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We report a georeferenced dataset of a biological survey carried out in lakes and reservoirs in Piedmont and Sardinia regions (Italy), that includes fish fauna, macroinvertebrates, macrophytes, and phytoplankton. This survey was carried out to test the standardised protocols adopted with the National Decree 260/210 by the Italian Ministry of the Environment, Land and Sea for the assessment of the ecological status of lakes and the ecological potential of reservoirs for satisfying the requirements of the European Water Framework Directive (WFD) 2000/60/EC. Occurrence data have been uploaded to the Global Biodiversity Information Facility (GBIF).

In this paper we describe a 25-year (1986-2010) dataset of phytoplankton cell density abundance and biovolume in Lake Candia, a eutrophic, natural, small, and shallow lake located in north-western Italy, with data that are made available through the GBIF repository. The lake belongs to the national (LTER-Italy), European (LTER-Europe) and International (ILTER) long-term ecological research (LTER) networks. Phytoplankton samples were collected approximately monthly at the maximum depth station of the lake (7.7 m) and analysed with the inverted microscope, estimating both the cell density abundance and biovolume of each taxon. The dataset includes 10,120 georeferenced occurrences related to 545 taxa. During this 25-year period, the lake underwent profound modifications mainly related to the lake biomanipulation activities addressed to the management of aquatic macrophyte and to the evolution of the trophic condition. Making this dataset available represents a contribution to the current activities of the LTER networks for defining and reconstructing spatial and temporal dynamics and to identify and compare reliable trends.

A first synoptic and trans-domain overview of plankton dynamics was conducted across the aquatic sites belonging to the Italian Long-Term Ecological Research Network (LTER-Italy). Based on published studies, checked and complemented with unpublished information, we investigated phytoplankton and zooplankton annual dynamics and long-term changes across domains: from the large subalpine lakes to mountain lakes and artificial lakes, from lagoons to marine coastal ecosystems. This study permitted identifying common and unique environmental drivers and ecological functional processes controlling seasonal and long-term temporal course. The most relevant patterns of plankton seasonal succession were revealed, showing that the driving factors were nutrient availability, stratification regime, and freshwater inflow. Phytoplankton and mesozooplankton displayed a wide interannual variability at most sites. Unidirectional or linear long-term trends were rarely detected but all sites were impacted across the years by at least one, but in many case several major stressor(s): nutrient inputs, meteo-climatic variability at the local and regional scale, and direct human activities at specific sites. Different climatic and anthropic forcings frequently co-occurred, whereby the responses of plankton communities were the result of this environmental complexity. Overall, the LTER investigations are providing an unparalleled framework of knowledge to evaluate changes in the aquatic pelagic systems and management options.

Long-term ecological research (LTER) is performed in many countries across the globe by scientists that gather and analyse multidecadal ecological observations and data, to support understanding and management of the environment. LTER data are used to describe the state and dynamics of an ecosystem. This valuable research is in charge of experts in ecology, and it is performed in the so-called LTER networks (for Europe, see http://www.lter-europe.net), usually organized at a national level; they consist of sites covering different ecosystem typologies, each one with research and monitoring facilities. In summer 2015, researchers of the Italian LTER network (LTER-Italy) have created a set of naturalistic trails, connecting sites of LTER-Italy (http://www.lteritalia.it/cammini), aiming to transfer and share the research results with citizens, through public events and informal science communication. Along one of these trails, performed on the Alps, the organizers proposed the use of two VGI apps to collect either biological or abiotic observations (http://www.lteritalia.it/it/content/citizenscience). The apps were chosen according to crucial characteristics, i.e. offline usage, operative system independence, strong development and support community, customization of user interfaces. This paper reports on this first test, discussing lessons learned and, in particular, the impact on the practice of research communities of participative, innovative tools, often neglected in the analysis of mobile application effects.

La pubblicazione descrive le procedure con cui l'E-Biodiversity Research Institute di LifeWatch Italia, il nodo italiano della European Research Infrastructure on Biodiversity and Ecosystems (LifeWatch-ERIC), ha implementato i suoi thesauri. I thesauri sono vocabolari controllati in cui i vari concetti sono rappresentati da termini e organizzati secondo precise gerarchie e relazioni. I thesauri implementati da LifeWatch Italia forniscono, attraverso questi termini e relazioni, la descrizione di un serie di concetti importanti in ambito ecologico, con un focus sugli organismi acquatici. Il vantaggio fondamentale alla base dell'utilizzo dei thesauri è di uniformare le informazioni utilizzate per descrivere dataset e dati, al fine di una migliore integrazione e interoperabilià delle diverse risorse di dati. Nel documento vengono descritte le varie fasi del processo aperto e partecipativo, basato sulla collaborazione tra esperti del dominio di conoscenza e componente ICT, che porta ad una versione condivisa dei thesauri. Vengono inoltre descritti gli elementi e le relazioni utilizzate e vengono presentate le prossime implementazioni.

In the last few decades, functional trait-based approaches have undergone an extraordinary expansion in phytoplankton ecology, due to the relative simplicity and the well-defined traits that determine the ecological niche of these organisms. A large quantity of heterogeneous and distributed data has been produced on phytoplankton traits and their use could be made more effective and efficient if data harmonization and interoperability would be improved. The use of controlled vocabularies and thesauri is an acknowledged good practice to establish the foundation for semantic interoperability, a critical requirement for reuse and sharing of data. In fact, thesauri, collectively constructed, bypass ambiguity issues in natural language, facilitating the identification and integration of the information available in multiple data sources and allowing both scientists and computer applications to interpret more effectively the meaning of data. Here we present a semantic resource on phytoplankton functional traits: the PhytoTraits thesaurus ( http://thesauri.lifewatchitaly.eu/PhytoTraits/index.php ). PhytoTraits is the result of the interdisciplinary collaboration of experts both from the phytoplankton functional domain and from information and communication technologies, working together within LifeWatch Italy, the Italian node of the e-science European infrastructure for biodiversity and ecosystem research. PhytoTraits is the first initiative to deal with the semantics of phytoplankton functional traits, focusing on morpho-functional traits towards standardized bio-volume assessment. It reflects the agreement of a scientific expert community to fix semantic properties (e.g. label, definition) of approximately 120 traits. Following semantic web standard technologies, the thesaurus was implemented in Simple Knowledge Organization System (SKOS), a common data model based on the Resource Description Framework (RDF). PhytoTraits is freely available online, it can be queried through a SPARQL endpoint ( http://thesauri.lifewatchitaly.eu/PhytoTraits/sparql.php ) and is also accessible via API ( http://thesauri.lifewatchitaly.eu/PhytoTraits/services.php ) for integration with other systems. If adopted as a standard and rigorously applied and enriched by the scientific community, PhytoTraits, providing harmonized concepts with associated unique and resolvable URIs, has the potential to significantly reduce the barriers to data discovery, integration, and exchange.

Introduction of alien species is one of the major threats to aquatic biota and knowledge of the major correlates of their occurrence is pivotal in planning reliable conservation strategies. 2. To understand whether specific freshwater habitats are more likely to be invaded than others, a dataset on the occurrence of 1604 species in 54 taxonomic groups from 181 sites across the Italian peninsula was gathered. 3. TheEUNIShabitatclassificationwas used, selectingfor the study's seven habitat types at thesecondEUNIS level, including lentic (EUNIS C1; 64 sites), lotic (EUNIS C2; 99 sites) and highly artificial (EUNIS J5; 18 sites) habitats. 4. The aim of the study was to test whether the overall number of alien species and the proportion of alien species for each taxonomic group differed between habitat types and could be explained by environmental, human-mediated, or climatic factors. 5. Using generalized linear mixed effect models to account for potential confounding factors, only average air temperature of the site was a significant positive predictor of the occurrence of alien species, regardless of habitat type, species richness, and other climatic variables. 6. A direct effect of temperature could be excluded given the origin of alien species, mostly from colder areas than Italy. Thus, an indirect effect could be hypothesized at the Italian latitudes, with warmer areas potentially

We present a data set on the biodiversity of Italian freshwaters, including lakeshores and riverbanks of natural (N=379: springs, streams and lakes) and artificial (N=11: fountains) sites. The data set belongs partly to the Italian Long Term Ecological Research network (LTER-Italy) and partly to LifeWatch, the European e-Science infrastructure for biodiversity and ecosystem research. The data included cover a time period corresponding to the last fifty years (1962-2014). They span a large number of taxa from prokaryotes and unicellular eukaryotes to vertebrates and plants, including taxa linked to the aquatic habitat in at least part of their life cycles (like immature stages of insects, amphibians, birds and vascular plants). The data set consists of 6463 occurrence data and distribution records for 1738 species. The complete data set is available in csv file format via the LifeWatch Service Centre.

Diatoms have been often used to track trophic changes from sedimentary records: recent studies demonstrated that these organisms can even be valuable indicators of climatic variability, although it is often difficult to discriminate the role of trophic and climatic drivers. Moving from the hypothesis that oligotrophication and climate affected the composition of the diatom assemblages by changing the resource ratio, we analysed the vernal diatoms succession in Lake Maggiore, between 1984 and 2007, using multivariate techniques (cluster analysis, canonical correspondence analysis, multivariate regression trees), in order to single out the oligotrophication effects from those attributable to climatic variability. Our results point out that Si, TP, temperature and wind emerged as key explanatory variables in species selection, with a stronger link between trophic and climatic drivers after the lake reached a stable oligotrophic status. Peculiar climate-driven events (deep mixing and floods) affected the in-lake Si:P ratio, giving an advantage to diatoms that are excellent P, but poor Si competitors. The classical role of Fragilaria and Tabellaria as early-warning indicators of eutrophication should be reconsidered, taking into account that both can be useful indicators of climate change, when links between their physiological resource needs and environmental data coming from robust limnological investigations can be established.

During the year 2002, the size variability of most of the species found in Lago Maggiore was analysed in detail, measuring through image analysis the main morphological parameters (maximum linear dimension, surface, volume) of the algal cells. Many individuals belonging to the same species were measured sampling by sampling, collecting about 28,000 data. This data set allowed us to evaluate the morphological plasticity of many species across the seasonal succession: through multivariate statistical analysis we compared the changes of cell volume, cell surface, maximum linear dimension and surface-to-volume ratio to the fluctuations of the main physical and chemical parameters. The responses we observed were variable, depending on the different taxonomic groups or species as well as on the morphometric parameter considered. As a general pattern, a strong seasonality of the size changes was observed, mainly dependent on the gradients of nutrients and temperature.

The present work aims at evaluating the state of art of phytoplankton production research in Italy. We present a synthesis of the main results achieved in three ecosystems where primary production studies have been carried out most intensively: a large subalpine lake (Lago Maggiore, LM), a shallow marine ecosystem with strong fluvial influence (the Northern Adriatic Sea, NAS), and a coastal area of the Southern Tyrrhenian Sea (the Gulf of Naples, GoN). The present yearly production values are around 150 g C m−2 yr−1 in LM and GoN; this ranges between 80 (offshore) and 150 g C m−2 yr−1 (coast) in the NAS. The temporal and spatial variations of phytoplankton production appeared, in each ecosystem, in accordance with the trophic changes. Significant correlations between production, chlorophyll, and light were generally observed for LM and for GoN. On the contrary, these parameters were poorly correlated in the NAS, hampering the use of predictive models in this ecosystem. Discrepancies between primary produc...

Summary 1. We applied Reynolds's approach to the study of phytoplankton ecology through functional associations of species to identify possible algal species, which associate with the freshwater cyanobacterium Synechococcus. Previously an association among Synechococcus spp. and small-celled chlorophytes (association Z) has been recognised by evaluating phytoplankton associations according to functional criteria. 2. Biomass data for phytoplankton and picocyanobacteria from Lago Maggiore spanning more years were organised in a matrix and a cluster analysis was performed. The results showed four groups separated at a linkage distance of 0.20. Mixotrophic species which clustered with Synechococcus spp. were Ceratium hirundinella, Chrysochromulina parva, Cryptomonas erosa, Cryptomonas ovata, Dinobryon bavaricum, Dinobryon sociale, Rhodomonas minuta and Uroglena americana. The redundancy analysis (RDA) consolidated the association of Synechococcus with C. hirundinella and R. minuta showing greater probability of occurrence than random aggregates of species. 3. The association Synechococcus spp. –C. hirundinella also appeared from temporal variation of their biomass. In early summer both these species increased at the same time; later, the peak of C. hirundinella (potential predator) coincided with a minimum of Synechococcus spp. suggesting a possible predator-prey interaction. This implied that phytoplankton assemblages which form a functional group cannot only have similar adaptations and requirements but can also exhibit trophic interactions. 4. We propose to enlarge the association Z and create an association ZMX (where MX stands for mixotrophs) which would include Synechococcus spp. and C. hirundinella as the most representative of the mixotrophic species found in the oligotrophic Lago Maggiore.

The limnological evolution of Lake Pusiano followed, starting 1970s, an increasing eutrophication process, attaining the maximum trophic level at the mid 1980s, when the lake reached an hypertrophic condition (around 200 mu g P l(-1) at winter overturn). Between mid 1980s and the beginning of this century, the phosphorus concentrations continuously decreased, until reaching TP values close to 60 mu g P l(-1). Despite this improvement in trophic conditions, since 1994 the cyanobacteria contribution increased: noticeable was a very intense bloom of Planktothrix rubescens, occurred during autumn 2001. The following year, when we carried out this research, this filamentous cyanobacterium strongly dominated the phytoplankton population for the whole seasonal cycle. However, after an intense flood occurred in November the P. rubescens population decreased again. This paper aims at describing the seasonal dynamics of the cyanobacterium P. rubescens in Lake Pusiano (North Italy) during year 2002, pointing out the environmental factors which favoured its large dominance during the whole seasonal cycle: particular attention will be paid to the role played by the physical factors in promoting the growth of P. rubescens, despite the nutrient reduction. Our experimental evidences suggest the involment of mechanisms already observed in other European lakes, such as the establishment of a metalimnetic niche. Moreover, our data point out a high sensitivity of this environment to the changes of the hydrological regime, which probably affect the seasonal phytoplankton dynamics.

Underwater light regime is widely considered the principal determinant of aquatic plant depth distribution. The majority of previous studies dealing with macrophytes in lakes have singled out Secchi disk transparency (SD) values as the key empirical proxy to explain the maximum depth of macrophyte colonization (Zc). Few studies have investigated the role played by lake morphometry in structuring macrophyte beds. Using a balanced dataset including 20 Italian lakes (10 shallow and 10 deep lakes), we analysed transparency and lake morphometric traits to investigate their possible effects on Zc. Our results demonstrate that lake area plays a significant role, and confirm a direct influence of SD values on Zc. Considering lakes with an equal degree of transparency, smaller lakes may yield a lower Zc than larger ones. Morphology has a great influence on lake ecological characteristics especially on water thermal conditions and mixing depth. Based on our data, we argue that the thermal stratification plays a non negligible role in explaining macrophytes zonation, due to its influence on macrophytes life cycles and phytoplankton vertical distribution. Therefore, the present data suggest the need to enhance and refine our knowledge about the relationship between aquatic plants distribution and lake thermal conditions to better model the response of macrophytes to climate change and eutrophication.

Optical satellite remote sensing represents an opportunity to integrate traditional methods for assessing water quality of lakes: strengths of remote sensing methods are the good spatial and temporal coverage, the possibility to monitor many lakes simultaneously and the reduced costs. In this work we present an overview of optical remote sensing techniques applied to lake water monitoring. Then, examples of applications focused on lake Maggiore, the second largest lake in Italy are discussed by presenting the temporal trend of chlorophyll-a (chl-a), suspended particulate matter (SPM), coloured dissolved organic matter (CDOM) and the z90 signal depth (the latter indicating the water depth from which 90% of the reflected light comes from) as estimated from the images acquired by the Medium Resolution Imaging Spectrometer (MERIS) in the pelagic area of the lake from 2003 to 2011. Concerning the chl-a trend, the results are in agreement with the concentration values measured during field surveys, confirming the good status of lake Maggiore, although occasional events of water deterioration were observed (e.g., an average increase of chl-a concentration, with a decrease of transparency, as a consequence of an anomalous phytoplankton occurred in summer 2011). A series of MERIS-derived maps (summer period 2011) of the z90 signal are also analysed in order to show the spatial variability of lake waters, which on average were clearer in the central pelagic zones. We expect that the recently launched (e.g., Landsat-8) and the future satellite missions (e.g., Sentinel-3) carrying sensors with improved spectral and spatial resolution are going to lead to a larger use of remote sensing for the assessment and monitoring of water quality parameters, by also allowing further applications (e.g., classification of phytoplankton functional types) to be developed.

International audience; Uncertainty is an important factor in ecological assessment, and has important implications for the ecological classification and management of lakes. However, our knowledge of the effects of uncertainty in the assessment of different ecological indicators is limited. Here, we used data from a standardized campaign of aquatic plant surveys, in 28 lakes from 10 European countries, to assess variation in macrophyte metrics across a set of nested spatial scales: countries, lakes, sampling stations, replicate transects, and replicate samples at two depth-zones. Metrics investigated in each transect included taxa richness, maximum depth of colonisation and two indicators of trophic status: Ellenberg’s N and a metric based on phosphorus trophic status. Metrics were found to have a slightly stronger relationship to pressures when they were calculated on abundance data compared to presence/absence data. Eutrophication metrics based on helophytes were found not to be useful in assessing the effects of nutrient pressure. These metrics were also found to vary with the depth of sampling, with shallower taxa representing higher trophic status. This study demonstrates the complex spatial variability in macrophyte communities, the effect of this variability on the metrics, and the implications to water managers, especially in relation to survey design.

Charophytes (stoneworts and bassweeds) are a typical macrophytic component of inland water ecosystems. Well-developed submerged meadows of charophytes are expression of clear water and rather low phytoplankton concentrations. Consequently, among aquatic macroscopic primary producers, charophytes are one of the most threatened groups being very sensitive to phosphorous availability, turbidity and water level perturbations. Accordingly, charophytes have been suffering a massive diversity loss worldwide over the last century, mainly because of human-induced pressures. During summer 2011, detailed field surveys were carried out with the main purpose of filling knowledge gaps concerning aquatic flora and vegetation of the lake Garda – the largest lake in Italy and one of the deepest in Europe. Along randomly selected transects, floristic data were collected following standard procedures, as imposed by the Water Framework Directive. Overall, 12 different species of charophytes were recorded, which accounts for 36% of total Italian charophytes and 19% of European species. The most diffuse species were Chara globularis and C. intermedia; whereas, the most interesting taxa were Chara polyacantha and Nitella hyalina, two species with narrow distribution in Italy. Overall in the lake Garda, dense stands of charophytes covered almost homogeneously the littoral sectors at a water depth between 3 and 12 m. The deepest species was C. globularis, which reached a maximum depth of colonisation of about 17.5 m. Charophytes represent a major element among the primary producers in the lake Garda. The high local charophyte diversity and the rather wide most colonised areas (~1000-1200 ha) confirm that the lake Garda is an important reserve for many rare and threatened charophytes. For the first time, these results highlight the key role of the lake Garda for charophyte diversity at a national and European level.

This study reports the first preliminary results of the DYRESM-CAEDYM model application to a mid size sub-alpine lake (Lake Pusiano North Italy). The in-lake modelling is a part of a more general project called Pusiano Integrated Lake/Catchment project (PILE) whose final goal is to understand the hydrological and trophic relationship between lake and catchment, supporting the restoration plan of the lake through field data analysis and numerical models. DYRESM is a 1D-3D hydrodynamics model for predicting the vertical profile of temperature, salinity and density. CAEDYM is multi-component ecological model, used here as a phytoplankton-zooplankton processes based model, which includes algorithms to simulate the nutrient cycles within the water column as well as the air-water gas exchanges and the water-sediments fluxes. The first results of the hydrodynamics simulations underline the capability of the model to accurately simulate the surface temperature seasonal trend and the thermal gradient whereas, during summer stratification, the model underestimates the bottom temperature of around 2 degrees C. The ecological model describes the epilimnetic reactive phosphorus (PO4) depletion (due to the phytoplankton uptake) and the increase in PO4 concentrations in the deepest layers of the lake (due to the mineralization processes and the sediments release). In terms of phytoplankton dynamics the model accounts for the Planktothrix rubescens dominance during the whole season, whereas it seems to underestimate the peak in primary production related to both the simulated algal groups (P. rubescens and the rest of the other species aggregated in a single class). The future aims of the project are to complete the model parameterization and to connect the in-lake and the catchment modelling in order to gain an integrated view of the lake-catchment ecosystem as well as to develop a three dimensional model of the lake.