Among mayflies, Baetidae are often considered as easy to recognise at the family level, but difficult to identify at lower level. In several faunistic or ecological studies, the identification remains at the family level; Baetidae are generally considered as widespread and ubiquitous, therefore as poorly informative for ecological studies or bioassessments. Here, a straightforward identification key is offered to larvae of the ten genera of Baetidae reported from Maghreb based on easily observable and understandable characters. The diversity, ecology, and distribution of each taxonomic unit (genera or subgenera) are discussed and the main difficulties for deeper identification are pointed out. Future challenges and remaining taxonomic riddles for Maghrebian Baetidae are detailed.

Ecdyonurus aurasiussp. nov., a micro-endemic species reported from several streams within the Aurès Mountains (north-eastern Algeria), is described and illustrated at nymphal, subimaginal and imaginal stages of both sexes. Critical morphological diagnostic characters distinguishing the new species are presented, together with molecular affinities as well as notes on the biology and distribution of the species.

A new species, Baetis (Baetis) dihyaesp. nov., belonging to the Baetis alpinus species group, is described and illustrated based on larval material collected in the Aurès Mountains (northeastern Algeria) in 2020–2021. This new species is closely related to three European species, e.g., Baetis (B.) alpinus (Pictet, 1843); B. (B.) nubecularis Eaton, 1898; and B. (B.) pasquetorum Righetti & Thomas, 2002 by the combination of the following characteristics: (i) more than one short, stout bristle at the tip of segment II of the maxillary palp and (ii) a well-developed paracercus. However, the new species clearly differs from all congeners of the Baetis alpinus species group primarily by the (a) structure of mouthparts—with 14–18 long submarginal setae arranged in a single irregular row on the dorsal surface of the labrum; 2–6 short, stout bristles at the tip of segment II of the maxillary palp; and segment II of the labial palp without a considerably developed apico-internal lobe); (b) setation of abdominal terga, with a few triangular-shaped scales sparsely scattered near the posterior margin only; and (c) a well-developed paracercus, comprised of more than 50 segments. Primary data on the biology and distribution of this new species are provided, and molecular affinities are verified by the analysis of COI (barcode) sequences. Detailed notes on the distribution of mayfly species belonging to the Baetis alpinus species group common in Western Europe and the western part of North Africa are presented. The historical movement of Baetis representatives between Europe, North West Africa, and subsequently Algeria, with the land bridges ‘Strait of Gibraltar’ and ‘Strait of Sicily’ as colonization routes, is discussed in detail and identified in the present study as the Western Algeria colonization path and Eastern Algeria colonization path, respectively.

With climate change escalating to global proportions over the past decade, along with a growing population, methods are being sought to help the natural and cultivated environment function in an ecologically balanced manner. Over the past few years, there has been a significantly increased interest in research on the use of natural substances for sustainable agriculture and horticulture. One of the most effective solutions to the emerging need is biochar, which has been the subject of environmental research for years due to its potential to increase soil carbon sequestration, reduce greenhouse gas emissions, remediate contaminated soil, and alleviate anthropogenic pressures. There is evidence of improved soil fertility and increased crop yields in agricultural production after biochar application. Our work comprehensively describes the effects of biochar on soil properties, crop productivity, and mitigating environmental stresses, and its remediation potential in heavy metal-contaminated soils. We analyzed a wide range of the literature on the most important properties of biochar for various potential uses. We summarized the results of research work over the past two decades to analyze soil and plant responses to biochar application.

Heavy metal and microplastic pollutions are prevalent in freshwater ecosystems, with many freshwater bodies being contaminated by one or both of these pollutants. Recent studies reported extreme detections of Cd, Pb and Zn, high concentrations of Cr, Pb and Cu and microplastics acting as vectors of pollutants, including heavy metals. Mayflies can serve as bioindicators of heavy metal contamination in freshwater ecosystems because changes in their community structure, physiology, and behaviour can reflect and help predict the concentrations of metals in these environments. This review discusses the ecological alterations induced by tissue metal concentration in mayflies and other macroinvertebrates. As sensitive taxa to heavy metal contamination, mayflies can reflect the impacts of this pollution through their ethology and relationship to the substrate, highlighting issues such as eutrophication, alterations in community structure, inhibitory effects and sediment toxicity. Mayflies are also highly affected by microplastic exposure, which leads to ingestion, bioaccumulation, biomagnification, habitat and community alteration, behavioural changes, physiology alteration and toxicity. Mayflies bioindication metrics for assessing the impact of heavy metals and microplastics include the examination of community alteration, functional feeding behaviour, molecular structure, dietary and toxicity impacts, bioaccumulation and biomagnification and biomarkers. Current challenges for the utilization of mayflies as bioindicators include temporal variations in sensitivity, lack of universally recognised protocols and need for standardised protocols for microplastic analysis. Additionally, the applicability of mayflies as bioindicators may vary across different ecosystems, emphasising the need for selecting suitable indicators that align with the unique characteristics of the ecosystem.

The Myśla River, a right-bank tributary of the Oder catchment, was the focus of our study on the impact of environmental parameters on macrozoobenthos diversity and composition. We surveyed 18 sites along the Myśla catchment, from upstream to the outlet, recording environmental features and sampling macrozoobenthos. The taxa composition (31 taxa) was dominated by insect larvae, particularly Diptera Chironomidae, with moderate contributions from mollusc families such as Sphaeriidae, Bithyniidae, and Planorbidae, which are primarily filter-feeders or grazers. Based on environmental affinities, the river was divided into three sections. Sites within lake areas and those with diverse sediment types exhibited the highest biodiversity. Conductivity, flow rate, nitrogen compound levels, dissolved oxygen, suspended particles, and current velocity most strongly influenced biodiversity, while substrate type shaped taxa composition. Lakes heavily disrupt the ecological continuity of the Myśla River, significantly altering natural ecological processes and causing deviations from the River Continuum Concept (RCC), whereas artificial structures exert only minor additional influence. We examined the applicability of the RCC by analyzing macrozoobenthos structure along the upstream-to-downstream gradient. This preliminary study contributes to ongoing regional research, highlighting the role of lakes in shaping the Myśla River ecosystem and assessing the relevance of RCC in unique river systems.