Evaluación de la diversidad en comunidades de tardígrados (Ecdysozoa: Tardigrada) en hábitats urbano y rural de la ciudad de Salta (Argentina) / Diversity assessment in tardigrades communities (Ecdysozoa, Tardigrada) in urban and rural habitats of the city of Salta (Argentina)

Este trabajo se realizó bajo la hipótesis de que existe una pérdida creciente de diversidad en las comunidades de tardígrados, desde las áreas rurales hacia las urbanas, incrementando la homogenización de sus comunidades producto de la urbanización. Para la ciudad de Salta, se tomaron muestras en áreas con tránsito vehicular alto y muestras en áreas rurales circundantes. Se identificaron en total ocho especies/morfoespecies. El inventario tuvo una completitud mayor al 94%. La comunidad rural fue más diversa y estructuralmente más uniforme que la comunidad urbana. Macrobiotus hufelandi Schultze, 1834 resultó especie indicadora y Milnesium sp. como detectora para el hábitat urbano, mientras que Paramacrobiotus areolatus Murray, 1907 resultó indicadora para el hábitat rural.

This work was carried out under the hypothesis that there is a growing loss of diversity in communities of tardigrades, from rural to urban areas, increasing the homogenization of its communities due to the urbanization. Samples were taken from the city of Salta in areas with high vehicular traffic and samples in surrounding rural areas. We identified a total of eight species/morphospecies. The inventory completeness was greater than 94%. The rural community was more diverse and structurally more uniform compared with the urban one, shown that both communities were different. Macrobiotus hufelandi Schultze, 1834 results as an indicator species, and Milnesium sp. as detector species from urban habitat; meanwhile Paramacrobiotus areolatus Murray 1907 was an indicator species for rural areas.

Evaluación de la diversidad en comunidades de tardígrados (Ecdysozoa: Tardigrada) en hábitats urbano y rural de la ciudad de Salta (Argentina)

RESÚMEN Este trabajo se realizó bajo la hipótesis de que existe una pérdida creciente de diversidad en las comunidades de tardígrados, desde las áreas rurales hacia las urbanas, incrementando la homogenización de sus comunidades producto de la urbanización. Para la ciudad de Salta, se tomaron muestras en áreas con tránsito vehicular alto y muestras en áreas rurales circundantes. Se identificaron en total ocho especies/morfoespecies. El inventario tuvo una completitud mayor al 94%. La comunidad rural fue más diversa y estructuralmente más uniforme que la comunidad urbana. Macrobiotus hufelandi Schultze, 1834 resultó especie indicadora y Milnesium sp. como detectora para el hábitat urbano, mientras que Paramacrobiotus areolatus Murray, 1907 resultó indicadora para el hábitat rural.

ABSTRACT This work was carried out under the hypothesis that there is a growing loss of diversity in communities of tardigrades, from rural to urban areas, increasing the homogenization of its communities due to the urbanization. Samples were taken from the city of Salta in areas with high vehicular traffic and samples in surrounding rural areas. We identified a total of eight species/morphospecies. The inventory completeness was greater than 94%. The rural community was more diverse and structurally more uniform compared with the urban one, shown that both communities were different. Macrobiotus hufelandi Schultze, 1834 results as an indicator species, and Milnesium sp. as detector species from urban habitat; meanwhile Paramacrobiotus areolatus Murray 1907 was an indicator species for rural areas.

Evaluación de la diversidad en comunidades de tardígrados (Ecdysozoa: Tardigrada) en hábitats urbano y rural de la ciudad de Salta (Argentina) / Diversity assessment in tardigrades communities (Ecdysozoa, Tardigrada) in urban and rural habitats of the city of Salta (Argentina)

Este trabajo se realizó bajo la hipótesis de que existe una pérdida creciente de diversidad en las comunidades de tardígrados, desde las áreas rurales hacia las urbanas, incrementando la homogenización de sus comunidades producto de la urbanización. Para la ciudad de Salta, se tomaron muestras en áreas con tránsito vehicular alto y muestras en áreas rurales circundantes. Se identificaron en total ocho especies/morfoespecies. El inventario tuvo una completitud mayor al 94%. La comunidad rural fue más diversa y estructuralmente más uniforme que la comunidad urbana. Macrobiotus hufelandi Schultze, 1834 resultó especie indicadora y Milnesium sp. como detectora para el hábitat urbano, mientras que Paramacrobiotus areolatus Murray, 1907 resultó indicadora para el hábitat rural.(AU)

This work was carried out under the hypothesis that there is a growing loss of diversity in communities of tardigrades, from rural to urban areas, increasing the homogenization of its communities due to the urbanization. Samples were taken from the city of Salta in areas with high vehicular traffic and samples in surrounding rural areas. We identified a total of eight species/morphospecies. The inventory completeness was greater than 94%. The rural community was more diverse and structurally more uniform compared with the urban one, shown that both communities were different. Macrobiotus hufelandi Schultze, 1834 results as an indicator species, and Milnesium sp. as detector species from urban habitat; meanwhile Paramacrobiotus areolatus Murray 1907 was an indicator species for rural areas.(AU)

[Population biology of Posthodiplostomum namum Dubois, 1937 (Trematoda, Diplostomidae) in Jenynsia lineata and Cnesterodon decemmaculatus (Pisces, Atheriniformes), of Chis-Chis Lagoon, Province of Buenos Aires, Argentina]. / Biología Poblacional de Posthodiplostomum nanum Dubois, 1937 (Trematoda, Diplostomidae) en Jenynsia lineata y Cnesterodon decemmaculatus (Pisces, Atheriniformes), de la Laguna de Chis-Chis, Provincia de Buenos Aires, Argentina.

The characteristics of the population dynamics of Posthodiplostomum nanum have been studied in two of its intermediate hosts, using prevalence, intensity and maturity of the metacercariae, considering the influence of the water temperature. In addition to this some ecological implications are described. There were made 18 samples monthly or bimonthly from may 1986 until march 1989, 1113 fishes were captured out of which 956 metacercariae were obtained. P. nanum was present along the year, having significant seasonal variation in prevalence and intensity of infestation. It was observed that the water temperature is a relevant factor in the maturation of the parasite. The values of the prevalence and intensity of infestation were higher in Jenynsia lineata than in Cnesterodon decemmaculatus. This could be explained by various factors: a) distribution of the first intermediate host; b) behavior of the second intermediate host and c) individual physiological differences of each host, specially in relation to reproduction. The relation S2/X fluctuated during the whole year, indicating the recruitment-period (autumn, spring) and the nonrecruitment-period (winter, summer) of metacercariae.