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Ecosystem services provided by communities are related to the diversity of functional traits, and biotic functional simplification occurs when this diversity is reduced. Thus, we used the approach of functional indices, applied to the abundance of fish larvae and traits of the spawning stock, to evaluate the spatial and temporal variations in the functional diversity of the fish community of a Neotropical reservoir. The following hypotheses were tested: (i) different environmental conditions between reproductive periods lead to temporal variations in the functional diversity of the community, and (ii) the spatial heterogeneity (longitudinal and lateral) of the environmental conditions formed in the reservoir causes functional biotic simplification to occur from lotic towards lentic areas since the original community was formed by rheophilic species. Larval collections were carried out monthly, at night, between October and March, from 2009 to 2016, with plankton nets equipped with a flowmeter in nine sample areas categorised into three longitudinal zones (fluvial‐FLU, transition‐TRA and lacustrine‐LAC) and three sides (upper‐UPP, middle‐MID and lower‐LOW). Water samples were obtained to measure the temperature and turbidity. Precipitation and reservoir quotas were obtained from official agencies. After the identification of captured larvae, we determined which species were present and used the functional traits of the adults (parental stock), obtained from specialised literature, and functional richness (FRic) and its corresponding standardised effect size (SES.FRic) were computed. The spatiotemporal variations in these indices were evaluated through the two‐way block factorial MANOVA/ANOVA. Their association with environmental variables was inferred through multiple linear regression models. Altogether, 51,995 larvae were captured with the highest abundance in the period V, longitudinally in LAC and TRA and laterally in LOW. Among these, the functional indices were higher in periods IV and V. The highest values of FRic occurred longitudinally in FLU and laterally in LOW. Among the abiotic conditions, rainfall and water temperature were the most influential variables over functional indices and total larvae abundance. The results indicate that fish reproduction is linked to spatiotemporal variations in abiotic conditions confirming our first hypothesis. The second hypothesis was partially supported because functional biotic simplification was observed in the longitudinal gradient, with reductions in FRic in LAC. However, this reduction was not observed in the lateral gradient. We showed that the temporal variability of abiotic conditions is important for the high functional diversity of reservoirs. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the differences of the macroinvertebrate community in two neotropical ecoregions. In this regard were sampled in 12 low-order streams, biological samples (benthic macroinvertebrates), water samples to determine physical and chemical characteristics (pH, dissolved oxygen, altitude, water temperature, alkalinity, water hardness, total nitrogen and total phosphorus) and was evaluated of the substrate in the riverbed. To compare attributes between the two ecoregions, was used the ANOVA and for the analysis of the structure and its relation with the physiographic parameters, the data were summarized by Principal Component Analysis. In addition, were classified the functional groups and indicator groups for each ecoregion. There were no differences between the ecoregions for attributes, however, the structure was different according to the PCA. Functional groups had different percentages for each ecoregion. The indicator taxa for Ecoregion 'A' were Baetidae, Aeshnidae, Coenagrionidae, Chironomidae and Ceratopogonidae and for Ecoregion 'B', the indicator taxa were Leptohyphidae, Caenidae, Perlidae, Pleidae and Psephenidae. The presence of the sensible indicator taxa infers that Ecoregion 'B' shows better habitat condition, It is due to the structural difference in substrate types, alkalinity, dissolved oxigen and water temperature. [ABSTRACT FROM AUTHOR]

The aim of this work was to evaluate the spermatic parameters of jundia, Rhamdia quelen, semen stored for short periods under different temperatures. Fifteen males were used in a time factorial experimental design (13 × 3 × 3 × 3). The sperm was stored at: 15; 25 and 35°C and activated in water at: 15; 25 and 35°C each, respectively, within storage periods of: 0; 2; 4; 6; 8; 10; 12; 16; 20; 24; 32; 40 and 48 h after collection. The treatments were performed in triplicates and in sequential protocols every 50 h. The motility parameters were evaluated using Pearson's correlation analysis and the significant parameters ( P < 0.05) were summarized using principal component analysis forming two predicted groups. Group 01 composed the following parameters: curvilinear velocity, wobble and linearity; group 02 comprised average path velocity, straight line velocity, beating cross frequency and motility rate. Effects ( P < 0.05) of treatments were observed only in group 02, with interaction between time and temperature of exposure and between exposure time and water temperature. Superior results of spermatic parameters of group 02 were observed right after collection. However, the exposure and spermatic activation at 15°C assured significant results 48 h after collection when compared with 25 and 35°C. [ABSTRACT FROM AUTHOR]

Abstract: The objective of this study was to evaluate the effects of three water and storage temperatures on the oocytes of the jundiá catfish, Rhamdia quelen. A factorial experimental design over time, with treatments completed in triplicate every 48h, was used (5×3×3×3) to study the exposure of the oocytes to temperatures of 15, 25 and 35°C and activated with water at 15, 25 and 35°C each at 0, 45, 90, 135 and 180minutes post-collection. Linear regression analysis for the response surface model indicated an interaction (p<0.05) between time and temperature of exposure with greater values for fertilization, hatching and normal larvae rates at the time of oocyte collection (70.2±8.4% fertilized oocytes, 66.7±29.4% hatched eggs and 30.3±25.0% normal larvae). According to the statistical model, the water temperature that resulted in the highest fertilization rate was 25.6°C (p<0.05). The rates of fertilization, hatching and normal larvae correlated positively (p<0.05) with one another, showing that these parameters can be used in the measurement of oocyte quality. Artificial fertilization of oocytes is recommended immediately after collection; if storage is necessary, it should be carried out at 15°C. [Copyright &y& Elsevier]