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Soil seed banks serve as reservoirs of taxonomic and genetic diversity and can buffer the effect of perturbations on plant communities, and thus are critical for community resilience. We studied the relationship of seed bank abundance and richness with different hydrological attributes, evaluated beta diversity patterns among wetlands in the Middle Parana River floodplain, and experimentally explored soil seed bank germination after a drought period. Seed abundance was positively related to drought intensity and, along with richness, negatively related to drought and flood frequency. Turnover and balanced variation in abundance greatly contributed to the total beta diversity probably associated with the environmental heterogeneity of the floodplain; nestedness had a lower contribution probably associated with different dispersal abilities of species. Germination behavior varied between rooted and free-floating plants. In conclusion, the soil seed banks studied are highly variable among habitats; drought and flood frequency, and drought intensity are related with the seed banks abundance and richness; and the germination responses after a drought phase differ among broad ecological groups of wetland plants.

All animals face the possibility of limitations in food resources that could ultimately lead to mortality caused by starvation. The primary goal of this study was to characterize the various physiological strategies that allow fish to survive starvation. A multiparametric approach, including morphological biomarkers, blood plasma metabolites, oxidative stress and energy reserves, was used to assess starvation effects on the fish Hoplosternum littorale. Adult specimens were maintained at four experimental groups: control (fed ad libitum), and starved (not fed) fish for 7 and 28 days. Significant changes were observed not only after 28 days, but also after 7 days of starvation. In the shorter period, the hepatosomatic index as well as plasma triglycerides and glucose were significantly lower in starved fish than in the control ones. These results were accompanied by reduced lipid, glycogen and protein reserves in liver and diminished glycogen content in muscle, suggesting the need of these macromolecules as fuel sources. In addition, increased antioxidant enzyme activities were observed in gills, without evidence of oxidative stress in any of the evaluated tissues. Most significant differences were found in 28-days starved fish: total body weight together with the hepatosomatic index was lower when compared to control fish. The plasmatic metabolites tested (glucose, triglyceride, cholesterol and protein), all energy reserves in liver and glycogen content in muscle decreased in 28-days starved fish. Lipid oxidative damage was reported in liver, kidney and brain, and antioxidant enzymes (GST, GR, GPx and CAT) were activated in gills. According to the multivariate analysis, oxidative stress markers and metabolic parameters were key biomarkers that contributed in separating starved from fed fish. Our study allowed an integrated assessment of the fish response to this particular condition. Fil: Rossi, Andrea Silvana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias; Argentina Fil: Cazenave, Jimena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias; Argentina Fil: Bacchetta, Carla. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina Fil: Campana, Mirta Claudia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina Fil: Parma, Maria Julieta E.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias; Argentina

The combined effects of two synthetic insecticides on a wide array of biomarkers in the freshwaterfish Piaractus mesopotamicus were studied. Fish were exposed to sublethal concentrations of endosul-fan (ED), lambda-cyhalothrin (LC), and the combination of both pesticides for 96 h. The set of analyzedbiomarkers included morphometric and hematological parameters, transaminases and alkaline phos-phatase activities, antioxidant enzymes activities and oxidative damage biomarkers measured in gills,liver, kidney, brain and muscle. According to the principal component analysis, the most significant effectswere produced by the ED?LC combination. So, the mixture of both insecticides produced an increase inthe liver-somatic index, hematological changes related to immunological biomarkers (increased whiteblood cells count, and alterations in the differential leukocytes count), decreased liver transaminasesactivity, antioxidant enzymes induction in almost every tissue, and lipid peroxidation levels increases inliver, kidney and brain of exposed fish. Our results suggest deleterious effects of ED and LC insecticidesin combination, and support the usefulness of the multi-biomarker approach for the characterization oftoxicological mechanisms induced by pesticides. Fil: Bacchetta, Carla. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina Fil: Rossi, Andrea Silvana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina Fil: Ale, Analía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina Fil: Campana, Mirta Claudia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina Fil: Parma, Maria Julieta E.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina Fil: Cazenave, Jimena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentina