Abstract: Abstract Benthic macroinvertebrates are organisms that are recognized as water quality bio-indicators. A wide variety of indices and metrics have been shown to respond to a variety of anthropogenic impacts, usually under a general condition of environmental impairment. The absence of a clear distinction in the relations between specific pollutants and biotic variables is very common and can lead to biased interpretation of biomonitoring. The aims of this research were to test taxonomic and non-taxonomic responses to specific environmental conditions instead to general conditions. For this purpose, we estimated the theoretical toxicity by comparing toxicity values published by EPA with metal concentrations in water and sediments. Then we tested the responses of biological variables to toxicity and other environmental conditions using the linear mixed effects models approach. We generated 32 models considering 24 different biological metrics and indices that were grouped in five levels. Taxonomic and abundance metrics were best predictor than functional or tolerance-based indexes. The strongest model was that which considered subfamily taxonomic resolution responding to Al_w and Cr_s.
Abstract: Abstract The pichi (Zaedyus pichiy; Cingulata: Chlamyphoridae) is an armadillo whose ectoparasite fauna is composed of ticks and fleas. Fleas were collected from 218 pichis in southern Mendoza, Argentina, in summer and winter of 2015 and 2016. Prevalences were analyzed and differences in the intensities of the total number of fleas related to host (age, sex, weight, size and physical condition) and environment-related (seasonality and year) factors evaluated. Phthiropsylla agenoris was the only species found. Intensities of fleas were higher in 2015, in juveniles, and in males. Individuals with poor physical condition were more parasitized than those with good or normal body condition. The main explanatory variable was sampling year. This factor was directly associated with precipitation. The extreme conditions and heavy rains during the El Niño event in 2015/2016 led to environmental changes that seem to have severely affected the life cycle of fleas.
Abstract: Abstract The Paraná-Etendeka Magmatic Province is associated with the distensive tectonics that caused the rupture of the Gondwana continent during the Lower Cretaceous and generated an intense volcanism that covers South America and the NW portion of Namibia in Africa. In Brazil, this volcanic sequence is named Serra Geral Group and predominantly consists of basalts and subordinated silicic rocks. The goal of this study is to characterize the geomorphological features observed in the Aparados da Serra region, southern Brazil, and to evaluate the relationship between these structures and the primary silicic volcanic structures. The geomorphological features were first identified using remote sensing and then correlated with flow structures observed in the field, as well as petrographic and geochemical data. AMS data were used to determine magnetic patterns and the direction of magmatic flow of the rocks. Despite the low degree of anisotropy, clear patterns of lineation and foliation were identified in the studied rocks. Our data shows that Units I and II correspond to silicic lava flows linked to effusive fissure eruptions, presenting a dome morphology caused by differential erosion. Unit III rocks may correspond to true volcanic domes, whereas the Unit IV corresponds to the effusive feeder structures.
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