Effects of urbanization on the tardigrade communities in the Argentine Republic

ANDREA X, GONZÁLEZ REYES; ROCHA, ALEJANDRA MARIANA; CORRONCA JA; SANDRA RODRIGUEZ ARTIGAS; DOMA, IRENE; OSTERTAG, B; GRABOSKY, A

Simposio; 14th International Symposium on Tardigrada; 2018

Background: Communities of urban tardigrades are little studied worldwide. For the ArgentineRepublic, a single study evaluated the diversity of tardigrades in an urban-rural gradient in the cityof Salta. In the present work, we continue this line of research, deepening on the effects thatvehicular traffic of the city (classified in High, Medium and Low) may have on tardigrade diversityin these different urban environments. Specifically, we want to determine if a process of biotichomogenization occurs in the area under study. Sites between 1100-1200 masl in the city of Saltawere selected, and lichens and mosses that grew on the trunks of trees were sampled. The sampleswere treated according to the usual methodology and the tardigrade and their eggs were mounted inpolyvinyl-lactophenol. Different variables of the micro-habitats were analysed and considered in theevaluations. The data analyses were carried out through PAST, PC-Ord and R programs.Results: Three thousand forty-nine specimens representing 16 species of heterotardigrades(Echiniscidae) and eutardigrades (species belonging to Milnesidae, Macrobiotidae, Hypsibidae)were collected. The environments with Medium vehicular traffic was 1.12 and 1.23 times morediverse than those with Low and High traffic, respectively. The environments with High trafficshowed the lowest diversity of tardigrades. The ordination analyses explained more than 60% of thetotal variance in two axes, showing a nested pattern in the three environments studied. The indicatorvalue analysis (IndVal) showed that one Milnesium species (Milnesium sp7) (46.6% p = 0.03) is anindicator for Medium vehicular traffic environments. The partition of the β diversity in its differentcomponents (replacement and loss of species) showed that the replacement of species was higheramong the communities with High and Medium traffic, while a loss of species was evidencedbetween the communities of High and Medium transit.Conclusions: The Salta urban tardigrade fauna shows a nested pattern between differentenvironments, evidencing a homogenization process of fauna in this area. This pattern implies asignificant loss of tardigrade species from High traffic to Medium transit environments.