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

Abstract

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 KruskalWallis 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.

Efecto del microhábitat sobre la abundancia y riqueza específica de los macroinvertebrados bentónicos en dos ríos tropicales de montaña, Guatemala

“…el arrastre de los organismos de un sitio a otro, lo cual es propio de la temporada lluviosa (Brown & Brussock, 1991;Reyes-Morales & Springer, 2014). Se seleccionaron ocho tipos de microhábitats: hojarasca, grava o cascajo, piedras o guijarro, roca o peña, musgo, vegetación acuática, pozas y cataratas (Tabla 1, Figura 2).…”

“…Dentro de la cuenca del lago Atitlán se ha generado información acerca de los macroinvertebrados que se encuentran en los principales ríos. Reyes-Morales y Springer (2014), recolectaron hasta 47,482 individuos de 54 familias y 16 ordenes en 12 sitios de muestreo con distintos usos de suelo. Arriola y Reyes (2016), determinaron que el río Tzununá obtuvo una mayor abundancia de organismos, mientras que el río Panasacar presentó el mayor número de taxa.…”