INVESTIGADORES
MISERENDINO Maria Laura
artículos
Título:
. Macroinvertebrates of a fluvial system in Patagonia: altitudinal zonation and functional structure
Autor/es:
MISERENDINO, M. L; PIZZOLON LINO
Revista:
ARCHIV FUR HYDROBIOLOGIE
Editorial:
E. Schweizerbartsche Verlagsbuchhandlung
Referencias:
Lugar: Germany; Año: 2000 vol. 150 p. 55 - 83
ISSN:
0003-9136
Resumen:
Most investigations of
altitudinal zonation of river macrobenthic communities have been conducted in
the Northern Hemisphere. Conversely, South American habitats, and specifically
the Argentinean ones, are poorly known.This is the first study of altitudinal zonation
of macrobenthic communities in the Patagonian Andes. It was carried out at 14
sampling stations along 51 km
of the Esquel-Percy
River system over a 1000 m altitudinal gradient.
Untreated sewage of Esquel
City discharges in the
middle section of the system. The main species assemblages of the monitored
sites were identified and a functional categorization of the taxa was produced.
Population distribution patterns were analyzed throughout a complete annual
cycle, and both qualitative and quantitative variations were interpreted as a
function of abiotic and biotic variables. The macrobenthic community found
along the Esquel-Percy system is rich and diverse, except at middle-stretch
stations, which are altered by anthropogenic perturbations. Specific composition,
diversity and density were influenced by the topographic gradient, geochemical (conductivity and total alkalinity) and anthropogenic factors (BOD and
oxygen saturation), and the seasonality of the system. Similarities with lotic
environments of Australia
and New Zealand
were found in specific composition, density, and community structure. The
biomass of shredders and predators decreased, while collectors increased,
downstream from the headwaters. Collector-gatherers were the most important
group at all sites. Functional organization showed better correspondence with
the RCC model if biomass was used instead macroinvertebrate density. We found
that local and regional characteristics produced deviations from the RCC model,
but it is still useful as a comprehensive framework for stream ecology in the
Patagonian Andes.