Leandro Juen

Universidade Federal do Pará, Belém, Brazil · Instituto de Ciências Biológicas

Experiments are useful scientific tools for testing hypotheses by manipulating variables of interest while controlling for other factors that can bias or confuse the results and their interpretation. However, to ensure accuracy and reproducibility, experiments must have transparent and repeatable methodologies. We experimentally tested the effect o...

Tropical and sub-tropical streams harbor great biodiversity and are responsible for crucial ecosystem services. Intending to contribute to the understanding of how anthropogenic stressors and pressures alter functional or taxonomic diversity in biotic assemblages or processes in these systems, Water Biology and Security published eight papers. The...

Hyphessobrycon heterorhabdus (Ulrey, 1894), popularly known as ‘Flag Tetra’ in English speaking countries, belongs to the genus Hyphessobrycon of the family Characidae, and is widely present in the eastern Amazon basin. Here, using Illumina sequencing, we report the complete mitogenome sequence of H. heterorhabdus. Overall, the mitogenome has 17,02...

Aquatic insects’ behavior changes due to physiological constraints, trophic interactions, habitat selection, and biotic interactions. Addressing these topics can help to potentiate our understanding of ecosystem services and community structure. Here, the larval behavior of seven Odonata species was studied in the laboratory to evaluate variations...

Odonata is amphibian insects, widely used in studies of aquatic ecosystems. In order for us to improve their use as bioindicator organisms, there is a need to increase our knowledge of how species distribution responds to the environmental gradient. Our study evaluates the relationship among habitat specificity, morphology and differences in spatia...

1. Human land-use change is a major threat to natural ecosystems worldwide. Nonetheless, the effects of human land-uses on the structure of plant and animal assemblages and their functional characteristics need to be better understood. Furthermore, the pathways by which human land uses affect ecosystem functions, such as biomass production, still n...

1. Environmental changes are increasingly frequent, resulting in adverse impacts on biodiversity. These effects are more harmful when superimposed on areas of high biodiversity such as the Amazon region, in which the gaps in knowledge of the number of existing species and how they are distributed. 2. This article reviews the known geographical dist...

The Amazon forests are under threat from multiple human land uses, but the effect of the different types of land uses on environmental heterogeneity and the α- and β-diversity of aquatic insects remains unclear. We studied how habitat features of streams and aquatic insect diversity in the orders Ephemeroptera, Plecoptera, and Trichoptera (hereafte...

Can we predict which taxonomic groups and morphological or behavioral traits are favoured during urbanization? Here we have revised those odonate (dragonflies and damselflies) species are present in urban areas around world, their body size, body colour, sexual dimorphism, flight mode, habitat preference and mate guarding strategy. We wanted to kno...

Aquatic insects comprise 64% of freshwater animal diversity and are widely used as bioindicators to assess water quality impairment and freshwater ecosystem health, as well as to test ecological hypotheses. Despite their importance, a comprehensive, global database of aquatic insect occurrences for mapping freshwater biodiversity in macroecological...

The Odonata have well resolved taxonomy, conspicuous diurnal adults, contact with aquatic and terrestrial environments, and a broad range of environmental sensitivity across species, making them a valuable group for environmental appraisals. Odonate nymphs are commonly tested in aquatic ecotoxicological and bioaccumulation studies and often applied...

Human activities such as logging, agriculture, and urbanization can drastically change and limit Odonata species distributions in aquatic and terrestrial environments. These modifications may culminate in extirpations of rare and resident species and homogenization of community composition across space. This chapter reviews how human land use is (r...

Pollution and climate change are among the main threats to the biodiversity of freshwater ecosystems in the 21st century. We experimentally tested the effects of microplastic and climate change (i.e., increase in temperature and CO2) on the survival and consumption by an Amazonian-stream shredder invertebrate. We tested three hypotheses. (1) Increa...

The efects of mining-induced changes on natural environments extend from terrestrial to aquatic ecosystems. Our study aimed to investigate how mining activities afect the functional beta diversity of Ephemeroptera nymphs and select species with specifc traits. We tested whether: (a) preserved streams have higher functional beta diversity of Ephemer...

Motivation: Aquatic insects comprise 64% of freshwater animal diversity and are

The way species respond to environmental changes depends on several factors, but mainly on their niche breadth in the face of habitat variability and changes. Our study evaluated, over a six-year period, how the abundance and richness of generalist and specialist genera of Ephemeroptera, Plecoptera and Trichoptera (EPT) respond to mining activities...

In this study, we assessed the effects of multiple land uses and local habitat variables on the composition of fish functional trophic groups (FTG’s) and on the ecomorphological traits of fish in Amazonian streams. We evaluated land use types and local habitat variables in 26 streams distributed within a land use gradient. Land use and habitat vari...

In recent decades, the conversion of native forests into anthropogenic landscapes has been impacting progressively the physical habitat of the aquatic systems of Brazilian Amazonia. Given this, we evaluated the effects of the loss of natural vegetation cover on the diversity and morphology of Amazonian odonates (Zygoptera and Anisoptera). To do so,...

We evaluated whether ecological thresholds could be detected along gradients of disturbances by using larval Odonata genera. Morphological, physiological, and behavioral differences between Odonata suborders may be reflected in different thresholds to anthropogenic disturbance. Therefore, we hypothesized that larval Zygoptera genera would have narr...

A new Epipleoneura Williamson, 1915 (Zygoptera, Coenagrionidae) from northern Brazil and notes on E. venezuelensis Rácenis, 1955 Abstract Epipleoneura lencionii sp. nov. is erected based on specimens from Acre State (holotype: 10º7′38.5″S; 67º38′6.7″W, 12.ix.2017, Miguel, T.B. leg). Additional material collected in Minas Gerais was also studied, bu...

Insects of the order Odonata have been used as indicators of environmental quality in different aquatic systems around the world. In this context, we conducted a bibliometric analysis to understand the general patterns of research on Odonata published in the past decade (2012–2021). We extracted literature from the Web of Science (WoS) in the advan...

The advance of agricultural frontiers and industrialization in Amazonia has increased natural resource deterioration, resulting in degraded physical habitat structure and reduced local aquatic biodiversity. We evaluated the relative sensitivities of the Biological Monitoring Working Party (BMWP) and Average Score Per Taxon (ASPT) biotic indexes bas...

The influence of food types, reproductive behaviour, and the existence of a possible stratification to the attractiveness of Calliphoridae and Mesembrinellidae flies may contribute to the definition of collection methodologies. Thus, we assessed the effectiveness of traps with two bait types exposed at two different heights in the forests for colle...

Psaironeura jeronimoi sp. nov. is described based on seven males (Holotype: ♂ (LABECO, N° 10002717), BRAZIL, Amazonas, Alto Maués Ecological Station, (-5.9852,-59.3182, 114 m asl, 12.v.2019) collected in the state of Amazonas (near Alto Maués Ecological Station) and Pará (municipality of Belterra). This new species fits into the tenuissima group bu...

Understanding the contribution of rare biological groups to functional diversity, especially in systems impacted by land use, is fundamental to comprehend the biodiversity patterns and establish more efficient conservation strategies. This study mainly aimed to identify the contribution of rare aquatic insects to functional diversity in environment...

Despite advances in recent years, there remains a lack of information on the habitat specificity of many aquatic insects, especially for the most recently described taxa and for very diverse regions such as the Amazon. This study evaluates the relationship between niche breadth and habitat specificity of aquatic insects in 219 streams. Local enviro...

the reduction of habitat integrity and canopy cover will lead to a lower richness of the Zygoptera sub-order, due to the restrictions of its thermoregulation and oviposition behavior in relation to Anisoptera, since the higher light input would favor heliother-mic and exophytic species; (3) alterations in habitat integrity create ecological thresho...

We conducted a systematic review to better understand this gap and analyzed i) in which global regions are studies usually conducted, ii) the taxon studied, iii) sampling methods and iv) how authors collaborated in these studies. We also tested the relationship between different types of land use and land cover and adult EPT communities using a met...

Eutrophication is a key threat to aquatic biodiversity around the world, but especially in the Cerrado biome that has undergone intensive land use conversion and fertilizer use. In this study, we investigated how water conditions and different taxonomic and functional indicators of phytoplankton communities responded to eutrophication over time and...

The Mariana disaster, resulting from the rupture of the Fundão tailings storage facility (TSF) in 2015, was a large‐scale environmental disaster that drastically affected the entire channel of the Rio Doce, southeastern Brazil. The disaster produced substantial channel siltation, increased turbidity, riparian damage and a massive fish kill. However...

Environmental and spatial heterogeneity affects the distribution of aquatic insects, determining or influencing the variation in local species composition. Dragonflies and damselflies (Odonata) have different strategies for oviposition site selection that depend on environmental conditions. However, Land Use and Land Cover (LULC) can reduce the ava...

Resumo: Esta revisão teve como objetivo avaliar o histórico da utilização de alguns grupos de Insetos Aquáticos como bioindicadores de alteração ambiental no estado do Pará, assim como discutir as perspectivas futuras dessa temática à luz das novas tecnologias. Verificou-se consideráveis avanços no uso das Ordens Ephemeroptera, Plecoptera, Trichopt...

Landscape changes have caused the decline of biodiversity and affected the integrity of aquatic ecosystems. In this study, we assessed the influence of industrialization associated with urban development on aquatic environments and the biodiversity of semiaquatic bugs (Gerromorpha) at different scales (water quality, habitat, and landscape). Using...

Here we present the first Odonata (Insecta) species list for the state of Acre, Northern Brazil, adding ecological aspects and notes on its taxonomy and conservation status. Regarding Odonata samplings, Acre is one of the least explored states in the northern region of Brazil and an area of geographic importance, as it is a transition between the A...

Stream degradation in Amazonia is outpacing our ability to effectively monitor it for three key reasons: (1) Many changes are cumulative and occur gradually; (2) Scientists have failed to clearly link anthropogenic disturbances with ecological and economic indicators of concern to decision makers and the public; (3) There are too many potential ind...

Species distribution depends on dispersal ability and species responses to the environment, where the anthropogenic landscape can facilitate or difficult for them to track the environmental gradients. Therefore, we assess how drivers and distribution patterns from Trichoptera metacommunity change in anthropogenically disturbed streams. We expected...

Among the oldest winged insects, odonates are a monophyletic order that have become important models for ecologicalstudies because of their highly diverse reproductive behaviors and their role as top predators and bioindicators. However,knowledge on evolutionary relationships within the order is still scarce compared to other taxa, and this situati...

Changes in riparian vegetation directly affect the entry of allochthonous material into aquatic systems, which is the main source of food and energy for different functional feeding groups (FFG) of aquatic insects that play important ecological roles in these ecosystems. Thus, reducing the fragmentation of organic matter affecting the energy flow a...

The Neotropical genus Heteragrion Selys, 1862 is the second most speciose among the Neotropical Zygoptera. However, most of its species are poorly known regarding their biology, distribution, and taxonomy, especially those from undersampled areas like Northern Brazil. Here we describe Heteragrion calafatiensis sp. nov. from the coastal environments...

The presence of environmental conditions that are suitable for the development of agricultural and cattle-raising activities has favored the expansion of land use in the Brazilian Amazon. This expansion changes the environmental conditions of aquatic ecosystems by altering the structure of the streambeds and the physicochemical conditions of the wa...

One of the major challenges of ecologists and biogeographers is to understand how species are globally distributed. Two of the most well-studied large-scale patterns in species distributions are the Rapoport’s rule and the Latitudinal Diversity Gradient (LDG). We aimed to address whether Neotropical odonates follow the Rapoport’s rule and if there...

The growth of agricultural and mining activities in the Amazon has impacted land-use and caused significant changes in the local environmental conditions of streams. In the face of these changes, our study aimed at assessing how environmental changes affect Odonata larval assemblages in streams in the eastern Amazon. We hypothesized that habitat co...

A major challenge in using recovery techniques, for the different natural ecosystems affected by mining, is a mutual relationship between the habitat and its biota response. This study aimed to do a review to identify the number of publications, which countries are publishing more and which recovery techniques and taxonomic group are used in mining...

Pollution and climate change are among the main threats to the biodiversity of freshwater ecosystems in the 21st century. We experimentally tested the effect of microplastic and climate change (i.e., increase in temperature and CO2) on the survival and consumption of an Amazon stream shredder. We tested the following hypotheses: (1) increasing micr...

As plantações de palma de dendê em grande escala (Elaeis guineensis Jacq.) têm se expandido progressivamente em todo o mundo nas últimas décadas devido ao seu uso crescente nas indústrias de alimentos, cosméticos e biocombustíveis.9 Essa expansão trouxe visões contrastantes e polêmicas sobre as mudanças ambientais e sociais nas comunidades rurais.

Headwater streams are facing increasing disturbances from human pressures worldwide, thus better knowledge about bioindicators, particularly aquatic insect responses to various pressures and stressors, are urgently needed. Multiple trait-based approaches consider species attributes filtered by the environment, allowing them to persist in ecosystems...

Land use influences the biodiversity of stream systems by changing the chemical composition of the water and the physical structure of the habitat. The present study evaluated the influence of these processes on the diversity metrics of Odonata at regional and local scales, testing the hypothesis that the two odonate suborders Anisoptera and Zygopt...

The increasing land use in the Amazon region has resulted in the widespread substitution of forest areas with pasture and bauxite mining. These land uses reduce the forest cover of streams and modify their characteristics, reducing the diversity of aquatic insect assemblages. In the present study, we aimed to identify the threshold of the assemblag...

Biodiversity conservation has faced many challenges, especially the conversion of natural areas that compete with use for agriculture, energy production and mineral extraction. This problem is further aggravated by lack of knowledge of the biodiversity that exists and the geographical distribution of different groups. The objectives of our study we...

Climatic seasonality provokes considerable variability in the physical conditions of streams. Although few studies have assessed systematically the temporal effects of climate on aquatic communities, the diversity and structure of odonate larval assemblages (suborders Anisoptera and Zygoptera) are predicted to be influenced by seasonality. To evalu...

Brasilocaenis atawallpa was recently described based on male imago from Colombian Amazon. The original description does not contain a designation of type specimens or locality, and it just states that the type series was studied in order to perform the cladistic analysis. In this context, we herein designate the lectotype and paralectotypes of B. a...

Brasilocaenis atawallpa was recently described based on male imago from Colombian Amazon. The original description does not contain a designation of type specimens or locality, and it just states that the type series was studied in order to perform the cladistic analysis. In this context, we herein designate the lectotype and paralectotypes of B. a...

Changes in natural habitats for human use can alter the distribution of biodiversity, favoring species that are more tolerant to environmental disturbance. Usually, these species comprise clades of habitat generalists, which have biological mechanisms to colonize environments with different environmental conditions. However, such effects are still...

Deforestation is a major threat globally, but especially in tropical regions because they are biodiversity strongholds and carbon storehouses. Some studies have reported changes in species richness and composition in lotic ecosystems with increased forest-loss in their catchment, presumably resulting from the replacement of sensitive taxa by more r...

A correction to this paper has been published: https://doi.org/10.1007/s10841-021-00328-5