Notas sobre el conocimiento limnológico de los gasterópodos paranenses y sus relaciones tróficas. I Ampullariidae

The limnological knowledge about the gasteropods of the Paraná River are rather poor, disperse and very diffícult to find and to be applied to the studies related to their múltiple relationships in the aquatic environment, including their participation in the water trophic cycles. Thus, a first approach to a syntesis of the several advances is intended here, in order to center the main problems and estimúlate possible developmentways as well. Aspects with applied interests are also included (fisheries, sanitary problems, weed control). The treatment of each group will be faced separately because of its extention, begining with the present notes on the Ampullaríidae. The limnological knowledge about the gasteropods of the Paraná River are rather poor, disperse and very diffícult to find and to be applied to the studies related to their múltiple relationships in the aquatic environment, including their participation in the water trophic cycles. Thus, a first approach to a syntesis of the several advances is intended here, in order to center the main problems and estimúlate possible developmentways as well. Aspects with applied interests are also included (fisheries, sanitary problems, weed control). The treatment of each group will be faced separately because of its extention, begining with the present notes on the Ampullaríidae.&nbsp

Contribución al conocimiento limnológico de moluscos pelecipodos en la Cuenca del Plata, con particular referencia a sus relaciones tróficas

Despite the undeniable limnological importance o f the malacological fauna in the waters o f Rio de la Plata Basin, the current knowledge on this topic is very poor, fragmentary and geographically limited. Moreover existing limnological literature generally focuses on their very complex taxonomic problems. Thus, this paper conceived on the basis o f available literature, unpublished data and our own research, represents a first attemt to bring together the most significant limnological Information related to the mollusks o f the above mencioned basin and to begin with, the pelecipod s. Also it intends to provide as far as posible a complete and integrative panorame of the role o f different species in its participation in trophic nets, specially those dealing with the fish and físheries. The effect and possible future consequences of the invasión on this waters by species o f the genus Corbicula, are also considered.Despite the undeniable limnological importance o f the malacological fauna in the waters o f Rio de la Plata Basin, the current knowledge on this topic is very poor, fragmentary and geographically limited. Moreover existing limnological literature generally focuses on their very complex taxonomic problems. Thus, this paper conceived on the basis o f available literature, unpublished data and our own research, represents a first attemt to bring together the most significant limnological Information related to the mollusks o f the above mencioned basin and to begin with, the pelecipod s. Also it intends to provide as far as posible a complete and integrative panorame of the role o f different species in its participation in trophic nets, specially those dealing with the fish and físheries. The effect and possible future consequences of the invasión on this waters by species o f the genus Corbicula, are also considered

Moluscos (Gastropoda e Bivalvia) da reserva natural de usos múltiplos ilha Martín García, Río de la Plata: Biodiversidade e ecologia

The Island of Martin Garcia is located in the Upper Río de la Plata, to the south of mouth the Uruguay River. The aim of the present study was to analyse the biodiversity of the island freshwater mollusks and their relationships to environmental variables. Twelve sampling sites were selected, five were along the littoral section of the island and seven were Inland ponds. Seven major environmental variables were measured: water and air temperature, percentage of oxygen saturation, dissolved oxygen, electrical conductivity, total dissolved solids and pH. Twenty-seven mollusk species were found, Antillorbis nordestensis, Biomphalaria tenagophila tenagophila, B. t. guaibensis, B. straminea, B. peregrina, Drepanotrema kermatoides, D. cimex, D. depressissimum, Chilina fluminea, C. rushii, C. megastoma, Uncancylus concentricus, Hebetancylus moricandi, Stenophysa marmorata, Heleobia piscium, H. parchappii, Potamolithus agapetus, P. buschii, P. lapidum, Pomacea canaliculata, P. megastoma Asolene platae, Corbicula fluminea, Eupera platensis, Pisidium sterkianum, P. taraguyense and Limnoperna fortunei. UPGMA clustering of species based on their occurrence in different ecological conditions revealed two main species groups. The Canonical Correspondence Analysis suggests that the species distribution is related to the physico-chemical condition of water. Axis two of the ordination diagram displayed the approximately 95.6% of the correlation between species and environmental variables. Dissolved oxygen, conductivity, water temperature and pH showed the highest fluctuations during the sampling period. The species richness (S) showed relationships mainly with water temperature and conductivity. The biodiversity of the gastropods and bivalves from Martín García Island amounts to up to 26 species. Among the Gastropoda, the Planorbidae family made the most sizeable contribution. The Lithogliphidae P. agapetus (26.28%) and P. buschii (9.50%) showed the highest relative frequencies of occurrence within the littoral environments, while the Planorbidae D. cimex (23.83%) and D. kermatoides (11.59%) likewise did so in the inland ponds.Facultad de Ciencias Naturales y Muse

Notas sobre el conocimiento limnológico de los gasterópodos paranenses y sus relaciones tróficas. II Planorbidae, con aspectos distribucionales y sanitarios

The present remarks on the family Planorbidae constitute a further work o f a series of contributions tending to fumish an integrated overview of the Paraná river’s malacologic fauna, the knowledge of which is most limited, particularly conceming thetaxonomic, biological and limnological aspects. To this effect, the aim of this work is, as well, to give an idea of its energy transfer to fishes and of its importance. This is best observed in the planorbids of the genus Biomphalaria, not particularly because of the importance of such energy contribution, but due to the preying capacity, consumption pressure, and consequent population control performed by certain fishes on these gastropods, some of which species are vectors of schistosomiasis. The fact becomes especially relevant when a sustained advance of this parasitosis towards Argentinianwaters is being noticed; for this reason, thorough investigations of this problem are suggested so as to prevent (or at least reduce) this serious threat which has to be realistically assumed..The present remarks on the family Planorbidae constitute a further work o f a series of contributions tending to fumish an integrated overview of the Paraná river’s malacologic fauna, the knowledge of which is most limited, particularly conceming thetaxonomic, biological and limnological aspects. To this effect, the aim of this work is, as well, to give an idea of its energy transfer to fishes and of its importance. This is best observed in the planorbids of the genus Biomphalaria, not particularly because of the importance of such energy contribution, but due to the preying capacity, consumption pressure, and consequent population control performed by certain fishes on these gastropods, some of which species are vectors of schistosomiasis. The fact becomes especially relevant when a sustained advance of this parasitosis towards Argentinianwaters is being noticed; for this reason, thorough investigations of this problem are suggested so as to prevent (or at least reduce) this serious threat which has to be realistically assumed

Una isla peculiar en el Río de la Plata

Navegando por las aguas color de león e internándonos en la inmensidad del Río de la Plata, la Isla Martín García surge como una formación rocosa, diferenciándose de las otras islas deltaicas originadas por acumulación aluvial acarreada por los ríos del Sistema del Plata

Moluscos (Gastropoda e Bivalvia) da reserva natural de usos múltiplos ilha Martín García, Río de la Plata: Biodiversidade e ecologia

The Island of Martin Garcia is located in the Upper Río de la Plata, to the south of mouth the Uruguay River. The aim of the present study was to analyse the biodiversity of the island freshwater mollusks and their relationships to environmental variables. Twelve sampling sites were selected, five were along the littoral section of the island and seven were Inland ponds. Seven major environmental variables were measured: water and air temperature, percentage of oxygen saturation, dissolved oxygen, electrical conductivity, total dissolved solids and pH. Twenty-seven mollusk species were found, Antillorbis nordestensis, Biomphalaria tenagophila tenagophila, B. t. guaibensis, B. straminea, B. peregrina, Drepanotrema kermatoides, D. cimex, D. depressissimum, Chilina fluminea, C. rushii, C. megastoma, Uncancylus concentricus, Hebetancylus moricandi, Stenophysa marmorata, Heleobia piscium, H. parchappii, Potamolithus agapetus, P. buschii, P. lapidum, Pomacea canaliculata, P. megastoma Asolene platae, Corbicula fluminea, Eupera platensis, Pisidium sterkianum, P. taraguyense and Limnoperna fortunei. UPGMA clustering of species based on their occurrence in different ecological conditions revealed two main species groups. The Canonical Correspondence Analysis suggests that the species distribution is related to the physico-chemical condition of water. Axis two of the ordination diagram displayed the approximately 95.6% of the correlation between species and environmental variables. Dissolved oxygen, conductivity, water temperature and pH showed the highest fluctuations during the sampling period. The species richness (S) showed relationships mainly with water temperature and conductivity. The biodiversity of the gastropods and bivalves from Martín García Island amounts to up to 26 species. Among the Gastropoda, the Planorbidae family made the most sizeable contribution. The Lithogliphidae P. agapetus (26.28%) and P. buschii (9.50%) showed the highest relative frequencies of occurrence within the littoral environments, while the Planorbidae D. cimex (23.83%) and D. kermatoides (11.59%) likewise did so in the inland ponds.Facultad de Ciencias Naturales y Muse

Una isla peculiar en el Río de la Plata

Navegando por las aguas color de león e internándonos en la inmensidad del Río de la Plata, la Isla Martín García surge como una formación rocosa, diferenciándose de las otras islas deltaicas originadas por acumulación aluvial acarreada por los ríos del Sistema del Plata.Fundación Museo La Plat

Una isla peculiar en el Río de la Plata

Navegando por las aguas color de león e internándonos en la inmensidad del Río de la Plata, la Isla Martín García surge como una formación rocosa, diferenciándose de las otras islas deltaicas originadas por acumulación aluvial acarreada por los ríos del Sistema del Plata.Fundación Museo La Plat

Diversity of benthic invertebrates of the Río de la Plata river

The Rio de la Plata river present along the south coastal fringe different invertebrate assemblages related with substrate type, size sediment grains and organic matter content into the bedsediments. Other important factors influencing the distribution of benthos community in this river are the salinity and suspended solids of the water and the proximity to the riverside which increases the diversity of the habitats. The purpose of this study is to describe the taxonomic composition and ecological characteristics of the meso and macrobenthos associated with the river bed from Delta del Paraná to Magdalena, in Buenos Aires province. The listed taxa are the result of the revised literature and original data obtained from periodical samplings since 1993 till 1998. The principal components of the zoobenthos in the studied area were the allochthonous molluscs Corbicula fluminea on sandy and muddy bottoms and Limnoperna fortunei on hard substrates of the riverside. The nematods and oligochaetes dominated sediments with high allochthonous organic matter content imported from urban effluents. Palaemonetes argentinus, Macrobrachium borelli, Claudicuma platensis, Sinelobus stanfordi, Basphaeroma rhonbofrontale and Trichodactylus panoplus were the more common crustaceans in non polluted areas.Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) - Instituto de Limnología "Dr. Raul A. Ringuelet" (ILPLA

Diversity of benthic invertebrates of the Río de la Plata river

The Rio de la Plata river present along the south coastal fringe different invertebrate assemblages related with substrate type, size sediment grains and organic matter content into the bedsediments. Other important factors influencing the distribution of benthos community in this river are the salinity and suspended solids of the water and the proximity to the riverside which increases the diversity of the habitats. The purpose of this study is to describe the taxonomic composition and ecological characteristics of the meso and macrobenthos associated with the river bed from Delta del Paraná to Magdalena, in Buenos Aires province. The listed taxa are the result of the revised literature and original data obtained from periodical samplings since 1993 till 1998. The principal components of the zoobenthos in the studied area were the allochthonous molluscs Corbicula fluminea on sandy and muddy bottoms and Limnoperna fortunei on hard substrates of the riverside. The nematods and oligochaetes dominated sediments with high allochthonous organic matter content imported from urban effluents. Palaemonetes argentinus, Macrobrachium borelli, Claudicuma platensis, Sinelobus stanfordi, Basphaeroma rhonbofrontale and Trichodactylus panoplus were the more common crustaceans in non polluted areas.Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) - Instituto de Limnología "Dr. Raul A. Ringuelet" (ILPLA