Original paper

Temporal variability of macroinvertebrate assemblages in a neotropical intermittent stream in Northwestern Venezuela.

Rincón, J.; Cressa, C.

Archiv für Hydrobiologie - Hauptbände Volume 148 Number 3 (2000), p. 421 - 432

45 references

published: Jun 14, 2000

DOI: 10.1127/archiv-hydrobiol/148/2000/421

BibTeX file

ArtNo. ESP141014803011, Price: 29.00 €

Download preview PDF Buy as PDF

Abstract

Changes in macroinvertebrate assemblages were identified among different flow phases during the dry and rainy seasons in a neotropical intermittent stream in Northwestern Venezuela. Invertebrates and physicochemical parameters were sampled during 9 months to assess temporal changes in biotic and abiotic variables. Macroinvertebrate densities decreased following either a high-flow or a stream drought. Three invertebrate assemblages were identified via PCA and cluster analysis. PCA ordination showed a temporal sequence between the sampling dates. A low flow association occurred in August, a period of rewetting after the stream drought in late July. A highflow association was established by sampling dates (September and November) with the highest flows registered during the study, and an intermediate-flow association occurred during the longer dry period after the rainy season. The low-flow group was dominated by the Philopotamidae (65 %). The intermediate-flow group showed a more even distribution of macroinvertebrate abundances. The high-flow group was dominated by Philopotamidae, Leptophlebiidae, Chironomidae and Baetidae. The lowest richness and highest density values were observed for the low-flow group. Average physicochemical parameters also were different between the PCA groups. A gradient of physicochemical parameters was observed from the "low-flow" group to the "high-flow" group. Temporal flow changes probably structure macroinvertebrate communities during extreme episodes of drought or spates, but during intermediate flow periods some biotic processes may determine community structure.

Keywords

macroinvertebrate assemblagesneotropical intermittent streamVenezuelaSouth America