Relations between environmental gradients and diversity indices of benthic invertebrates in lotic systems of northern Italy

Abstract. The relations between environmental gradients, as measured by 19 independent variables, and traditional diversity indices (taxonomic richness, diversity and evenness) of benthic macroinvertebrate communities in the lotic systems of northern Italy were analyzed. Redundancy analysis (RDA) was used to describe the response of taxa to environmental gradients. Diversity indices were analyzed using generalized linear models (GLMs) with explanatory variables the first two major RDA axes. The results from RDA showed that taxa variance is mostly explained by altitude/latitude and combined pollution gradients. Taxonomic richness and diversity was higher in the low polluted upland sites (LPUs) in comparison to high polluted lowland sites (HPLs), suggesting that headwater streams have higher taxonomic richness than downstream reaches. On the other hand, evenness was lower in LPUs, probably due to the dominance of some taxa (e.g., Plecoptera) that are more tolerant of colder conditions

Multi-scale spatio-temporal patchiness of macrozoobenthos in the Sacca di Goro lagoon (Po River Delta, Italy)

1 - In this study, the macrobenthos from different habitats in the Sacca di Goro lagoon (Po River Delta, Italy) is analysed by following a multi-scale spatio-temporal approach, with the aim of evaluating the spatial patchiness and stability of macroinvertebrate assemblages in the lagoon. The scale similarity is examined by using a taxonomic metrics based on the Kullback-Leibler divergence and a related index of similarity.2 - Data were collected monthly during one year in four dominant habitat types, which were classified on the basis of main physiognomic traits (type of vegetation and anthropogenic impact). Three of the selected habitats were natural (macroalgal beds, bare sediment and Phragmitetum) and one anthropogenically modified (the licensed area for Manila clam farming). Each habitat was sampled in a variable number of stations representative of specific microhabitats, with three replicates each.3 - Of the 47 taxa identified, only few species were found exclusively in one habitat type, with low densities. No taxon was dominant in all the considered habitats.4 - The results show that, in spite of the large overlapping of species, the spatio-temporal dissimilarity within each habitat type was higher than expected on the basis of the common physiognomic traits. This suggests that local factors (mainly hydrodynamism, quality and quantity of vegetal matter) play a significant role in determining the structure of the macroinvertebrate assemblages.5 - The dissimilarity between habitats was significant and maintained all over the seasonal progression, indicating that the macroinvertebrate assemblages were steadily different. Each habitat allowed some specific taxa to maintain a significant population size, which is a prerequisite for preserving biodiversity.6 - The variety of vegetation types and hydrodynamic conditions in the lagoon emerges as crucial for sustaining biodiversity and capacity to recover from disturbances

Modeling soil nitrate accumulation and leaching in conventional and conservation agriculture cropping systems

Nitrate is a major groundwater inorganic contaminant that is mainly due to fertilizer leaching. Compost amendment can increase soils' organic substances and thus promote denitrification in intensively cultivated soils. In this study, two agricultural plots located in the Padana plain (Ferrara, Italy) were monitored and modeled for a period of 2.7 years. One plot was initially amended with 30 t/ha of compost, not tilled, and amended with standard fertilization practices, while the other one was run with standard fertilization and tillage practices. Monitoring was performed continuously via soil water probes (matric potential) and discontinuously via auger core profiles (major nitrogen species) before and after each cropping season. A HYDRUS-1D numerical model was calibrated and validated versus observed matric potential and nitrate, ammonium, and bromide (used as tracers). Model performance was judged satisfactory and the results provided insights on water and nitrogen balances for the two different agricultural practices tested here. While water balance and retention time in the vadose zone were similar in the two plots, nitrate leaching was less pronounced in the plot amended with compost due to a higher denitrification rate. This study provides clear evidence that compost addition and no-tillage (conservation agriculture) can diminish nitrate leaching to groundwater, with respect to standard agricultural practices

Assessment of the intrinsic vulnerability of agricultural land to water and nitrogen losses: case studies in Italy and Greece

Abstract. LOS indices (abbr. of Losses) can be used for the assessment of the intrinsic vulnerability of agricultural land to water and nitrogen losses through percolation and runoff. The indices were applied on the lowland region of Ferrara Province (FP) in Italy and the upland region of Sarigkiol Basin (SB) in Greece. The most vulnerable zones in FP were the coastal areas consisting of high permeability sandy dunes and the areas close to riverbanks and palaeochannels, and in SB were the areas characterized by high slopes and high permeability soils at high altitude and areas belonging to the upper part of the alluvial plain close to the boundaries between agricultural land and mountainous regions. The application of LOS indices highlighted the specific features of both lowland and upland regions that contribute to water and nitrogen losses and showed their ability for use as tools in designing environmental management plans

A regional fish inventory of inland waters in Northern Italy reveals the presence of fully exotic fish communities

The aim of the study is to present a complete and updated fish inventory of inland waters of the Emilia-Romagna region, Northern Italy, and to highlight the presence of fully exotic fish communities. Overall, based on 208 sampling locations, the observed fish fauna consisted of 45 species, 22 native and 23 exotics. A significant element of the inventory is the identification of xenodiversity hotspots (spatially clustered sites, one lowland and one upland region), where a complete substitution of native species by exotic species was observed (in total seven sites in the lowland and two sites in the upland with no native species presence). These xenodiversity hotspots were found to host specific combinations of exotic species, which may be able to constitute balanced exotic communities. The hotspots of the lowland region are located in the northeast lowland part of the territory, hosting exotic species combinations mainly composed by wels catfish (Silurus glanis Linnaeus, 1758, a large predator), common carp (Cyprinus carpio Linnaeus, 1758, a large benthivore), crucian carp (Carassius spp., a small-bodied generalist) and other less dominant exotic species. The hotspots in the upland region were located in the southwest part of the territory and were dominated by only one exotic species (rainbow trout, Oncorhynchus mykiss (Walbaum, 1792)). A difference between these xenodiversity hotspots is that in the lowland the introductions were mostly unintentional and are not continued, while in the upland the introduction of rainbow trout is intentional and currently carried out by local fishermen

The role of first use of inhalants within sequencing pattern of first use of drugs among Brazilian university students.

The present study investigated the role of first use of inhalants within a first drug sequencing pattern. In a representative sample of university students from 27 Brazilian capitals (n = 12,711), we analyzed the patterns of transition from/to first use of inhalants to/from the first use of alcohol, tobacco, cannabis, cocaine, hallucinogens, ecstasy, amphetamines, prescription opioids, and tranquilizers. Cox proportional hazards models were used to analyze data. Drugs that were not specified as the pair of drugs tested in each model were included as time-varying covariates in all models. In this sample, first use of inhalants was preceded only by the first use of alcohol and tobacco. However, first use of inhalants preceded first use of cannabis, amphetamines, cocaine, and tranquilizers. First use of inhalants preceded the first use of prescription opioids, and vice versa. This study highlights the need to intervene early with youths who are at risk of or just beginning to use inhalants, because this class of drugs seems to be the first illegal drug in Brazil to be experimented by respondents in our sample. There is also a call for attention to individuals who have already first used inhalants because of their higher chance to experiment with other drugs such as cannabis, cocaine, and prescription drugs. All these findings show an in-transition culture of drug use, which should be tracked through time, because some classical models (i.e., gateway model) might be outdated and might also not fit within different settings

The role of drug use sequencing pattern in further problematic use of alcohol, tobacco, cannabis, and other drugs

Background: There has been considerable debate regarding what typically occurs after experimentation with drugs throughout the life of young people who used various drugs. Aims: To evaluate the clinical importance of the most common sequence for the first use of a drug by two models (the “gateway model” and the “alternative model”, which is the most popular sequence for Brazilian university students according to a previous study) regarding the problematic use of alcohol, tobacco, cannabis and other illegal drugs, assessed by ASSIST. Method: People who had already experimented with three or more drugs across different stages of the two models were selected from a representative sample of university students from 27 Brazilian capitals (n = 12 711). Findings: There were no differences regarding the problematic use of the most consumed drugs in Brazil (alcohol, tobacco and cannabis) between the models. Multiple drug seekers and violators had more problematic use of illegal drugs other than cannabis than individuals in the model sequence. However, in the case of violators, this was only evident in the alternative model. Conclusions: Multiple drug seekers and violators deserve special attention due to their increased risk of problematic use of other illegal drugs

Perfluorooctanoic acid exposure assessment on common carp liver through image and ultrastructural investigation

Perfluorooctanoic acid (PFOA) poses particular concern as an emerging pollutant in both surface and ground waters. Fish, as a natural inhabitant of these waters and being highly representative of vertebrates, represents an ideal animal model to assess the toxic effects of PFOA. Hereby, liver microscopic texture was comparatively evaluated in individuals of common carp subchronically exposed to PFOA using grayscale differential box counting, a fractal analysis method. Furthermore, liver cytoplasmic glycogen areas and ultrastructure were also evaluated and compared to the image analysis findings. Redundancy Analysis was performed to assess, in summary, how much the variation of fractal dimension and lacunarity was explained by the concentration of PFOA in liver, the mass of liver and the number of proliferating cell nuclear antigen (PCNA)-immunoreactive nuclei. Treatment group ordination was better determined by fractal dimension than lacunarity. Interestingly, a significant complexity increase was associated with the modification of liver microscopic texture due to PFOA exposure. This complexity increase was related to “cloudy swelling”, possibly representing a primarily adaptive strategy against PFOA challenge, rather than a slight, reversible form of degeneration as traditionally proposed. The occurrence of endoplasmic reticulum stress, unfolded protein reaction and hormetic response was proposed and discussed

High-resolution global grids of revised Priestley–Taylor and Hargreaves–Samani coefficients for assessing ASCE-standardized reference crop evapotranspiration and solar radiation

Abstract. The objective of the study is to provide global grids (0.5°) of revised annual coefficients for the Priestley–Taylor (P-T) and Hargreaves–Samani (H-S) evapotranspiration methods after calibration based on the ASCE (American Society of Civil Engineers)-standardized Penman–Monteith method (the ASCE method includes two reference crops: short-clipped grass and tall alfalfa). The analysis also includes the development of a global grid of revised annual coefficients for solar radiation (Rs) estimations using the respective Rs formula of H-S. The analysis was based on global gridded climatic data of the period 1950–2000. The method for deriving annual coefficients of the P-T and H-S methods was based on partial weighted averages (PWAs) of their mean monthly values. This method estimates the annual values considering the amplitude of the parameter under investigation (ETo and Rs) giving more weight to the monthly coefficients of the months with higher ETo values (or Rs values for the case of the H-S radiation formula). The method also eliminates the effect of unreasonably high or low monthly coefficients that may occur during periods where ETo and Rs fall below a specific threshold. The new coefficients were validated based on data from 140 stations located in various climatic zones of the USA and Australia with expanded observations up to 2016. The validation procedure for ETo estimations of the short reference crop showed that the P-T and H-S methods with the new revised coefficients outperformed the standard methods reducing the estimated root mean square error (RMSE) in ETo values by 40 and 25 %, respectively. The estimations of Rs using the H-S formula with revised coefficients reduced the RMSE by 28 % in comparison to the standard H-S formula. Finally, a raster database was built consisting of (a) global maps for the mean monthly ETo values estimated by ASCE-standardized method for both reference crops, (b) global maps for the revised annual coefficients of the P-T and H-S evapotranspiration methods for both reference crops and a global map for the revised annual coefficient of the H-S radiation formula and (c) global maps that indicate the optimum locations for using the standard P-T and H-S methods and their possible annual errors based on reference values. The database can support estimations of ETo and solar radiation for locations where climatic data are limited and it can support studies which require such estimations on larger scales (e.g. country, continent, world). The datasets produced in this study are archived in the PANGAEA database (https://doi.org/10.1594/PANGAEA.868808) and in the ESRN database (http://www.esrn-database.org or http://esrn-database.weebly.com)

Use transition between illegal drugs among Brazilian university students

Purpose: The aim of the present study was to test whether the first use of an illicit drug increases the chance of first use of other illicit drugs. Method: The transitions from the first use of a drug to the first use of another drug were analyzed. Comparisons were made between first drug users and non-users. Survival analysis methods were used to compare the cumulative probability of second drug use after adjusting for socio-demographic covariates and the intermediate use of alcohol and/or tobacco. A total of 12,721 Brazilian university students participated in this study. Results: Inhalants and marijuana were used prior to the use of several other drugs, whereas the opposite pattern was not found. Ecstasy was used before other drugs in several instances. Other well-examined drugs, such as amphetamines, cocaine and hallucinogens, were used both before and after other illicit drugs without any marked predominance for either of the two roles. Conclusions: This study supports the role of the use of marijuana and inhalants almost exclusively before the use of other illicit drugs, whereas the use of ecstasy has an opposite role. These roles could be linked to the prevalence of lifetime use and whether individuals were at an earlier or later age during experimentation