Resumo Compreender os fatores ambientais que moldam a diversidade de macroinvertebrados é particularmente importante porque os rios nos neotrópicos são continuamente afetados por mudanças no uso da terra. O principal objetivo deste trabalho foi analisar como as variáveis ambientais associadas a diferentes níveis de atividade humana moldam a comunidade de macroinvertebrados no rio Ranchería. Várias variáveis ambientais foram medidas em cada uma das nove estações de amostragem distribuídas ao longo de três gradientes de atividade humana na bacia do rio Ranchería. O desenho de amostragem incluiu três estações na zona de elevação alta (P9, P8, P7; 595 a 308 metros acima do nível do mar), três na zona de elevação média (P6, P5, P4; 153 a 112 metros acima do nível do mar) e três na zona de baixa elevação (P3, P2, P1; 90 a 22 metros acima do nível do mar). Para os macroinvertebrados aquáticos, foram coletadas cinco amostras mensais de janeiro a maio de 2010 nestas nove estações. Um total de 4.615 indivíduos foram coletados, distribuídos em 16 ordens, 54 famílias e 83 táxons. Os táxons com maior abundância relativa foram Simulium (Diptera), Melanoides sp. (Thiaridae) e Orthocladiinae (Diptera: Chironomidae), com 20, 11 e 9% respectivamente. Constatou-se que os impactos antropogênicos moldam as variáveis ambientais e a estrutura das comunidades de macroinvertebrados na bacia do rio Ranchería.

Abstract Understanding the environmental factors that shape macroinvertebrate diversity is particularly important because rivers in the neotropics are continuously affected by changes in land use. The main objective of this work was to analyze how environmental variables associated with different levels of human activity shape the macroinvertebrate community in the Ranchería River. Various environmental variables were measured at each of the nine sampling stations distributed across three gradients of human activity in the Ranchería River Basin. The sampling design included three stations in the high elevation zone (P9, P8, P7; 595 to 308 masl), three in the medium elevation zone (P6, P5, P4; 153 to 112 masl), and three in the low elevation zone (P3, P2, P1; 90 to 22 masl). For aquatic macroinvertebrates, five monthly samples were taken from January to May 2010 from these nine stations. A total of 4,615 individuals were collected, distributed across 16 orders, 54 families, and 83 taxa. The taxa with the highest relative abundance were Simulium (Diptera), Melanoides sp. (Thiaridae), and Orthocladiinae (Diptera: Chironomidae), with 20, 11, and 9% respectively. It was found that anthropogenic impacts shape the environmental variables and the structure of macroinvertebrate communities in the Ranchería River Basin.

Resumo Os córregos e suas muitas nascentes são locais importantes para a formação dos rios e geralmente também são hotspots de biodiversidade aquática na bacia hidrográfica. As atividades humanas impactam a saúde desses ambientes, muitas vezes com a retirada da vegetação ciliar e também a entrada de sedimentos no leito do curso d’água, além da carga de poluentes como agrotóxicos. Este estudo teve como objetivo avaliar a comunidade macrobentônica em três riachos de cabeceira, ao longo de nove meses, monitorando a qualidade da água e a composição da comunidade com diferentes usos do solo. As concentrações das variáveis de qualidade da água, condutividade elétrica e sólidos suspensos totais, foram mais elevados no trecho fluvial em Extrema (EX), o que pode estar associado ao manejo da pastagem. No córrego em Toledo (TO), a temperatura da água e o fosfato foram mais elevados, provavelmente devido à retirada de mata ciliar e fertilizantes utilizados no cultivo de hortaliças, respectivamente. Quanto à comunidade bentônica, as métricas Dominância (D), % EPT, EPT/Chironomidae e o índice de diversidade de Shannon-Wiener (H') mostraram claramente um gradiente de saúde ambiental existente nos riachos estudados, sendo o de Monte Verde (MV) o mais preservado, seguido pelos córregos de Extrema (EX) e Toledo (TO). Esses dados evidenciam o impacto deletério de práticas agrícolas insustentáveis. Concluímos que tais atividades agrícolas influenciaram negativamente a qualidade ambiental e a comunidade de macroinvertebrados bentônicos nesses córregos de cabeceira.

Abstract Headwater streams play a crucial role in the formation of rivers; they boast numerous springs and serve as hotspots for aquatic biodiversity within watersheds. However, human activities frequently compromise the health of these environments. Common disturbances include the removal of riparian vegetation, sedimentation in the streambed, and the introduction of pollutants such as pesticides. This study sought to assess the macrobenthic community in three headwater rivers over a 9-month period, examining variations in water quality and community composition across different land uses. Key water quality variables - electrical conductivity and total suspended solids - were elevated at the Extrema (EX) Stream, likely attributable to pasture management practices. The Toledo (TO) Stream had higher water temperature and phosphate levels, potentially linked to the removal of riparian forest and the use of fertilizers in vegetable cultivation, respectively. Regarding the benthic community, metrics such as dominance (D); the percentage of Ephemeroptera, Plecoptera, and Trichoptera (% EPT); the EPT/Chironomidae ratio; and the Shannon-Wiener diversity index (H') revealed a clear gradient in environmental health among the three study sites. The Monte Verde (MV) stream emerged as the most pristine one, followed by the EX and TO sites. These data underscore the deleterious impact of unsustainable agricultural practices. In conclusion, such agricultural activities exert a negative influence on both environmental quality and benthic macroinvertebrate communities in headwater streams.

Resumen Introducción: La Familia Chironomidae es reconocida por su gran abundancia y diversidad en los ecosistemas de agua dulce alrededor del mundo. Sin embargo, el conocimiento taxonómico de esta familia es limitado, particularmente en Colombia. Objetivos: Estimar la abundancia y diversidad a nivel de género de la Familia Chironomidae y su dinámica espacio-temporal en tres quebradas, afluentes del Río Combeima en el centro de Colombia. Métodos: Este estudio describe la evaluación taxonómica y ecológica de las larvas de quironómidos presentes en tres quebradas altoandinas (Tolima, Colombia), denominadas Las Perlas (PE), La Plata (PL) y Cay (CA). Entre 2015-2016 se realizaron seis campañas de muestreo en periodos climáticos contrastantes, en nueve puntos de muestreo (tres por quebrada: parte alta, media, y baja). Las recolectas se realizaron con red Surber en diferentes sustratos. Resultados: Se registraron 15 594 larvas, correspondientes a tres subfamilias y 20 géneros. La más abundante fue Orthocladiinae con 13 698 larvas (87.84 %), dominada por Cricotopus spp. (66.19 %), seguida de Chironominae con 1 367 individuos (8.77 %) y Polypedilum spp. (5.18 %), y Tanypodinae con 530 organismos (3.40 %) y Pentaneura spp. (2.91 %). La mayor abundancia se encontró en PL3 (parte baja; 27.84 %), seguido de CA2 (parte media; 20.47 %) y PE1 (parte alta; 1.93 %). Las tres quebradas presentaron la mayor abundancia durante febrero 2016 (25.93 %; transición a la época de lluvias), seguido de noviembre 2015 (20.59 %; precipitaciones bajas) y octubre 2015 (3.94 %; precipitaciones altas). Conclusiones: Los resultados obtenidos amplían las listas taxonómicas de quironómidos en zonas altoandinas (1 419-2 586 m), y la caracterización detallada de los 20 géneros registrados en las quebradas seleccionadas, que constituyen aportes relevantes para el reconocimiento de estos dípteros y su rol ecológico en los sistemas acuáticos de los Andes colombianos.

Abstract Introduction: The Family Chironomidae is recognized for its great abundance and diversity in freshwater ecosystems around the world. However, taxonomic knowledge of this family is limited, particularly in Colombia. Objectives: To estimate the abundance and diversity at the genus level and its spatiotemporal dynamics in three streams, tributaries of the Combeima River in central Colombia. Methods: This study describes the taxonomic and ecological evaluation of chironomid larvae present in three high Andean streams (Tolima, Colombia), called Las Perlas (PE), La Plata (PL) and Cay (CA). Between 2015-2016, six sampling campaigns were conducted in contrasting climatic periods, at nine sampling points (three per stream: upper, middle, and lower). The collections were made with Surber net on different substrates. Results: 15 594 larvae were recorded, corresponding to three subfamilies and 20 genera. The most abundant subfamily was Orthocladiinae with 13 698 larvae (87.84 %), dominated by Cricotopus spp. (66.19 %), followed by Chironominae with 1 367 individuals (8.77 %) and Polypedilum spp. (5.18 %), and Tanypodinae with 530 organisms (3.40 %) and Pentaneura spp. (2.91 %). The highest abundance was found in PL3 (lower part; 27.84 %), followed by CA2 (middle part; 20.47 %) and PE1 (upper part; 1.93 %). The three streams presented the highest abundance during February 2016 (25.93 %; transition to the rainy season), followed by November 2015 (20.59 %; low rainfall) and October 2015 (3.94 %; high rainfall). Conclusions: The results obtained expands the taxonomic lists of chironomids in high Andean areas (1 419-2 586 m), and the detailed characterization of the 20 genera recorded in the selected streams, which constitute relevant contributions for the recognition of these dipterans and their ecological role in the aquatic systems of the Colombian Andes.

Resumen Introducción: La cuenca del rio Tambo es uno de los principales sistemas hidrográficos de la vertiente occidental del Perú y fuente de desarrollo para la agricultura, agroindustria, ganadería y consumo doméstico en el valle de Tambo y la ciudad de Arequipa. Objetivo: Analizar la estructura de macroinvertebrados en el río Tambo, Perú y evaluar la calidad del agua a través de esta comunidad. Métodos: Entre diciembre del 2018 y noviembre del 2019 se realizaron cinco muestreos en 12 estaciones, empleando una red Surber (500 μm). Los macroinvertebrados se identificaron a nivel de familia. Se registró la riqueza, dominancia de Simpson, equidad de Pielou, y diversidad verdadera de orden 1, para evaluar la estructura de la comunidad. Para estimar la similitud, se utilizó nMDS (índice de Bray-Curtis). Para verificar si existen diferencias en la estructura comunitaria, se empleó MANOVA de dos vías y ANOSIM. Para establecer la contribución de las familias a la similitud entre muestras, se utilizó SIMPER. La relación entre variables fisicoquímicas y biológicas se determinó con ACC. Se aplicó el índice ABI para evaluar la calidad ecológica. Resultados: se reconocieron 32 familias, siendo las más abundantes: Baetidae, Chironomidae, Leptohyphidae, Simuliidae, Hydroptilidae y Elmidae. La mayor y menor diversidad se presentó en la parte media y baja de la cuenca respectivamente. Existieron diferencias significativas (P < 0.05) de los índices de estructura comunitaria entre las 12 estaciones. Se evidenció mayor similitud entre las 12 estaciones en diciembre. Los puntajes del índice ABI se incrementan de la parte baja del río a la media, que se presentó la mejor calidad ecológica. Conclusión: Las comunidades de macroinvertebrados del río Tambo reflejan el estado del ecosistema. Los ambientes con impacto por actividad humana registran menor diversidad y calidad ecológica, ya que se altera la estructura, hábitat y calidad de agua del río.

Abstract Introduction: The River Tambo basin is one of the main hydrographic systems of the Peruvian western watershed, being a source of development for agriculture, agroindustry, livestock, and domestic use in the Tambo Valley and Arequipa City. Objective: To analyze the structure of macroinvertebrates in River Tambo, Perú and assess the water quality through this community. Methods: Five sampling events were conducted between December 2018 and November 2019 in 12 stations, using a Surber net (500 μm). Macroinvertebrates were identified at a family level. To assess community structure, richness, Simpson’s dominance index (D), Pielou’s evenness (J’), and true diversity of order 1 were determined. A nMDS based on the Bray-Curtis index was used to evaluate dissimilarity. To check for differences in community structure, ANOSIM and two-way MANOVA were used. SIMPER was used to establish family contribution to sample similarity. Relations between physicochemical and biological variables were determined by CCA. ABI index was applied to assess ecological quality. Results: 32 families were recognized, being the most abundant: Baetidae, Chironomidae, Leptohyphidae, Simuliidae, Hydroptilidae, and Elmidae. The middle and low zones of the basin showed the highest and lowest diversity respectively. There were significant differences (P < 0.05) in the community structure indices among the 12 stations differed. There was a higher similarity among the 12 stations in December. ABI scores increased from the low to the middle part of the river, which showed the highest ecological quality. Conclusion: Macroinvertebrate communities from River Tambo reflect ecosystem conditions. Environments impacted by human activities show lower diversity and ecological quality, due to the structure, habitat, and water quality of the river being altered.

ABSTRACT This study evaluates the water quality of the main tributary and efluent of the Santo Domingo Lagoon. The objectives were to analyze the physical-chemical and biological characteristics of the water to determine its influence on water quality, using the ICA-NSF, ICA-Dinius, ABI and IBF indices. For this, samplings were carried out during the months of April and June, evaluating a total of 15 parameters and identifying the benthic macroinvertebrates present in the water bodies. Physicochemical indicators show a slightly higher water quality in April (maximum value 42.2%) compared to June (maximum value 35.5%). Meanwhile, the biological evaluation showed poor water quality at the sampling points with values from 14 to 21 according to the ABI index, while the IBF index indicated excellent quality at the points, suggesting a discrepancy between biological and physicochemical quality. This discrepancy suggests the presence of contaminants that could affect biodiversity in the long term, so it is important to carry out constant and more in-depth monitoring to establish the health of the aquatic ecosystem.

RESUMEN El presente estudio evalúa la calidad del agua del principal afluente y efluente de la Laguna Santo Domingo. Los objetivos fueron analizar las características físico-químicas y biológicas del agua para determinar su influencia en la calidad del agua, utilizando los índices ICA-NSF, ICA-Dinius, ABI e IBF. Para esto, se realizaron muestreos durante los meses de abril y junio, evaluando un total de 15 parámetros e identificando los macroinvertebrados bentónicos presentes en los cuerpos de agua. Los indicadores fisicoquímicos muestran una calidad del agua ligeramente superior en abril (valor máximo 42,2%) respecto a junio (valor máximo 35,5%). Mientras que, la evaluación biológica exhibió mala calidad del agua en los puntos de muestreo con valores de 14 hasta 21 según el índice ABI, en tanto que el índice IBF indicó una calidad excelente en los puntos, sugiriendo una discordancia entre la calidad biológica (según el IBF) y fisicoquímica. Esta discrepancia sugiere la presencia de contaminantes que podrían afectar la biodiversidad a largo plazo, por lo que, es importante realizar un monitoreo constante y más profundo para establecer la salud del ecosistema acuático.

RESUMEN Antecedentes. El índice de calidad del agua (ICA) es una herramienta práctica y útil para estimar la calidad de los cuerpos de agua, este método se ha utilizado en muchos países. Objetivos. Evaluar la calidad del agua de la cuenca del río Ayuquila-Armería, con base en dos categorías de posible uso del recurso agua, uso en riego agrícola, protección de la vida acuática y uso potable. Métodos. Se realizó el análisis de variables físicas y químicas, análisis de metales pesados y nutrientes y la caracterización de aniones y cationes; además se complementaron las variables con la utilización de un índice de integridad biótica basado en familias de macroinvertebrados acuáticos, para estimar la contaminación orgánica y la determinación de coliformes fecales, en los cuarenta sitios de muestreo a lo largo de la parte alta, media y baja de la cuenca. Resultados. De los cuarenta sitios, la calidad del agua para uso en riego agrícola presento rangos del ICA de condiciones regulares (35%), buenas (27.5%) y excelentes (37.5 %). En cuanto a la comparación realizada para la calidad del agua para protección de la vida acuática y uso potable, se encontró que ocho sitios (44.4%) presenta condiciones de mala calidad, otros ocho sitios (44.4%) presentan buena calidad y solo dos sitios (11.11%) una condición de calidad excelente. Conclusiones. Para el uso de agua en riego agrícola no se encuentra ningún sitio que presente mala calidad del recurso, además mediante la utilización de diferentes parámetros relacionados con la agricultura se puede asegurar que no existe riesgo de pérdida o daño en cultivos por utilizar el agua para irrigación. Para el caso de la calidad del agua en cuanto a la protección de la vida acuática y uso potable, en general la cuenca presenta malas condiciones. En este sentido los organismos acuáticos están sufriendo afectaciones tanto en su hábitat como en las condiciones fisicoquímicas que pueden menguar sus poblaciones, por otra parte, las comunidades humanas cercanas a los cauces hídricos serán más susceptibles a tener problemas relacionados con la salud.

ABSTRACT Background. The water quality index (ICA) is a practical and useful tool to estimate the quality of water bodies, this method has been used in many countries. Goals. Evaluate the water quality of the Ayuquila-Armería river basin, based on two categories of possible use of the water resource, use in agricultural irrigation, protection of aquatic life and drinking use. Methods. The analysis of physical and chemical variables, analysis of heavy metals and nutrients and the characterization of anions and cations were carried out; In addition, the variables were complemented with the use of a biotic integrity index based on families of aquatic macroinvertebrates, to estimate organic contamination and the determination of fecal coliforms, in the forty sampling sites along the upper, middle, and lower part. of the basin. Results. Of the forty sites, the quality of the water for use in agricultural irrigation presented ICA ranges of regular (35%), good (27.5%) and excellent (37.5%) conditions. Regarding the comparison made for the quality of water for the protection of aquatic life and drinking use, it was found that eight sites (44.4%) present poor-quality conditions, another eight sites (44.4%) present good quality and only two sites (11.11%) an excellent quality condition. Conclusions. For the use of water in agricultural irrigation, there is no site that presents poor quality of the resource, in addition, by using different parameters related to agriculture, it can be ensured that there is no risk of loss or damage to crops by using water for irrigation. In the case of water quality in terms of the protection of aquatic life and potable use, in general the basin presents poor conditions. In this sense, aquatic organisms are suffering effects both in their habitat and in the physicochemical conditions that can decrease their populations, on the other hand, human communities near watercourses will be more susceptible to health-related problems.

RESUMEN Antecedentes: los manantiales son una buena opción como suministro de agua, ante esto, su explotación lleva a una disminución de las aguas subterráneas, afectando la cantidad y calidad del recurso. Objetivo: evaluar la calidad del agua de manantiales y determinar el índice de integridad biótica asociado a macroinvertebrados acuáticos, para evaluar el grado de conservación de los manantiales. Método: se evaluaron ocho manantiales en épocas de estiaje (mayo) y post lluvias (diciembre) a partir de un muestreo selectivo. De acuerdo a diversas Normas Mexicanas se determinaron algunos parámetros físico-químicos y bacteriológicos; simultáneamente se realizó la colecta de macroinvertebrados acuáticos. Posterior a esto, se determinó el índice de calidad del agua mediante tres métodos. Se realizaron análisis de correspondencia sin tendencia y, por último, se determinó el índice de integridad biótica asociado a macroinvertebrados acuáticos (IIBAMA). Resultados: los valores de los parámetros físico-químicos y bacteriológicos analizados indican contaminación mostrando valores más altos en la época de post lluvias. De acuerdo al IIBAMA, siete de ocho sitios (87.5 %) se valoran como impactados, al clasificarse en las categorías de “pobre y regular”, sólo el sitio Arroyo Guajolote está en la categoría de bueno (12.5 %). Conclusiones: Los manantiales de estudio se encuentran en cierta medida impactados debido a actividades antropogénicas relacionadas con el abastecimiento de agua para la población y actividades recreativas, esto compromete el buen funcionamiento del ecosistema y por consecuencia la calidad de los servicios ecosistémicos brindados.

ABSTRACT Background: springs are a good option for water supply, but their exploitation leads to a decrease in groundwater, affecting the quantity and quality of the resource. Aim: to evaluate the quality of spring water and determine the index of biotic integrity associated with aquatic macroinvertebrates to determine the degree of conservation of the springs. Methods: eight springs were evaluated during low water (May) and post rainfall (December) periods based on selective sampling. In accordance with various Mexican Standards, some physicochemical and bacteriological parameters were determined; simultaneously, aquatic macroinvertebrates were collected. Subsequently, the water quality index was determined using three methods. Correspondence analyses were performed without trend and finally, the index of biotic integrity associated with aquatic macroinvertebrates (IIBAMA) was determined. Results: the values of the physical-chemical and bacteriological parameters analyzed indicate contamination, showing higher values in the post-rainy season. According to IIBAMA, seven of eight sites (87.5 %) are rated as impacted, being classified in the “poor and fair” categories; only the Arroyo Guajolote site is in the “good” category (12.5 %). Conclusions: the springs studied are impacted due to anthropogenic activities related to water supply for the population and recreational activities, this compromises the proper functioning of the ecosystem and consequently the quality of ecosystem services provided.

Resumen Los macroinvertebrados como indicadores, son una alternativa adecuada para medir la calidad del agua de los manantiales de montaña y, los cambios ambientales en los ecosistemas, producto de las actividades antropogénicas que impactan en el suelo. Determinamos el índice FBI-ANIMAS de calidad del agua a través del índice biológico, tomando en consideración comunidades de insectos acuáticos como el índice FBI-PR. Estos nuevos índices combinan los valores de tolerancia con la abundancia de cada familia y el número total de individuos. Se calculó el coeficiente de correlación de Pearson para medir la asociación entre las familias como indicadores. Se observó que el índice FBI-ANIMAS se ajustó a la caracterización fisicoquímica de los manantiales de montaña y a las cantidades de Oxígeno Disuelto presentes en ellos. El índice FBI-ANIMAS para los manantiales de montaña (M1, M2, M3, M4 y M6) se ubicó en los parámetros numéricos de 4 a 1, lo que indica que cuentan con aguas de calidad regular a excelente, por el contrario, el manantial de montaña M5 se mantuvo en mala calidad.

Resumo Os macroinvertebrados, como indicadores, são uma alternativa adequada para medir a qualidade da água das nascentes das montanhas e as mudanças ambientais nos ecossistemas, produto das atividades antrópicas que impactam no solo. Determinamos o índice FBI-ANIMAS de qualidade da água através do índice biológico, levando em consideração comunidades de insetos aquáticos como o índice FBI-PR. Este novo índice combina os valores de tolerância com a abundância de cada família e o número total de indivíduos. O coeficiente de correlação de Pearson foi calculado para medir a associação entre os indicadores familiares. Observou-se que o índice FBI-ANIMAS foi ajustado à caracterização físico-química das nascentes montanhosas e às quantidades de Oxigênio Dissolvido nelas presentes. O índice FBI-ANIMAS para as nascentes de montanha (M1, M2, M3, M4 e M6) ficou nos parâmetros numéricos de 4 a 1, o que indica que possuem águas de regular a excelente qualidade, ao contrário, a nascente de montanha M5, permaneceu em má qualidade.

Abstract Macroinvertebrates as indicators, are an alternative that is adequate to measure the mountain springs water quality and, the environmental changes in ecosystems, product of the anthropogenic activities that impact on the ground. We determined the FBI-ANIMAS index of water quality through the biological index, taking into consideration aquatic insect communities like FBI-PR index, These new index combines the tolerance values with the abundance of each family and the total number of individuals. The Pearson correlation coefficient was calculated to measure the association between the families like indicators. It was observed that FBI-ANIMAS index was adjusted to the physicochemical characterization of the mountain springs and to Disolved Oxigen amounts present in them. The FBI-ANIMAS index for the mountain springs (M1, M2, M3, M4 and M6) was in the numeric parameters from 4 to 1, which indicates that they have regular to excellent quality waters, conversely, mountain spring M5, it remained in poor quality.

SUMMARY This is a review of studies related with the effects generated by the fast-growing exotic plantations (PECR) of Pinus radiata and Eucalyptus spp. on water quality of watersheds in south-central Chile, at different spatial and temporal scales. The analyzed data comes from a region between 36° - 40° S in the Central Valley and includes both mountain ranges, the Coastal and the Andes. Studies on the watershed’s capacity to export nutrients indicate that the conversion from native forests to forest plantations implies a net loss in nitrogen (N) and phosphorus (P) retention capacity. Consequently, watersheds with plantations coverage experience a net loss of these nutrients. Similarly, in watersheds dominated by Eucalyptus globulus, nitrogen retention decreases, especially NO3-N, and is partially reversed as a wider riparian vegetation is maintained. Studies of soil erosion and sediment transport losses show that clearcut harvesting has significant impacts on water quality, increasing sediment transport rates in streams. However, when soil conservation measures are practiced, erosion rates decrease significantly during forest harvesting. Some of the physical-chemical characteristics of the water, such as pH and temperature, are similar between streams with native forests and forest plantations. There is also a tendency for a decrease of richness and abundance of the macrobenthic invertebrates community due to the replacement of riparian vegetation by Eucalyptus spp.

RESUMEN Se presenta una revisión de estudios acerca de los efectos que generan las plantaciones exóticas de crecimiento rápido (PECR) de Pinus radiata y Eucalyptus spp. sobre la calidad del agua de cuencas en el centro-sur de Chile, a diferentes escalas espaciales y temporales. Los datos analizados provienen de una región comprendida entre los 36°- 40° S, en el Valle Central y en ambas cordilleras de la Costa y de los Andes. Los estudios acerca de la capacidad de las cuencas para exportar nutrientes indican que la conversión de bosques nativos por plantaciones forestales, implican una pérdida en la capacidad de retención de nitrógeno (N) y fósforo (P), por lo que las cuencas con cobertura de plantaciones presentan pérdidas netas de estos nutrientes. En cuencas donde predomina Eucalyptus globulus, la retención de N disminuye, especialmente NO3-N y se revierte parcialmente a medida que se mantiene un mayor ancho de vegetación ribereña. Los estudios de pérdidas de suelo por erosión y transporte de sedimentos muestran que la cosecha a tala rasa produce fuertes impactos sobre la calidad del agua, aumentando las tasas de transporte de sedimentos en los cauces de agua. Sin embargo, cuando se practican medidas de conservación de suelos las tasas de erosión disminuyen notablemente durante la cosecha forestal. Algunas de las características físico-químicas del agua, como pH y temperatura, son similares en esteros con bosques nativos y plantaciones forestales. Finalmente, se detectó una tendencia a la disminución de la riqueza y abundancia de la comunidad de macro invertebrados bentónicos debido al reemplazo de la vegetación ribereña de especies boscosas nativas por Eucalyptus spp.

Resumen La construcción de carreteras puede generar amenazas a la biodiversidad de una importante red hidrológica conformada por riachuelos conocidos comúnmente como quebradas en la amazonia peruana. El objetivo del estudio fue determinar la composición, riqueza, abundancia, diversidad, dominancia y similaridad de hábitats de comunidades de macroinvertebrados bentónicos de cinco quebradas ubicadas en el área de influencia del eje carretero Iquitos-Nauta (Loreto, Perú). Las colectas se realizaron en cuatro épocas (vaciante, seca, creciente y llena), usando una red tipo D-net. La comunidad de macroinvertebrados bentónicos estuvo compuesta por 68 taxones y 4 556 individuos, distribuidos en 4 filos (Arthropoda, Annelida, Mollusca y Nematoda). El análisis de similitud indica que hubo diferencias significativas (p < 0.05) entre las épocas de vaciante-seca con las de creciente-llena; siendo la época seca la de mayor valor de riqueza, abundancia y diversidad; y creciente la de mayor dominancia. Chironomidae, Leptophlebiidae, Elmidae y Palaemonidae; fueron los taxones más dominantes. El presente trabajo es un aporte al conocimiento de las comunidades de macroinvertebrados que habitan los pequeños ecosistemas lóticos de la selva baja peruana.

Abstract The construction of roads can generate threats to the biodiversity of an important hydrological network made up of streams known as quebradas in the Peruvian Amazon. The objective of the study was to determine the composition, richness, abundance, diversity, dominance, and similarity of habitats of benthic macroinvertebrate communities of five streams located around the Iquitos-Nauta highway axis (Loreto, Peru). The collections were made in four periods (empty, dry, growing, and full), using a D-net type network. The benthic macroinvertebrate community was composed of 68 taxa and 4556 individuals, distributed in 4 phyla (Arthropoda, Annelida, Mollusca and Nematoda). The similarity analysis indicates that there were significant differences (p < 0.05) between the empty-dry seasons and the growing-full seasons; The dry season being the one with the greatest value of wealth, abundance, and diversity; and increasing the one with greater dominance. Chironomidae, Leptophlebiidae, Elmidae and Palaemonidae; were the most dominant taxa. The present work is a contribution to the knowledge of the macroinvertebrate communities that inhabit the small lotic ecosystems of the Peruvian lowland forest.

Resumen Los objetivos de este trabajo fueron evaluar el efecto de los cultivos de cobertura (CC) y las secuencias de cultivos sobre algunas propiedades del suelo y la abundancia de la macrofauna edáfica; y la influencia de estas propiedades sobre la presencia de las principales familias de macroinvertebrados. Se trabajó en un experimento instalado en Zavalla (Santa Fe) cuyos tratamientos incluyeron CC de vicia y triticale como antecesores de maíz y soja, respectivamente, además de dos tratamientos de barbecho con los mismos cultivos de cosecha sucesores. Los muestreos se realizaron después del ciclo de los CC (Mcc-b) y de los cultivos de cosecha (Mf). Entre las propiedades edáficas, el carbono orgánico particulado registró un incremento en las secuencias que incluyeron CC, en tanto que la resistencia mecánica a la penetración y el porcentaje de agregados estables al agua presentaron variaciones a corto plazo que estuvieron vinculadas con la actividad de las raíces de los CC, particularmente luego de la supresión de la vicia. Por su parte, los cambios en la abundancia de macrofauna se asociaron con las condiciones edáficas generadas por los distintos tratamientos. En el Mcc-b existió una diferenciación entre ambos CC, y de éstos con respecto al barbecho, en tanto que en el Mf las muestras que incluyeron CC mostraron condiciones edáficas más favorables respecto a las del barbecho. Finalmente, los CC indujeron la presencia de organismos de la macrofauna pertenecientes a distintos grupos tróficos debido a la cobertura generada y al aporte de recursos alimenticios.

Abstract The objectives of this study were to evaluate the effects of cover crops (CC) and crop sequences on some soil properties and macrofauna abundance; and the influence of these properties on the presence of the main macroinvertebrates’ families. We worked on an experiment installed in Zavalla (Santa Fe) which treatments included CC of vetch and triticale before maize and soybean, respectively, and two treatments of fallow with the same cash crops. Samplings were done after CC (Mcc-b) and cash crops (Mf) cycles. Among edaphic properties, particulate organic carbon registered an increase in sequences with CC, while mechanical penetration resistance and water stable aggregates percentage showed short term variations that were linked with CC´s root development, particularly after vetch suppression. Changes in the abundance of macrofauna were associated with edaphic conditions generated by the treatments. In Mcc-b there was a differentiation between samples of both CC, and between them and fallow ones, while in Mf samples which included CC showed more favorable edaphic conditions in relation with fallow ones. Finally, CC leaded the presence of macrofaunal organisms from different trophic groups due to the coverage generated and the input of food resources.

Resumo 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.

Abstract 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.

Abstract: Aim Macroinvertebrates are extensively employed as bioindicators for evaluating how stream ecosystems respond to alterations in physical and chemical habitats caused by human activity. Although family-taxonomic level is usually used to identify macroinvertebrates in biomonitoring programs, coarser taxonomic resolution may provide similar information. We aim to evaluate taxonomic sufficiency by comparing macroinvertebrate communities at the order and family levels to differentiate the effects of different land uses. Methods We conducted colonization experiments using artificial substrates in streams representing three land use types: urban (U, n=3), intensive agriculture - dairy production (AD, n=4), and extensive cattle ranching (CR, n=4). Results We obtained similar results using both taxonomic levels, which effectively distinguished the impacts of different land uses. In the sites examined, the majority of indicator groups exhibited only one family per order, with the exception of Ephemeroptera (Leptophlebiidae, Baetidae, and Caenidae). Notably, Baetidae and Caenidae were more prevalent in streams associated with extensive cattle ranching (CR). Conclusions Although this study provides a clear precedent, further investigation of these systems and other land uses (e.g., afforestation) is needed to validate this pattern. Coarser taxonomic assessment holds potential as a cost-effective method for stream monitoring and assessment in Uruguay.

Resumo: Objetivo Os macroinvertebrados são amplamente utilizados como bioindicadores para avaliar a forma como os ecossistemas de riachos respondem às alterações dos habitats físicos e químicos causadas pela atividade humana. Embora o nível taxonômico de família seja normalmente utilizado para identificar macroinvertebrados em programas de biomonitoramento, uma resolução taxonômica mais grosseira pode fornecer informações semelhantes. O objetivo é avaliar a suficiência taxonómica, comparando as comunidades de macroinvertebrados ao nível da ordem e da família, para diferenciar os efeitos de diferentes usos do solo. Métodos Realizamos experimentos de colonização utilizando substratos artificiais em cursos de água representativos de três tipos de uso do solo: urbano (U, n=3), agricultura intensiva - produção de leite (AD, n=4), e pecuária extensiva (CR, n=4). Resultados Obtivemos resultados semelhantes utilizando ambos os níveis taxonômicos, o que permitiu distinguir eficazmente os impactos dos diferentes usos do solo. Nos locais examinados, a maioria dos grupos indicadores apresentava apenas uma família por ordem, com exceção dos Ephemeroptera (Leptophlebiidae, Baetidae e Caenidae). Notavelmente, Baetidae e Caenidae foram mais predominantes em riachos associados à criação extensiva de gado (CR). Conclusões Embora este estudo forneça um precedente claro, é necessária uma investigação mais aprofundada destes sistemas e de outras utilizações do solo (por exemplo, reflorestamento) para validar este padrão. A avaliação taxonômica mais grosseira tem potencial para ser um método económico de monitoramento e avaliação de cursos de água no Uruguai.

Abstract Conulariids are extinct scyphozoans, have benthic and sessile life modes, and inhabited shallow marine platforms. Taphonomic studies of these animals from the Parnaíba Basin are scarce, distinctly from the Paraná Basin. The present work seeks to analyze the taphonomic characteristics of Conularia quichua from the Pimenteira Formation, Parnaíba Basin, and infer deposition events that influenced this fossiliferous concentration. The material is housed at Laboratório de Paleontologia de Macroinvertebrados (LAPALMA) and consists of 43 specimens. The taphonomic signatures used in the analyses were orientation in relation to the bedding plane, concentration, degree of preservation, and theca filling. The cluster and correspondence analyses evidenced two taphonomic classes for single-unit, fragile skeletons of conulariids from Pimenteira Formation: the taphonomic class 1 comprehends obliquely, filled, and complete skeletons; the taphonomic class 2 comprehends concordantly, fragmented, flattened, grouped, and isolated skeletons. A high-stand system tract, after the maximum transgressive surface of the Pimenteira Formation, is interpreted to be the depositional environment of this concentration, where an episodic high-energy event was responsible for the fossiliferous lens. In addition, the lack of preserved calcium carbonate shells suggests acidic conditions, assuming that diagenetic control occurred in this accumulation.

Abstract This study was designed to assess the ichthyofaunal diversity of River Panjkora, Khyber Pakhtunkhwa, Pakistan. For this purpose, a total of 1189 fish from six different sites were collected along the river and identified using standard keys. The fish collected and identified were representing 38 species, belonging to 7 families. The investigation spanned a year, from July 2021 to May 2022. The most dominant family was Cyprinidae 76% (n=906/1189), followed by Nemacheilidae 5.8% (n=69/1189), Channidae 5.2% (n=62/1189), Sisoridae 5.1% (n=61/1189), Mastacembelidae 4.9% (n=58/1189), Salmonidae 2.6% (n=31/1189) and least was Bagridae 0.17 (n=2/1189). The most abundant speices was Schizothorax plagiostomus with relative density of 16.8. Family Cyprinidae was represented by 21 species, Sisoridae by 7 species, Nemacheilidae by 5 species, Channidae by 2 species, while Bagridae, Salmonidae and Mastacembelidae, were each represented by a single species. PAST 3, XLSTAT and EXCEL 2019 were used for principal component analysis to study correlation of fish diversity and richness. Eigenvalue obtained from Kumrat to Busaq were 3.32, 1.01, 0.80, 0.44, 0.31 and 0.10 respectively. The higher value at Kumrat shows higher diversity. The water quality assessment showed average value of water temperature 10.4 ͦC, pH 7.0, electrical conductivity 184 mg/L, dissolved oxygen 7.9 mg/L, turbidity 43.73 mg/L, total dissolved solids 101 mg/L, total suspended solids 34.72 mg/L, total solids 135.53 mg/L, total alkalinity 75.77 mg/L, total hardness 58.37 mg/L, ammonia 0.46 mg/L, sulphate 26.03 mg/L, chloride 14.67 mg/L, calcium 69.11 mg/L, chromium 0.18 mg/L, copper 0.03, cobalt mg/L 0.04, nickel 0.039 mg/L, lead 0.02 mg/L and Zinc 0.35 mg/L. The findings of this study indicated that most of the physicochemical parameters remained within the acceptable limits throughout the study period. Analysis of fish gut contents included; nymphs, insect larvae, the presence of algae, protozoans and macroinvertebrates in the river ecosystem.

Resumo Este estudo foi projetado para avaliar a diversidade da ictiofauna do rio Panjkora, Khyber Pakhtunkhwa, Paquistão. Para isso, foram coletados um total de .1189 peixes de seis locais diferentes ao longo do rio e identificados através de chaves-padrão. Os peixes coletados e identificados representavam 38 espécies, pertencentes a 7 famílias. A investigação durou um ano, de julho de 2021 a maio de 2022. A família mais dominante foi Cyprinidae 76% (n=906/1189), seguida por Nemacheilidae 5,8% (n=69/1189), Channidae 5,2% (n=62/ 1189), Sisoridae 5,1% (n=61/1189), Mastacembelidae 4,9% (n=58/1189), Salmonidae 2,6% (n=31/1189), e o mínimo foi Bagridae 0,17 (n=2/1189). A espécie mais abundante foi Schizothorax plagiostomus com densidade relativa de 16,8. A família Cyprinidae foi representada por 21 espécies, Sisoridae por 7 espécies, Nemacheilidae por 5 espécies, Channidae por 2 espécies, enquanto Bagridae, Salmonidae e Mastacembelidae foram representados cada um por uma única espécie. PAST 3, XLSTAT e EXCEL 2019 foram utilizados para análise de componentes principais para estudar a correlação entre diversidade e riqueza de peixes. Os autovalores obtidos de Kumrat para Busaq foram 3,32, 1,01, 0,80, 0,44, 0,31 e 0,10, respectivamente. O valor mais alto em Kumrat mostra maior diversidade. A avaliação da qualidade da água apresentou valor médio de temperatura da água 10,4 ͦC, pH 7,0, condutividade elétrica 184 mg/L, oxigênio dissolvido 7,9 mg/L, turbidez 43,73 mg/L, sólidos totais dissolvidos 101 mg/L, sólidos suspensos totais 34,72 mg/L, sólidos totais 135,53 mg/L, alcalinidade total 75,77 mg/L, dureza total 58,37 mg/L, amônia 0,46 mg/L, sulfato 26,03 mg/L, cloreto 14,67 mg/L, cálcio 69,11 mg/L, cromo 0,18 mg /L, cobre 0,03, cobalto mg/L 0,04, níquel 0,039 mg/L, chumbo 0,02 mg/L e zinco 0,35 mg/L. Os resultados deste estudo indicaram que a maioria dos parâmetros físico-químicos permaneceu dentro dos limites aceitáveis durante todo o período de estudo. Análise do conteúdo intestinal dos peixes incluiu ninfas, larvas de insetos, presença de algas, protozoários e macroinvertebrados no ecossistema fluvial.