Influence of flow variability on macroinvertebrate assemblages in an intermittent stream of semi-arid Brazil

• Published in: Journal of arid environments Vol. 85; pp. 33 - 40
• Main Authors: Rocha, L.G., Medeiros, E.S.F., Andrade, H.T.A.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.10.2012; Elsevier
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Biological and medical sciences; Chironomidae; Communities; Composition effects; Density; Desiccants; Drying; Fresh water ecosystems; Freshwater; Fundamental and applied biological sciences. Psychology; Insects; Intermittent stream; Macroinvertebrate community; Semi-arid stream; Streams; Survival; Synecology; Terrestrial ecosystems; South America; Brazil; America; ASW, Brazil; Chironomidae; Macroinvertebrate community; Semi-arid stream; Intermittent stream; Arid environment; Insecta; Rivers; Temporary water; Semi arid zone; Arthropoda; Stream; Invertebrata; Diptera; Community
• ISSN: 0140-1963; 1095-922X
• DOI: 10.1016/j.jaridenv.2012.04.001

This study aims to evaluate the effects of variable water flow on macroinvertebrate composition and taxon richness in a semi-arid intermittent stream. Chironomid larvae were the most abundant group of insects in the intermittent stream studied. Nevertheless, their response to flow was similar to the macroinvertebrate fauna as a whole. Macroinvertebrates were more abundant in the late wet phase and in the drying phase. A higher richness was also observed during this period, when new taxa where registered. Discharge, temperature, conductivity and dissolved oxygen were the main variables explaining the variation in richness and density of macroinvertebrate. These variables were also important in explaining the variation in community composition through time. It is suggested that invertebrates cope with the extreme intermittent flows by resilience during variable flows in the wet phase and by resistance during the dry phase. It is however important to notice that frequently high discharges drive the community to lower richness and densities, whereas the resistance during the dry phase is characterized by a taxonomic shift resultant from the survival of the few taxa that supports the initial desiccation and the opportunism of colonizing predaceous taxa overcoming non-resistant taxa. ► Discharge regulated composition and abundance of benthic macroinvertebrates. ► Environment variables associated with water flow also regulated fauna composition. ► Chironomidae responses to variable flows were similar to the macroinvertebrate fauna as a whole. ► Invertebrates cope with the variable flows by resilience during the wet phase and by resistance during the dry phase.