The impact of significant input of fine sediment on benthic fauna at tributary junctions: A case study of the Bermejo-Paraguay River confluence, Argentina

Martín C.M. Blettler, Mario L. Amsler, Inés Ezcurra de Drago, Luis A. Espinola, Eliana Eberle, Aldo Paira, James L. Best, Daniel R. Parsons, Edmundo E. Drago

Research output: Contribution to journalArticle

Abstract

This study examines the morphological features, suspended sediment inputs and hydraulic conditions within a large river in association with ecological patterns before and after a tributary confluence. In order to examine these effects, the macroinvertebrate distributions from three reaches of the Paraguay and Bermejo Rivers (Paraguay-Argentina) are investigated. The Bermejo River is a tributary that supplies significant quantities of fine sediment to the Paraguay River, primarily in suspension. Two reaches were examined on the Paraguay River, upstream and downstream of the Bermejo River junction, with the third study reach located on the Bermejo River, upstream of the confluence with the Paraguay River. The results provide clear evidence that a significantly increased loading of fine sediment at a river confluence has effects on the distribution and potential movement of benthic invertebrates in the lotic environment by representing physical barriers at affected sites. These effects may be important at both local and regional scales, and such increases in suspended sediment (especially associated with anthropogenic change) may thus pose a major threat to ecosystem integrity that has been historically underestimated.

Original languageEnglish (US)
Pages (from-to)340-352
Number of pages13
JournalEcohydrology
Volume8
Issue number2
DOIs
StatePublished - Mar 1 2015

Keywords

  • Benthic invertebrates
  • Confluence sediment dynamics
  • Ecohydrology
  • Fine sediment load
  • Large river

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Aquatic Science
  • Ecology
  • Earth-Surface Processes

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    Blettler, M. C. M., Amsler, M. L., Ezcurra de Drago, I., Espinola, L. A., Eberle, E., Paira, A., Best, J. L., Parsons, D. R., & Drago, E. E. (2015). The impact of significant input of fine sediment on benthic fauna at tributary junctions: A case study of the Bermejo-Paraguay River confluence, Argentina. Ecohydrology, 8(2), 340-352. https://doi.org/10.1002/eco.1511