QUANTIFYING CHANGES IN OLIGOCHAETA ASSEMBLAGES INFLUENCED BY PHOTIC ZONES IN NEOTROPICAL RESERVOIRS
Research was carried out to determine whether the influence of the photic zones have significant impacts on Oligochaeta assemblage structure in 13 reservoirs in the State of São Paulo (Brazil) during the period of June 2014 to July 2016. The sampling design considered two groups of sites: Euphotic and Aphotic. Secchi depth was used to calculate the light attenuation coefficient, adjusted to tropical environments. Oligochaeta assemblage samples and water physiochemistry, were evaluated at each site. Statistical analyzes comprise combination of multivariate and univariate procedures, as well the Indicator Species Analysis (IndVal) over the biotic and environmental datasets. Water temperature, pH, dissolved oxygen and electrical conductivity are responsible for explaining environmental conditions changes between treatments. During the study, five subfamilies, 12 genera, and 28 species were recorded. We found a clear decrease in abundance, richness and species diversity at the aphotic assemblages when compared to the euphotic. Aphotic assemblages present high average values of Simpson dominance index. IndVal indicated significant relationships of species Dero righii, Dero digitata, Dero sawayai, Branchiura sowerbyi, Stephensoniana trivandrana, and Nais communis with euphotic sites. Tubificinae density presents a strong association with aphotic sites.
Guilherme Gorni (Primary Presenter/Author), São Paulo University - USP, firstname.lastname@example.org;
Juliano Corbi (Co-Presenter/Co-Author), University of São Paulo, email@example.com;
Vanessa Colombo-Corbi (Co-Presenter/Co-Author), University of Araraquara - UNIARA, firstname.lastname@example.org;
Douglas Girolli (Co-Presenter/Co-Author), University of Araraquara - UNIARA, email@example.com;