Community Structure and Water Quality Assessment of Benthic Macroinvertebrates in Hongze Lake.

This study investigated the species, density, biomass and physicochemical factors of benthic macroinvertebrates in Hongze Lake from 2016 to 2020. Redundancy analysis (RDA) was used to analyze the relationship between physicochemical parameters and the community structure of macroinvertebrates. Macroinvertebrate-based indices were used to evaluate the water quality conditions in Hongze Lake. The results showed that a total of 50 benthic species (10 annelids, 21 arthropods and 19 mollusks) were collected. The community structure of benthic macroinvertebrates varied in time and space. The dominant species were Limnodrilus hoffmeisteri (L.hoffmeisteri), Corbicula fluminea (C.fluminea), Nephtys oligobranchia (N.oligobranchia). In 2016, arthropods such as Grandidierella sp. were the dominant species of benthos in Hongze Lake while annelids and mollusks dominated from 2017 to 2020, such as L.hoffmeisteri, N.oligobranchia, C.fluminea. The benthic fauna of Chengzi Lake and Lihewa District were relatively abundant and showed slight variation, while the benthic macroinvertebrates of the Crossing the water area were few and varied greatly. RDA showed that changes in benthic macroinvertebrate structure were significantly correlated with dissolved oxygen (DO), Pondus Hydrogenii (pH) and transparency (SD). The Shannon Wiener, Pielou, and Margalef indices indicate that Hongze Lake is currently in a moderately polluted state. Future studies should focus on the combined effects of various physicochemical indicators and other environmental factors on benthic communities.

Towards harmonized standards for freshwater biodiversity monitoring and biological assessment using benthic macroinvertebrates.

Monitoring programs at sub-national and national scales lack coordination, harmonization, and systematic review and analysis at continental and global scales, and thus fail to adequately assess and evaluate drivers of biodiversity and ecosystem degradation and loss at large spatial scales. Here we review the state of the art, gaps and challenges in the freshwater assessment programs for both the biological condition (bioassessment) and biodiversity monitoring of freshwater ecosystems using the benthic macroinvertebrate community. To assess the existence of nationally- and regionally- (sub-nationally-) accepted freshwater benthic macroinvertebrate protocols that are put in practice/used in each country, we conducted a survey from November 2022 to May 2023. Responses from 110 respondents based in 67 countries were received. Although the responses varied in their consistency, the responses clearly demonstrated a lack of biodiversity monitoring being done at both national and sub-national levels for lakes, rivers and artificial waterbodies. Programs for bioassessment were more widespread, and in some cases even harmonized among several countries. We identified 20 gaps and challenges, which we classed into five major categories, these being (a) field sampling, (b) sample processing and identification, (c) metrics and indices, (d) assessment, and (e) other gaps and challenges. Above all, we identify the lack of harmonization as one of the most important gaps, hindering efficient collaboration and communication. We identify the IUCN SSC Global Freshwater Macroinvertebrate Sampling Protocols Task Force (GLOSAM) as a means to address the lack of globally-harmonized biodiversity monitoring and biological assessment protocols.

Aquatic insects for monitoring the health status of riverine potholes: A case study in Chalakudy river basin, Kerala, India.

Potholes are microhabitats in riverine ecosystems that substantially contribute to the unique regional faunal diversity and community composition. Investigations on the ecological status of potholes in riverine habitats are very scanty. The present work is of utmost importance, particularly as a pioneering study to evaluate the health status of riverine potholes using aquatic insects as potential biological indicators. Samples of water and aquatic insects were collected and analyzed during the pre-monsoon season from February 2022 to May 2022 in the potholes at Athirappilly and the Ezhattumugham regions of the Chalakudy river basin. The present study identified 208 individuals represented by 15 families in the potholes at Athirappilly, whereas 94 individuals belong to 10 families at Ezhattumugham. The computation of water quality parameters and benthic metrics revealed a significant variation between the stations. Spearman correlation analysis revealed that the water temperature, electrical conductivity, dissolved oxygen concentration, and biochemical oxygen demand were influencing the distribution of aquatic insects in the potholes. Families such as Perlidae, Ephemeridae, Baetidae, Stenopsychidae, and Hydropsychidae (sensitive families) reported from the well-oxygenated potholes at Athirappilly, where the water temperature and biochemical oxygen demand were minimum. The significantly high percentage composition of Ephemeroptera, Plecoptera, and Trichoptera taxa and a low family biotic index value indicate good health condition of the potholes at Athirappilly. In contrast, the low percentage composition of Ephemeroptera, Plecoptera, and Trichoptera taxa and high family biotic index values, with the abundance of tolerant families (Micronectidae, Caenidae, and Chironomidae), reflect the impact of organic pollution at Ezhattumugham.

Assessment of the impacts of GABA and AChE targeting pesticides on freshwater invertebrate family richness in English Rivers.

Globally, riverine system biodiversity is threatened by a range of stressors, spanning pollution, sedimentation, alterations to water flow, and climate change. Pesticides have been associated with population level impacts on freshwater invertebrates for acute high-level exposures, but far less is known about the chronic impact of episodic exposure to specific classes of pesticides or their mixtures. Here we employed the use of the UK Environment Agency's monitoring datasets over 40 years (covering years 1980 to 2019) to assess the impacts of AChE (acetylcholinesterase) and GABA (gamma-aminobutyric acid) receptor targeting pesticides on invertebrate family richness at English river sites. Concentrations of AChE and GABA pesticides toxic to freshwater invertebrates occurred (measured) across 18 of the 66 river sites assessed. For one of the three river sites (all found in the Midlands region of England) where data recorded over the past 40 years were sufficient for robust modelling studies, both AChE and GABA pesticides associated with invertebrate family richness. Here, where AChE total pesticide concentrations were classified as high, 46 of 64 invertebrate families were absent, and where GABA total pesticide concentration were classified as high, 16 of 64 invertebrate families were absent. Using a combination of field evidence and laboratory toxicity thresholds for population relevant endpoints we identify families of invertebrates most at risk in the selected English rivers to AChE and GABA pesticides. We, furthermore, provide strong evidence that the absence of the invertebrate family Polycentropodidae (caddisfly) from one field site is due to exposure effects to AChE pesticides.

Assessing the ecological health of the upper and middle Awash River, Ethiopia, using benthic macroinvertebrates community structure and selected environmental variables.

Research on the Awash River focused on the upper section, while the middle and lower regions received little attention. Thus, the goal of this study was to evaluate the impact of anthropogenic activities on the upper and middle Awash River. The study took place in nine sampling locations in dry and wet seasons from September 2021 to April 2022 using a multi-habitat sampling approach. We used macroinvertebrate metrics, environmental variables, and multivariate analysis to evaluate ecological health. The highest concentrations of NO3, soluble reactive phosphorus, and total phosphorus (0.50-0.93 mg L-1) were recorded at the river-mouth of the upper Awash, while the locations below Metehara had the lowest levels of dissolved oxygen (1.81-2.33 mg L-1). Redundancy analysis indicated that dissolved oxygen, NH3, temperature, NO2, pH, TSS, NO3, and TDS influenced macroinvertebrate distribution. The presence of the sensitive groups Caenidae, Hydropsychidae, Heptageniidae, and Aeshnidae at upstream sites indicated better ecological conditions. The middle and downstream sites supported moderately tolerant and tolerant taxa demonstrating water quality impairment. The lowest Ethiopian biotic score was recorded at the river-mouth of the upper Awash. The study sites below Metehara demonstrated severe ecological impairment since highly tolerant taxa were abundant and had strong correlations with temperature, TSS, and TDS levels. Pollutants from agricultural farms and domestic and industrial wastes from Addis Ababa, Metehara, and Merti towns most likely affect the impaired sites. This study demonstrated that the middle Awash experienced substantial ecological deterioration, indicating the need for restoration works to fit the water for socio-economic development.

A versatile and economical method for collecting macroinvertebrates using Hester-Dendy multiplate samplers.

We present an inexpensive, versatile, and robust mounting system for Hester-Dendy (HD) multiplate samplers that are useful in aquatic biological studies and freshwater biomonitoring programs. Detailed instructions are provided outlining the construction and deployment of a concrete block system featuring threaded anchors for screwing in HD columns in a vertical position. Additionally, eye bolts provide a central attachment point for cabling the block securely to the stream or river bank, and for attachment of a buoy or physiochemical data logger if desired. All the components of the block system are inexpensive, readily available, and assembled with no special skills required. The system offers superior ease-of-use and a more standardized sampling device compared to other methods.

Assessment of the impact of dams on aquatic food webs using stable isotopes: Current progress and future challenges.

Dams have disrupted natural river systems worldwide and although population and community level effects on aquatic biota have been well documented, food web responses remain poorly understood and difficult to characterize. The application of stable isotope analysis (SIA) provides a means to assess the effect of dams on food webs. Here we review the effect of dams on aquatic food webs using SIA, aiming to detect knowledge gaps in the field of dam impacts on aquatic food webs and propose a conceptual framework to help formulate hypotheses about dam impacts on food webs guided by food web theory. Dams can affect aquatic food webs via two pathways: a bottom-up pathway with altered basal food sources and their transfer to consumers through changes in flow, nutrients, temperature and sediment, and a top-down pathway with consumer species composition altered mainly through habitat fragmentation and related physiochemical changes. Taking these mechanisms into consideration, the impact of dams on food web attributes derived from SIA was evaluated. These studies generally apply mixing models to determine how dams alter the dominant carbon sources supporting food webs, use δ15N to examine how dams alter food-chain length, or use Layman metrics of isotope variability to assess niche changes for invertebrate and fish assemblages. Most studies compare the patterns of SIA metrics spatially (e.g. upstream vs reservoir vs downstream of dams; regulated vs unregulated rivers) and temporally (before vs after dam construction), without explicit hypotheses and/or links to theoretical concepts of food webs. We propose several steps to make SIA studies of dam impacts more rigorous and enhance their potential for producing novel insights. Future studies should quantify the shape and strength of the effect of dams on SIA-measured food web response, be conducted at larger temporal and spatial scales (particularly along the river longitudinal continuum and the lateral connected ecosystems (e.g., floodplains)), and consider effects of dams on food web resilience and tipping points.

Fatty-acid based assessment of benthic food-web responses to multiple stressors in a large river system.

Rivers are often exposed to multiple stressors, such as nutrients and contaminants, whose impacts on the river food webs may not be distinguished by sole assessment of biological community structures. We examined the benthic algal assemblages and the fatty acids (FA) of benthic macroinvertebrates in the lower Athabasca River in Canada, aiming to assess the changes in algal support and nutritional quality of the benthic food web in response to cumulative exposure to natural bitumen, municipal sewage discharge (hereafter, "sewage"), and oil sands mining ("mining"). Data show that the decline in water quality (increases in nutrient concentrations and total suspended solids) was associated with decreases in benthic diatom abundance, and was driven mainly by sewage-induced nutrient enrichment. Responses in nutritional quality of benthic macroinvertebrates, indicated by their polyunsaturated FA (PUFA) concentrations, were taxon- and stressor-specific. Nutritional quality of the larval dragonfly predator, Ophiogomphus, decreased nonlinearly with decreasing benthic diatom abundance and was lowest at the sewage-affected sites, although exposure to natural bitumen also resulted in reduced Ophiogomphus PUFA concentrations. In contrast, the PUFA concentrations of mayfly grazers/collector-gatherers were not affected by natural bitumen exposure, and were higher at the sewage and sewage+mining sites. The PUFA concentrations of the shredder Pteronarcys larvae did not change with cumulative exposure to the stressors. Sediment metal and polycyclic aromatic compound concentrations were not associated with the macroinvertebrate FA changes. Overall, we provide evidence that sewage induced reduction in trophic support by PUFA-rich diatoms, and was the predominant driver of the observed changes in FA composition and nutritional quality of the benthic macroinvertebrates. Fatty-acid metrics are useful to untangle effects of concurrent stressors, but the assessment outcomes depend on the functional feeding guilds used. A food-web perspective using multiple trophic levels and feeding guilds supports a more holistic assessment of the stressor impacts.

Research Priorities for the Environmental Risk Assessment of Per- and Polyfluorinated Substances.

Per- and polyfluorinated substances (PFAS) are a group of thousands of ubiquitously applied persistent industrial chemicals. The field of PFAS environmental research is developing rapidly, but suffers from substantial biases toward specific compounds, environmental compartments, and organisms. The aim of our study was therefore to highlight current developments and to identify knowledge gaps and subsequent research needs that would contribute to a comprehensive environmental risk assessment for PFAS. To this end, we consulted the open literature and databases and found that knowledge of the environmental fate of PFAS is based on the analysis of <1% of the compounds categorized as PFAS. Moreover, soils and suspended particulate matter remain largely understudied. The bioavailability, bioaccumulation, and food web transfer studies of PFAS also focus on a very limited number of compounds and are biased toward aquatic biota, predominantly fish, and less frequently aquatic invertebrates and macrophytes. The available ecotoxicity data revealed that only a few PFAS have been well studied for their environmental hazards, and that PFAS ecotoxicity data are also strongly biased toward aquatic organisms. Ecotoxicity studies in the terrestrial environment are needed, as well as chronic, multigenerational, and community ecotoxicity research, in light of the persistency and bioaccumulation of PFAS. Finally, we identified an urgent need to unravel the relationships among sorption, bioaccumulation, and ecotoxicity on the one hand and molecular descriptors of PFAS chemical structures and physicochemical properties on the other, to allow predictions of exposure, bioaccumulation, and toxicity. Environ Toxicol Chem 2023;42:2302-2316. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

A novel approach for the assessment of invertebrate behavior and its use in behavioral ecotoxicology.

Sublethal effects are becoming more relevant in ecotoxicological test methods due to their higher sensitivity compared to lethal endpoints and their preventive nature. Such a promising sublethal endpoint is the movement behavior of invertebrates which is associated with the direct maintenance of various ecosystem processes, hence being of special interest for ecotoxicology. Disturbed movement behavior is often related to neurotoxicity and can affect drift, mate-finding, predator avoidance, and therefore population dynamics. We show the practical implementation of the ToxmateLab, a new device that allows monitoring the movement behavior of up to 48 organisms simultaneously, for behavioral ecotoxicology. We quantified behavioral reactions of Gammarus pulex (Amphipoda, Crustacea) after exposure to two pesticides (dichlorvos and methiocarb) and two pharmaceuticals (diazepam and ibuprofen) at sublethal, environmentally relevant concentrations. We simulated a short-term pulse contamination event that lasted 90 min. Within this short test period, we successfully identified behavioral patterns that were most pronounced upon exposure to the two pesticides: Methiocarb initially triggered hyperactivity, after which baseline behavior was restored. On the other hand, dichlorvos induced hypoactivity starting at a moderate concentration of 5 µg/L - a pattern we also found at the highest concentration of ibuprofen (10 µg/L). An additional acetylcholine esterase inhibition assay revealed no significant impact of the enzyme activity that would explain the altered movement behavior. This suggests that in environmentally realistic scenarios chemicals can induce stress - apart from mode-of-action - that affects non-target organisms' behavior. Overall, our study proves the practical applicability of empirical behavioral ecotoxicological approaches and thus represents a next step towards routine practical use.

Legacy and novel perfluoroalkyl substances in major economic species of invertebrates in South China Sea: Health implication from consumption.

Continuously release of perfluoroalkyl substances (PFASs) would pose non-negligible impacts on environment, organisms, and human health. In present study, 18 PFASs in 7 typical economic invertebrates and their habitats were investigated from the South China Sea. The higher concentrations of PFASs in the nearshore water (6.61-15.54 ng/L) and sediment (0.82-8.84 ng/g) obviously due to frequent human activities. Long-chain PFASs have tendency to accumulate in sediment, however, short-chain PFASs dominated in biota. The acute reference dose (%ARfD) and hazard ratios (HR) of major PFASs in biota were all <100 %, and also below 1, respectively, which means that consumption of PFASs from seafood does not pose risk and threat to human health. However, it should be taken into account that the HR of PFHxA in Mimachlamys nobilis reached 0.82. Potential adverse effects toward human health induced by short-chain PFASs (such as <6 C) via invertebrate seafood consumption should be concerned.

New ecological frontiers in the plastisphere: Diatoms and macroinvertebrates turnover assessment by a traits-based approach.

To date, there are very few studies regarding the colonization of artificial substrates in wetlands by macroinvertebrates and diatoms and even fewer are the studies in Italy that take into consideration the diatomic guilds and the biological and ecological traits proposed in literature. Wetlands are at the forefront through the most delicate and threatened freshwater ecosystems. In this study, we want to evaluate the colonization capacity of plastics of diatoms and macroinvertebrates and characterize the diatomic and macroinvertebrate communities using a "traits-based" approach focusing on the colonization of virgin substrates made of polystyrene and polyethylene terephthalate. The study was conducted within the 'Torre Flavia wetland Special Protection Area' a protected wetland area in Central Italy. The study was conducted from November 2019 to August 2020. The results obtained in this study show a tendency of diatom species to colonize artificial plastic supports placed in lentic environments without differences related to the plastic type and water depth. There is also a greater number of species belonging to the "Motile" guild, endowed with a high motility that they exploit to search for more ecologically suitable habitats for settlement. Macroinvertebrates, prefer settlement on polystyrene supports, those on the surface, probably due to the anoxic conditions present on the bottom and the physical structure of the polystyrene that provides shelter to many animal taxa. The analysis on traits highlighted the establishment of an ecologically diverse community mainly formed by univoltine organisms, with dimensions between 5 and 20 mm, predators, choppers and scrapers feeding on plant organisms and animals, but without the formation of a clear ecological system, that is, without evidence of ecological relationships established between two or more taxa. Our research can contribute to underline the ecological complexity of biota inhabiting plastic litter in freshwaters and the implications for plastic-impacted ecosystems biodiversity enrichment.

Fasting increases investment in soma upon refeeding at the cost of gamete quality in zebrafish.

Fasting increases lifespan in invertebrates, improves biomarkers of health in vertebrates and is increasingly proposed as a promising route to improve human health. Nevertheless, little is known about how fasted animals use resources upon refeeding, and how such decisions affect putative trade-offs between somatic growth and repair, reproduction and gamete quality. Such fasting-induced trade-offs are based on strong theoretical foundations and have been recently discovered in invertebrates, but the data on vertebrates are lacking. Here, we report that fasted female zebrafish, Danio rerio, increase investment in soma upon refeeding, but it comes at a cost of egg quality. Specifically, an increase in fin regrowth was accompanied by a reduction in 24 h post-fertilization offspring survival. Refed males showed a reduction in sperm velocity and impaired 24 h post-fertilization offspring survival. These findings underscore the necessity of considering the impact on reproduction when assessing evolutionary and biomedical implications of lifespan-extending treatments in females and males and call for careful evaluation of the effects of intermittent fasting on fertilization.

Community characteristics of macroinvertebrates and ecosystem health assessment in Qin River, a main tributary of the Yellow River in China.

To know well the ecosystem health status of Qin River, a main tributary of the Yellow River and the largest river in Jincheng region, macroinvertebrates from 49 sampling sites in the Qin River and its largest tributary, the Dan River, were investigated, and community characteristics were analyzed in the autumn of 2020; a Benthic index of Biotic Integrity (B-IBI) was established based on four metrics by a series of steps. The results showed that a total of 38 species of macroinvertebrates were collected and identified, belonging to 6 orders and 19 families, consisting of 17 Insecta species, 13 Gastropoda species, and 4 Oligochaeta species. Four species in Insecta belonged to EPT (E, Ephemeroptera; P, Plecoptera; T, Trichoptera); 10 species in Insecta belonged to Chironomidae and Tipulidae families. All species in Gastropoda belonged to Basematophora order, and, especially, Bellamya aeruginosa is highly tolerant to nutrients. All species in Oligochaetes belonged to Tubificidae family, which indicates eutrophication and low-dissolved oxygen. The dominant species in the study were Ephemera orientalis, Chironomus riparius Meigen, and Limnodrilus claparedianus. The final B-IBI scores varied from 0.75 to 3.75, with 5 sites in "excellent," 10 sites in "good," 10 sites in "normal" status, 12 sites in "poor" status, 12 sites in "very poor." "Very poor" and "poor" sites were mainly located in the middle reach of the Qin River and upper-middle reach of the Dan River in Jincheng region. B-IBI strongly differentiated the reference sites and impaired sites, suggesting the suitability of the B-IBI in the Qin River basin. Significantly negative correlations between NH4+-N, TN, and B-IBI indicated the B-IBI characterized well the influence of nitrogen pollution.

Toxicity and risk management of oil-spiked sediments by diluted bitumen for two freshwater benthic invertebrates.

Diluted bitumen (dilbit) is an unconventional oil produced by the oil sands industry in Canada. Despite the knowledge available on hydrocarbon toxicity, the effects of diluted bitumen on benthic organisms are still largely unknown. Moreover, in Quebec there are only provisional threshold values of 164 mg/kg C10-C50 for chronic effects and 832 mg/kg for acute effects. The protectiveness of these values for benthic invertebrates has not been tested for heavy unconventional oils such as dilbit. Two benthic organisms, the larvae of Chironomus riparius and Hyalella azteca, were exposed to these two concentrations and to an intermediate concentration (416 mg/kg) of two dilbits (DB1 and DB2) and a heavy conventional oil (CO). The aim of the study was to assess the sublethal and lethal effects of spiked sediment by dilbit. The oil was rapidly degraded in the sediment, especially in the presence of C. riparius. Amphipods were much more sensitive to oil than chironomids. LC50-14d values for H. azteca were 199 mg/kg C10-C50 for DB1, 299 mg/kg for DB2 and 8.42 mg/kg for CO compared to LC50-7d values for C. riparius of 492 mg/kg for DB1, 563 mg/kg for DB2 and 514 mg/kg for CO. The size of the organisms was reduced compared to controls for both species. The defense enzymes (GST, GPx, SOD and CAT) were not good biomarkers in these two organisms for this type of contamination. The current provisional sediment quality criteria seem too permissive for heavy oils and should be lowered.

Assessment of the biological water quality and response of freshwater macroinvertebrates to thermal stress in an Afrotropical warm spring.

Freshwater macroinvertebrates have been widely used as environmental stress indicators. However, information on their response to natural thermal stress is relatively scarce, particularly in the tropics. Using the multimetric macroinvertebrate approach, the biological water quality of the warm and cold springs of the Ikogosi Warm Spring in Nigeria was evaluated, with a view to ascertaining the response of freshwater macroinvertebrates to natural thermal stress. Macroinvertebrates and water samples were collected from the warm (stressed) and cold (less-stressed) springs, as well as the confluence stream, within the renowned Ikogosi Warm Spring of Southwest Nigeria. The less-stressed cold spring had much more dissolved oxygen than the warm spring and other thermally stressed stations but less than the warm spring and other thermally stressed stations for water temperature, electrical conductivity, total dissolved solids, Ca2+, Mg2+, and water hardness. Generally, the macroinvertebrate taxonomic richness (30 species) and EPT richness (3 species) of the Ikogosi Warm Spring indicated an impaired freshwater system. Using the multimetric macroinvertebrate index (MMI), the warm spring was of poor biological water quality while the cold spring was of good biological water quality. At the confluence of both springs, the MMI declined to poor and moderate water quality. Although the thermal stress of the Ikogosi Warm Spring is natural, the government should take the necessary steps to regulate tourist activities so that the site's naturalness is preserved and the water quality is not further degraded on account of human-induced stressors such as deforestation, waste dumping, and washing activities.

A Multi-Community Approach in Biodiversity Assessment of a Peat Bog in the Southern Carpathians (Romania) and Implications for Conservation.

Although natural peatlands have been recognized as an important type of wetlands because they support high biodiversity and provide important ecosystem services, the value of peatlands both in biodiversity research and conservation is still largely underestimated. Our study characterizes the biodiversity and conservation value of Pesteana peat bog, an upland mesotrophic peat bog, located in the Southern Carpathians, Romania. More specifically, we: (1) characterized the invertebrate (i.e., top soil, surface litter, and plant-dwelling) and plant communities along a humidity gradient in Pesteana peat bog and nearby habitats (i.e., treeline, ecotone, lowland and highland meadow, and forest), (2) assessed the main environmental factors driving the invertebrate community diversity and composition, and (3) determined the relationship between invertebrate community diversity and vegetation, focusing on the top soil invertebrates. Our study revealed a high diversity of invertebrates spanning over 43 taxonomic groups and a high number of plant indicator species, emphasizing the role of natural peatlands in preserving diverse communities in a small area. The results showed that the composition of top soil invertebrate community was determined by depth of organic layer, vegetation cover, and soil compaction. We found that the diversity of top soil invertebrate community was strongly influenced by habitat type and soil attributes and weakly by vegetation. Overall, the invertebrate and plant communities showed different responses to habitat conditions along the humidity gradient. This highlights the importance of using a multi-community approach to support the design of effective conservation and management actions beneficial for a wide range of taxa.

Are standard aquatic test species and methods adequate surrogates for use in environmental risk assessment of pesticides in tropical environments?

In regulatory risk assessment, surrogate species of fish, aquatic invertebrates, and primary producers are tested to assess toxicity and subsequently the risk of pesticides to freshwater biota. This study evaluates whether the standard, surrogate test species (mostly temperate in latitudinal distribution) used in many parts of the world are suitable surrogates for first-tier risk assessments involving tropical freshwater biota. Data for the toxicity of pesticides to tropical fish, invertebrates, and primary producer species were extracted from the USEPA ECOTOX database and peer-reviewed literature. For each pesticide, the most sensitive regulatory endpoint extracted from the US Environmental Protection Agency (USEPA) and European Food Safety Authority (EFSA) dossiers for freshwater fish, invertebrates, and primary producers was selected. The ratios of the endpoint for tropical species and for the most sensitive regulatory endpoint for the appropriate taxonomic group were determined. A value >1 indicates that the tropical species is less sensitive than the respective standard regulatory species. Tropical fish species were less sensitive than standard fish species in 84% of the comparisons, and in 93.5% of the comparisons, tropical fish were less or similarly sensitive (within a factor of 5). For aquatic invertebrates, 78.1% of the evaluated tropical species were less sensitive than standard species and 93.3% of tropical invertebrates species were less or similarly sensitive. For primary producers, 96% of tropical species were less sensitive than standard test species. Overall, standard species used globally were more sensitive or similarly sensitive compared to tropical species in more than 93% of the cases. In conclusion, the data show that freshwater toxicity data for pesticides from tests using standard test species, tested according to international accepted guidelines, are appropriate for use in first-tier risk assessments for tropical environments. Integr Environ Assess Manag 2023;19:202-212. © 2022 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Fish and macroinvertebrate assemblages reveal extensive degradation of the world's rivers.

Rivers suffer from multiple stressors acting simultaneously on their biota, but the consequences are poorly quantified at the global scale. We evaluated the biological condition of rivers globally, including the largest proportion of countries from the Global South published to date. We gathered macroinvertebrate- and fish-based assessments from 72,275 and 37,676 sites, respectively, from 64 study regions across six continents and 45 nations. Because assessments were based on differing methods, different systems were consolidated into a 3-class system: Good, Impaired, or Severely Impaired, following common guidelines. The proportion of sites in each class by study area was calculated and each region was assigned a Köppen-Geiger climate type, Human Footprint score (addressing landscape alterations), Human Development Index (HDI) score (addressing social welfare), % rivers with good ambient water quality, % protected freshwater key biodiversity areas; and % of forest area net change rate. We found that 50% of macroinvertebrate sites and 42% of fish sites were in Good condition, whereas 21% and 29% were Severely Impaired, respectively. The poorest biological conditions occurred in Arid and Equatorial climates and the best conditions occurred in Snow climates. Severely Impaired conditions were associated (Pearson correlation coefficient) with higher HDI scores, poorer physico-chemical water quality, and lower proportions of protected freshwater areas. Good biological conditions were associated with good water quality and increased forested areas. It is essential to implement statutory bioassessment programs in Asian, African, and South American countries, and continue them in Oceania, Europe, and North America. There is a need to invest in assessments based on fish, as there is less information globally and fish were strong indicators of degradation. Our study highlights a need to increase the extent and number of protected river catchments, preserve and restore natural forested areas in the catchments, treat wastewater discharges, and improve river connectivity.

Anchor scour from shipping and the defaunation of rocky reefs: A quantitative assessment.

Anchor scour from shipping is increasingly recognised as a global threat to benthic marine biodiversity, yet no replicated ecological assessment exists for any seabed community. Without quantification of impacts to biota, there is substantial uncertainty for maritime stakeholders and managers of the marine estate on how these impacts can be managed or minimised. Our study focuses on a region in SE Australia with a high proportion of mesophotic reef (>30 m), where ships anchor while waiting to enter nearby ports. Temperate mesophotic rocky reefs are unique, providing a platform for a diversity of biota, including sponges, ahermatypic corals and other sessile invertebrates. They are rich in biodiversity, provide essential food resources, habitat refugia and ecosystem services for a range of economically, as well as ecologically important taxa. We examined seven representative taxa from four phyla (porifera, cnidaria, bryozoan, hydrozoa) across anchored and 'anchor-free' sites to determine which biota and which of their morphologies were most at risk. Using stereo-imagery, we assessed the richness of animal forest biota, morphology, size, and relative abundance. Our analysis revealed striking impacts to animal forests exposed to anchoring with between three and four-fold declines in morphotype richness and relative abundance. Marked compositional shifts, relative to those reefs that were anchor-free, were also apparent. Six of the seven taxonomic groups, most notably sponge morphotypes, exhibited strong negative responses to anchoring, while one morphotype, soft bryozoans, showed no difference between treatments. Our findings confirm that anchoring on reefs leads to the substantial removal of biota, with marked reductions of biodiversity and requires urgent management. The exclusion of areas of high biological value from anchorages is an important first step towards ameliorating impacts and promoting the recovery of biodiversity.