Competition is the main factor, compared to non-lethal threat of predation, affecting life-history traits of Aedes aegypti (Diptera, Culicidae) mosquitoes.

BACKGROUND: Mosquito larvae coexist with different species of predators in small freshwater bodies. These environments can vary widely in terms of the amount of food and larval densities. Our objective was to understand the impacts of the non-lethal threat of predation, combined with competition effects on Aedes aegypti development and adult life cycle. We tested the effects of two types of non-lethal threat of predation, divided into nine combinations of larvae densities and resource availability on Ae. aegypti larvae. We measured their isolated and combined impacts on larval mortality rate, time to reach pupation, adult size, and lifespan. RESULTS: Real non-lethal threat of predation resulted in a higher larval mortality (71%), compromised the sizes of the individuals (-7%) and prolonged the lifespan (19%) compared to control. Simulated treatment, the anti-predation behaviors led to an increase in larval mortality (21%) compared to the control treatment. Accelerating the larva's development time (-14%) to escape from a dangerous environment severely compromised the size of the individuals (-23%) and increased adult life (10%). CONCLUSION: The scarcity of food resources, high levels of competition, and non-lethal threat of predation as well, are effective stressors for Ae. aegypti. We observed that resources (food and space) were more important than predation risk for the fitness of the survivors. However, these stressors, individually or combined, can result in high larvae mortality, altered larval development and pupation, affecting the emergence of the adults, with small sizes and altered lifespan, ultimately reducing the fitness of the individuals. © 2024 Society of Chemical Industry.

Nectopsyche sp (Trichoptera: Leptoceridae) sublethal effects caused by different concentrations of arsenic (As): a biochemical markers approach.

Environmental impacts related to arsenic (As) contamination are a persistent issue of particular interest in Latin American countries with increasing mining activities. In Ecuador, the redefinition of public policies to promote the increase in mining since 2008 has led to a significant rise in the presence of this heavy metal in rivers and effluents, sometimes exceeding the 0.1 mg L-1, limit recommended by Ecuadorian Environmental Regulations. This study aimed to evaluate the sublethal effects through the detection of biochemical biomarker changes (Catalase, Antioxidant capacity by FRAP, and Glutathione S-transferase) generated in larvae of Nectopsyche sp following prolonged exposure to different concentrations of As (C1 = 0.05 mg L-1, C2 = 0.1 mg L-1, C3 = 0.8 mg L-1) in a controlled environment, emulating the maximum limits allowed by current Ecuadorian legislation. While As concentration levels in water increased, so did levels in the tissue of Nectopsyche sp specimens. On the other hand, behavioral parameters (mortality and mobility) did not show differences in either time or As concentrations. However, both Catalase and Antioxidant capacity by FRAP levels tended to decrease with increasing As concentration, and in both cases, the differences were significant. Additionally, Glutathione S-transferase activity did not increase significantly. These results preliminarily demonstrate that biochemical responses change with varying As concentrations in Nectopsyche sp and are affected at behavioral and biochemical levels produced by the As at chronic levels.

Declining glacier cover drives changes in aquatic macroinvertebrate biodiversity in the Cordillera Blanca, Perú.

Ongoing climate change threatens the biodiversity of glacier-fed river ecosystems worldwide through shifts in water availability and timing, temperature, chemistry, and channel stability. However, tropical glacier-fed rivers have received little attention compared to those in temperate and Arctic biomes, despite their unique biodiversity potentially responding differently due to additional stress from higher altitude locations thus lower oxygen availability, diurnal freeze-thaw cycles, and annual monsoon rainfall disturbances. However, tropical glacier-fed rivers have received little attention compared to those in temperate and Arctic biomes, despite their unique biodiversity potentially responding differently due to additional stress from higher altitude locations thus lower oxygen availability, diurnal freeze-thaw cycles, and annual monsoon rainfall disturbances. This study quantified aquatic biodiversity responses to decreasing glacier cover in the Cordillera Blanca range of the Peruvian Andes. Ten rivers were studied along a gradient of decreasing glacier cover in the Parón, Huaytapallana, and Llanganuco basins, with a specific focus on macroinvertebrates and physicochemical parameters in both the dry and wet seasons. We found higher temperatures, more stable and lower turbidity rivers as glacier cover decreased, which were related significantly to higher local diversity and lower ß-diversity. Analysis of similarity revealed significant differences in the macroinvertebrate community among rivers with high, medium, or low glacier cover, illustrating turnover from specialists to generalists as glacial influence decreased. Redundancy analysis demonstrated that there were more species found to prefer stable beds and water temperatures in medium and low glacier cover in a catchment rivers. However, certain taxa in groups such as Paraheptagyia, Orthocladiinae, Anomalocosmoecus, and Limonia may be adapted to high glacial influence habitats and at risk of glacier retreat. Although species composition was different to other biomes, the Cordillera Blanca rivers showed similar benthic macroinvertebrate biodiversity responses to glacier retreat, supporting the hypothesis that climate change will have predictable effects on aquatic biodiversity in mountain ranges worldwide.

Untangling the complex food webs of tropical rainforest streams.

Food webs depict the tangled web of trophic interactions associated with the functioning of an ecosystem. Understanding the mechanisms providing stability to these food webs is therefore vital for conservation efforts and the management of natural systems. Here, we first characterised a tropical stream meta-food web and five individual food webs using a Bayesian Hierarchical approach unifying three sources of information (gut content analysis, literature compilation and stable isotope data). With data on population-level biomass and individually measured body mass, we applied a bioenergetic model and assessed food web stability using a Lotka-Volterra system of equations. We then assessed the resilience of the system to individual species extinctions using simulations and investigated the network patterns associated with systems with higher stability. The model resulted in a stable meta-food web with 307 links among the 61 components. At the regional scale, 70% of the total energy flow occurred through a set of 10 taxa with large variation in body masses. The remaining 30% of total energy flow relied on 48 different taxa, supporting a significant dependency on a diverse community. The meta-food web was stable against individual species extinctions, with a higher resilience in food webs harbouring omnivorous fish species able to connect multiple food web compartments via weak, non-specialised interactions. Moreover, these fish species contributed largely to the spatial variation among individual food webs, suggesting that these species could operate as mobile predators connecting different streams and stabilising variability at the regional scale. Our results outline two key mechanisms of food web stability operating in tropical streams: (i) the diversity of species and body masses buffering against random and size-dependent disturbances and (ii) high regional diversity and weak omnivorous interactions of predators buffering against local stochastic variation in species composition. These mechanisms rely on high local and regional biodiversity in tropical streams, which is known to be strongly affected by human impacts. Therefore, an urgent challenge is to understand how the ongoing systematic loss of diversity jeopardises the stability of stream food webs in human-impacted landscapes.

As teias alimentares representam um emaranhado de interações tróficas associadas ao funcionamento de um ecossistema. Compreender os mecanismos que proporcionam estabilidade a estas teias alimentares é, portanto, vital para os esforços de conservação e gestão dos sistemas naturais. Aqui, primeiro caracterizamos uma meta teia alimentar de riachos tropicais e cinco teias alimentares individuais usando uma abordagem hierárquica Bayesiana unificando três fontes de informação (análise de conteúdo estomacal, compilação de literatura, dados de isótopos estáveis). Com dados sobre biomassa em nível populacional e massa corporal medida individualmente, aplicamos um modelo bioenergético e avaliamos a estabilidade da cadeia alimentar usando um sistema de equações Lotka­Volterra. Em seguida, avaliamos a resiliência do sistema às extinções de espécies individuais usando simulações e investigamos os padrões de rede associados a sistemas com maior estabilidade. O modelo resultou em uma meta teia alimentar estável com 307 ligações entre os 61 componentes. Na escala regional, 70% do fluxo total de energia ocorreu através de um conjunto de dez taxa com grande variação nas massas corporais. Os restantes 30% do fluxo total de energia dependiam de 47 taxa diferentes, apoiando uma dependência significativa de uma comunidade diversificada. A meta teia alimentar foi estável contra extinções de espécies individuais, com uma maior resiliência em teias alimentares que abrigam espécies de peixes onívoros capazes de conectar múltiplos compartimentos da teia alimentar através de interações fracas e não especializadas. Além disso, estas espécies de peixes contribuíram amplamente para a variação espacial entre as cadeias alimentares individuais, sugerindo que estas espécies poderiam operar como predadores móveis conectando diferentes riachos e estabilizando a variabilidade à escala regional. Nossos resultados descrevem dois mecanismos principais de estabilidade da cadeia alimentar operando em riachos tropicais: (i) a diversidade de espécies e massas corporais que protegem contra distúrbios aleatórios e dependentes do tamanho (ii) alta diversidade regional e fracas interações onívoras de predadores que protegem contra a variação estocástica local na composição de espécies. Estes mecanismos dependem de uma elevada biodiversidade local e regional em riachos tropicais, que são conhecidos por serem fortemente afetados pelos impactos humanos. Portanto, um desafio urgente é compreender como a contínua perda sistemática de diversidade põe em risco a estabilidade das teias alimentares em paisagens impactadas pelo homem.

Concordance among lacustrine communities are low and inconsistent in the conterminous United States.

Concordance occurs when two or more biological groups are correlated to each other. Examining the degree of concordance between communities has been a central goal in ecology. However, few studies have assessed the levels of community concordance at large spatial scales. We used a dataset obtained by the National Lakes Assessment (United States Environmental Protection Agency) to evaluate whether (i) the levels of concordance between aquatic communities were higher at the continental scale than within individual ecoregions of the United States and (ii) whether the levels of concordance between phytoplankton and zooplankton were higher than those between the plankton and macroinvertebrates communities. At the continental scale, the levels of concordance between different pairs of aquatic communities were low and did not exceed those within the ecoregions. Furthermore, levels of concordance varied considerably among ecoregions. Our results suggest that interactions between aquatic communities likely determined concordance patterns; however, the expectation of higher levels of concordance between the phytoplankton and zooplankton communities than between them and the macroinvertebrates community was not supported. The consistently low and variable levels of concordance suggest that using surrogate groups is not recommendable for monitoring lakes in the United States, both at the continental and regional scales. According to our results, the prospect of using the surrogacy approach was low even for aquatic communities that are highly interactive or driven by similar environmental factors.

Heavy Metal Bioaccumulation in Peruvian Food and Medicinal Products.

To better query regional sources of metal(loid) exposure in an under-communicated region, available scientific literature from 50 national universities (undergraduate and graduate theses and dissertations), peer-reviewed journals, and reports published in Spanish and English were synthesized with a focus on metal(loid) bioaccumulation in Peruvian food and medicinal products utilized locally. The study considered 16 metal(loid)s that are known to exert toxic impacts on humans (Hg, Al, Sb, As, Ba, Be, Cd, Cr, Sn, Ni, Ag, Pb, Se, Tl, Ti, and U). A total of 1907 individual analyses contained within 231 scientific publications largely conducted by Peruvian universities were analyzed. These analyses encompassed 239 reported species classified into five main food/medicinal groups-plants, fish, macroinvertebrates and mollusks, mammals, and "others" category. Our benchmark for comparison was the World Health Organization (Codex Alimentarius) standards. The organisms most frequently investigated included plants such as asparagus, corn, cacao, and rice; fish varieties like trout, tuna, and catfish; macroinvertebrates and mollusks including crab and shrimp; mammals such as alpaca, cow, chicken eggs, and milk; and other categories represented by propolis, honey, lichen, and edible frog. Bioaccumulation-related research increased from 2 to more than 25 publications per year between 2006 and 2022. The results indicate that Peruvian food and natural medicinal products can have dangerous levels of metal(loid)s, which can cause health problems for consumers. Many common and uncommon food/medicinal products and harmful metals identified in this analysis are not regulated on the WHO's advisory lists, suggesting the urgent need for stronger regulations to ensure public safety. In general, Cd and Pb are the metals that violated WHO standards the most, although commonly non-WHO regulated metals such as Hg, Al, As, Cr, and Ni are also a concern. Metal concentrations found in Peru are on many occasions much higher than what has been reported elsewhere. We conclude that determining the safety of food/medicinal products is challenging due to varying metal concentrations that are influenced not only by metal type but also geographical location. Given the scarcity of research findings in many regions of Peru, urgent attention is required to address this critical knowledge gap and implement effective regulatory measures to protect public health.

Soil macrofauna communities in Brazilian land-use systems.

Background: Soil animal communities include more than 40 higher-order taxa, representing over 23% of all described species. These animals have a wide range of feeding sources and contribute to several important soil functions and ecosystem services. Although many studies have assessed macroinvertebrate communities in Brazil, few of them have been published in journals and even fewer have made the data openly available for consultation and further use. As part of ongoing efforts to synthesise the global soil macrofauna communities and to increase the amount of openly-accessible data in GBIF and other repositories related to soil biodiversity, the present paper provides links to 29 soil macroinvertebrate datasets covering 42 soil fauna taxa, collected in various land-use systems in Brazil. A total of 83,085 georeferenced occurrences of these taxa are presented, based on quantitative estimates performed using a standardised sampling method commonly adopted worldwide to collect soil macrofauna populations, i.e. the TSBF (Tropical Soil Biology and Fertility Programme) protocol. This consists of digging soil monoliths of 25 x 25 cm area, with handsorting of the macroinvertebrates visible to the naked eye from the surface litter and from within the soil, typically in the upper 0-20 cm layer (but sometimes shallower, i.e. top 0-10 cm or deeper to 0-40 cm, depending on the site). The land-use systems included anthropogenic sites managed with agricultural systems (e.g. pastures, annual and perennial crops, agroforestry), as well as planted forests and native vegetation located mostly in the southern Brazilian State of Paraná (96 sites), with a few additional sites in the neighbouring states of São Paulo (21 sites) and Santa Catarina (five sites). Important metadata on soil properties, particularly soil chemical parameters (mainly pH, C, P, Ca, K, Mg, Al contents, exchangeable acidity, Cation Exchange Capacity, Base Saturation and, infrequently, total N), particle size distribution (mainly % sand, silt and clay) and, infrequently, soil moisture and bulk density, as well as on human management practices (land use and vegetation cover) are provided. These data will be particularly useful for those interested in estimating land-use change impacts on soil biodiversity and its implications for below-ground foodwebs, ecosystem functioning and ecosystem service delivery. New information: Quantitative estimates are provided for 42 soil animal taxa, for two biodiversity hotspots: the Brazilian Atlantic Forest and Cerrado biomes. Data are provided at the individual monolith level, representing sampling events ranging from February 2001 up to September 2016 in 122 sampling sites and over 1800 samples, for a total of 83,085 ocurrences.

Assessment of aquatic macro-invertebrates communities and water quality parameters of River Zhob, Balochistan, Pakistan / Avaliação das comunidades de macroinvertebrados aquáticos e parâmetros de qualidade da água do rio Zhob, Baluchistão, Paquistão

Environmental stress caused by pollution is often assessed by diversity of macro-invertebrate species in specific aquatic habitat. To find out seasonal fluctuations in various macro-invertebrates communities and different water quality parameters of River Zhob, a research trial was conducted on River Zhob, Balochistan. Samples of macro-invertebrates and water were taken from four different stations of River Zhob. A total 18 taxa of various macro-invertebrates were identified from the area. Phylum Arthropoda constitute 94.8% of the total population followed by Mollusca (3.6%) and Annelida (1.4%). A large number of arthropods were belonged to order Diptera (1148), while the order Trichoptera was stood second with respect to macro-invertebrate´s number (441). The maximum numbers of macro-invertebrates were observed in the month of January. All physico-chemical parameters of River Zhob such as air temperature, water temp, pH, dissolved oxygen (DO) and total dissolved solids (TDS) were within the range, suitable for the healthy growth of macro-invertebrates. Diversified populations of various macro-invertebrates confirm good ecological condition of environment and water in the studied site especially ample concentration of DO in River. The documented data on macro-invertebrates in studied site will provide a baseline for future research.

O estresse ambiental causado pela poluição é frequentemente avaliado pela diversidade de espécies de macroinvertebrados em habitats aquáticos específicos. Para descobrir as flutuações sazonais em várias comunidades de macroinvertebrados e diferentes parâmetros de qualidade da água do rio Zhob, foi realizado um teste de pesquisa no rio Zhob, Baluchistão. Amostras de macroinvertebrados e água foram retiradas de quatro estações diferentes do rio Zhob. Um total de 18 táxons de vários macroinvertebrados foram identificados na área. O filo Arthropoda constitui 94,8% da população total, seguido por Mollusca (3,6%) e Annelida (1,4%). Um grande número de artrópodes pertencia à ordem Diptera (1148), enquanto a ordem Trichoptera ocupava o segundo lugar em número de macroinvertebrados (441). Os números máximos de macroinvertebrados foram observados no mês de janeiro. Todos os parâmetros físico-químicos do rio Zhob, como temperatura do ar, temperatura da água, pH, oxigênio dissolvido (OD) e sólidos dissolvidos totais (TDS), estavam dentro da faixa, adequada para o crescimento saudável de macroinvertebrados. Populações diversificadas de vários macroinvertebrados confirmam boas condições ecológicas do ambiente e da água no local estudado, especialmente a ampla concentração de DO no rio. Os dados documentados sobre macroinvertebrados no local estudado fornecerão uma linha de base para pesquisas futuras.

Benthic community ecology for Algerian river Seybouse / Ecologia da comunidade bêntica para o rio Seybouse da Argélia

Abstract The Seybouse is the second largest river basin in Algeria, hosting an important biodiversity and providing various ecosystem services. This watershed is highly influenced by agricultural and industrial activities, which threaten its biodiversity and ecosystem integrity. The use of benthic macroinvertebrates as biological indicators has a long tradition in developed countries and integrated into all assessments of the ecological quality of river systems. However, the macroinvertebrates of many North African regions are still not well studied, including those of the Seybouse river. The aim of this study is to assess the inventory and ecological role of benthic macroinvertebrates in inland waters of the Seybouse River and determine the impact of pollution on their spatial distributions. We sampled the benthic macrofauna of Wadi Seybouse and its affluents using regular surveys in three sites, of which one was in the upper Seybouse Bouhamdane in Medjez Amar and two in the middle Seybouse. Between December 2019 and May 2020, 10 physico-chemical parameters (pH, EC, OD, water speed, NO3, Salinity, NO2, MES, turbidity, depth) were measured in order to establish a health state diagnosis of these aquatic ecosystems. The complementary biological approach by the analysis of populations of macroinvertebrates identified 7482 individuals and 40 taxa divided into five classes: Crustaceans which were the most dominant, insects with the main orders (Ephemeroptera, Diptera, Trichoptera, Heteroptera and Odonata), Molluscs, Nematodes and Annelids. The physico-chemical analyzes and the application of the organic pollution indices indicated a strong to excessive pollution for all sites, especially in Seybouse upstream

Resumo O Seybouse é um rio no nordeste da Argélia, é o segundo maior rio, tem uma área de captação de cerca de 6.500 km2 que acolhe cerca de 1,5 milhões de habitantes. Importantes atividades agrícolas e industriais são desenvolvidas nesta bacia hidrográfica. O uso de macroinvertebrados bentônicos como indicadores biológicos tem uma longa tradição em países desenvolvidos e está integrado em todas as avaliações da qualidade ecológica dos sistemas fluviais. O objetivo deste estudo foi revisar o inventário e o papel ecológico dos macroinvertebrados bentônicos nas águas interiores do rio Seybouse e determinar o impacto da poluição em suas distribuições. Resultados semelhantes foram relatados para outros países e rios argelinos. Este estudo enfoca a macrofauna bentônica de Wadi Seybouse e seus afluentes. Foram prospectados 03 locais, um no alto Seybousse Bouhamdane em Medjez Amar e dois no meio Seybousse Salah Salah Salah e Oued Zimba. Entre dezembro de 2019 e maio de 2020, dez parâmetros físico-químicos (pH, CE, DO, velocidade da água, NO3, Salinidade, NO2, MES, turbidez, deth) foram medidos para estabelecer um diagnóstico do estado de saúde desses ecossistemas aquáticos. A abordagem biológica complementar pela análise de populações de macroinvertebrados identificou 7.482 indivíduos e 40 táxons divididos em cinco classes: Crustáceos que são os mais dominantes, Insetos com as ordens principais (Ephemeroptera, Diptera, Trichoptera, Heteroptera e Odonata), Moluscos, Nematóides e Anelídeos. As análises físico-químicas e a aplicação dos índices de poluição orgânica, indicaram uma poluição forte a excessiva para todos os locais especialmente Salah Salah Salah.

Benthic community ecology for Algerian river Seybouse

Abstract The Seybouse is the second largest river basin in Algeria, hosting an important biodiversity and providing various ecosystem services. This watershed is highly influenced by agricultural and industrial activities, which threaten its biodiversity and ecosystem integrity. The use of benthic macroinvertebrates as biological indicators has a long tradition in developed countries and integrated into all assessments of the ecological quality of river systems. However, the macroinvertebrates of many North African regions are still not well studied, including those of the Seybouse river. The aim of this study is to assess the inventory and ecological role of benthic macroinvertebrates in inland waters of the Seybouse River and determine the impact of pollution on their spatial distributions. We sampled the benthic macrofauna of Wadi Seybouse and its affluents using regular surveys in three sites, of which one was in the upper Seybouse Bouhamdane in Medjez Amar and two in the middle Seybouse. Between December 2019 and May 2020, 10 physico-chemical parameters (pH, EC, OD, water speed, NO3, Salinity, NO2, MES, turbidity, depth) were measured in order to establish a health state diagnosis of these aquatic ecosystems. The complementary biological approach by the analysis of populations of macroinvertebrates identified 7482 individuals and 40 taxa divided into five classes: Crustaceans which were the most dominant, insects with the main orders (Ephemeroptera, Diptera, Trichoptera, Heteroptera and Odonata), Molluscs, Nematodes and Annelids. The physico-chemical analyzes and the application of the organic pollution indices indicated a strong to excessive pollution for all sites, especially in Seybouse upstream

Resumo O Seybouse é um rio no nordeste da Argélia, é o segundo maior rio, tem uma área de captação de cerca de 6.500 km2 que acolhe cerca de 1,5 milhões de habitantes. Importantes atividades agrícolas e industriais são desenvolvidas nesta bacia hidrográfica. O uso de macroinvertebrados bentônicos como indicadores biológicos tem uma longa tradição em países desenvolvidos e está integrado em todas as avaliações da qualidade ecológica dos sistemas fluviais. O objetivo deste estudo foi revisar o inventário e o papel ecológico dos macroinvertebrados bentônicos nas águas interiores do rio Seybouse e determinar o impacto da poluição em suas distribuições. Resultados semelhantes foram relatados para outros países e rios argelinos. Este estudo enfoca a macrofauna bentônica de Wadi Seybouse e seus afluentes. Foram prospectados 03 locais, um no alto Seybousse Bouhamdane em Medjez Amar e dois no meio Seybousse Salah Salah Salah e Oued Zimba. Entre dezembro de 2019 e maio de 2020, dez parâmetros físico-químicos (pH, CE, DO, velocidade da água, NO3, Salinidade, NO2, MES, turbidez, deth) foram medidos para estabelecer um diagnóstico do estado de saúde desses ecossistemas aquáticos. A abordagem biológica complementar pela análise de populações de macroinvertebrados identificou 7.482 indivíduos e 40 táxons divididos em cinco classes: Crustáceos que são os mais dominantes, Insetos com as ordens principais (Ephemeroptera, Diptera, Trichoptera, Heteroptera e Odonata), Moluscos, Nematóides e Anelídeos. As análises físico-químicas e a aplicação dos índices de poluição orgânica, indicaram uma poluição forte a excessiva para todos os locais especialmente Salah Salah Salah.

Variabilidad de comunidades de macroinvertebrados acuáticos en charcas temporales del norte de Colombia

Introducción: Las charcas temporales son ecosistemas acuáticos variables en su estructura física y biótica, efímeros en el paisaje e importantes en el flujo de materia y energía. Los macroinvertebrados acuáticos constituyen el grupo más abundante y diverso en estos ecosistemas y requieren mayor estudio, particularmente en los trópicos. Objetivo: Evaluar la diversidad alfa y beta de las comunidades de macroinvertebrados acuáticos de seis charcas temporales durante dos épocas climáticas en el norte de Colombia. Métodos: En Magdalena, Colombia, hicimos seis arrastres aleatorios con redes manuales en la zona litoral, y seis arrastres en zigzag con redes tipo D en la zona lacustre; recolectamos macrofauna en tres lances con una draga Ekman; y muestreamos cada charca durante la alta precipitación (noviembre, 2020) y la baja precipitación (febrero, 2021). Resultados: Identificamos 3 358 individuos (13 órdenes, 39 familias y 68 géneros). La mayor abundancia y diversidad (N= 485, 0D= 32) durante la época de lluvia se presentó en Los Campanos, mientras que la charca Villa Leidy tuvo el mayor número de taxones comunes (18) y dominantes (14). En la época de sequía, la charca Los Trillizos presentó la mayor abundancia (533) y diversidad (43); mientras que Villa Leidy y El Miquito el mayor número de taxones dominantes (16). Las charcas tienen composiciones particulares (sin agrupamientos espaciales o temporales); el recambio de taxones es alto, y la correspondencia canónica se agrupa por temporada. Conclusiones: la composición de las comunidades de macroinvertebrados acuáticos de las charcas temporales son muy diversas, presentando alto recambio tanto espacial como temporal, reflejando altos valores de remplazo de taxones entre épocas climáticas. La zona litoral mantuvo una composición similar durante las dos temporadas.

Introduction: Temporary ponds are variable aquatic ecosystems in their physical and biotic structure, ephemeral in the landscape and important in the flow of matter and energy. Aquatic macroinvertebrates constitute the most abundant and diverse group in these ecosystems and need further study, particularly in the tropics. Objective: To evaluate the alpha and beta diversity of the aquatic macroinvertebrate communities of six temporary pools during two climatic seasons in Northern Colombia. Methods: In Magdalena, Colombia, we did six random trawls with hand nets in the coastal zone, and six zig zag trawls with D nets in the lacustrine zone; we collected macrofauna in three random hauls with an Ekman dredge; and sampled each pond in high rainfall (November 2020) and low rainfall (February 2021). Results: We identified 3 358 individuals (13 orders, 39 families and 68 genera). The highest rainy season abundance and diversity (N= 485, 0D= 32) were in Los Campanos, while Villa Leidy Pond had the highest number of common (18) and dominant (14) taxa. During the dry season, Los Trillizos Pond had the highest abundance (533) and diversity (43); while Villa Leidy and El Miquito had the largest number of dominant taxa (16). The pools have a particular composition (no spatial or temporal grouping); taxa turnover is high, and the canonical correspondence clustered by season. Conclusions: The aquatic macroinvertebrate communities of the temporary ponds are diverse and have high turnover in space and time, reflecting high replacement of taxa between climatic periods. The littoral zone had a similar composition in the two seasons.

Automated software for counting and measuring Hyalella genus using artificial intelligence.

Amphipods belonging to the Hyalella genus are macroinvertebrates that inhabit aquatic environments. They are of particular interest in areas such as limnology and ecotoxicology, where data on the number of Hyalella individuals and their allometric measurements are used to assess the environmental dynamics of aquatic ecosystems. In this study, we introduce HyACS, a software tool that uses a model developed with the YOLOv3's architecture to detect individuals, and digital image processing techniques to extract morphological metrics of the Hyalella genus. The software detects body metrics of length, arc length, maximum width, eccentricity, perimeter, and area of Hyalella individuals, using basic imaging capture equipment. The performance metrics indicate that the model developed can achieve high prediction levels, with an accuracy above 90% for the correct identification of individuals. It can perform up to four times faster than traditional visual counting methods and provide precise morphological measurements of Hyalella individuals, which may improve further studies of the species populations and enhance their use as bioindicators of water quality.

Grupos Funcionales Alimentarios de Macroinvertebrados Acuáticos de Caño Baranda en la Reserva Natural El Diamante de las Aguas (Guaviare, Colombia) / Functional Feeding Groups of Aquatic Macroinvertebrates of Caño Baranda in the Diamante de las Aguas Natural Reserve (Guaviare, Colombia)

Introducción: Los macroinvertebrados son un componente biológico importante de los ecosistemas acuáticos al estar vinculados de forma activa en el flujo de materia y energía. Objetivo: Identificar los Grupos Funcionales Alimentarios (GFA) de macroinvertebrados bentónicos presentes en Caño Baranda. Materiales y métodos: Se midieron características físicas y químicas en 5 estaciones a lo largo de Caño Baranda en temporada de lluvia, así mismo se recolectaron macroinvertebrados acuáticos utilizando red Surber, red Tienneman, red de Patada y recolecta manual. Se obtuvieron muestras en cada estación para estimar la densidad de macroinvertebrados y se asignaron GFA por taxón. Resultados: Se recolectaron 251 organismos pertenecientes a 32 familias, distribuídas en 9 órdenes. Las familias más abundantes fueron Leptophlebiidae con 35% y Glossosomatidae con 12%. Se recolectaron organismos de cinco GFA donde los grupos dominantes fueron recolectores (45%) seguido por los depredadores (23%) presentando correlaciones positivas con el pH. Por su parte el grupo menos colectado fueron los trituradores (1%) donde su presencia se relacionó con el aumento de oxígeno disuelto. Conclusiones: La presencia de colectores y depredadores se relacionó con pH y temperaturas bajas; para los fragmentadores se relacionó con menores porcentajes de oxígeno disuelto; para los raspadores se relacionó con pH bajos y mayores caudales y para los trituradores se relacionó con una elevada concentración de oxígeno en el agua.

Introduction: Macroinvertebrates are an important biological component of aquatic ecosystems as they are actively linked in the flow of matter and energy. Objective: To identify the Functional Feeding Groups (FFG) of benthic macroinvertebrates present in Caño Baranda. Materials and method: Physical and chemical characteristics were measured in 5 sampling points along Caño Baranda during the rainy season, likewise aquatic macroinvertebrates were collected using Surber net, Tienneman net, Kick net and hand collection. Samples were obtained at each sampling point to estimate the density of macroinvertebrates and FFG per taxa. Results: 251 organisms belonging to 32 families were collected, sorted into 9 orders. The most abundant families were Leptophlebiidae (35%) and Glossosomatidae (12%). Collected organisms were associated to five FFG, the dominant being collectors (45%) followed by predators (23%) which presented positive correlations with pH. On the other hand, the least collected group was shredders (1%) whose presence was related to the increase in dissolved oxygen.

Neurotoxicity and Oxidative Stress Development in Adult Atya lanipes Shrimp Exposed to Titanium Dioxide Nanoparticles.

Titanium dioxide is a type of nanoparticle that is composed of one titanium atom and two oxygen atoms. One of its physicochemical activities is photolysis, which produces different reactive oxygen species (ROS). Atya lanipes shrimp affect detrital processing and illustrate the potential importance of diversity and nutrient availability to the rest of the food web. It is essential in removing sediments, which have an important role in preventing eutrophication. This study aimed to determine the toxic effect of changes in behavior and levels of oxidative stress due to exposure to titanium dioxide nanoparticles in Atya lanipes and to determine the effective concentration (EC50) for behavioral variables. The concentrations of TiO2 NPs tested were 0.0, 0.50, 1.0, 2.0, and 3.0 mg/L with the positive controls given 100 µg/L of titanium and 3.0 mg/L of TiO2 NPs ± 100 µg/L of titanium. After 24 h of exposure, significant hypoactivity was documented. The EC50 was determined to be a concentration of 0.14 mg/L. After the exposure to 10 mg/L of TiO2 NPs, oxidative stress in gastrointestinal and nervous tissues was documented. The toxic effects of this emerging aquatic pollutant in acute exposure conditions were characterized by sublethal effects such as behavior changes and oxidative stress.

Evaluation of the ecological status of the Ánimas River through multimetric indexes in Cerinza, Boyacá / Evaluación del estado ecológico del río ánimas mediante índices multimétricos en cerinza, boyacá

RESUMEN El estado o calidad ecológica es un concepto integral que refleja el grado de deterioro de los ambientes acuáticos. Para medirlo se han diseñado protocolos que evidencian los cambios en la estructura y funcionamiento de las comunidades bióticas en respuesta a las presiones antropogénicas. Se evaluó el estado ecológico del río Ánimas a lo largo de su eje longitudinal, mediante los índices IMEERA, IMARBO y BMWP-Col. Se realizaron muestreos en épocas seca y lluviosa en cuatro tramos del eje longitudinal. Se tomaron datos fisicoquímicos del agua y datos hidromorfológicos. Se colectaron macroinvertebrados mediante una red Surber. Los iones disueltos en el agua fueron los factores más relevantes del conjunto de variables fisicoquímicas. El índice hidromorfológico indicó que los puntos a menor elevación en la cuenca presentaron una puntuación deficiente. En cuanto a la abundancia y composición de macroinvertebrados, se reflejó una mayor abundancia en época seca y una mayor riqueza en época de lluvias. Los índices IMEERA y BMWP-Col tuvieron un comportamiento similar con valores menores en la época seca, mientras que en la fase lluviosa alcanzaron los registros más altos, revelando diferencias claras en el estado ecológico de los puntos de muestreo. El índice IMARBO presentó un comportamiento distinto, según el cual los puntos de menor elevación (uno y dos) reflejaron una condición de mayor deterioro en comparación con los puntos más altos (tres y cuatro). Para los tres índices, este último punto presentó la mejor condición de calidad. Este estudio contribuye al conocimiento del comportamiento de ríos andinos frente a índices de calidad ecológica.

ABSTRACT Ecological or quality status is an integral concept that reflects the degree of deterioration of aquatic environments. To measure it, protocols have been designed that demonstrate changes in the structure and functioning of biotic communities in response to anthropogenic pressures. The ecological status of the Ánimas River was evaluated along its longitudinal axis, using the IMEERA, IMARBO, and BMWP-Col indices. The samplings were carried out in dry and rainy seasons, in four sections of the longitudinal axis. Physicochemical data of the water and hydromorphological data were taken. Macroinvertebrates were collected using a Surber net. The ions dissolved in the water were the most relevant factors of the set of physicochemical variables. The hydromorphological index indicated that the points at lower elevations in the basin presented a deficient score. Regarding the abundance and composition of macroinvertebrates, a greater abundance was reflected in the dry season and a greater richness in the rainy season. The IMEERA and BMWP-Col indices had a similar behavior with lower values in the dry season, while in the rainy phase they reached the highest records, revealing clear differences in the ecological status of the studied points. The IMARBO index presented a different behavior according to which the lowest elevation points (one and two) reflected a condition of greater deterioration compared to the highest points (three and four). In this last point, the three indices showed the best quality condition. This study contributes to the knowledge of the behavior of Andean rivers in relation to ecological quality indices.

Trophic network of temporary ponds of the northern of department of la Guajira (Colombia) / Redes tróficas de charcas estacionales del norte del departamento de la guajira (colombia)

RESUMEN Las redes tróficas permiten conocer dinámicas de flujos de energía dentro de un ecosistema a través de las relaciones de consumo. Esta investigación describe las redes tróficas de dos charcas estacionales (Manaure y Maicao) al norte del departamento de la Guajira. Los macroinvertebrados y vertebrados acuáticos se recolectaron en zona litoral y limnética en dos muestreos por charca (llena de agua) entre octubre del 2018 y enero del 2019. Para evaluar las relaciones tróficas se realizaron análisis de contenidos estomacales. Estos datos se agruparon por porcentajes encontrados en estómagos (materia orgánica particulada fina y gruesa, microalgas y material animal). Las relaciones de consumo se analizaron en matrices binarias de depredador vs. presa. Con dichas matrices y usando el programa Network3D se realizaron los modelos de redes tróficas. Además, se realizó un análisis de componentes principales para asociar los ítems alimenticios con los taxones. La charca Manaure mostró mayor riqueza (25 géneros) y mayor número de individuos (3121), mayor densidad de links (5.10 L/S) y número de enlaces tróficos (171 L), asimismo se evidenció canibalismo que no se presentó en Maicao. El recurso que predominó en los dos ecosistemas fue la materia orgánica particulada fina. A partir de los datos obtenidos se observa a la charca Manaure con una red trófica más compleja. Estos datos sirven como grandes aportes para el conocimiento inicial de las relaciones tróficas de estas charcas estacionales y se pueden comparar con datos de redes tróficas en charcas de otras partes del mundo.

ABSTRACT Food webs allow us to understand the dynamics of energy flows within an ecosystem through consumption relationships. This research describes the food webs of two seasonal pools (Manaure and Maicao) in the north of the department of La Guajira. The aquatic macroinvertebrates and vertebrates were collected in the littoral and limnetic zones in two samplings per pound (filled with water) between October 2018 and January 2019. To evaluate the trophic relationships, an analysis of stomach contents was performed. These data were grouped by percentages found in stomachs (fine and coarse particulate organic matter, microalgae and animal material). Consumption relationships were analyzed in binary matrices of predator vs. prey. With these matrices and using the Network3D program, the food web models were made. In addition, a principal component analysis was performed. The Manaure pond showed greater richness (25 genera) and greater number of individuals (3121), higher density of links (5.10 L/S) and number of trophic links (171 L), probably evidenced cannibalism that did not occur in Maicao. The resource that predominated in both ecosystems was fine particulate organic matter. From the data obtained, the Manaure pond is observed with a more complex trophic network. These data serve as great contributions to the initial knowledge of the trophic relationships of these seasonal ponds and can be compared with data on food webs in ponds from other parts of the world.

Assessment of aquatic food web and trophic niche as a measurement of recovery function in restored mangroves in the Southern Gulf of Mexico.

Mangroves are coastal wetlands with high biodiversity and productivity, with great interaction with coastal environments. In the face of worldwide mangrove loss, restoration projects attempt to recover ecosystem composition and functioning over time. Our objective was to examine and compare the food webs in mangrove areas with different restoration times and in a reference mangrove in Términos Lagoon, Mexico. We estimated the trophic structure, identified the carbon resources that maintain aquatic consumers through the analysis of stable isotopes, and compared the trophic niche of the restored mangroves with the reference mangrove. We analyzed environmental variables, trophic structure, and contributions of resources during three seasons: rainy, dry, and "nortes". Environmental changes and food structure changed in response to regional seasons. Bayesian mixing models indicated that food webs varied seasonally as a response to the primary productivity developed at Términos Lagoon. As expected, the assimilation of C3 plants in the reference mangrove was highest, as a primary ("nortes" season) and secondary resource (dry and rainy seasons). The restored mangroves depended mainly on allochthonous resources (seagrass, epiphytes, and phytoplankton). The assimilation of these resources highlighted the importance of connectivity and the input of sources of carbon from nearby coastal environments. Trophic niche analysis showed that the area with longer restoration time was more similar to the reference mangrove, which is evidence of the importance and efficacy of the restoration process, as well as the restoration of the ecosystem function over time.

Land-use intensification systematically alters the size structure of aquatic communities in the Neotropics.

Land-use and land-cover transitions can affect biodiversity and ecosystem functioning in a myriad of ways, including how energy is transferred within food-webs. Size spectra (i.e. relationships between body size and biomass or abundance) provide a means to assess how food-webs respond to environmental stressors by depicting how energy is transferred from small to larger organisms. Here, we investigated changes in the size spectrum of aquatic macroinvertebrates along a broad land-use intensification gradient (from Atlantic Forest to mechanized agriculture) in 30 Brazilian streams. We expected to find a steeper size spectrum slope and lower total biomass in more disturbed streams due to higher energetic expenditure in physiologically stressful conditions, which has a disproportionate impact on large individuals. As expected, we found that more disturbed streams had fewer small organisms than pristine forest streams, but, surprisingly, they had shallower size spectrum slopes, which indicates that energy might be transferred more efficiently in disturbed streams. Disturbed streams were also less taxonomically diverse, suggesting that the potentially higher energy transfer in these webs might be channelled via a few efficient trophic links. However, because total biomass was higher in pristine streams, these sites still supported a greater number of larger organisms and longer food chains (i.e. larger size range). Our results indicate that land-use intensification decreases ecosystem stability and enhances vulnerability to population extinctions by reducing the possible energetic pathways while enhancing efficiency between the remaining food-web linkages. Our study represents a step forward in understanding how land-use intensification affects trophic interactions and ecosystem functioning in aquatic systems.

Determination of the ecological water quality in the Orienco stream using benthic macroinvertebrates in the Northern Ecuadorian Amazon.

In recent years, pollution of watercourses in nearby protected ecosystems has increased due to urbanization. Standard physiochemical methods and probes are one way to monitor watercourses for quality. However, they often do not provide the full ecological status of the body of water. In this work, we set out to assess the ecological water quality of an urban stream by using benthic macroinvertebrates as bioindicators. We conducted the work on the Orienco stream in Lago Agrio in the province of Sucumbíos in the Northern Ecuadorian Amazon (NEA). The stream has become a sink of raw domestic sanitary wastewater from rural and urban areas. A total of 4511 macroinvertebrates from 10 families were identified across 17 sampling points. We compared our results from the biotic indices derived from the macroinvertebrates to standard water-quality parameters (temperature, conductivity, dissolved oxygen, biochemical oxygen demand, chemical oxygen demand, total suspended solids, ammonia-nitrogen, and pH) simultaneously sampled in the stream. The standard parameter results indicated that the water-quality levels of the stream met the Ecuadorian water-quality criteria most of the time. However, the results from the biotic indices classified the stream water as poor or very poor water quality. The results from the Biological Monitoring Working Party, Average Score per Taxon, and Family Biotic Indices had overall scores of heavily polluted waters of 45, 4.5, and 8.74, respectively. Furthermore, these results were consistent with reduced richness and evenness, and overall lower Shannon diversity and relatively higher Simpson Dominance indices of 0.71 and 2.56, respectively. We conclude that the macroinvertebrates were better indicators of the ecological water quality of the Orienco stream than the water-quality parameters from standard methods and probes alone. Our findings highlight the need for more integrated ecological assessments, which can provide critical information to the management and conservation strategies of urban watercourses in the NEA region. Integr Environ Assess Manag 2023;19:615-625. © 2022 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Effects of Pesticides on the Survival of Shredder Nectopsyche sp. (Trichoptera) and Leaf Decomposition Rates in Tropical Andes: A Microcosm Approach.

Andean streams are becoming increasingly impacted by agricultural activities. However, the potential effects of pesticides on their aquatic biodiversity remain unassessed. In order to address this knowledge gap, we conducted an experiment over 37 days in microcosms to assess the effect of two pesticides commonly used in Ecuador (Engeo and Chlorpyrifos) on the aquatic insect Nectopsyche sp. (Trichoptera: Leptoceridae) at 0, 0.10, 5 and 10 µg L-1 concentrations. The highest concentration corresponds to the maximum concentration allowed by the Equatorian legislation. We assessed insect mortality every 24 h, with leaf litter decomposition rates of organic matter determined by deploying Andean alder (Alnus acuminata) dry leaf packs in the microcosms. We found significant mortality of Nectopsyche sp. at high concentrations of Chlorpyrifos, whereas leaf litter was not significantly affected by any of the treatments. We conclude that the environmental legislation of Ecuador might not be fully protecting aquatic biodiversity from pesticide pollution. Further studies are needed, especially when considering that the maximum permitted concentration is very likely exceeded in many areas of the country. We also suggest that the maximum permissible values should be reviewed, considering each pesticide individually.