Search

Urban ecosystems are dynamic and complex, with human disturbances that lead to biotic homogenization. We consider the changes suffered by the diversity of tardigrades in Santa Rosa city (Argentina) under different intensity of vehicular traffic (high, medium and low), evaluating whether there are biotic and abiotic factors that can influence the structuring of their communities. Moss and lichen samples were extracted and studied, and different environmental variables, microhabitat, and substrate were measured. Eight species were recorded. Habitat with high vehicular traffic contained the highest tardigrade abundance; while low vehicular traffic had the highest species richness. The assemblages of the three urban communities were different, with a strong dominance of three species: Milnesium quiranae, Ramazzottius oberhaeuseri and Macrobiotus kristenseni. Milnesium kogui turned out to be an indicator species for high vehicular traffic community. Ordination analysis showed a nesting pattern in the studied urban habitats, showing a high turnover of species in the high vehicular traffic community, while in medium vehicular traffic community a high nesting. There was a high loss of species in habitat with low vehicular traffic, while in the habitat with medium and high vehicular traffic there was a high turnover of species. The observed nesting pattern could be explained by the loss of microhabitat due to the replacement of urban trees. [ABSTRACT FROM AUTHOR]

Limno-terrestrial tardigrades of Argentina had been studied starting in 1908 and for a long time by European researchers, most frequently in the Patagonian region (incl. the Land of Fire). Starting during the 1980s, Claps, Rossi and collaborators published many surveys, studying other regions also, but with taxonomic criteria at that time. Since the 2000s, methodical and continuous studies using more modern criteria, have been carried out at the National University of La Pampa, contributing to the faunistic, taxonomic and ecological knowledge (including new species descriptions). This paper provides a comprehensive list of the limno-terrestrial tardigrade fauna reported from Argentina, with pertinent evaluations, owing to a careful study of every pertinent piece of literature since 1908, also solving some problems of discordance between the main past checklists. Summarizing, 39 genera and 119 species are present; of these, 72 represent records accepted by the literature, while 47 are records questioned in the literature but which represent distinct taxa surely present in Argentina; 14 additional taxa, instead, are clearly dubious. The authors also report the correct genus assignment to Viridiscus rufoviridis (du Bois-Reymond Marcus, 1944), which now becomes Barbaria rufoviridis comb. nov. [ABSTRACT FROM AUTHOR]

Urban tardigrades are studied little worldwide. In Salta (Argentina), two studies have evaluated their diversity in an urban–native gradient. Vehicular traffic in Salta city has increased over the last decade, increasing environmental pollution. Our aim is to determine whether biotic homogenization occurs in this city. Sampling sites were selected considering different vehicular traffic intensities (high, medium and low). Tardigrades were sampled from bryophytes growing on tree trunks. Specimens were treated according to the usual study methodology. Different biotic and environmental abiotic variables of the microhabitat were considered. A total of 3049 specimens of 16 species of heterotardigrades and eutardigrades were reported. The low vehicular transit habitat was more diverse than the others. Ordination analyses evidenced a nested pattern in the studied urban habitats. Milnesium sp. nov. 3 and Minibiotus sp. nov. 1 were reported as detector species for habitats with medium vehicular traffic. The partition of the β diversity showed that the species turnover was higher among low and high vehicular traffic communities than medium, whereas a loss of species was evidenced between high and medium habitats. The high diversity of tardigrades in Salta city and their assemblages are partly dependent on several factors, including vehicular traffic. [ABSTRACT FROM AUTHOR]