Indici per la valutazione della qualit? ecologica dei laghi

Collection of methods to evaluate lake quality using biological element

Recent and subfossil diatom assemblages as indicators of environmental change (including fish introduction) in a high-mountain lake

We investigated modern-littoral and subfossil sediment-core diatoms in the shallow (max depth 6.4 m) high mountain Lake Balma in the Orsiera Rocciavr`e Nature Park (Italian Western Alps). Our study provided evidence that might be related to the response of diatom assemblages to fish introduction, in particular the decreasing of the nutrient-enrichment sensitive low-profile life-form/ecological guild and the increase in species known to react positively to the augmented nutrient availability due to fish excretions (e.g., Fragilaria nanana, Pseudostaurosira brevistriata, Staurosirella neopinnata). We are, however, aware that some of these effects could as well have been caused by pastures and cattle watering, and by increased temperatures due to global warming, and we acknowledge the typical complex-interaction pattern among different stressors. High-mountain lakes are \u2018\u2018early warning systems\u2019\u2019 for the whole alpine system and can contribute valuable information also on the interactions between environmental global changes and anthropogenic impacts. Benthic diatoms, in particular, can provide useful indications on the deleterious effects of non-native fish introduction, cattle grazing, and global warming, and thus support an adaptive and sustainable management of high-mountain lakes for the sake of nature conservation

Diatom biodiversity in karst springs of Mediterranean geographic areas with contrasting characteristics: islands vs mainland

Karst ecosystems are considered as priority environments for the protection of biodiversity on a global scale. This study provides a first comparative analysis of epilithic diatom flora from karst springs in two Mediterranean geographic areas (Spain and Italy) with contrasting characteristics (islands vs mainland). We investigated twenty-three springs with different anthropogenic impact levels once in the winter season between 2007 and 2017 (N = 23). A total of 176 diatom taxa (56 genera) were found of which 101 (44 genera) were observed in single sites. A general good biotic integrity was revealed by structural indices (species richness, diversity and evenness). However, crenophilous species were generally present and abundant in less impacted springs. Comparing islands and mainland, significant differences were found in species composition and diversity (H\u2019) based on multivariate analyses (global R = 0.610; p = 0.001) and t-test (t = 2.304; p = 0.031). Discharge and Cl 12 were the most significant variables in determining diatom assemblages. Our results confirm the role of springs as multiple ecotones and refuges for rare species and suggest that the geographic insularity may be an important factor in maintaining diatom biodiversity

Applicazione dell'indice dello stato ecologico delle comunit\ue0 ittiche (ISECI) in alcuni corpi idrici del Friuli Venezia Giulia

The Authority of Friuli Venezia Giulia has planned the Regional Water Protection Plan (PRTA), in respect of the Water Framework Directive 2000/60/CE, received in Italy by the D.L. 152/2006. After the identification of 564 water bodies, which are included in four hydroecoregions, has being planned a monitoring program using some bioindicators and supported by chemical and physical analysis. In this study, results of monitoring the fish communities and of the application of the Ecological State of the Fish Communities index (ISECI) for the 29 regional streams of Friuli Venezia Giulia are reported. In addition, the comparisons between results of the ISECI and other indices, which are included in the D.M. 260/2010, are discussed. Finally is discussed a comparison with results of the Ecological State of Macrodescriptor pollution (LIMeco) for chemical-physical analysis

DNA sequence and taxonomic gap analyses to quantify the coverage of aquatic cyanobacteria and eukaryotic microalgae in reference databases: Results of a survey in the Alpine region

30restrictedInternationalInternational coauthor/editorThe taxonomic identification of organisms based on the amplification of specific genetic markers (metabarcoding) implicitly requires adequate discriminatory information and taxonomic coverage of environmental DNA sequences in taxonomic databases. These requirements were quantitatively examined by comparing the determination of cyanobacteria and microalgae obtained by metabarcoding and lightmicroscopy. Weused planktic and biofilm samples collected in 37 lakes and 22 rivers across the Alpine region.We focused on two of the most used and best represented genetic markers in the reference databases, namely the 16S rRNA and 18S rRNA genes. A sequence gap analysis using blastn showed that, in the identity range of 99–100%, approximately 30% (plankton) and 60% (biofilm) of the sequences did not find any close counterpart in the reference databases (NCBI GenBank). Similarly, a taxonomic gap analysis showed that approximately 50% of the cyanobacterial and eukaryotic microalgal species identified by light microscopy were not represented in the reference databases. In both cases, themagnitude of the gaps differed between the major taxonomic groups. Even considering the species determined under the microscope and represented in the reference databases, 22% and 26% were still not included in the results obtained by the blastn at percentage levels of identity≥95% and≥97%, respectively. The main causes were the absence of matching sequences due to amplification and/or sequencing failure and potential misidentification in the microscopy step. Our results quantitatively demonstrated that in metabarcoding the main obstacles in the classification of 16S rRNA and 18S rRNA sequences and interpretation of high-throughput sequencing biomonitoring data were due to the existence of important gaps in the taxonomic completeness of the reference databases and the short length of reads. The study focused on the Alpine region, but the extent of the gaps could be much greater in other less investigated geographic areas.restrictedSalmaso, Nico; Vasselon, Valentin; Rimet, Frédéric; Vautier, Marine; Elersek, Tina; Boscaini, Adriano; Donati, Claudio; Moretto, Marco; Pindo, Massimo; Riccioni, Giulia; Stefani, Erika; Capelli, Camilla; Lepori, Fabio; Kurmayer, Rainer; Mischke, Ute; Klemenčič, Aleksandra Krivograd; Novak, Katarina; Greco, Claudia; Franzini, Giorgio; Fusato, Giampaolo; Giacomazzi, Federica; Lea, Alessia; Menegon, Silvia; Zampieri, Chiara; Macor, Arianna; Virgilio, Damiano; Zanut, Elisa; Zorza, Raffaella; Buzzi, Fabio; Domaizon, IsabelleSalmaso, N.; Vasselon, V.; Rimet, F.; Vautier, M.; Elersek, T.; Boscaini, A.; Donati, C.; Moretto, M.; Pindo, M.; Riccioni, G.; Stefani, E.; Capelli, C.; Lepori, F.; Kurmayer, R.; Mischke, U.; Klemenčič, A.K.; Novak, K.; Greco, C.; Franzini, G.; Fusato, G.; Giacomazzi, F.; Lea, A.; Menegon, S.; Zampieri, C.; Macor, A.; Virgilio, D.; Zanut, E.; Zorza, R.; Buzzi, F.; Domaizon, I