The Fluvial Forests as Indicators of the Flow and Permanence of Water

We evaluated the influence of the horizontal flows of the Paraná River on the composition and distribution of the floodplain landscape and we defined the ecohydrologicalsignature of some species-index in the low Paraná River section, (27° 38? 04? S and 58° 50? 46? W). During the drought phase, the structure of the vegetation were characterizad using a Cottam & Curtis method. The trees were positioned in the topographic gradients during the flood phase, taking as reference the river water sheet in the nearest hydrometric gauge. To obtain the pulse attributes in different positions of the geomorphological gradient, PULSO software was used considering the daily water levels at Corrientes city between 1985 and 2015. Two main types of flooded forests were identified: pionner forest, dominated by one or two species (Salix humboldtiana, Tessaria integrifolia) in recent bars and islands, and pluri-specific flooded forests (Albizia inundata, Cecropia pachystachya, Croton urucurana, Inga uruguensis, Ocotea diospyrifolia, Nectandra angustifolia and Peltophorum dubium) occupying bars of the highest islands, with shorter flood phases, with trees are distributed in 2-3 strata in a closed canopy. Pulses were more frequent in pioneer forests than in multispecific forests. The ecohydrological signature allows the optimum condition and distribution limits of each species to be established. It is a tool to know the adjustment of biotic elements (populations) to the river variability regime. The procedure usedcan be used to anticipate the possible reorganization of the river plain landscape as a result of flow variations predicted by climate change models.Fil: Zambiasio, Violeta Amancay. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Casco, Sylvina Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Neiff, Juan Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentin

Distribution pattern of trees in a hydrological gradient below the Paraná-Paraguay River confluence

Riparian and riverine aquatic plant species have evolved within the context of flowing water habitats for which the flooding and droughts are the forcing factors that shape the community features, either through a positive or negative effect on the ecosystem’s function, according to the timing, frequency and magnitude of such events. In the Paraná floodplain landscape, topographic position is a crude indicator of the position along the complex gradient, but it also includes information about flood/drought periods and trees’ resilience to extreme hydrological phases. We present the occurrence of major tree species in riparian forests of the Paraná River on islands of different topographies in a section of the Paraná River downstream from the confluence with the Paraguay River. Our results suggest that each tree species had a preferred position in the topographic gradient, sites where the observed counts were more frequent. This trees species were more frequent between 2 and 8 m in the topographic position and were affected by 5 and 202 hydrosedi- mentologic pulses between 1949 and 1999. We suggest that knowledge of the distribution curves of the vegetation spe- cies present can help draw possible future scenarios of the river landscape. Future engineering works to alter the hydro- logical dynamics of Paraná should pay more attention to the distribution of riparian forests because they are indicators of changes at the landscape level and they are the support for the wildlife of the river.Fil: Casco, Sylvina Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Nordeste. Centro de Ecologia Aplicada del Litoral (i); Argentina;Fil: Neiff, Juan Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Nordeste. Centro de Ecologia Aplicada del Litoral (i); Argentina

Los bosques fluviales como indicadores del flujo y permanencia del agua

Los bosques fluviales reflejan la dinámica hidrológica en series largas de tiempo y constituyen una herramienta para el análisis de impactos de los embalses. En este trabajo se analizó la distribución de los bosques fluviales aguas abajo del embalse de Yacyretá, comparando la información actual con la del período previo a la obra, definiendo la firma hidrológica de algunas especies indicadoras. Los bosques fueron analizados en una sección del río Paraná, (25°19´47´´S; 58°47´04´´W) a dos escalas espaciales. Para su identificación y clasificación a nivel de paisaje se utilizaron imágenes Google Earth Pro y la Clasificación Ecológica de Tierras. En escala de campo se realizó el reconocimiento que permitió posicionar los elementos del paisaje y de la vegetación en los gradientes de inundación. Complementariamente se realizaron censos utilizando el método de los cuartos para describir la estructura de dichos bosques. Con la información de campo se construyeron curvas de distribución para las especies más conspicuas. Se distinguieron bosques inundables dominados por una o dos especies (Salix humboldtiana, Tessaria integrifolia) en la parte baja del gradiente topográfico y bosques inundables pluriespecíficos (Albizia inundata, Banara arguta, Cecropia pachystachya, Croton urucurana, Ocotea diospyrifolia, Nectandra angustifolia, Peltophorum dubium, entre otras) que ocupan barras o albardones de las islas más altas, con fases de inundación más cortas. Nuestros resultados indican que la mayoría de las especies tienen nichos amplios, con importante superposición en su distribución en el gradiente de inundación que les permite absorber una parte de los disturbios hidrológicos. Se pudo establecer la firma hidrológica de algunas especies indicadoras en la zona de estudio y analizar los cambios en su distribución.Fil: Zambiasio, Violeta Amancay. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Casco, Sylvina Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Neiff, Juan Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentin

Influence of water hyacinth floating meadows on limnological characteristics in shallow subtropical waters

The effects of free-floating mats of the water hyacinth Eichhornia crassipes (Mart.) Solms on the limnological characteristics of two lakes located on the fringing floodplain of the lower Paraná River (27˚27´S, 58˚55´W) were studied monthly between April 1998 and April 1999. The mobility of the free-floating vegetation at both locations prevented continual observation. Therefore, to carry out the intensive sampling needed for this study, two experimental ponds (A and B) were filled with water from the Paraná River in 1996. Pond A was designed to reproduce conditions similar to those of lakes vegetated with water hyacinth. Pond B was designed to recreate the limnological conditions of these lakes, such as a high concentration of dissolved and fine particulate organic matter and a peat layer on the bottom; however, pond B lacked acrophytes. Natural lakes covered with free-floating vegetation were very similar to pond A, but these water bodies showed a lower temperature, dissolved oxygen level and pH and a higher conductivity than the non-vegetated pond. Our results indicated that water hyacinth has a strong local influence on the limnological conditions in subtropical shallow lakes. Our results may assist in developing causeconsequence models by demonstrating the relevance of the effect of thermal damping produced by floating meadows.Fil: Casco, Sylvina Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentina. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura; ArgentinaFil: Carnevali, Romina Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentina. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura; ArgentinaFil: Poi, Alicia Susana G.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentina. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura; ArgentinaFil: Neiff, Juan Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentin

Influence of Macrophyte Complexity and Environmental Variables on Macroinvertebrate Assemblages Across a Subtropical Wetland System

Different architectures in aquatic plants with different levels of morphological complexity provide environmental heterogeneity in freshwater ecosystems, and consequently influence invertebrate assemblages. We investigated the relative importance of the structural complexity of macrophytes and environmental variables on the abundance and richness of the macroinvertebrate assemblages associated with aquatic plants across the Esteros del Iberá. This protected wetland system located in Corrientes (Argentina) is fed by rain. Macrophyte habitat complexity was quantified by measuring fractal geometry dimensions of area and perimeter and plant biomass. We sampled macroinvertebrates associated with five species of macrophyte (Egeria najas, Cabomba caroliniana, Potamogeton gayi, Eichhornia azurea and Salvinia biloba) in five shallow lakes during two different seasons (dry and rainy) between 2007 and 2008. Regression analyses revealed that macrophyte structural complexity was an important factor on macroinvertebrate assemblages, whereas explanatory power of environmental variables was low. In both seasons, the fractal dimension of area was the variable with the highest explanatory power on richness, and plant biomass was in the case of macroinvertebrate abundance. To conserve macroinvertebrate diversity in Esteros del Iberá, it would be necessary to maintain the natural heterogeneity indicated by the different structural complexities of the macrophytes across the wetland.Fil: Poi, Alicia Susana G.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Gallardo, Luciana Irene. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Casco, Sylvina Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Sabater, Lara Milena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Úbeda, Bárbara. Universidad de Cadiz. Facultad de Ciencias; Españ

nundações no Baixo Paraná: ¿pode-se vincular a gestão social a partir de comportamento hidrológico anterior?

Los ríos con tramos de llanura tienen dos subsistemas bióticos de distinta distribución y dinámica temporal: a) las poblaciones naturales (vegetación y fauna) cuya distribución y permanencia responde al régimen de pulsos (sequías + inundaciones) en cada posición geográfica y topográfica; b) los asentamientos humanos, que colonizan y se consolidan en períodos de sequía son fuertemente condicionados por las inundaciones extremas. En esta contribución se presenta el análisis de los niveles en que están asentados varios conglomerados humanos en sitios inundables/anegables, los niveles de riesgo (niveles de alerta y de evacuación) y la posibilidad de un ordenamiento de estos asentamientos, utilizando el análisis de recurrencia, duración e intensidad de las inundaciones ocurridas en el último siglo, para lo cual se analizó la fluctuación diaria del río Paraná en el período 1970-2008 para la provincia de Corrientes (Argentina) en un tramo de 354 km. El análisis indica que la respuesta socio-tecnológica a estas inundaciones depende principalmente de la frecuencia, intensidad y duración con que ocurren. Se concluye que la planificación, mantenimiento de estructuras y servicios (rutas, puentes, áreas de servicio), así como los márgenes de seguridad en el diseño debieran realizarse considerando los niveles críticos históricos de inundación, para evitar el colapso de los servicios, a la vez que mantener un programa permanente de concientización y de participación social.Fil: Casco, Sylvina Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Natenzon, Claudia Eleonor. Facultad Latinoamericana de Ciencias Sociales; ArgentinaFil: Basterra, Norma Indiana. Universidad Nacional del Nordeste. Centro de Gestion Ambiental y Ecología; ArgentinaFil: Neiff, Juan Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; Argentin

Lagunas periurbanas de Corrientes (Argentina): de la mesotrofía a la eutrofia un camino de ida y vuelta en 20 años

More than 50,000 sub-rounded shallow lakes fed by rain are found on sandy hills fed by rain in Corrientes Province. We selected two lakes near Saladas city as representative of the wetlands prevailing in the region. The aim of this study is to describe the changes in the ecological state of Soto and Sánches lakes, from the use of the basin and recurrence of wet and dry periods. Thirty non periodic samplings were carried out in each lake between 1992 and 2014, during years with different rainfall regime. According to the annual precipitation we distinguish three periods: 1992-1999 (with high rainfalls); 2000-2010 (with prolonged droughts) and 2011-2014 (with heavy rains concentrated in autumn and spring). At both lakes the aquatic plant volume infested differed over the years. In the first period, Soto Lake became eutrophic due to illegal sewage connections from a new neighborhood. The high ratio depth/depth of the photic zone indicates the state of turbid water with dominance of cyanobacteria and high mean and maximum chlorophyll a. After operation of the treatment plant sewage, Soto Lake became characterized as mesotrophic during the dry period and subsequently oligotrophic. During the study period, Sánches Lake had clear water with a high phosphorus concentration, but it had a single bloom of cyanobacteria in the last period. In lakes fed by rain, long-term studies that include dry and wet periods allow for more accurate diagnosis of the ecological state. The use of different indicators, besides the nutrient content is recommended to determine the trophic state.Facultad de Ciencias Naturales y Muse

Lagunas periurbanas de Corrientes (Argentina)

More than 50,000 sub-rounded shallow lakes fed by rain are found on sandy hills fed by rain in Corrientes Province. We selected two lakes near Saladas city as representative of the wetlands prevailing in the region. The aim of this study is to describe the changes in the ecological state of Soto and Sánches lakes, from the use of the basin and recurrence of wet and dry periods. Thirty non periodic samplings were carried out in each lake between 1992 and 2014, during years with different rainfall regime. According to the annual precipitation we distinguish three periods: 1992-1999 (with high rainfalls); 2000-2010 (with prolonged droughts) and 2011-2014 (with heavy rains concentrated in autumn and spring). At both lakes the aquatic plant volume infested differed over the years. In the first period, Soto Lake became eutrophic due to illegal sewage connections from a new neighborhood. The high ratio depth/depth of the photic zone indicates the state of turbid water with dominance of cyanobacteria and high mean and maximum chlorophyll a. After operation of the treatment plant sewage, Soto Lake became characterized as mesotrophic during the dry period and subsequently oligotrophic. During the study period, Sánches Lake had clear water with a high phosphorus concentration, but it had a single bloom of cyanobacteria in the last period. In lakes fed by rain, long-term studies that include dry and wet periods allow for more accurate diagnosis of the ecological state. The use of different indicators, besides the nutrient content is recommended to determine the trophic state.More than 50,000 sub-rounded shallow lakes fed by rain are found on sandy hills fed by rain in Corrientes Province. We selected two lakes near Saladas city as representative of the wetlands prevailing in the region. The aim of this study is to describe the changes in the ecological state of Soto and Sánches lakes, from the use of the basin and recurrence of wet and dry periods. Thirty non periodic samplings were carried out in each lake between 1992 and 2014, during years with different rainfall regime. According to the annual precipitation we distinguish three periods: 1992-1999 (with high rainfalls); 2000-2010 (with prolonged droughts) and 2011-2014 (with heavy rains concentrated in autumn and spring). At both lakes the aquatic plant volume infested differed over the years. In the first period, Soto Lake became eutrophic due to illegal sewage connections from a new neighborhood. The high ratio depth/depth of the photic zone indicates the state of turbid water with dominance of cyanobacteria and high mean and maximum chlorophyll a. After operation of the treatment plant sewage, Soto Lake became characterized as mesotrophic during the dry period and subsequently oligotrophic. During the study period, Sánches Lake had clear water with a high phosphorus concentration, but it had a single bloom of cyanobacteria in the last period. In lakes fed by rain, long-term studies that include dry and wet periods allow for more accurate diagnosis of the ecological state. The use of different indicators, besides the nutrient content is recommended to determine the trophic state

Lagunas periurbanas de Corrientes (Argentina): de la mesotrofía a la eutrofia un camino de ida y vuelta en 20 años

More than 50,000 sub-rounded shallow lakes fed by rain are found on sandy hills fed by rain in Corrientes Province. We selected two lakes near Saladas city as representative of the wetlands prevailing in the region. The aim of this study is to describe the changes in the ecological state of Soto and Sánches lakes, from the use of the basin and recurrence of wet and dry periods. Thirty non periodic samplings were carried out in each lake between 1992 and 2014, during years with different rainfall regime. According to the annual precipitation we distinguish three periods: 1992-1999 (with high rainfalls); 2000-2010 (with prolonged droughts) and 2011-2014 (with heavy rains concentrated in autumn and spring). At both lakes the aquatic plant volume infested differed over the years. In the first period, Soto Lake became eutrophic due to illegal sewage connections from a new neighborhood. The high ratio depth/depth of the photic zone indicates the state of turbid water with dominance of cyanobacteria and high mean and maximum chlorophyll a. After operation of the treatment plant sewage, Soto Lake became characterized as mesotrophic during the dry period and subsequently oligotrophic. During the study period, Sánches Lake had clear water with a high phosphorus concentration, but it had a single bloom of cyanobacteria in the last period. In lakes fed by rain, long-term studies that include dry and wet periods allow for more accurate diagnosis of the ecological state. The use of different indicators, besides the nutrient content is recommended to determine the trophic state.Facultad de Ciencias Naturales y Muse

Lagunas periurbanas de Corrientes (Argentina): de la mesotrofía a la eutrofia un camino de ida y vuelta en 20 años

More than 50,000 sub-rounded shallow lakes fed by rain are found on sandy hills fed by rain in Corrientes Province. We selected two lakes near Saladas city as representative of the wetlands prevailing in the region. The aim of this study is to describe the changes in the ecological state of Soto and Sánches lakes, from the use of the basin and recurrence of wet and dry periods. Thirty non periodic samplings were carried out in each lake between 1992 and 2014, during years with different rainfall regime. According to the annual precipitation we distinguish three periods: 1992-1999 (with high rainfalls); 2000-2010 (with prolonged droughts) and 2011-2014 (with heavy rains concentrated in autumn and spring). At both lakes the aquatic plant volume infested differed over the years. In the first period, Soto Lake became eutrophic due to illegal sewage connections from a new neighborhood. The high ratio depth/depth of the photic zone indicates the state of turbid water with dominance of cyanobacteria and high mean and maximum chlorophyll a. After operation of the treatment plant sewage, Soto Lake became characterized as mesotrophic during the dry period and subsequently oligotrophic. During the study period, Sánches Lake had clear water with a high phosphorus concentration, but it had a single bloom of cyanobacteria in the last period. In lakes fed by rain, long-term studies that include dry and wet periods allow for more accurate diagnosis of the ecological state. The use of different indicators, besides the nutrient content is recommended to determine the trophic state.Facultad de Ciencias Naturales y Muse