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

A Simplistic Approach for Assessing Hydroclimatic Vulnerability of Lakes and Reservoirs with Regulated Superficial Outflow

Demertzi, K.; Papadimos, D.; Aschonitis, V.; Papamichail, D. A Simplistic Approach for Assessing Hydroclimatic Vulnerability of Lakes and Reservoirs with Regulated Superficial Outflow. Hydrology 2019, 6, 61This study proposes a simplistic model for assessing the hydroclimatic vulnerability of lakes/reservoirs (LRs) that preserve their steady-state conditions based on regulated superficial discharge (Qd) out of the LR drainage basin. The model is a modification of the Bracht-Flyr et al. method that was initially proposed for natural lakes in closed basins with no superficial discharge outside the basin (Qd = 0) and under water-limited environmental conditions {mean annual ratio of potential/reference evapotranspiration (ETo) versus rainfall (P) greater than 1}. In the proposed modified approach, an additional Qd function is included. The modified model is applied using as a case study the Oreastiada Lake, which is located inside the Kastoria basin in Greece. Six years of observed data of P, ETo, Qd, and lake topography were used to calibrate the modified model based on the current conditions. The calibrated model was also used to assess the future lake conditions based on the future climatic projections (mean conditions of 2061-2080) derived by 19 general circulation models (GCMs) for three cases of climate change (three cases of Representative Concentration Pathways: RCP2.6, RCP4.5 and RCP8.5). The modified method can be used as a diagnostic tool in water-limited environments for analyzing the superficial discharge changes of LRs under di erent climatic conditions and to support the design of new management strategies for mitigating the impact of climate change on (a) flooding conditions, (b) hydroelectric production, (c) irrigation/industrial/domestic use and (d) minimum ecological flows to downstream rivers. Hydrology 6(3), 61. https://doi.org/10.3390/hydrology603006

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

ANALYSIS OF PRIESTLEY-TAYLOR METHOD FOR THE ASSESSMENT OF REFERENCE EVAPOTRANSPIRATION IN GREECE

Στόχος της εργασίας είναι η εύρεση του εποχιακού σφάλματος στην εκτίμηση της εξατμισοδιαπνοής καλλιέργειας αναφοράς ΕΤο με τη μέθοδο Priestley-Taylor (P-T) και ο επαναπροσδιορισμός του συντελεστή μεταγωγής apt χρησιμοποιώντας τη μέθοδο Penman-Monteith κατά ASCE. Η ανάλυση έγινε για όλο τον ελλαδικό χώρο με χρήση GIS και μέσα μηνιαία κλιματικά δεδομένα της περιόδου 1950-2000. Η ανάλυση σφάλματος για το θερινό εξάμηνο Απριλίου-Σεπτεμβρίου έδειξε ότι η μέθοδος P-T παρουσιάζει αποδεκτές τιμές στο 75.3%, ενώ για το χειμερινό εξάμηνο Οκτωβρίου-Μαρτίου στο 20.2% της ελληνικής επικράτειας. Ο επαναπροσδιορισμός της μέσης τιμής του apt για το χειμερινό και θερινό εξάμηνο έδειξε ότι η χωρική μεταβλητότητά του παρουσιάζει συσχέτιση της τάξεως του ~94% με το έλλειμμα πίεσης κορεσμού υδρατμών. Από την ανάλυση της εποχιακής μεταβολής του συντελεστή apt εκτιμήθηκε η μέση τιμή του σε 1.29 και 1.51 για τη θερινή και χειμερινή περίοδο, αντίστοιχα.The aim of the study is to estimate the seasonal error in the assessment of reference crop evapotranspiration ΕΤο using the Priestley-Taylor (P-T) method and to revise the advection coefficient apt using as a base the ASCE standardized Penman-Monteith method. Analysis was performed for the Greek territory using GIS and gridded data which cover the mean monthly values of climatic parameters for the period 1950-2000. The analysis of seasonal error showed that P-T presents acceptable values in the 73.5% and 20.2% coverage of the greek territory for the dry-warm season (April-September) and the cold-wet season (October-March), respectively. Recalculation of apt for both seasons showed that its spatial variation is described at ~94% level by the vapor pressure deficit. The mean values of apt for the dry-warm season and the cold wet season were found to be 1.29 και 1.51, respectively

Assessment of specific vulnerability to nitrates using LOS indices in the Ferrara Province, Italy

A set of indices (LOS), based on a deterministic approach and regression analysis were used to assess intrinsic and specific vulnerability to nitrates in Ferrara Province, in northern Italy. To calibrate the LOS indices, using multiple regression analysis, the simulation results of GLEAMS model for combinations of different soil properties, topography and climatic conditions of a reference fieldcrop were used as “observed values”. Results of model were introduced in a GIS environment to obtain the vulnerability maps. Maps of water and nitrogen losses under the root zone (LOSW-P and LOSN-PN respectively) were used to obtain the map of relative concentration of percolated water (RCPW). Data on individual crops were used to calculate specific crop evapotranspiration rates (ETc) from potential evapotranspiration (PE). ETc values replaced PE values in the indices, to obtain both specific vulnerability map for water and nitrogen losses under the root zone (LOSW-P mod; LOSN-PN mod) and for relative nitrogen concentration of percolated water (RCPW mod). The RCPW mod map shows that concentration of nitrogen losses under the root zone is under water drinking limit of 50 mg/L (WFD; 2006/118/EC) all over the territory with highest concentrations along small areas of the coastal zone, where sandy textured soil are present (coastal dunes) and lowest concentrations where ETc is higher

Comparison of three different methods for groundwater intrinsic vulnerability mapping in the Ferrara Province (IT)

Nitrogen losses from non point agricultural sources, mainly originated by fertilizers’ application, have been recognized as one of the most serious threats for pollution of groundwater. The assessment of nitrogen losses from the soil surface and the degree of groundwater pollution constitutes the fundamental element in order to apply the measures and limitations established in the European Community Framework Directive for water protection (WFD). Several vulnerability methods have been developed in order to describe the intrinsic vulnerability of the groundwater to contamination. The LOS, SINTACS and GOD methods were applied in this study in order to assess the groundwater intrinsic vulnerability of the Ferrara Province. The first method is based on deterministic approach and regression analysis, while the other two are parametric methods based on weights and ratings. The three methods were applied and evaluated using experimental data obtained by a network of 56 piezometers, distributed in the whole area. The piezometers were installed in order to monitor both water table fluctuations and nitrogen inorganic species variation in the shallow aquifer over time. This study shows that the intrinsic vulnerability mapping of the study area is appreciably different using the three methods. This is mainly attributed to the different kind and number of parameters involved in the different methods, more than to their different weights and ratings. On the basis of the collected data, the LOS indices method provided the best estimates. Nevertheless, SINTACS and GOD methods can be used for a preliminary assessment of intrinsic vulnerability, prior to apply the LOS indices which are more data and time requiring

Swoon over the moon: The influence of environmental factors on glass eels entering Mediterranean coastal lagoons

none5siThe European eel (Anguilla anguilla, Linnaeus 1758) is a critically endangered species that completes its life cycle between the freshwaters of Europe (and North Africa) and spawning grounds in the Sargasso Sea. Its marine larvae are planktonic and metamorphose into post-larval glass eels near the coast. The relationship between environmental variables and the migration of glass eels into brackish water and estuaries is not well understood, but has important implications for European eel conservation and management. Using linear mixed effects (LME) models, we investigated the combined role of meteorological (wind direction and strength and rainfall), oceanographical (tide amplitude), astronomical (moon phase and illumination), temporal and water quality variables on the timing and magnitude of glass eel migration from marine to brackish waters in the Comacchio Lagoon, Northern Adriatic Sea. We used this site as a test case because it was historically prominent in glass eel wild harvest for extensive aquaculture in the Mediterranean region. We found that meteorological factors and tide amplitude had a weak effect on the migration of glass eels into the lagoon. On the contrary, astronomical variables strongly influenced glass eel movement, with waxing phases and intermediate illumination enhancing movement towards the lagoon. We also identified at least two distinct migration pulses during our study period, which were not affected by temporal and water quality variables. Temporal and water quality variables affected body size of glass eels, with bigger glass eels caught later in the season. Identifying the importance of environmental variables affecting glass eels recruitment to brackish waters can help promoting eel stocks restoration through local management.noneLanzoni M.; Gavioli A.; Castaldelli G.; Aschonitis V.; Milardi M.Lanzoni, M.; Gavioli, A.; Castaldelli, G.; Aschonitis, V.; Milardi, M

A Review and Synthesis of Bivariate Non-Linear Models to Describe the Relative Variation of Ecological, Biological and Environmental Parameters

There is a plethora of non-linear models to describe bivariate relationships related to ecological, biological and environmental problems, and this makes difficult to have a general aspect about the suitable models for a new-born dataset. Additionally, there is a special interest for bivariate non-linear models which can describe the relative variation of the dependent variable (NLR models) (i.e. these models provide a restricted range of values between 0 and 1) because they can easily be adjusted to fit different datasets which describe the same relationship. The aim of this study is to provide a review and synthesis of NLR models which can be used to describe bivariate relationships which follow bell-shaped, simple-double sigmoid, bilinear and periodical patterns. This attempt aims to save time and effort for the selection of a NLR model based on five steps (a) preparation of data, (b) visual identification of the suitable model based on pre-constructed graphs, (c) a starting point using the simpler form (base function) of the selected models which are given in complex general forms, (d) directions to increase the number of coefficients in order to improve fitting and (e) techniques to modify the given NLR models in order to derive new ones with inverted patterns

Variation of the hydraulic properties in sandy soils induced by the addition of graphene and classical soil improvers

In this study, for the first time, the changes in relevant hydraulic parameters (e.g., hydraulic conductivity, effective porosity, and dispersivity) induced by the introduction of graphene in a calcareous sandy soil and a siliciclastic riverine soil were monitored and modelled via leaching column experiments. Column experiments were also run with traditional soil improvers (compost, biochar, and zeolite) to compare the changes induced by graphene versus well-studied soil improvers. Constant pressure head tests were used to calculate the hydraulic conductivity of each column, while leaching experiments were run to estimate porosity and specific retention, and for each treatment three replicates were done. Columns were then run in saturated conditions via a low flow peristaltic pump and monitored for electrical conductivity, temperature, and chloride. CXTFIT 2.0 was employed to inversely model the column experiments and retrieve parameters like effective porosity, longitudinal dispersivity, bulk thermal diffusivity, and thermal retardation factor. Results highlighted small changes of hydraulic conductivity, porosity, and effective porosity induced by graphene addition (as well as by the other soil improvers) for both soils. A marked increase (nearly 20 %) of specific retention values was instead recorded in the amended columns with respect to control ones. Chloride breakthrough curves modelling showed that graphene doubled dispersivity in the calcareous sandy soil (5.82 +/- 1.4 cm) compared to the control (2.6 +/- 0.29 cm), while it halved dispersivity in the siliciclastic riverine soil (0.31 +/- 0.05 cm) with respect to the control (0.65 +/- 0.06 cm). Thermal retardation factors were decreased by graphene by approximately 20 % for both soils. The model fitting via TDS (derived from the electrical conductivity monitoring) produced unreliable dispersivity values in most of the experiments due to the nonconservative nature of this parameter compared to chloride. The results highlight that graphene affected dispersivity but did not significantly alter other physical parameters relevant for solutes transport in sandy soils in comparison to classical improvers, thus future studies should focus on the graphene's effects on nutrients and agrochemicals leaching in unsaturated flow conditions

Land use intensification rather than land cover change affects regulating services in the mountainous Adige river basin (Italy)

Land Cover (LC) and Land Use (LU) changes are usually considered as one change, limiting the understanding of their individual effects on Ecosystem Services (ESs). The aim of this study is to investigate the different effects of LC change and LU intensification on four regulating ESs (carbon storage, water regulation and supply, nitrogen retention) using the InVEST model in the mountainous Adige river basin (Northern Italy) during 1960–2012. The role of establishing protected areas (PAs) in the four regulating ESs was also investigated. The results showed that pasture abandonment and agricultural intensification were the most important LC and LU changes, respectively. The total value of crops’ production raised four times, mainly due to agricultural intensification (increase of fertilization rates), while nitrogen losses increased threefold during 1960–2012. Significant changes on carbon storage and water balance components were not observed due to LC and LU changes at basin scale. The results highlighted the tradeoff between crop production and nitrogen losses that affect water quality regulation. PAs establishment was not enough to mitigate nitrogen losses. The results of the study highlighted that LC change and LU intensification should be considered separately to better understand the consequences of anthropogenic impact on regulating ESs