Spatial and temporal patterns of macroinvertebrates in drift and on substrate of a mountain stream (Cordoba, Central Argentina)

Abstract

Aims: The aims of this study are to evaluate the effects of spatial and temporal variability of the macroinvertebrate fauna in drift and in the substrate of a mountain stream. Methods: The study site is located in Achiras stream (Central, Argentina). This is an endorheic fluvial course whose headwaters are located in the southern extreme of Los Comechingones Mountains. Three replicate Surber samples were collected from benthos with 300 µm, 0.09 m 2 nets. Three drifting fauna samples were collected using drift nets, 1 m long, 300 µm and 0.0192 m 2 . The taxonomic identification of specimens was performed according to the lowest possible taxonomic level. In order to characterize the drifting and benthic fauna, total abundance, taxonomic richness, Shannon and evenness indices were estimated and they were tested with two-way analysis of variance (ANOVA). In order to assess the distribution patterns of drift and benthos samples, we performed Canonical Correspondence Analysis (CCA). Results: A total of 61 taxa were identified in drift and 82 in benthos. A 26.3% taxonomic similarity between the two assemblages was observed, according to the Jaccard index. In drift and benthos, Arthropoda presented higher abundance and Insecta contributed with more taxa and it was also the most abundant. The most abundant orders were Ephemeroptera, Trichoptera and Diptera. In the present study, Anacroneuria sp. (Perlidae) and Podonominae (Chironomidae) were first recorded for benthic community of Achiras stream. Conclusion: In this study we found that the structural organization of the drifting and benthic macroinvertebrate community shows different patterns of variation at spatial and temporal scales.

Variación espacio-temporal de Chironomidae (Diptera) bentónicos y derivantes en un arroyo serrano en Córdoba, Argentina

“…En el sitio estudiado se han registrado los mismos taxones citados en otros sistemas lóticos de la región central de Argentina (PrinCiPe et al, 2007(PrinCiPe et al, , 2008BarBero et al, 2013). La densidad relativa total estuvo dominada por los Chironominae (47%), continuando con los Orthocladiinae (28%) y Tanypodinae (25%).…”

“…Medina & Paggi (2004) reportan también a Tanytarsus sp. como dominante mientras que en otros estudios de la provincia de Córdoba dominaron distintos géneros: Polypedilum (PrínCiPe et al, 2008;gualdoni et al, 2009), Onconeura y Rheotanytarsus (BarBero et al, 2013); Rheotanytarsus (gualdoni & oBerto, 2012). Tanytarsus es un género euritópico que se encuentra en diferentes hábitats, incluyendo aguas salobres (Pinder & reiss, 1983;ePler, 2001).…”

“…2. Datos similares fueron registrados por PrinCiPe & Corigliano (2006) y BarBero et al (2013). Corynoneura y Cricotopus son géneros con muchas especies, cosmopolitas y las larvas son comunes en los ambientes lóticos (ePler, 2001) además, son muy propensas a ser arrastradas río abajo por la corriente (C. M. Gualdoni, obs.…”

“…El bentos se muestreó con redes de Surber (300 µm, 0,09 m 2 ) y la deriva con redes de 100 cm de largo, 300 µ y un área modificada de 24 x 8 cm (0,019 m 2 ) (BarBero et al, 2013). Se colocaron durante 30 minutos en la mitad de la columna de agua para excluir el neuston y el bentos, y entre las 9:00 y 11:00 hs para evitar la deriva comportamental.…”

“…Numerosos estudios han analizado la deriva de invertebrados evaluando composición de especies y factores ambientales que la condicionan (fleCker, 1992;koetsier & Bryan, 1996;gualdoni & Corigliano, 1999;BarBero et al, 2013), sin embargo, pocos reportan información acerca del aporte de larvas de Chironomidae a la fracción derivante (Molineri, 2008;Marziali et al, 2009).…”