An evaluation of alternative procedures using the bou-rouch method for sampling hyporheic invertebrates

摘要

This study assesses the influence of well design, pumping rate, and sample volume on hyporheic invertebrate density and richness estimates in three streams differing in sediment composition. A comparison of five well designs, i.e., temporary wells with no pores and with 4-, 6-, and 8-mm pores along the lower 15 cm and permanent wells with 6-mm pores, revealed no significant differences in either total invertebrate densities or taxon richness. Pumping rates i.e., 1.5 versus 4 L centre dot min~(-1),significantly affected density estimates at two streams and taxon richness at one of the three streams, shown by higher values at the faster pumping rate. A comparison of five sample volume sizes, i.e., 0.5, 1.0, 1.5, 2.0, and 2.5 L, indicated that smaller sample volumes produced significantly higher estimates of density, while larger sample volumes gave significantly higher estimates of taxon richness. These results underscore the importance of maintaining consistent pumping rates and sample volume sizes throughout the course of a study.