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.

Diversity patterns of aquatic macroinvertebrates in a tropical high-Andean catchment

Introduction: Glacierised catchments are remote and hostile environments, in which streams from different water sources (e.g., glacier melt, rain/snowmelt, groundwater) converge, creating a complex mosaic of stream sites with varying levels of glacial influence and environmental conditions. This environmental heterogeneity, in turn, influences the assemblage and composition of aquatic communities and produces complex patterns of species diversity at the catchment scale. Objectives: In this contribution, we assessed biodiversity and community composition of aquatic macroinvertebrate communities from 51 stream site types in a glacierised catchment in the tropical Andes. The aim of our study was to: (1) determine diversity, rarity, commonness and spatial distribution patterns of aquatic macroinvertebrate communities from sites with different water sources, and (2) identify which environmental variables influence the density and presence of macroinvertebrate taxa and, in particular, of the subfamilies of the ubiquitous chironomids. Methods: Our study sites were grouped according to their water source and to their percentage of glacier coverage in the catchment (GCC). At each site we sampled aquatic macroinvertebrates, measured environmental variables and assessed community differences and environmental influence with ordination analyses and generalized linear models. Results: Kryal and mixed sites had an important proportion of rare taxa. Mean richness was highest in the mixed sites and lowest in the sites with the highest glacier cover; while sites with an intermediate percentage of glacier cover, had the highest values of α and β diversity. We found that 13 taxa (15.9%) were common to all stream site types. SIMPER analysis showed that Orthocladiinae, Hyalella sp. and Andesiops sp. contributed the most to the dissimilarity between site types (˃ 45% of cumulative contribution). RDA showed that kryal sites were associated with high turbidity and density of Podonomids, and with low temperature, amount of CPOM and densities of both Anomalocosmoecus sp. and Andesiops sp. Orthocladinae was associated with high current velocity and chlorophyll a concentration, whereas Hyalella sp. had a positive relationship with higher pH and streambed stability. Generalized linear models showed that GCC was the main variable explaining all faunal metrics. Current velocity explained macroinvertebrate abundance, water temperature was related to chironomid density and chlorophyll a influenced Orthocladiinae presence-absence. Conclusions: Our results suggest that by favoring the presence of rare taxa and taxa turnover, glacier influence may increase biodiversity in glacierised catchments. In terms of biodiversity conservation, this study confirms an urgent need to increase knowledge of high-Andean stream biodiversity, especially in highly heterogenous glacierised catchments, to better describe regional biodiversity patterns and community composition of these highly vulnerable freshwater ecosystems. Detailed analyses of benthic communities and development of databases are key for conservation strategies. Water management municipalities and/or enterprises should consider water quality and stream types for more sustainable management of these important ecosystems.

Introducción: Las cuencas glaciares son entornos remotos y hostiles, en los que los arroyos de diferentes fuentes de agua (p.ej., deshielo de glaciares, lluvia/deshielo, agua subterránea) convergen, creando un mosaico complejo de tramos con diferentes niveles de influencia glacial y condiciones ambientales. Esta heterogeneidad ambiental influye, a su vez, en el ensamblaje y composición de las comunidades acuáticas y produce complejos patrones de diversidad a la escala de la cuenca. Objetivos: En esta contribución, evaluamos la biodiversidad y composición de comunidades de macroinvertebrados acuáticos en 51 sitios de una cuenca glaciar en los Andes tropicales. Los objetivos de nuestro estudio fueron: (1) determinar la diversidad, la contribución de taxones raros y comunes y los patrones de distribución espacial de las comunidades de macroinvertebrados acuáticos en sitios con diferentes fuentes de agua, y (2) identificar qué variables ambientales influyen en la densidad y presencia de taxones de macroinvertebrados y, en particular, de las subfamilias de los omnipresentes quironómidos. Métodos: Agrupamos a nuestros sitios de estudio según su fuente de agua y su porcentaje de cobertura de glaciar en la cuenca (GCC). En cada sitio donde muestreamos macroinvertebrados acuáticos, medimos variables ambientales y evaluamos las diferencias entre comunidades y la influencia ambiental con análisis de ordenación y modelos lineales generalizados. Resultados: Los sitios kryal y mixtos tuvieron una proporción importante de taxones raros. La riqueza media fue más alta en los sitios mixtos y más baja en los sitios con mayor cobertura glaciar; mientras que los sitios con un porcentaje intermedio de cobertura glaciar tuvieron los valores más altos de diversidad α y β. Encontramos que 13 taxones (15,9%) fueron comunes a todos los tipos de sitios de estudio. El análisis SIMPER mostró que Orthocladiinae, Hyalella sp. y Andesiops sp. contribuyeron más a la disimilitud entre tipos de sitios (˃ 45% de la contribución acumulada). El RDA mostró que los sitios kryal estaban asociados con alta turbidez y densidad de podonómidos, y con baja temperatura, cantidad de CPOM y densidad de Anomalocosmoecus sp. y Andesiops sp. Orthocladinae se asoció con una alta velocidad de corriente y concentración de clorofila a, mientras que Hyalella sp. tuvo una relación positiva con pH más alto y estabilidad del lecho del río. Los modelos lineales generalizados mostraron que GCC fue la variable principal para explicar todas las métricas de fauna. La velocidad de corriente explicó la abundancia de macroinvertebrados, la temperatura del agua estuvo relacionada con la densidad de los quironómidos y la clorofila influenció la presencia-ausencia de Orthocladiinae. Conclusiones: Nuestros resultados sugieren que, al favorecer la presencia de taxones raros y la rotación de taxones, la influencia de los glaciares puede aumentar la biodiversidad en cuencas con influencia glaciar. En términos de conservación de la biodiversidad, este estudio confirma la necesidad urgente de incrementar el conocimiento de la biodiversidad en arroyos de la región altoandina, especialmente en cuencas glaciares altamente heterogéneas, para describir mejor los patrones de biodiversidad regional y la composición de las comunidades en estos ecosistemas altamente vulnerables. Análisis detallados de las comunidades bentónicas y el desarrollo de bases de datos son claves para diseñar estrategias de conservación. Los municipios y/o empresas administradoras de agua deben considerar la calidad del agua y los tipos de arroyos para una gestión más sostenible de estos importantes ecosistemas.

Aquatic Oligochaete Communities in Amazonian Streams, Saracá-Taquera National Forest, Pará, Brazil / Comunidade de oligoquetos aquáticos em riachos amazônicos, Floresta Nacional Saracá-Taquera, Pará, Brasil

Abstract: The aim of this study was to analyze aquatic oligochaete distribution in relation to water column physicochemical variables, structural environmental variation, and predominant substrates in the preserved Amazonian streams of the Saracá-Taquera National Forest (FLONA Saracá-Taquera), northwest Pará, Brazil. Oligochaetes are widely used as bioindicators for monitoring aquatic environments as they are very sensitive to pollution and environmental changes. Physicochemical and structural variables were measured from 100 stream segments in order to understand the distribution of oligochaetes in Amazonian streams. Biotic samples were collected using Surber samplers in three of the most predominant substrate types in each segment. PERMANOVA testing showed that there was a significant difference in the oligochaete community among some substrates, potentially caused by a difference in the abundance of the most common taxa. Canonical Correspondence Analysis showed that physical variables drive the distribution of oligochaetes in preserved Amazonian streams, as they determine the formation of different substrates along the stream, from the source to the mouth; favoring the presence of oligochaetes with more specific ecological needs in low-order streams, and the presence of oligochaetes capable of colonizing various types of substrates and deeper zones in high-order streams. These results suggest that water depth and channel width are the main drivers of aquatic oligochaete distribution along Amazonian streams, determining the formation of unstable and low-quality substrates and, consequently, the low colonization by oligochaetes in high-order streams; and more diverse and stable substrate formation in low-order streams, favoring the colonization by diverse taxa of aquatic oligochaetes in low-order Amazonian streams.

Resumo: O objetivo deste trabalho foi analisar a distribuição da comunidade de oligoquetos em relação às variáveis físico-químicas da coluna da água, variação estrutural do ambiente, e substratos predominantes em riachos amazônicos conservados na FLONA Saracá-Taquera, noroeste do Pará, Brasil. Oligochaetes são amplamente utilizados como bioindicadores para monitoramento de ambientes aquáticos, pois são muito sensíveis à poluição e às mudanças ambientais. Variáveis físico-químicas e estruturais de 100 trechos de riachos foram mensuradas para entender a distribuição de oligoquetos em riachos amazônicos. Amostras bióticas foram coletadas com amostrador Surber em três dos tipos de substratos mais predominantes em cada trecho. A PERMANOVA mostrou que há uma diferença significativa da comunidade de oligoquetos entre alguns substratos, possivelmente baseada nas diferenças no número do táxon mais comum. A Análise de Correspondência Canônica mostrou que as variáveis físicas controlam a distribuição da comunidade de oligoquetos em riachos amazônicos preservados, porque estas variáveis determinam a formação dos diferentes substratos ao longo do riacho, desde a nascente até a foz, favorecendo a presença de oligoquetos com necessidades ecológicas mais específicas em riachos de baixa ordem, e oligoquetos capazes de colonizar diferentes tipos de substrato e zonas mais profundas em riachos de ordem maior. Os resultados deste trabalho sugerem que a profundidade da água e a largura do canal são as variáveis que controlam a distribuição da comunidade de oligoquetos em riachos amazônicos, determinando a formação de substratos instáveis e de baixa qualidade, e consequentemente baixa colonização de oligoquetos, em riachos de ordem maior; e formação de substratos mais diversificados, mais estáveis e de qualidade em riachos de baixa ordem, favorecendo a colonização de diversos taxa de oligoquetos aquáticos em riachos amazônicos de baixa ordem.

Calidad biológica y fisicoquímica de tres fuentes de agua y su relación con el fenómeno de El Niño y La Niña / Biological and physicochemical quality from three water sources and its relation to the El Niño and La Niña phenomenon

RESUMEN En el municipio de El Carmen de Viboral, Antioquia, la cuenca de la quebrada La Cimarronas y sus afluentes Los Andes y La Madera son las principales fuentes de abastecimiento del acueducto de la localidad. Además, en estas y en otras cinco estaciones de muestreo, ubicadas en la parte alta de la microcuenca y sus afluentes, se realizó la evaluación fisicoquímica, microbiológica y biológica, mediante el uso de los macroinvertebrados acuáticos, en tres periodos del ciclo hidrológico de El Niño (2016), los cuales, fueron comparados con tres muestreos del ciclo de La Niña (2011). Se pudo identificar la capacidad de resiliencia ambiental bajo un déficit y exceso de precipitaciones del sistema acuático. Durante el ciclo afectado por El Niño, se presentó mayor concentración de oxígeno disuelto, pH circumneutral, menor temperatura del agua y mayores concentraciones de nitritos, nitrógeno amoniacal y coliformes totales. Durante el ciclo afectado por La Niña, se manifestó mayor temperatura del agua, sólidos totales, dureza, nitratos, fósforo total y mejores condiciones de calidad biológica del agua, según el índice BMWP. No se registraron variaciones estadísticamente significativas del caudal, la temperatura del agua, la conductividad eléctrica y los índices comunitarios (diversidad, equidad, dominancia y riqueza).

ABSTRACT In the municipality of El Carmen de Viboral, Antioquia, the basin of the La Cimarronas stream and its tributaries Los Andes and La Madera, are the main sources of supply of the local aqueduct. In addition, of these, other five sampling stations located in the upper part of the basin and its tributaries, the physico-chemical, microbiological and biological evaluation was carried out through the use of aquatic macroinvertebrates in three periods of the El Niño hydrological cycle (2016), which were compared with three samplings of the La Niña cycle (2011). The capacity of environmental resilience could be identified under a deficit and excess precipitation of the aquatic system. During the cycle affected by El Niño there was a higher concentration of dissolved oxygen, circumneutral pH, lower water temperature and higher concentrations of nitrites, ammonia nitrogen and total coliforms. During the cycle affected by La Niña, there was a higher water temperature, total solids, hardness, nitrates, total phosphorus and better conditions of biological water quality according to the BMWP index. There were no statistically significant variations in flow, water temperature, electrical conductivity and community indices (diversity, equity, dominance and richness).

Comparison of Water Quality Between Two Andean Rivers by Using the BMWP/COL. and ABI. Indices / Comparación de la calidad del agua en dos ríos altoandinos mediante el uso de los índices bmwp/col. y abi

RESUMEN Se comparó la calidad ecológica del río Tota durante agosto 2007 y febrero 2008, y el curso alto del río Bogotá entre los meses de octubre 2013 y enero 2014, aplicando los índices BMWP/Col y ABI. Los puntos de muestreo corresponden a la parte alta, media y baja del gradiente longitudinal. En el río Tota se determinaron 27 familias correspondientes a 11 órdenes, donde las más abundantes fueron Baetidae (25,43 %), Leptohyphidae (16,43 %), Naididae (13,76 %), Chironomidae (11,42 %) y Hyalellidae (10,30 %). En el curso alto del río Bogotá se determinaron 32 familias correspondientes a 13 órdenes, y las más abundantes fueron Chironomidae (28,94 %), Leptoceridae (25,20 %), Naididae (18,34 %) y Simuliidae (8,63 %). En el río Tota, El BMWP/Col. presentó una calidad de agua buena, mientras que el ABI presentó una calidad aceptable. Por otra parte, en la parte alta del Río Bogotá, tanto el BMWP/ Col. como el ABI presentaron variaciones en la calidad del agua entre aceptable y muy crítica. El ACC para el río Tota mostró correlaciones entre la temperatura y conductividad con las familias Hyalellidae y Leptohyphidae mientras que el caudal se relaciona con Sphaeriidae; mientras que el curso alto del río Bogotá se correlacionó el caudal, la conductividad y la temperatura con la familia Veliidae. A manera de conclusión, los resultados obtenidos denotan que el índice ABI, que es un índice creado para sistemas andinos de montaña, es más sensible a los impactos que el índice BMWP/Col.

ABSTRACT The ecological quality of the Tota River was evaluated during August 2007 and February 2008 and compared to the upper part from Bogotá River between October 2013 and January 2014, by applying the BMWP/Col and ABI indexes. The sampling points corresponding to the high, medium and low part of the longitudinal gradient. In the Tota River, 27 families were determined corresponding to 11 orders, where the most abundant were Baetidae (25.43 %), Leptohyphidae (16.43 %), Naididae (13.76 %), Chironomidae (11.42 %) and Hyalellidae (10.30 %). In the upper course of Bogotá River, 32 families were determined to conform 13 orders, where the most abundant were Chironomidae (28.94 %), Leptoceridae (25.20 %), Naididae (18.34 %) and Simuliidae (8.63 %). In the river Tota, The BMWP/Col. The index showed a good status, while the ABI index exhibited an acceptable quality. On the other hand, in the upper part of the Bogotá River, both the BMWP/Col. and ABI showed variations in quality between acceptable and very critical. The CCA for the Tota River exhibited correlations between temperature and conductivity with the families Hyalellidae and Leptohyphidae while the stream flow was linked with the family Sphaeriidae. On the other hand, in the upper part of Bogotá River the stream flow, conductivity and temperature were correlated with the occurrence of the family Veliidae. Our results showed that the ABI index is more sensitive to impacts that the BMWP/Col index is showing its ability to evaluate the Andean mountain systems.

Feeding preference of the shredder Phylloicus sp. for plant leaves of Chrysophyllum oliviforme or Miconia chartacea after conditioning in streams from different biomes / Preferência alimentar do fragmentador Phylloicus sp. por folhas de Chrysophyllum oliviforme e Miconia chartacea após condicionadas em riachos de dois biomas

Abstract Macroinvertebrate shredders consume preferably leaves conditioned by fungi and bacteria which offer greater palatability to them. Plant species in Cerrado present high concentration of chemical elements such as lignin and cellulose, phenols and tanins thus making them less attractive for shredders consumption and limiting the palatability. This study aimed to evaluate the feeding preference of a macroinvertebrate shredder of the genus Phylloicus for plant material from two different biomes (Cerrado and Mata Atlântica), after conditioning in a stream of Mata Atlântica and observing their physical and chemical characteristics. Senescent leaves were collected, monthly from the litterfall of riparian vegetation in a 500 m stretch of a stream in each biome from August 2014 to January 201. The most abundant species in each stream was selected for the experiment. The experimental design consisted in with two treatments. The first (T1) comprised leaf discs from Chrysophyllum oliviforme (Cerrado species) together with leaf discs of Miconia chartacea (Atlantic Forest species) which were conditioned in the Atlantic Forest stream. The second treatment (T2) involved leaf discs of Miconia chartacea conditioned in Mata Altlântica and Cerrado streams. Both tests had showed significant differences between the two treatments (T1 and T2). For T1, there was consumption of M. chartacea leaf discs by Phylloicus sp., but there was no consumption of C. oliviforme discs. For T2, there was preference for M. chartaceae leaves conditioned in a stream of Mata Atlântica than in Cerrado stream. The results showed that Phylloicus sp., had presented preference for food detritus of the Mata Antlântica biome and rejection to the one from Cerrado biome.

Resumo Macroinvertebrados fragmentadores consomem folhas preferencialmente condicionadas por fungos e bactérias que lhes oferece uma maior palatabilidade. Nas espécies do cerrado esse condicionamento está também associado às altas concentrações de elementos químicos limitantes à palatabilidade como alto teor de lignina e celulose, que tornam as folhas menos atrativas para os fragmentadores. O trabalho teve como objetivo avaliar a preferência alimentar de macroinvertebrados fragmentador ( Phylloicus sp.) por material vegetal de dois diferentes biomas (Cerrado e Mata Atlântica), após condicionamento em riacho de Mata Atlântica, observando suas características físicas e químicas. Foram coletadas folhas senescentes do aporte vegetal (AV) de espécies nativas da vegetação ripária nesses dois biomas, com periodicidade mensal em um trecho de 500 m de um córrego em cada bioma. O experimento foi delineado com dois tratamentos. O primeiro (T1) compreendeu discos de folhas do Cerrado (Chrysophyllum oliviforme) mais discos de folhas da Mata Atlântica (Miconia chartacea) que foram condicionadas em córrego de Mata Atlântica. O segundo tratamento (T2) envolveu discos de folhas da Mata Atlântica condicionadas em córrego da Mata Atlântica mais discos de folhas da Mata Atlântica condicionadas em córrego do Cerrado. Os dois testes apontaram diferenças significativas entre os dois tratamentos (T1 e T2). Para T1 houve consumo de discos de folha de M. chartacea por Phylloicus sp, mas não houve consumo dos discos de C. oliviforme , de Cerrado. Para T2, houve o consumo, porém a preferência pelas folhas de M. chartaceae condicionadas no córrego da Mata Atlantica foi consideravelmete maior. Os resultados apontam que Phylloicus sp, apresentou preferência alimentar pelo detrito de bioma de Mata Atlântica e rejeição pelo detrito do bioma Cerrado.

Evaluación de la calidad ecológica de quebradas andinas en la cuenca del río magdalena, colombia / Evaluation of the ecological quality of andean creeks in the magdalena river basin, colombia

Se evaluó la calidad ecológica de cuatro quebradas andinas afluentes de los ríos Nare y Guatapé, cuenca del río Magdalena, Colombia. Se realizaron cuatro muestreos entre junio de 2011 y febrero de 2012, en tres sitios por quebrada, para un total de 12 evaluados. Se recolectaron muestras de macroinvertebrados, utilizando el método D-net, con malla de 500µm y colección manual sobre sustratos. El hábitat del río y la vegetación ribereña fueron evaluados, mediante el establecimiento de estaciones de referencia y la aplicación del Índice de Hábitat Fluvial (IHF), el Índice de calidad de la vegetación de ribera Andina (QBR-And), adaptado para los ríos andinos, el Índice Biological Monitoring Working Party (BMWP/Col) y el índice ECOSTRIAND (ECOlogical STatus RIver ANDean). Se establecieron siete sitios de referencia, caracterizados por vegetación ribereña en ambos márgenes, sin alteraciones o con un bajo grado de alteración antrópica, los cuales, presentaron altos valores de IHF, QBR-And, BMWP/Col, indicando buena calidad ecológica para los ensamblajes de macroinvertebrados. Cinco sitios se determinaron como alterados con alta afectación antrópica, vegetación ribereña reducida o ausente en los dos márgenes, predominio de pastos y actividades agrícolas y bajos valores en los índices antes mencionados, lo que indica una menor calidad ecológica.

The ecological quality of four Andean creeks tributaries of the Nare and Guatapé Rivers, Magdalena River Basin, Colombia was evaluated. Four field samplings were carried out between June 2011 and February 2012, at three sites for each creek, for a total of 12 sites evaluated. Macroinvertebrates samples were caught using the D-net method with mesh of 500µm and manual collection on substrates. The river habitat and riparian vegetation were evaluated through of the establishment of reference stations and the application of the River Habitat Index (IHF), the Riparian-Andean vegetation quality index (QBR-And) adapted for Andean rivers, the Biological Monitoring Working Party-Colombia index (BMWP / Col), and the ECOSTRIAND index (ECOlogical STatus RIver ANDean). Seven reference sites were established, which were characterized by riparian vegetation in both sides, without alterations or with a low degree of anthropic disturbance, presented high values of IHF, QBR-And, BMWP/Col, indicating good ecological quality for macroinvertebrates and fish assemblage's. Five sites were determined as altered with high anthropogenic disturbance, riparian vegetation reduced or absent in the two margins, predominance of pastures and agricultural activities, and low values in the afore mentioned indexes, which indicates less ecological quality.

Aquatic oligochaeta (Annelida: Clitellata) in extractive reserve Lake Cuniã, Western Brazilian Amazon / Oligoquetos aquáticos (Annelida: Clitellata) na reserva extrativista Lago do Cuniã, Amazônia Ocidental Brasileira

Abstract Oligochaeta is one of the most common and abundant taxon in continental aquatic fauna. However, knowledge of their distribution in Brazilian ecosystems is still incomplete and fragmented. Thus, the aim of this study was to develop an inventory of aquatic oligochaetes in the Extractive Reserve of Lake Cuniã in the State of Rondônia, Brazil. Collections of data were performed during the dry (August 2015) and rainy seasons (February 2016). The sediment samples were collected near the lakeside region using the kick sampling method and a kick-net sampler (mesh size of 0.25mm). This paper provides a catalog with 12 taxon from a total of 383 specimens, distributed into two families: Naididae (95.08%) and Opistocystidae (4.92%). The Pristininae subfamily was the most significant (85.68%), followed by subfamilies: Naidinae (8.36%), Tubificinae (0.52%) and Rhyacondrilinae (0.52%). In addition, some species such as Allonais inaequalis, Aulophorus furcatus, Dero nivea, Pristina synclites, Pristina menoni and Opistocysta serrata, were recorded for the first time in the Brazilian Amazon region. Therefore, the results of this study contribute to increase knowledge on the distribution of the Oligochaeta class in Brazil, particularly in the North of the country, which is so extensive and rich in water resources, but not extensively studied.

Resumo Oligochaeta é um dos táxons mais comuns e abundantes na fauna aquática continental. No entanto, o conhecimento da sua distribuição nos ecossistemas brasileiros ainda é incompleto e fragmentado. Assim, o objetivo deste estudo foi desenvolver um inventário de oligoquetos aquáticos na Reserva Extrativista do Lago Cuniã no estado de Rondônia, Brasil. Foram realizadas duas coletas, cobrindo o período seco (agosto 2015) e chuvoso (fevereiro 2016). As amostras de sedimento foram coletadas perto da região marginal do lago pelo método de amostragem Kick sampling usando um amostrador Kick-net (malha de 0,25 mm). Nós catalogamos 12 táxons do total de 383 espécimes, distribuídos em duas famílias: Naididae (95,08%) e Opistocystidae (4,92%). A subfamília Pristininae foi a mais significativa (85,68%), seguida das subfamílias: Naidinae (8,36%), Tubificinae (0,52%) e Rhyacondrilinae (0,52%). Além disso, algumas espécies, como Allonais inaequalis, Aulophorus furcatus, Dero nivea, Pristina synclites, Pristina menoni e Opistocysta serrata, tiveram o primeiro registro na Amazônia brasileira. Assim, os resultados deste estudo contribuem para aumentar o conhecimento da distribuição da classe Oligochaeta no Brasil, particularmente no Norte do país, que é tão extenso e rico em recursos hídricos, porém pouco estudado.

Feeding preference of the shredder Phylloicus sp. for plant leaves of Chrysophyllum oliviforme or Miconia chartacea after conditioning in streams from different biomes

Abstract Macroinvertebrate shredders consume preferably leaves conditioned by fungi and bacteria which offer greater palatability to them. Plant species in Cerrado present high concentration of chemical elements such as lignin and cellulose, phenols and tanins thus making them less attractive for shredders consumption and limiting the palatability. This study aimed to evaluate the feeding preference of a macroinvertebrate shredder of the genus Phylloicus for plant material from two different biomes (Cerrado and Mata Atlântica), after conditioning in a stream of Mata Atlântica and observing their physical and chemical characteristics. Senescent leaves were collected, monthly from the litterfall of riparian vegetation in a 500 m stretch of a stream in each biome from August 2014 to January 201. The most abundant species in each stream was selected for the experiment. The experimental design consisted in with two treatments. The first (T1) comprised leaf discs from Chrysophyllum oliviforme (Cerrado species) together with leaf discs of Miconia chartacea (Atlantic Forest species) which were conditioned in the Atlantic Forest stream. The second treatment (T2) involved leaf discs of Miconia chartacea conditioned in Mata Altlântica and Cerrado streams. Both tests had showed significant differences between the two treatments (T1 and T2). For T1, there was consumption of M. chartacea leaf discs by Phylloicus sp., but there was no consumption of C. oliviforme discs. For T2, there was preference for M. chartaceae leaves conditioned in a stream of Mata Atlântica than in Cerrado stream. The results showed that Phylloicus sp., had presented preference for food detritus of the Mata Antlântica biome and rejection to the one from Cerrado biome.

Resumo Macroinvertebrados fragmentadores consomem folhas preferencialmente condicionadas por fungos e bactérias que lhes oferece uma maior palatabilidade. Nas espécies do cerrado esse condicionamento está também associado às altas concentrações de elementos químicos limitantes à palatabilidade como alto teor de lignina e celulose, que tornam as folhas menos atrativas para os fragmentadores. O trabalho teve como objetivo avaliar a preferência alimentar de macroinvertebrados fragmentador ( Phylloicus sp.) por material vegetal de dois diferentes biomas (Cerrado e Mata Atlântica), após condicionamento em riacho de Mata Atlântica, observando suas características físicas e químicas. Foram coletadas folhas senescentes do aporte vegetal (AV) de espécies nativas da vegetação ripária nesses dois biomas, com periodicidade mensal em um trecho de 500 m de um córrego em cada bioma. O experimento foi delineado com dois tratamentos. O primeiro (T1) compreendeu discos de folhas do Cerrado (Chrysophyllum oliviforme) mais discos de folhas da Mata Atlântica (Miconia chartacea) que foram condicionadas em córrego de Mata Atlântica. O segundo tratamento (T2) envolveu discos de folhas da Mata Atlântica condicionadas em córrego da Mata Atlântica mais discos de folhas da Mata Atlântica condicionadas em córrego do Cerrado. Os dois testes apontaram diferenças significativas entre os dois tratamentos (T1 e T2). Para T1 houve consumo de discos de folha de M. chartacea por Phylloicus sp, mas não houve consumo dos discos de C. oliviforme , de Cerrado. Para T2, houve o consumo, porém a preferência pelas folhas de M. chartaceae condicionadas no córrego da Mata Atlantica foi consideravelmete maior. Os resultados apontam que Phylloicus sp, apresentou preferência alimentar pelo detrito de bioma de Mata Atlântica e rejeição pelo detrito do bioma Cerrado.

Effects of forest conversion on the assemblages' structure of aquatic insects in subtropical regions

The effects of forest conversion to agricultural land uses on assemblages of aquatic insects were analyzed in subtropical streams. Organisms and environmental variables were collected in six low-order streams: three streams located in a forested area, and three in areas converted to agricultural land uses. We expected that the aquatic insects' assemblage attributes would be significantly affected by forest conversion, as well as by environmental variables. Streams in converted areas presented lower species richness, abundance and proportion of sensitive insect taxa. The ANOSIM test evidenced strong difference in EPT assemblage structure between streams of forested and converted areas. The ISA test evidenced several EPT genera with high specificity to streams in forested areas and only one genus related to streams in converted areas. Thus, the impacts of the conversion of forested area to agricultural land uses have significantly affected the EPT assemblages, while environmental variables were not affected. We suggest that the effects detected can be influenced by two processes related to vegetation cover: i) lower input of allochthonous material, and ii) increased input of fine sediments in streams draining converted areas.

Biomass of macroinvertebrates and physicochemical characteristics of water in an Andean urban wetland of Colombia / Biomassa de macroinvertebrados e características físicas e químicas da água em um pantanal urbano dos Andes na Colômbia

Aquatic macroinvertebrates (AMI) play an important role in the ecology of wetlands, either by their job as regulators of the cycles of matter, as for their energy storage function represented in their biomass, which is transferred to higher trophic levels. To answer the question of how biomass of different AMI trophic guilds is related with physicochemical variables in the wetland Jaboque (Bogotá, Colombia), four samplings were achieved between April 2009 and January 2010, according to periods of rain and drought in the region. The AMI biomass values obtained were rated as of intermediate rank. No temporal but spatial significant differences were found. Apparently these spatial differences appear to be associated with variations in anthropogenic pressure, which differs in each area of the wetland. In dry months (January and August), biomass was greater and dominated by detritivores. We observed a positive relationship between the specific conductance of water and the biomass of predators and detritivores and between water temperature and the biomass of detritivores and shredders. These relationships suggest that the physical and chemical variables influence the distribution, abundance, and biomass of functional groups. The physical and chemical conditions of water exhibited spatiotemporal fluctuations related to changes in the concentration of organic matter and nutrients, which presumably were related to the affluents discharges and the high impact of local human populations.

Macroinvertebrados aquáticos (MIA) desempenham um importante papel na ecologia das zonas úmidas, quer pelo seu emprego como reguladores dos ciclos da matéria, como para a sua função de armazenamento de energia representada na sua biomassa, que é transferido para elevados níveis tróficos. Para responder à questão de como a biomassa de diferentes categorias tróficas de MIA está relacionada com as variáveis físicas e químicas da água do pantanal Jaboque (Bogotá, Colômbia), quatro amostragens foram realizadas entre abril de 2009 e janeiro de 2010, de acordo com os períodos de chuva e seca na região. Os valores de biomassa de MIA obtidos foram classificados como de grau intermediário. Nós não encontramos nenhuma diferença significativa no tempo, mas foram observadas diferenças espaciais. Aparentemente, estas diferenças parecem estar associadas com as variações espaciais na pressão antrópica, que difere em cada região do pantanal. Nos meses de menor precipitação (janeiro e agosto), a biomassa foi maior e dominado por detritívoros. Observou-se uma relação positiva entre a condutividade específica da água ena biomassa de predadores e detritívoros e entre a temperatura da água e a biomassa de detritívoros e trituradores. Estas relações sugerem que as variáveis físicas e químicas influenciam a distribuição, abundância e biomassa de grupos funcionais. As condições físicas e químicas da água tiveram flutuações espaço-temporais relacionadas com alterações na concentração de matéria orgânica e nutrientes, que foram presumivelmente relacionadas com a descarga do efluente e o elevado impacto das populações humanas locais.

Patrones de variación espacial y temporal de los macroinvertebrados acuáticos en la Laguna de Tecocomulco, Hidalgo (México)

Spatial and temporal variation patterns in aquatic macroinvertebrates of Tecocomulco Lake, Hidalgo (México). Lake Tecocomulco, Hidalgo, is a relic of the ancient lakes of Anahuac, important for the conservation of resident and migratory birds. However, the composition of aquatic macroinvertebrates is unknown; this is an important gap in conservation as they play an important role in the food web. This study analyzed the spatial and temporal variations in macroinvertebrate assemblages and their relationship with habitat characteristics. We carried out four monitoring campaigns covering the rainy and dry seasons. The monitoring was conducted at six study sites (four in the littoral zone and two in the middle part of the lake), environmental factors were recorded at each study site, water samples were collected for their physical and chemical analysis and aquatic macroinvertebrates were collected. A principal component analysis (PCA) was used to group study sites based on physical and chemical characteristics. Richness of taxa was analysed with rarefaction. We assessed the importance value index of each taxon (considering their frequency of occurrence and abundance). Similarity analyzes were performed between study sites and similarity of taxa with indices of Jaccard and Bray-Curtis, respectively. We performed a canonical correspondence analysis (CCA) between environmental factors and macroinvertebrate taxa. The PCA showed a marked seasonal variation represented by warm periods, with high values of conductivity, alkalinity, hardness, sulfates, and macronutrients (N and P) and the cold period with low values. We found a total of 26 taxa of aquatic macroinvertebrates and the highest richness was found in August. The Jaccard similarity analysis found differences between the littoral area and the limnetic zone, which differ also in the composition of macrophytes. The littoral zone had the highest taxa richness of macroinvertebrates and macrophytes, while the lowest diversity was found in the offshore zone. The CCA related physicochemical characteristics of the water body with macroinvertebrate taxa showing the influence of both physicochemical characteristics and the composition of macrophytes in the spatio-temporal patterns of aquatic macroinvertebrates in the lake. The dominance of Corixidae highlights a strong grazing activity in the lake and in turn suggests an important amount of food available for higher trophic levels. Our study shows that the macroinvertebrates of Tecocomulco Lake have spatial and seasonal variations that are related to both environmental and biotic factors with groups being dominant. Rev. Biol. Trop. 62 (Suppl. 2): 81-96. Epub 2014 April 01.

La Laguna de Tecocomulco (Hidalgo) es un relicto de los antiguos Lagos del Anáhuac con suma importancia para la conservación de aves acuáticas. No obstante, se desconoce su composición de macroinvertebrados. En el presente estudio se analizaron las variaciones espaciales y temporales de los macroinvertebrados acuáticos de la laguna. Se realizaron cuatro campañas de monitoreo (lluvias y estiaje). Se estudiaron seis sitios (litorales y en interior de la laguna), se registraron factores ambientales, se determinaron parámetros de calidad del agua y se recolectaron macroinvertebrados acuáticos. Se obtuvo la riqueza de familias y se calculó su Índice de Valor de Importancia. Se realizaron análisis multivariados de ordenación por componentes principales (ACP) con base en sus características físicas y químicas y de similitud entre sitios y familias con los índices de Jaccard y Bray-Curtis. Tambien se hizo un análisis de correspondencias canónicas (ACC) de factores ambientales y macroinvertebrados acuáticos y macrófitas. El ACP mostró la variación estacional, con el período cálido (mayo y agosto) y el periodo frío (noviembre y enero) mostrando altos valores de conductividad, alcalinidad, dureza, sulfatos y macronutrientes (N y P). Se encontraron 26 familias de macroinvertebrados, con la máxima riqueza en agosto. El análisis de similitud de Jaccard diferenció los sitios litorales por su mayor riqueza de familias de la zona limnética, mismos que presentan diferencias en la composición de macrófitas. El estudio revela que la Laguna de Tecocomulco tiene variaciones espaciales y temporales relacionadas tanto con factores ambientales como bióticos con la presencia de grupos dominantes. En ese sentido, y considerando su diversidad de macroinvertebrados, la Laguna de Tecocomulco debe ser sujeta a un plan de conservación y manejo.

The Andean Biotic Index (ABI): revised tolerance to pollution values for macroinvertebrate families and index performance evaluation

Score-based biotic indices are widely used to evaluate the water quality of streams and rivers. Few adaptations of these indices have been done for South America because there is a lack of knowledge on macroinvertebrate taxonomy, distribution and tolerance to pollution in the region. Several areas in the Andes are densely populated and there is need for methods to assess the impact of increasing human pressures on aquatic ecosystems. Considering the unique ecological and geographical features of the Andes, macroinvertebrate indices used in other regions must be adapted with caution. Here we present a review of the literature on macroinvertebrate distribution and tolerance to pollution in Andean areas above 2 000masl. Using these data, we propose an Andean Biotic Index (ABI), which is based on the BMWP index. In general, ABI includes fewer macroinvertebrate families than in other regions of the world where the BMWP index has been applied because altitude restricts the distribution of several families. Our review shows that in the high Andes, the tolerance of several macroinvertebrate families to pollution differs from those reported in other areas. We tested the ABI index in two basins in Ecuador and Peru, and compared it to other BMWP adaptations using the reference condition approach. The ABI index is extremely useful for detecting the general impairment of rivers but class quality boundaries should be defined independently for each basin because reference conditions may be different. The ABI is widely used in Ecuador and Peru, with high correlations with land-use pressures in several studies. The ABI index is an integral part of the new multimetric index designed for high Andean streams (IMEERA). Rev. Biol. Trop. 62 (Suppl. 2): 249-273. Epub 2014 April 01.

Los índices bióticos basados en puntuación son ampliamente utilizados para evaluar la calidad del agua de los arroyos y ríos. Varias áreas de los Andes están densamente pobladas y hay necesidad de métodos para evaluar el impacto de la creciente presión humana sobre los ecosistemas acuáticos. Dadas las características ecológicas y geográficas únicas de los Andes, los índices de macroinvertebrados utilizados en otras regiones deben adaptarse con cautela. Aquí se presenta una revisión de la literatura sobre distribución de macroinvertebrados y la tolerancia a la contaminación en las zonas andinas por encima de 2 000msnm. Usando estos datos, se propone un Índice Biolótico Andino (ABI), que se basa en el índice de BMWP. En general, ABI incluye un menor número de familias de macroinvertebrados que en otras regiones del mundo donde se ha aplicado el índice BMWP porque la altitud restringe la distribución de varias de ellas. Nuestra revisión muestra que la tolerancia de varias familias a la contaminación en los ríos altoandinos difiere de lo reportado en otras áreas. Probamos el índice ABI en dos cuencas en Ecuador y Perú, y comparamos con otras adaptaciones BMWP utilizando el enfoque de condición de referencia. Nuestros resultados muestran que el índice de ABI es extremadamente útil para detectar el deterioro general de los ríos, pero que los límites entre las clases de calidad deben ser definidos independientemente para cada cuenca debido a que las condiciones de referencia pueden ser diferentes. El ABI es ampliamente utilizado en Ecuador y Perú, y es parte integral del nuevo índice multimétrico diseñado para corrientes altas andinas (IMEERA).

Application of the BMWP-Costa Rica biotic index in aquatic biomonitoring: sensitivity to collection method and sampling intensity

The use of aquatic macroinvertebrates as bio-indicators in water quality studies has increased considerably over the last decade in Costa Rica, and standard biomonitoring methods have now been formulated at the national level. Nevertheless, questions remain about the effectiveness of different methods of sampling freshwater benthic assemblages, and how sampling intensity may influence biomonitoring results. In this study, we compared the results of qualitative sampling using commonly applied methods with a more intensive quantitative approach at 12 sites in small, lowland streams on the southern Caribbean slope of Costa Rica. Qualitative samples were collected following the official protocol using a strainer during a set time period and macroinvertebrates were field-picked. Quantitative sampling involved collecting ten replicate Surber samples and picking out macroinvertebrates in the laboratory with a stereomicroscope. The strainer sampling method consistently yielded fewer individuals and families than quantitative samples. As a result, site scores calculated using the Biological Monitoring Working Party-Costa Rica (BMWP-CR) biotic index often differed greatly depending on the sampling method. Site water quality classifications using the BMWP-CR index differed between the two sampling methods for 11 of the 12 sites in 2005, and for 9 of the 12 sites in 2006. Sampling intensity clearly had a strong influence on BMWP-CR index scores, as well as perceived differences between reference and impacted sites. Achieving reliable and consistent biomonitoring results for lowland Costa Rican streams may demand intensive sampling and requires careful consideration of sampling methods. Rev. Biol. Trop. 62 (Suppl. 2): 275-289. Epub 2014 April 01.

En Costa Rica el uso de macroinvertebrados acuáticos como bioindicadores de la calidad ambiental del agua ha aumentado considerablemente en la última década, y se han aplicado métodos estandarizados a nivel nacional. Sin embargo, aún existe controversia sobre la efectividad de los métodos de muestreo y su intensidad. En este estudio comparamos una metodología cualitativa y otra cuantitativa, en 12 sitios de nueve ríos localizados en la cuenca baja del río Sixaola, al sur de la vertiente del Caribe de Costa Rica. Muestras cualitativas fueron recolectadas con un colador durante un período de tiempo establecido y los macroinvertebrados fueron separados en el campo. En el muestreo cuantitativo se recolectaron diez muestras utilizando un Surber y los macroinvertebrados fueron separados en el laboratorio utilizando con esteroscopio. El colador produjo un número menor de individuos y familias que las muestras cuantitativas. Como resultado, la puntuación del índice biótico Biological Monitoring Working Party-Costa Rica (BMWP-CR) en cada sitio dependió del método. La categoría de calidad de agua con ese índice también diferió entre los dos métodos en 11 de los 12 sitios en 2005, y en 9 de los 12 sitios en 2006. La intensidad de muestreo claramente tuvo una fuerte influencia en los resultados del índice BMWP-CR, así como diferencias entre sitios de referencia y los sitios afectados. Debido a la coherencia en los resultados es posible aceptar el método cuantitativo pero con una cantidad prudente de repeticiones en estudios de biomonitoreo acuático.

Efecto del esfuerzo de muestreo en la riqueza de táxones de macroinvertebrados acuáticos y el índice BMWP/Atitlán

Effect of sampling effort on taxa richness of aquatic macroinvertebrates and the BMWP/Atitlán index. Aquatic macroinvertebrates are the group of organisms most commonly used to determine ecosystem health in water quality studies and freshwater biomonitoring. Nevertheless, the methods and collecting time of biomonitoring have not yet been sufficiently adapted and tested in tropical aquatic environments. Twelve rivers in the Lago de Atitlán watershed in Guatemala were assessed with different collecting times, during the dry season. The method involved the collection of organic and inorganic material including benthic organisms, from different microhabitats, for a pre-established time period (5, 10, 15min) with a D-frame net. Samples were preserved with 95% ethanol in the field, and sorted in the laboratory. As expected, the analysis showed that the abundance and taxonomic richness was higher with increasing sampling effort. The water quality categories obtained from the newly proposed BMWP/Atitlán index varied among sampling times. However, the Kruskal-Wallis test showed no significant differences between the categories obtained with the index and the number of taxa collected at 10 and 15min. Therefore, we recommend a reduction of sample time, but maintaining the tree subsamples in order to include most variety of microhabitats and assure a representative sample of the aquatic macroinvertebrates. Rev. Biol. Trop. 62 (Suppl. 2): 291-301. Epub 2014 April 01.

Los macroinvertebrados son los organismos más utilizados para determinar el estado de salud de los ecosistemas en estudios de calidad del agua y biomonitoreo acuático. No obstante, los métodos para monitoreo y tiempos de recolecta no han sido efectivamente adaptados a ambientes acuáticos tropicales. En la cuenca del Lago de Atitlán, Guatemala, se evaluaron 12 ríos con diferentes tiempos de recolecta, durante la temporada seca. El método consistió en la recolecta de material orgánico e inorgánico incluyendo organismos bénticos, en diferentes microhabitats, por un periodo de tiempo (5, 10, 15min) con una red “D” y preservados en etanol al 95%; la separación y clasificación se realizó posteriormente en el laboratorio. Como se esperaba, los análisis de datos revelaron que la abundancia y riqueza de taza es mayor al incrementar el esfuerzo de muestreo. Las categorías de calidad del agua obtenidas del cálculo del índice biótico BMWP/Atitlán variaron con el esfuerzo de muestreo. Sin embargo, el análisis de Kruskall-Wallis no mostró diferencias significativas entre las categorías obtenidas con el índice y el número de táxones recolectados en los 10 y 15min. Por lo tanto, recomendamos que el tiempo mínimo de recolecta puede ser de 10 minutos, siempre y cuando se mantenga el mismo número de submuestras (tres) para que se incluya la mayor variedad posible de micro-hábitats durante el muestreo.

Grupos tróficosdde macroinvertebrados acuáticos en un humedal urbano andino de Colomiia / Macroinvertebrate Trophic Groups in an Andean Wetland of Colombia

En el humedal Jaboque (Bogotá, Colombia) se analizaron las condiciones físicas y químicas del agua y se estudió la comunidad de macroinvertebrados acuáticos por grupos dietarios entre abril de 2009 y enero de 2010. Las aguas del humedal presentaron un carácter ligeramente ácido con valores altos de nitratos, nitrógeno amoniacal y fósforo, por lo que este ecosistema se clasifica como eutrófico a hipereutrófico. La comunidad de macroinvertebrados acuáticos registró seis grupos alimenticios, los cuales estuvieron formados por 27 familias, 26 géneros confirmados y nueve géneros aún por confirmar, con un total de 6403 individuos recolectados en 28 muestras de macrófitas. La mayor abundancia correspondió a detritívoros (43,5 %), colectores-raspadores (31,5 %) y colectores-fragmentadores (14,1 %), los cuales fueron más abundantes en los meses de menor precipitación. Los contenidos estomacales de algunos de los organismos evidenciaron que la mayoría de estos individuos consumieron más de un tipo de alimento, además de altas cantidades de materia orgánica. El análisis de correspondencia linealizado (ACL) mostró una organización espacial (estaciones) y temporal (épocas climáticas) en la que los gremios tróficos se agrupan de acuerdo a sus requerimientos de nicho, fluctuaciones ambientales o factores de intervención humana. Las variaciones en los grupos dietarios reflejaron cambios en la comunidad de macroinvertebrados desde una perspectiva funcional e indicaron que el humedal es un sistema muy alterado por las actividades urbanas.

In the wetland Jaboque (Bogotá, Colombia) the physical and chemical properties of the water and the food dietary guilds of the aquatic macroinvertebrate community were analyzed from April 2009 to January 2010. The wetland waters had a slightly acid character with high values of nitrate, ammonia and orthophosphate, so this ecosystem is classified as eutrophic to hypereutrophic. In the aquatic macroinvertebrate community six food groups were recorded; they were conformed by 27 families, 26 confirmed genera and nine to be confirmed, with a total of 6,403 individuals collected in 28 samples of macrophytes. The highest abundances corresponded to detritivores (43.5 %), collector-scrapers (31.5 %), and collector-shredders (14.1 %), which were more abundant in the months of low rainfall. Stomach contents of some of the organisms showed that most of these individuals consumed more than one food type and high amounts of organic matter. Detrended correspondence analysis (DCA) showed a spatial (stations) and temporal (climatic seasons) organization, in which trophic guilds are grouped according to their niche requirements, environmental fluctuations or anthropogenic factors. Variations in dietary groups reflected changes in the macroinvertebrate community from a functional perspective and indicated that the wetland is very disturbed by urban activities.

Grupos funcionales alimentarios de macroinvertebrados acuáticos en el río Gaira, Colombia

Functional feeding groups of macroinvertebrates in Gaira river, Colombia. Tropical rivers are frequently described on their biodiversity but few studies have considered the ecological value of this richness in their food webs. We determined the trophic structure of aquatic macroinvertebrate communities (expressed in the richness and abundance of taxa and biomass proportions of different functional feeding groups) at the level of the river, stretch and microhabitats (functional units - UFs). We evaluated the spatial and temporal variation of these descriptors during wet and dry events, and selected three sites associated with different altitudinal belts. We reported 109 taxa, with 11 167 individuals who contributed 107.11g of biomass. Density of macroinvertebrates was favored with increasing height, and biomass showed the opposite pattern (K-W=10.1, d.f.=1, p<0.05), due to the addition of large crustaceans (Macrobrachium), and the taxa diversity was higher in the middle stretch of the river (H’=3.16). The Gaira stream runs through a mid-sized river basin, for this reason we found mainly bedrock (epilithon=50.5%), gravel and sand (43.7%). The functional unit with more habitat and food resources that contains a higher abundance of leaf litter macroinvertebrates was foliage followed by epilithon, fine sediment and gravel-sand (K-W=25.3, d.f.=3, p<0.05). The biomass values of these organisms were higher in leaves followed by gravel-sands, epilithon and sediment (K-W=15.3, d.f.=3, p<0.05). Autochthonous biomass input by different functional feeding groups can be considered very low, but they define the functionality of the stream, being represented almost exclusively by shredders (Macrobrachium, 73%), present only in the lower reaches, followed by shredder Leptonema with 15%, located mostly in the upper reaches and predatory stoneflies of the genus Anacroneuria to 6.56%, which dominated in the middle stretch of stream. Excluding Macrobrachium from the analysis, there was dominance of Anacroneuria in the lower reaches. Between rainfall and drought events, biomass of functional feeding groups was higher in rain (W=10.1, d.f.=1, p<0.05), favoring the growth of decapods, but the abundance was much higher during drought events. Rev. Biol. Trop. 59 (4): 1537-1552. Epub 2011 December 01.

Para Colombia, la información sobre grupos funcionales alimentarios de macroinvertebrados acuáticos es muy escasa. Por lo tanto, en este estudio se determinó la riqueza, abundancia y biomasa de los GFAs de estos organismos a escala de río, tramo y unidades funcionales, con el objeto de evaluar su variación espacio-temporal. Se seleccionaron tres tramos de 200m. En total se reportan 109 táxones, con una abundancia de 11 167 individuos que aportaron una biomasa de 107.11g. La densidad de los macroinvertebrados se vio favorecida con el incremento en la altura, la biomasa presentó un patrón inverso pues fue mayor hacia el tramo bajo y la diversidad de táxones fue mayor en el tramo medio del río (H’=3.16). Los valores de biomasa de estos organismos fueron mayores en hojarasca seguida de gravas-arenas, epiliton y sedimento. El tramo bajo fue dominado por Macrobrachium con el 73%, seguido de Leptonema con el 15 % en el tramo alto y Anacroneuria con el 6.56 %, en el tramo medio del río. Entre eventos de lluvia y sequía, la biomasa aportada por los grupos funcionales alimentarios fue mayor en lluvia, pero la abundancia fue muy superior durante eventos de sequía.

Caracterizaciónllimnológica de humedales de la lanicie de inundación del río oorinoco (orinoquía, Cooombia) / Limnological characterization of wetlands of the floodplain of the Orinoco river ( Orinoco , Colombia )

En este estudio se desarrolló una caracterización física y química de los principales ríos, quebradas y humedales de la región aledaña a la ciudad de Puerto Carreño (Vichada, Colombia) en la época de aguas altas y bajas del Río Orinoco; y una caracterización biológica durante la época de aguas bajas. La mayor parte de los sistemas presentaron pH ácido y una baja concentración de iones y nutrientes. El régimen hidrológico tuvo un impacto importante sobre los ecosistemas acuáticos: Durante el periodo de agua altas, aumentó la transparencia y la concentración de algunos nutrientes y se presentó una reducción en la conductividad y la clorofila-a. En aguas bajas, los grupos dominantes de algas fueron Bacillariophyceae y Zygnemaphyceae; la composición taxonómica del zooplancton fue común a la encontrada en otros sistemas del complejo Amazónico-Orinoqués. Las comunidades de macroinvertebrados estuvieron dominadas por Coleoptera, Odonata y Ephemeroptera y la mayor diversidad de grupos funcionales y de morfotipos se presentó en sustratos de hojarasca. Los resultados sugieren que la vegetación de la ribera juega un papel muy importante en el mantenimiento de una fuente de energía y un refugio para las comunidades acuáticas durante el periodo de aguas bajas. Así mismo, la baja mineralización de estos ecosistemas los hace muy susceptibles a contaminación de fuentes urbanas, agrícolas y ganaderas.

We carried out a physical and chemical characterization of the major rivers, streams and wetlands of the surrounding area of the town of Puerto Carreño ( Vichada , Colombia ) in the flooding and dry seasons, as well as a biological characterization in the dry season. Most of the studied systems showed an acid pH and low ion and nutrient concentrations. The hydrologic regime has an important impact on aquatic ecosystems: during the flooding season, transparency and the concentration of some nutrients increased but conductivity and chlorophyll-a levels decreased. During the dry season, the dominant algal groups were Bacillariophyceae and Zygnemaphyceae, and the taxonomic composition of zooplankton was similar to those found in other systems of the Amazon-Orinoco complex. Macroinvertebrate communities were dominated by Coleoptera, Odonata and Ephemeroptera, and the greatest diversity of functional groups and morphotypes was recorded in litter substrates. Results suggest that the bank vegetation plays a very important role in providing a source of energy and shelter to aquatic communities during the dry season, but at the same time the low mineralization of these ecosystems renders them very susceptible to pollution from urban, agricultural and cattle ranching sources.

Litter production and aquatic macroinvertebrates on a headwater subtropical stream in Rio Grande do Sul State, Brazil - DOI: 10.4025/actascibiolsci.v31i3.355 / Produção de folhiço e fauna associada de macroinvertebrados aquáticos em curso dágua de cabeceira em Floresta Ombrófila do Estado do Rio Grande do Sul, Brasil - DOI: 10.4025/actascibiolsci.v31i3.355

The aim of the study was to verify the temporal variation of allochthonous material input into a stream, and which structures contribute to the organic material pool, as well as to analyze the occurrence of macroinvertebrates associated with the litter. Samples were taken from October, 2004 to October, 2005 in two transects along the riparian zone. At each transect, three sampling stations were chosen. At each one, submersed and suspended collectors (1.5 m above bottom) were installed. Input and retention of coarse benthic organic material were analyzed and classified as flowers and diaspores, (seeds and fruits) and vegetative structures (leaves and branches). There were no statistical differences between input of material in suspended and submersed collectors. Therefore, no statistical differences were verified for exposure time for both the suspended and submersed collectors. Vegetative and seeds and fruits and flowers structures differed in relation to their vegetal composition input for total exposure times for both collectors. Leaves were the most important structure for biomass. Aquatics insects, crustaceans, mussels and worms were the most common macroinvertebrates associated with litter. Insecta-Diptera, mainly Chironomidae and Oligochaeta were the most abundant taxa associated with the submerged and suspended collectors. The major taxa richness was found in submerged

Os objetivos deste estudo foram verificar a entrada sazonal de material alóctone e a composição de suas estruturas vegetais e da fauna de macroinvertebrados aquáticos associados ao material alóctone em um riacho de cabeceira em clima subtropical. Foram analisadas, trimestralmente, duas transecções longitudinais no curso dágua, onde foram instalados coletores submersos e suspensos (1,5 m acima da calha) de outubro de 2004 a outubro de 2005. Em ambos os coletores, não se verificou diferença para a entrada de material alóctone entre os períodos de coletas, o que sugere ausência definida de sazonalidade. Também não foram verificadas, temporalmente, diferenças para os componentes, flores, frutos e sementes (diásporos), folhas e galhos (vegetativas). O componente foliar foi o item com maior biomassa na formação do material alóctone em ambos os coletores. Larvas de insetos aquáticos, crustáceos, moluscos e vermes oligoquetos correspondem aos grupos com maior representatividade. Chironomidae (Insecta, Diptera) e Oligochaeta foram os taxa mais abundantes em ambos os coletores, porém a maior riqueza foi observada nos coletores submersos.

Efeitos da ocupação urbana sobre a macrofauna de invertebrados aquáticos de um Igarapé da cidade de Manaus/AM - Amazônia Central

Conditions of water quality and of the invertebrate fauna in the stream Mindú, originating in undisturbed forest area and crossing the city of Manaus/AM, were studied from 1993 to 1995. Deforestation and invasive colonization along the headwater streams and pollution in the city center caused drastic alterations of the limnological and faunistic conditions. Thus, water temperature, conductivity, pH values and quantity of sediments in suspension rose significantly, while oxygen levels dropped. Together with the natural reduction of flow speed and increased solar radiation these alterations resulted in eutrophication and a marked change of the composition of the invertebrate fauna.

A qualidade da água e a fauna composta pelos macroinvertebrados aquáticos do Igarapé do Mindú, o qual tem suas nascentes em áreas florestadas e atravessa a cidade de Manaus (Amazonas, Brasil), foram estudadas de 1993 a 1995. Desmatamentos e ocupação das áreas ao longo do igarapé, juntamente com a poluição orgânica doméstica causaram drásticas alterações nas características físico-químicas das águas e na composição da fauna aquática. Assim, temperatura da água, condutividade elétrica, pH e sedimentos em suspensão aumentaram significativamente, enquanto que os valores de oxigênio dissolvido na água diminuíram. Esses fatores de alterações, associados com a redução natural da velocidade de corrente d'água e aumento da radiação solar, resultaram em eutrofização e mudança marcante da fauna bentônica.