positively with most nutrient-related variables, indicating that this species can serve as sentinel organisms of nutrient enrichment. We suggest that the high tolerance to anoxia and detritivorous diet of P. akamusi larvae may allow the species to benefit from nutrient enrichment. The vertical niche differentiation and the avoidance of benthivorous predator by vertical sediment migration behavior may also contribute to its high dominance in eutrophic freshwaters. peerReviewed

We used two-dimensional hydrodynamic models for the assessment of water diversion effects on benthic macroinvertebrates and associated habitat in a montane stream in Yosemite National Park, Sierra Nevada Mountains, CA, USA. We sampled the macroinvertebrate assemblage via Surber sampling, recorded detailed measurements of bed topography and flow, and coupled a two-dimensional hydrodynamic model with macroinvertebrate indicators to assess habitat across a range of low flows in 2010 and representative past years. We also made zero flow approximations to assess response of fauna to extreme conditions. The fauna of this montane reach had a higher percentage of Ephemeroptera, Plecoptera, and Trichoptera (%EPT) than might be expected given the relatively low faunal diversity of the study reach. The modeled responses of wetted area and area-weighted macroinvertebrate metrics to decreasing discharge indicated precipitous declines in metrics as flows approached zero. Changes in area-weighted metrics closely approximated patterns observed for wetted area, i.e., area-weighted invertebrate metrics contributed relatively little additional information above that yielded by wetted area alone. Loss of habitat area in this montane stream appears to be a greater threat than reductions in velocity and depth or changes in substrate, and the modeled patterns observed across years support this conclusion. Our models suggest that step function losses of wetted area may begin when discharge in the Merced falls to 0.02 m3/s; proportionally reducing diversions when this threshold is reached will likely reduce impacts in low flow years.

Evaluation of the ecological status of river sites in Canada is supported by building models using the reference condition approach. However, geography, data scarcity and inter-operability constraints have frustrated attempts to monitor national-scale status and trends. This issue is particularly true in Atlantic Canada, where no ecological assessment system is currently available. Here, we present a reference condition model based on the River Invertebrate Prediction and Classification System approach with regional-scale applicability. To achieve this, we used biological monitoring data collected from wadeable streams across Atlantic Canada together with freely available, nationally consistent geographic information system (GIS) environmental data layers. For the first time, we demonstrated that it is possible to use data generated from different studies, even when collected using different sampling methods, to generate a robust predictive model. This model was successfully generated and tested using GIS-based rather than local habitat variables and showed improved performance when compared to a null model. In addition, ecological quality ratio data derived from the model responded to observed stressors in a test dataset. Implications for future large-scale implementation of river biomonitoring using a standardised approach with global application are presented.

Pesticide loads in streams are potentially one of the most relevant stressors for macroinvertebrate communities. Nevertheless, real effects provoked at the community level are still largely unknown. Model ecosystems are frequently used as tools for the risk assessment of pesticides, especially for their regulation, however, they can be also applied to site-specific risk assessment in order to gain better understanding of the responses of aquatic ecosystems to chemical stress. In the present work, an experimental system was composed of 5 artificial streams that reproduced a mountain lotic environment under controlled conditions. This study was aimed to better understand, whether (and how) the biological community was influenced by pesticides pulse exposures. 5 mixture load events were simulated over the productive season (March-July 2010): biological community was regularly sampled and nominal concentrations of water were tested. The results were interpreted comparing the output of different metrics and statistical methodologies. The sensitivity of different metrics was analyzed considering single exposure events (maximum Toxic Units) as well as overall temporal trends. Results showed how some common taxonomic metrics (e.g. taxa richness, Shannon's index, total abundance of organisms, and the Extended Biotic Index) were not suitable to identify the effects of pesticides at community level. On the contrary EPT%, SPEAR(pesticide) and the Principal Response Curve methodology proved to be sensitive to this kind of stress, providing comparable results. Temporal trends of these metrics proved to be related to the concentration of chemicals. Remarkably, the first Principal Response Curve illustrates the trend followed by the most vulnerable species, while the second is more related to the trend of opportunistic species. A high potential risk for the invertebrate community was highlighted by a statistically significant decline of 40 points (comparison with the control) in both SPEAR(pesticide) and EPT%.

Glacial retreat creates new habitat which is colonized and developed by plants and animals during the process of primary succession. While there has been much debate about the relative role of deterministic and stochastic processes during terrestrial succession, evidence from freshwater ecosystems remains minimal and a general consensus is lacking. Using a unique 27 years record of community assembly following glacial recession in southeast Alaska, we demonstrate significant change in the trait composition of stream invertebrate communities as catchment glacial cover decreased from ∼70% to zero. Functional diversity increased significantly as glacier cover decreased and taxonomic richness increased. Null modelling approaches led to a key finding that niche filtering processes were dominant when glacial cover was extensive, reflecting water temperature and dispersal constraints. Thereafter the community shifted towards co-occurrence of stochastic and deterministic assembly processes. A further novel discovery was that intrinsic functional redundancy developed throughout the study, particularly because new colonizers possessed similar traits to taxa already present. Rapid glacial retreat is occurring in Arctic and alpine environments worldwide and the assembly processes observed in this study provide new fundamental insights into how glacially influenced stream ecosystems will respond. The findings support tolerance as a key primary successional mechanism in this system, and have broader value for developing our understanding of how biological communities in river ecosystems assemble or restructure in response to environmental change.

Recent and increasing interest in tempo- rary ponds as biodiversity reservoirs fosters our need to test sampling techniques for characterising their biological communities. We compared the efficiency of dip-netting to that of fyke nets in sampling the macroinvertebrate assemblage of a temporary pond in Don˜ ana National Park (SW Spain). We sampled the pond at four different times—morning, afternoon, evening and night—distinguishing between deep and shallow zones. In our sampling, dip-netting captured a higher number of taxa, and higher abundances of individuals than fyke nets. However, both techniques captured exclusive taxa, not recorded with the other device. Fyke nets distinguished between nocturnal and diurnal macroinvertebrates, and hence are more appropriate to study macroinvertebrate diel activity. We detected nocturnal activity in Gerris thoracicus larvae, and adults of Colymbetes fuscus, Rhantus suturalis, Rhantus hispanicus and Hydrochara flav- ipes. Conversely, larvae of Sympetrum fonscolombei and Notonecta spp., and adults of Notonecta glauca were mainly diurnal. The overall diel activity pattern of the macroinvertebrate assemblage depended on the diel activities of their integrating taxa and stages. Although dip-netting was more appropriate to sample macroinvertebrate assemblages in different micro- habitats, fyke nets better captured nocturnal and fast- swimming invertebrates. Consequently, the joint use of both sampling techniques would capture a better picture of the representative macrofauna of a tempo- rary pond than either one on its own

Purpose Approaches in environmental risk assessment for pesticides are becoming more and more realistic. Thereby, risk assessment has to be protective in a way that no long-lasting (adverse) effects on populations will occur in the environment. Since this imperative includes species generally showing high population vulnerability due to their life history traits, prospective risk assessment should be based on realistic worst cases. Based on life history traits, the purpose of the current study was to verify whether a worst case combination of low potential for intrinsic recovery and low ability for recolonisation can be found in the field. Methods Combinations of traits related to dispersal ability and reproduction of macroinvertebrates were investigated using monitoring data from edge of field water bodies in Germany. The relative distribution of traits was analyzed across different agricultural regions and across sites of different potential for exposure to pesticides. Species were sorted in a tiered approach in order to gain a list of realistic worst case species. Results Life history traits were found equally distributed across different regions. Thereby, dispersal ability and voltinism were not randomly combined. Within the data analysed, low dispersal ability was found to be exclusive to semivoltine taxa. Owing to their appearance in reference sites, poor dispersal ability and a long time reproduction, three species were considered potentially worst case. Conclusions The trait approach was found to be suitable in comparing trait distributions within different regions and in compiling a list of critical taxa for consideration in environmental risk assessment.

In the present work, based on material from several localities in Brazil, we present a contribution to the taxonomy of the Terpides lineage, a monophyletic group of Neotropical mayflies that encompasses three genera: Terpides, Tikuna, and Fittkaulus. A new species of Terpides is described from the States of Espírito Santo and Mato Grosso, based on nymphs, male and female imagos. The male imago of the type species of Terpides, T. guyanensis, the nymph and male imago of Tikuna bilineata, and the nymph of Fittkaulus cururuensis are described for the first time. © EDP Sciences, 2009.

The general aim of this work has been to check the ecological impact of metals on the Ebro river basin. In order to evaluate this, metal behavior considering water, sediment as well as metal bioaccumulation in fish has been studied. Total concentrations of metals, as well as the potentially bioavailable fraction of metals in sediment has also been analyzed by the application of the sequential extraction method (BCR method). In order to evaluate the influence of metal pollution on the river ecological status, according to the Water Framework Directive (WFD), diverse biological indices such as macroinvertebrates (IBMWP), diatoms (IPS) and macrophytes (IVAM), have been considered from an integrated point of view. Considering both water and sediment, metals which contributed in higher extend to the reduction of biological quality have been demonstrated to be Pb and Zn, as they presented a negative influence on macroinvertebrates, diatoms and macrophytes communities. As and Cr that seemed to have a significant influence on macroinvertebrates and diatoms too, while Ni negatively influenced only diatom communities. This study also demonstrated that monitoring programs only based on total metal determination in water are inefficient, as metals present even at undetectable concentrations in water are strongly accumulated in fish. Moreover, the high concentrations of Hg found in sediments indicated that this river basin may present pollution problems regarded to this metal, as demonstrated by the high Hg levels found in fish., This study was funded by the Spanish Ministry of Economics and Competitiveness through the project Scarce (Consolider-Ingenio 2010 CDS2009-00065).

Land-use practices have long been associated with alterations in stream ecosystem structure and function, however, 'exurbanization' and its impact on streams is poorly understood. This study compares the ecosystem structure and function of 9 southern Appalachian streams of differing land-use (forested, exurban, agricultural). Impacts of land-use on leaf breakdown are examined in Chapter 1. Leaf breakdown rates were significantly related to land-use. Forested streams exhibited the slowest breakdown rates, followed by exurban streams, with agricultural streams having the fastest rates. Leaf breakdown was most strongly related to discharge (white oak) and some fine sediment metrics (red maple). Our results suggest that the altered hydrological regimes in agricultural streams, as well as the influx of fine sediments into streams from exurban development, can play a role in altering in-stream organic matter processing. The taxa and number of shredders present may play a role to a lesser extent. Impacts of land-use on macroinvertebrate assemblages are examined in Chapter 2. Shannon diversity, %EPT, and NCBI were significantly related to land-use regime. There were significant negative relationships between macroinvertebrate diversity and conductivity and temperature. In addition, biotic integrity had a significant negative relationship with conductivity. Canonical Correspondence Analysis (CCA) showed that agricultural streams were characterized by temperature and flow, forested streams by MPS and standing stock course particulate organic matter (SSCPOM), and two of three exurban streams by conductivity and temperature. Principal Coordinates Analysis (PCoA) revealed that while macroinvertebrate communities overlapped, some differences in community assemblage could be seen between land-use types. Master of Science

The UK River Habitat Survey (RHS) method for the assessment of hydro-morphological features was applied within the EU STAR project simultaneously with the collection of biological data. A subset of data from 79 sites affected by hydro-morphological alteration and belonging to 7 different stream types was analysed. The different features recorded within RHS were evaluated separately considering the characteristics associated with banks, channel and riparian zone. Different scores were assigned to selected features representing hydro-morphological alteration and naturalness of habitat. The ability of the different compartments to represent the quality gradient of sites was investigated. In addition, the link between macroinvertebrate community and hydro-morphological data was investigated, directly relating indices and metrics calculated from taxa list collected in a site to scores assigned to the RHS features. The sections highly affected by morphological alteration were channel geometry and bank profile. Metrics showing the best correlation with the features selected were EPT taxa, ASPT and ICMi (Inter-calibration Common Metric index). Among the indices studied, the HQA score (Habitat Quality Assessment) apparently played the most important role in structuring biological communities and the lentic-lotic character of rivers was also important.

Muitas espécies de Ephemeroptera são conhecidas somente em um estágio, normalmente adulto ou ninfa. Nesse estudo é proposto uma metodologia para transporte e criação de ninfas em campo Rearing and Transport of Mayfly Nymphs in the Field Abstract. Many species of Ephemeroptera are known in only one phase, adult or nymph. In this study, we propose a methodology for transport and rearing nymphs in the field.

The cycling of nutrients is a fundamental process in streams and rivers, and scientists are increasingly recognizing the importance of animal communities to nutrient dynamics in these ecosystems. Despite growing evidence that animal excretion (i.e. urine) can supply limiting nutrients to primary producers in small streams, the importance of excretion is uncertain in large rivers. Accordingly, I used three estimation approaches based on past and new excretion rate data to determine nitrogen (N) and phosphorus (P) excretion inputs from insect communities in four large rivers (discharge > 10 cubic meters per second) in North America, and I compared these rates to both the total demand for nutrients by primary producers and background nutrient levels. Additionally, I compared the ratio of excreted nutrients (N:P) to water nutrient limitation (N-limitation or P-limitation) to understand whether excretion by insects could serve as a potential source of limited nutrients to free-floating primary producers in large river ecosystems. Across all three estimation approaches, total insect community N excretion rates ranged from 18.9 to 1070.1 ��g N m-2 hr-1, while community P excretion rates ranged from 16.3 to 378.7 ��g P m-2 hr-1. Across all rivers and estimation approaches, community N and P excretion was equal to 0.7 to 32.4% and 0.1 to 6.0% of total N and P demand, respectively. Additionally, excreted N and P was equivalent to 0.5 to 62.3% and 0.2 to 5.5% of background N and P levels, respectively. Excreted N:P ratios suggested that excretion may serve as an important pathway in the alleviation of nutrient limitation for some primary producers in large rivers, although additional research will be required. Compared to smaller stream ecosystems, in which animal excretion can supply >50% of total N demand, and also match > 100% of background N levels, insect excretion appears to play a smaller role in nutrient dynamics of large rivers, although excretion may contribute significantly in rivers with high animal biomass and low background nutrient levels, as for N in the North Platte River in this study.

Comprehensive research on the structural and functional variability of benthic macroinvertebrate communities within headwater streams is limited, despite the fact that the majority of streams within a watershed are headwater streams that form the primary link between terrestrial and aquatic ecosystems. Therefore, we investigated the structure and function of benthic macroinvertebrate communities in four headwater streams at two different spatial scales (i.e., sampling sites (i.e., reaches) >samples (i.e., riffles)) over three seasons (i.e., spring, summer and autumn) of the year. Community indices, functional feeding guilds and habit trait guilds varied significantly depending on the seasons rather than on sites in two-way ANOVA based on spatial (i.e., sampling sites) and seasonal effects in each headwater stream. Non-metric multidimensional scaling analyses showed the differences between communities according to the considered spatial and temporal scales. At the individual stream scale, the differences between samples followed seasonal variation more than spatial differences. Site differences became more important when performing an ordination within a single season (i.e., spring, summer, and autumn). Continued research and monitoring employing both multidisciplinary and multidimensional approaches are required to maintain macroinvertebrate diversity within headwater streams.