Abstract Information on the life cycle and spatio-temporal dynamics of an individual invertebrate species is essential for understanding the structure and functions of stream ecosystems. Limnocentropus insolitus is a unique caddisfly species, the larvae of which bear a case with a characteristic silken stalk adhered to substratum, float in the water column, and capture drifting insects and other organic materials in mountainous streams. We clarified the life cycle, larval microdistribution, seasonal changes in larval density, and temporal patterns in drift propensity for this species. The studied population of L . insolitus was univoltine; larvae hatched in early summer, and adults emerged in late spring. Mean larval density was higher in emerged boulders that partially protruded from the water surface than in other microhabitat types when precipitation and discharge were high. The emerged boulders may provide the most suitable microhabitat during high-flow events. The larvae drifted actively and often exhibited diurnal peaks in the drift, possibly to minimizing predation risk from nocturnal fish. The drift propensity increased in summer, when larvae developed rapidly, and may need to address an increasing demand for suitable places to capture prey effectively. Larval density decreased temporally in late summer, coinciding with high discharge. It did not show noticeable changes during winter. Our findings provided some insight into when and where L . insolitus is functionally significant in a stream ecosystem.

The Amazon, home to the planet’s greatest biodiversity, faces increasingly intense and frequent degradation due to land-use changes and land conversion. These actions, although dominant in terrestrial systems, have a severe impact on aquatic ecosystems, which are closely dependent on surrounding landscapes, particularly riparian vegetation. Given this scenario, this study evaluated the influence of forest loss on environmental conditions and Ephemeroptera (Insecta) diversity in 21 streams of the Guaporé River basin, Rondônia, Brazil. Using 1-km buffer zones around watersheds, we classified the forest cover gradient based on existing forest percentages and analyzed habitat structure, water physicochemical parameters, and stream dimensions (width, canopy cover, and depth). Results showed that forest loss significantly increased stream depth and had a negative impact on canopy cover. Contrary to our initial hypothesis, genus richness was positively correlated with forest loss, with 33% of the variance in genus richness explained by the quadratic regression model, indicating a non-linear relationship. However, abundance was unaffected by land-use gradients. Distance-based redundancy analysis (db-RDA) revealed that 55% of the variation in Ephemeroptera genus distribution was explained by restrictive environmental variables (e.g., turbidity, water temperature, depth, discharge, and canopy cover), highlighting their role in community structuring. These findings demonstrate that forest degradation alters habitat structure and the composition of Ephemeroptera communities, with potential consequences for the health of aquatic ecosystems. Forest restoration in altered areas and conservation in less impacted ones is urgently needed to ensure water quality and biodiversity preservation.

Cyanobacterial blooms affect zooplankton feeding due to mechanical (blooms) and chemical interference (cyanotoxins). In Lake Zumpango, the frequency of toxin-producing cyanobacterial consortia has increased in the last decade due to elevated nutrient loads and higher average water temperature. Here, we evaluated the combined effects of crude cyanobacterial extracts from Lake Zumpango and temperature on the demography of Ceriodaphnia dubia. We conducted tests to estimate the median lethal concentration using eight proportions of diluted crude extracts containing microcystin-LR at 12.6, 18.9, 25.3, 31.6, 37.9, 44.2, 50.6, and 56.9 µg L− 1 and three temperatures (18, 23, and 30 ± 1 °C). Toxicity tests (population growth and life table) were conducted using sub-lethal concentrations (1.4, 2.9, 5.8, and 8.8 µg L− 1) at the above-mentioned temperatures. The LC50 results ranged from 18.10 to 38.13 µg L− 1 eq MC. The population growth rates ranged from 0.06 to 0.20 d− 1. At all temperatures, the growth rate of C. dubia exposed to crude extracts with 5.8 and 8.8 µg L− 1 was significantly lower than the controls. The life table experiments indicated that the combined effects of temperature and the cyanobacterial extract resulted in a 25% decrease in the survivorship as compared to controls. During blooms, which are more prevalent in warm (> 20 °C) conditions, cyanobacteria decompose and cyanotoxins are liberated into the medium. This research contributes to understanding the combined effect of toxin-producing cyanobacteria and temperature on cladocerans, and implications under warmer conditions.

Abstract The Tocantins–Araguaia Basin, one of the largest and most ecologically significant watersheds in South America, harbors high biodiversity and provides essential ecosystem services. This study offers a comprehensive assessment of the scientific literature on the Tocantins–Araguaia River Basin using automated content analysis. We compared publication trends and research topics across major Brazilian river basins and applied Structural Topic Modeling (STM) to identify dominant themes, their relationships, and temporal dynamics in studies focused on the Tocantins–Araguaia Basin. Publication trends showed a steady increase in scientific output across all basins, with the Amazon and Paraná accounting for the highest number of papers. Keyword analysis revealed distinct thematic profiles, with research terms for the Tocantins–Araguaia Basin closely resembling those of the São Francisco Basin, both emphasizing aquatic biodiversity, hydropower, and land-use change. For the Tocantins–Araguaia Basin specifically, STM identified ten main research themes, with “Fish Morphology” and “Aquatic Communities” being the most frequent. Topics such as “Biodiversity & Fossils”, “Dams & Fisheries”, and “Agricultural Practices” showed high lexical overlap with other themes, indicating broader thematic integration. Temporal analyses revealed the growing prominence of applied and interdisciplinary themes, such as “Aquatic Communities”, “Agricultural Practices”, and “Land Use & Cerrado”, reflecting global scientific priorities in biodiversity conservation and water management. Despite increased scientific output, topics such as invasive species and eDNA remain underrepresented. The analytical framework applied here provides a transferable approach for identifying research trends and gaps in other understudied regions.