Resumo: Objetivo estudar a composição e a dinâmica populacional de Chironomidae (Diptera) de um riacho tropical de altitude no Equador. Métodos As amostras foram coletadas no rio Saltana entre abril de 2009 e novembro de 2010. Os parâmetros físico-químicos como fluxo, oxigênio dissolvido, condutividade, pH e temperatura foram medidos em cada campanha de amostragem. Larvas e pupas foram coletadas com um amostrador Hess em diferentes substratos. Já os adultos foram amostrados com armadilhas anfíbias de emergência por 24 horas durante cada campanha de amostragem. Todo o material coletado foi triado e identificado no laboratório. A biomassa foi calculada usando o peso individual das larvas de diferentes ínstares multiplicado pela densidade de cada ínstar em cada amostra. Resultados Um total de 18 táxons larvais foi encontrado em 14 gêneros diferentes nas amostras bentônicas. A subfamília Orthocladiinae apresentou a maior riqueza (12 gêneros), seguida por Podonominae, Diamesinae e Chironominae, com dois gêneros cada. Os táxons mais frequentes foram Cricotopus sp3, C. (Oliveiriella) rieradevallae e Genus 1 sp a. As densidades totais flutuaram muito de um mês para outro, seguindo as mudanças das espécies mais abundantes, e apenas uma espécie mostrou relação com os substratos. Os valores de biomassa são mais baixos de junho a agosto em ambos os anos, o que corresponde à estação de alto fluxo. Conclusões A temperatura fria do rio Saltana durante todo o ano (6-7 °C) e a variabilidade do fluxo determinam os baixos valores de riqueza e densidade. Não está claro se os indivíduos apresentaram ciclos de vida muito curtos ou longos devido à temperatura constante durante todo o ano. No entanto, há uma clara assincronia nos ciclos de vida devido à presença de adultos emergentes ao longo do ano. Resumo Diptera (Diptera Equador 200 2010 físicoquímicos físico químicos dissolvido condutividade amostragem substratos 2 laboratório amostra bentônicas 12 (1 gêneros, , gêneros) Podonominae Chironominae sp3 C Oliveiriella (Oliveiriella outro abundantes anos 67 6 7 (6- °C entanto 20 201 ( (6

Abstract: Aim To study the composition and population dynamics of Chironomidae (Diptera) from a high-altitude tropical stream in Ecuador. Methods Samples were taken at Saltana River between April 2009 and November 2010. Physico-chemical parameters, such as flow, dissolved oxygen, conductivity, pH, and temperature, were measured in each sampling campaign. Larvae and pupae sampling was conducted with a Hess sampler in different substrates. During each sampling campaign, adults were sampled using amphibious emergence traps for 24 hours. All materials collected were separated and classified in the laboratory. The biomass was calculated using the individual weight of the larvae of different instars multiplied by the density of each instar at each sample. Results A total of 18 larval taxa were found in 14 different genera in the benthic samples. The subfamily Orthocladiinae showed the highest richness (12 genera), followed by Podonominae, Diamesinae, and Chironominae, with two genera each. The most frequent taxa were Cricotopus sp.3, C. (Oliveiriella) rieradevallae, and Genus 1 sp.a. Total densities fluctuate very much from one month to another following the changes of the most abundant species, and only one species showed a relationship with the substrates. Biomass values are lower from June to August of both years, which matches the high flow season. Conclusions The Saltana River’s cold temperature (6-7 °C) and the flow variability determine the low richness, density and biomass throughout the year. It is unclear if individuals showed very short or long-life cycles due to constant temperature throughout the year. However, there is a clear asynchrony in life cycles due to the presence of emerging adults throughout the year. Abstract Diptera (Diptera highaltitude altitude Ecuador 200 2010 Physicochemical Physico chemical parameters oxygen conductivity pH campaign substrates 2 hours laboratory sample samples 12 (1 genera, , genera) Podonominae Diamesinae Chironominae sp3 sp 3 sp.3 C Oliveiriella (Oliveiriella rieradevallae spa sp.a years season Rivers s 67 6 7 (6- °C year longlife long However 20 201 ( sp. (6

Resumen Introducción: Los quironómidos (Diptera: Chironomidae) son los insectos acuáticos de mayor diversidad y distribución mundial. A pesar de su prevalencia en los sistemas lóticos, se sabe poco acerca de su ecología y diversidad, especialmente de especies tropicales en relación con otros taxones de insectos acuáticos, particularmente en etapas inmaduras. Objetivo: Caracterizar la diversidad de quironómidos a través de un gradiente altitudinal en el suroeste de Ecuador, además de identificar los parámetros fisicoquímicos asociados con su composición. Métodos: Las muestras se recolectaron utilizando una red Surber en cuarenta ríos dentro de cuatro cuencas hidrográficas en los Andes Sur del Ecuador, en ecosistemas de bosques montanos y secos de tierras bajas abarcando un gradiente altitudinal de 3 120 m.s.n.m. Se midieron las variables fisicoquímicas: oxígeno, conductividad, sólidos disueltos totales, temperatura y pH. Resultados: En general, las variables ambientales se correlacionaron fuertemente con la composición de las comunidades de quironómidos. La variación en la comunidad de quironómidos se asoció fuertemente con el oxígeno, la conductividad y el pH. La presencia de los géneros Parametriocnemus, Cricotopus f4, Cricotopus sp3, Cricotopus (Isocladius), Oliveiriella, Onconeura, Alotanypus y Pentaneura se asoció a temperaturas bajas, alto oxígeno disuelto y baja conductividad, mientras que Cricotopus sp., Rheotanytarsus, Tanytarsus y Chironomus se asociaron con alta conductividad y bajas concentraciones de oxígeno disuelto. El análisis RELATE mostró que las características ambientales locales determinan la composición de la comunidad de quironómidos. Conclusiones: La similitud entre los factores ambientales locales se correlacionó fuertemente con la similitud entre los conjuntos de Chironomidae, especialmente con variables como la concentración de oxígeno, el pH y la conductividad, cuyas variables están altamente correlacionadas con el uso de la tierra y la vegetación dominante en las cuencas hidrográficas muestreadas.

Abstract Introduction: Chironomids (Diptera: Chironomidae) are the most globally diverse and widely distributed aquatic insects. Despite their prevalence in lotic systems, little is known about the ecology and diversity of tropical species relative to other aquatic insect taxa, particularly at the immature stages. Objective: Characterize chironomid diversity across an elevational gradient in Southwestern Ecuador and water quality parameters associated with their composition. Methods: Samples were collected using a Surber net in forty rivers within four watersheds in the Ecuadorian Andes comprised of montane and dry lowland forest and spanning an elevational gradient of 3 120 m.a.s.l. Various physic chemical variables were measured including oxygen, conductivity, total dissolved solids, temperature, and pH. Results: Generally, environmental variables were strongly correlated with the composition of chironomid communities. Variation in the chriomid communities was most strongly associated with oxygen, conductivity and pH. The presence of Parametriocnemus, Cricotopus f4, Cricotopus sp3., Cricotopus (Isocladius), Oliveiriella, Onconeura, Alotanypus and Pentaneura was associated with lower temperatures, high dissolved oxygen and low conductivity while assemblages of Cricotopus sp., Rheotanytarsus, Tanytarsus, and Chironomus were associated with high conductivity and low concentrations of dissolved oxygen. The RELATE analysis showed that local environmental characteristics are determine the composition of the chironomid community. Conclusions: Similarity among local environmental factors was strongly correlated to similarity among Chironomidae assemblages, especially with variables such as oxygen concentration, pH and conductivity, whose variables are highly correlated to land use and dominant vegetation in the watersheds sampled.

To understand the physical, chemical and hydromorphological variability of tropical highland Andean rivers (2000 m.a.s.l.), 123 localities in eight river basins in Ecuador and Perú were sampled. The sites were selected according to their latitude, altitude, and impairment degree. The samples were taken between October 2007 and October 2008 coinciding with the dry season at both countries. In each locality both, physical and chemical (i.e., temperature, dissolved oxygen, conductivity, phosphates, nitrites, nitrates, ammonia, etc.) and hydromorphological (i.e., altitude, riparian quality index (QBR), degree of vegetal cover in the stream zone, riparian cover structure and quality, naturalness of the stream channel, aquatic habitat quality index (IHF), substrate composition, rapids frequency, elements of heterogeneity) variables were measured. At regional level (between basins), the mineralization, the hydromorphological features and the aquatic habitat heterogeneity were the most important factors explaining environmental variability. Meanwhile the temperature dissolved, oxygen and habitat heterogeneity parameters were shown to be relevant in the altitudinal gradient, while the mineralization was it in the latitudinal gradient. The importance of each factor is related to the spatial scale studied (site, basin, region). However, the altitude and variables changing with it, as temperature and dissolved oxygen, shown similar patterns regardless of the latitudinal location of the basin.

Para comprender la variabilidad física, química e hidromorfológica de los ríos en la zona altoandina tropical (sobre los 2000 msnm) se muestrearon 123 ríos de ocho cuencas hidrográficas de Ecuador y Perú, seleccionados según criterios de distribución en latitud y altitud, así como el grado de alteración antrópica. Los muestreos se realizaron entre octubre 2007 y octubre 2008, coincidiendo con la época seca en ambos países. En cada localidad se midieron tanto parámetros físicos y químicos (i.e., temperatura, oxígeno disuelto, conductividad, fosfatos, nitritos, nitratos, amonio, etc.) como hidromorfológicos (i.e., altitud, índice de calidad riparia (QBR), calidad y naturalidad de la cubierta vegetal de la ribera, naturalidad del canal fluvial, índice del hábitat fluvial (IHF), frecuencia de rápidos, composición del sustrato). A nivel regional (entre cuencas) la mineralización, las características hidromorfológicas y la heterogeneidad del hábitat mostraron ser los factores de mayor importancia para explicar la variabilidad encontrada. La temperatura, oxígeno disuelto y heterogeneidad del hábitat fueron los parámetros relevantes en el gradiente altitudinal, mientras que la mineralización lo fue en el gradiente latitudinal. La significación o importancia de un factor u otro parecen estar determinados en gran medida por el nivel espacial estudiado (localidad, cuenca, región). Sin embargo, se determinó que a nivel regional la altitud y las variables que cambiaron con ella, como temperatura y oxígeno disuelto, son siempre significativas independientemente de la ubicación latitudinal de la cuenca.