Reservoir operations alter, eliminate or restrain the natural hydrologic cycles. Biotic community has become subject to these non-cyclic events, responding by reducing the species diversity. Ephemeroptera species present distinct responses to environmental deterioration such that poses this assemblage between the most useful groups in biomonitoring programs. We hypothesized an alteration in beta diversity at the longitudinal species gradient, which will be influenced mainly by species losses between zones. Changes in temporal beta diversity is also expected, but the main drivers of such alterations will be the species turnover between the sampling period. Ephemeroptera community was monitored in nine sampling points from Itaipu Reservoir, where were installed three sets of substrates composed by a float and 2 wooden substrates. We took biological samples in triplicates monthly, from June-01 to August-02. Our initial hypothesis was partially supported and with significant variations only for spatial approach, between the Reservoir zones. The generated ordering from Non-Metric Dimensional Scale – NMDS - corroborated with spatial analyzes, with the formation of two groups along the gradient zonation of the reservoir. The temporal ordination showed no clear pattern. As expected, the contribution to beta diversity was different for our two approaches, such that the loss of species was more important along the spatial gradient and despite of no significant result, the species replacement was more important among months. The spatial results lead us to infer that differences in limnological characteristics between zones are important for determining differences in Ephemeroptera composition and can reflect the dependency degree of the species in relation to the lentic and sometimes-lotic conditions, mainly in the riverine zone of reservoirs. On the other hand, the absence of a temporal pattern can be result of chaotic variations in the physical and chemical attributes imposed by the reservoir operation, disrupting continuity of the biota and natural succession processes.

Aim Wetland areas have high environmental complexity and support high biodiversity. Therefore, global efforts are required to preserve these areas. Here, we show the results of three decades of monitoring programs regarding macroinvertebrate species from the upper Paraná River floodplain, which is an important wetland conservation area in the neotropics. Methods We searched the literature from 1990 to 2020 and selected studies that addressed questions related to benthic or macrophyte-associated macroinvertebrates in the study area. Results We retained 92 articles that matched the criteria. We noticed that the number of publications increased after 2009, and most studies were related to lentic environments. Sediment was the most studied substrate, showing the highest taxa record and diversity, followed by aquatic macrophytes. We found records of 517 taxa, from which the families Chironomidae, Cyprididae, and Naididae presented the highest taxonomic richness. The taxa richness observed in our study was lower than the bootstrap richness estimated. Conclusions The lack of signs of curve stabilisation through time for both observed and estimated taxa richness could indicate the macroinvertebrate richness from the upper Paraná River floodplain must be underestimated. In this way, once most of the studies reported results related to long-term ecological research, we argue for the continuity of such studies in floodplains as a powerful tool to assess biodiversity, which can provide useful data for the creation of conservation strategies that enhance the maintenance of biodiversity in such areas.

We present a novel approach to structure and interpret long-term environmental monitoring data, by combining the Adverse Outcome Pathway (AOP) concept with probabilistic causal modeling. We applied this framework to a monitoring program following the 2015 tailings dam collapse in southeastern Brazil. Six years of data (2018-2024) spanning river-to-sea gradients included dissolved metal(loid)s, fish bioaccumulation, and sub-individual biomarkers. Metal(loid)s in water were first integrated into an index representing spatial variation in toxic pressure. Within the AOP framework, biomarkers of antioxidant defense, oxidative damage, and tissue injury were linked to a growth-related outcome using piecewise structural equation mixed-effects models, accounting for species-level and temporal variability. Toxic pressure was consistently higher in the river and decreased towards the sea. Biomarker responses reflected these gradients: in the river, metallothionein, lipid peroxidation, and histopathological lesions were strongly associated with toxic pressure and specific metals, whereas in marine environments, responses were weaker and more variable. Across models, species and temporal variability accounted for a substantial share of explained variance, highlighting the importance of mixed-effects approaches to unravel biological heterogeneity. Lesions were consistently linked to oxidative stress and, in the freshwater, negatively associated with fish condition index, suggesting that tissue-level damage can scale up to growth impairment. Overall, responses revealed both expected and unexpected patterns, highlighting the context-dependent nature of defense mechanisms under mixed-metal exposure and the value of integrated approaches to environmental monitoring.

Large-scale disasters can result in chronic pollution of coastal environments with unanticipated and poorly quantified impacts, such as the reshaping of marine connectivity. A recent example is the collapse of the Fundão tailings dam in 2015 that released about 50 million m3 of mine waste into the Doce River, affecting one of Brazil’s largest estuarine–mangrove systems. Here, we combine a high-resolution CROCO hydrodynamic simulation with an individual-based Lagrangian model (Ichthyop) to track the dispersal of mangrove crab (Ucides cordatus) larvae from four estuaries along the southeastern Brazilian margin between 2022 and 2024. Trajectories crossing toxicity fields derived from in situ collections (msPAF, based on species sensitivity distributions) were used to quantify larval exposure to contaminants from mine waste. Results show that surface shelf flow and mesoscale activity in the vicinity of the Doce river mouth contribute to offshore export of larvae, while the reef-dominated Abrolhos shelf promotes retention. Interannual variability alternates between long-distance export and local retention, likely reflecting climate-driven anomalies such as ENSO. Larval mortality rates caused by offshore advection and lethal temperature are high (65–75%), with surviving cohorts frequently crossing high-contamination zones. This suggests that the regional connectivity of U. cordatus is under chronic stress that likely compromises the integrity and resilience of coastal populations, since southern estuaries depend strongly on northern larval sources. The integration of Lagrangian simulations with in-situ contaminant monitoring and spatially explicit exposure metrics demonstrate that transport pathways regulate not only connectivity among estuaries but also the duration and intensity of larval exposure to pollutants.

A partir da exposição de materiais científicos em eventos abertos ao público, o projeto “Resiliência em sistemas socioambientais ribeirinhos na Amazônia” do Programa Amazônia+10, tem exitosamente feito a difusão de informações sobre a correlação entre a importância da conservação do bioma amazônico e os ecossistemas paranaenses. O projeto é desenvolvido em parceria entre docentes e discentes da Universidade Estadual de Maringá, da Universidade Federal do Amazonas, da Universidade Federal de Alagoas e do Instituto Nacional de Pesquisas da Amazônia e, em maio de 2024, participou da Exposição Feira Agropecuária, Industrial e Comercial de Maringá (Expoingá) com uma mostra de materiais sobre rios voadores e comunidades tradicionais ribeirinhas. Ao longo dos 10 dias de evento, cerca de 200 mil pessoas visitaram o pavilhão com a exposição do projeto. Durante as visitas, o público da feira pôde observar os materiais e tirar dúvidas com os discentes voluntários. Dentre as interações, uma pequena parcela do público apresentou conhecimentos prévios sobre os conceitos relacionados às comunidades, a maioria, nativa da macrorregião Norte. Além disso, a maioria do público interessado tinha idade acima dos 30 anos. Ações de divulgação científica como essa, quando realizadas durante grandes eventos, fornecem informações valiosas ao público visitante, que pode levar esse conhecimento para suas cidades, estimulando a criação de iniciativas semelhantes, ampliando o alcance de iniciativas de divulgação científica e ações de conservação ambiental.