The macrobenthos and its relation with salinity fluctuations from rivers and swamps of the Eastern Chaco (Argentina)

In the area comprised between the Pilcomayo river (Formosa province) and the Amores river (Santa Fe province) 17 streams and rivers, and 4 swamps ("esteros") were studied in their lower reaches during low and high water periods. The salinity was high in some of them, specially during low w...

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Autores principales: Varela, María E., Bechara, José A., Andreani, Nora L.
Formato: Artículo revista
Lenguaje:Español
Publicado: Centro de Ecología Aplicada del Litoral (Consejo Nacional de Investigaciones Científicas y Técnicas - Universidad Nacional de Nordeste) 2023
Acceso en línea:https://revistas.unne.edu.ar/index.php/sub/article/view/7175
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spelling I48-R154-article-71752023-12-06T15:43:02Z The macrobenthos and its relation with salinity fluctuations from rivers and swamps of the Eastern Chaco (Argentina) El macrobentos y su relación con las fluctuaciones de salinidad en ríos y esteros del Chaco Oriental (Argentina) Varela, María E. Bechara, José A. Andreani, Nora L. In the area comprised between the Pilcomayo river (Formosa province) and the Amores river (Santa Fe province) 17 streams and rivers, and 4 swamps ("esteros") were studied in their lower reaches during low and high water periods. The salinity was high in some of them, specially during low water. Samples were taken with a Dietz-LaFond and modified Drzycimski dredges, according to the substrate characteristics, and filteres through a 500μm mesh size. Relative abundance and density (ind. m-2) were analized in relation with the main environmental factors, as current speed, conductivity, dissolved oxigen and sediment granulometry. The benthic macrofauna occurring in the streams and rivers showed important differences in their composition and density, being oligochaetes (Naididae and Tubificidae), chironomids (Chironominae) and molluscs (Hydrobiidae), the main groups.The swamp bottom fauna was rather poor, with abundance of oligochaetes, which could be due to the scarcity of dissolved oxygen and the high proportion of organic matter. The well oxigenated lotic environments, with moderate conductivity values, showed the richest and most abundant macrofauna, in contrast with those of high salinity, specially when the water level decreased. Conductivity was negatively correlated with the species number ( P < 0,01) and abundance (P< 0,01). In the area comprised between the Pilcomayo river (Formosa province) and the Amores river (Santa Fe province) 17 streams and rivers, and 4 swamps ("esteros") were studied in their lower reaches during low and high water periods. The salinity was high in some of them, specially during low water. Samples were taken with a Dietz-LaFond and modified Drzycimski dredges, according to the substrate characteristics, and filteres through a 500μm mesh size. Relative abundance and density (ind. m-2) were analized in relation with the main environmental factors, as current speed, conductivity, dissolved oxigen and sediment granulometry. The benthic macrofauna occurring in the streams and rivers showed important differences in their composition and density, being oligochaetes (Naididae and Tubificidae), chironomids (Chironominae) and molluscs (Hydrobiidae), the main groups.The swamp bottom fauna was rather poor, with abundance of oligochaetes, which could be due to the scarcity of dissolved oxygen and the high proportion of organic matter. The well oxigenated lotic environments, with moderate conductivity values, showed the richest and most abundant macrofauna, in contrast with those of high salinity, specially when the water level decreased. Conductivity was negatively correlated with the species number ( P < 0,01) and abundance (P< 0,01). Centro de Ecología Aplicada del Litoral (Consejo Nacional de Investigaciones Científicas y Técnicas - Universidad Nacional de Nordeste) 2023-12-06 info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion Artículo revisado por pares application/pdf https://revistas.unne.edu.ar/index.php/sub/article/view/7175 Ambiente Subtropical; Núm. 1 (1986): AMBIENTES ANEGABLES DEL CHACO ORIENTAL Primera parte; 134-147 spa https://revistas.unne.edu.ar/index.php/sub/article/view/7175/6609
institution Universidad Nacional del Nordeste
institution_str I-48
repository_str R-154
container_title_str Revistas UNNE - Universidad Nacional del Noroeste (UNNE)
language Español
format Artículo revista
author Varela, María E.
Bechara, José A.
Andreani, Nora L.
spellingShingle Varela, María E.
Bechara, José A.
Andreani, Nora L.
The macrobenthos and its relation with salinity fluctuations from rivers and swamps of the Eastern Chaco (Argentina)
author_facet Varela, María E.
Bechara, José A.
Andreani, Nora L.
author_sort Varela, María E.
title The macrobenthos and its relation with salinity fluctuations from rivers and swamps of the Eastern Chaco (Argentina)
title_short The macrobenthos and its relation with salinity fluctuations from rivers and swamps of the Eastern Chaco (Argentina)
title_full The macrobenthos and its relation with salinity fluctuations from rivers and swamps of the Eastern Chaco (Argentina)
title_fullStr The macrobenthos and its relation with salinity fluctuations from rivers and swamps of the Eastern Chaco (Argentina)
title_full_unstemmed The macrobenthos and its relation with salinity fluctuations from rivers and swamps of the Eastern Chaco (Argentina)
title_sort macrobenthos and its relation with salinity fluctuations from rivers and swamps of the eastern chaco (argentina)
description In the area comprised between the Pilcomayo river (Formosa province) and the Amores river (Santa Fe province) 17 streams and rivers, and 4 swamps ("esteros") were studied in their lower reaches during low and high water periods. The salinity was high in some of them, specially during low water. Samples were taken with a Dietz-LaFond and modified Drzycimski dredges, according to the substrate characteristics, and filteres through a 500μm mesh size. Relative abundance and density (ind. m-2) were analized in relation with the main environmental factors, as current speed, conductivity, dissolved oxigen and sediment granulometry. The benthic macrofauna occurring in the streams and rivers showed important differences in their composition and density, being oligochaetes (Naididae and Tubificidae), chironomids (Chironominae) and molluscs (Hydrobiidae), the main groups.The swamp bottom fauna was rather poor, with abundance of oligochaetes, which could be due to the scarcity of dissolved oxygen and the high proportion of organic matter. The well oxigenated lotic environments, with moderate conductivity values, showed the richest and most abundant macrofauna, in contrast with those of high salinity, specially when the water level decreased. Conductivity was negatively correlated with the species number ( P < 0,01) and abundance (P< 0,01).
publisher Centro de Ecología Aplicada del Litoral (Consejo Nacional de Investigaciones Científicas y Técnicas - Universidad Nacional de Nordeste)
publishDate 2023
url https://revistas.unne.edu.ar/index.php/sub/article/view/7175
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