Littoral chironomids and oligochaetes in the subalpine Lake Maggiore: a first dataset

A dataset of 227 oligochaetes and 373 chironomids occurrence records from the subalpine Lake Maggiore, a large and deep temperate lake in Northern-Western Italy and Switzerland was developed within the Interreg Italy-Switzerland 2014-2020 Parchi Verbano Ticino Project (ID:481668) funded by the European Regional Development Fund (ERDF). The lake belongs to the national (LTER-Italy), European (LTER-Europe) and International (ILTER) long-term ecological research networks. Data were collected during the summer-autumn period in 2019-2021. Chironomids (Insecta, Diptera) and oligochaetes (Annelida, Clitellata) were identified to genus/species gr./species level by the authors. All 600 occurrence records are georeferenced and organised in a standardised Darwin Core Archive format. These data gathered along the littoral areas of Lake Maggiore will contribute to the development of common implementation strategies for shared and sustainable water management level of the lake, with particular reference to the protected natural areas (sites belonging to Natura 2000 network in Italy and to the Emerald Network in Switzerland). The authors strongly believe in the great potential of open access occurrence records in biogeographical studies and ecological research in the context of global environmental changes. For that reason, the dataset has been uploaded to the Global Biodiversity Information Facility (GBIF), an intergovernmental free and open access biodiversity data infrastructure

Evoluzione stagionale e a lungo termine delle caratteristiche chimiche del Lago Maggiore e bilancio dei nutrienti a Lago (Azoto e Fosforo)

Not availableRicerche sull\u27evoluzione del Lago Maggiore. Aspetti limnologici. Programma triennale 2013-2015. Campagna 2014. Evoluzione stagionale e a lungo termine delle caratteristiche chimiche del Lago Maggiore e bilancio dei nutrienti a Lago (Azoto e Fosforo). Chimica di base e contenuto ionico delle acque lacustri. Nutrienti a lago (composti dell\u27Azoto e del Fosforo e silicati). Ossigeno disciolto. Metalli in tracce. Apporti chimici dai tributari e dell\u27emissario. Concentrazioni medie areali. Carichi chimici e bilanci di Azoto e Fosforo

Lake Orta chemical status 25 years after liming: problems solved and emerging critical issues

Lake Orta, located in Piedmont, northwestern Italy, has been severely affected by industrial pollution since the 1930s. A successful liming intervention, performed in 1988-1990, returned pH levels in the lake to neutrality, and accelerated the reduction of aqueous trace metal concentrations. In this paper, we present an update knowledge of the chemical status of Lake Orta, focusing on the data collected from 1990 to 2014. In this period we sampled the lake at its deepest point (Qualba station), on a monthly (1990-2000) or seasonal (since 2001) basis. Samples were collected at nine depths through the water column, and analyzed for pH, conductivity, alkalinity, major ions, nutrients, and trace metals. Collectively, these data allowed us to evaluate the long-term response of the lake to the restoration treatment, with particular regard to its acid-base status; they also provided insights into emerging or potential critical issues, including eutrophication and re-suspension of trace metals that still linger in the lake. Furthermore, the evaluation of the present chemical condition of the lake is a precondition for any successive restoration measure, such as fish introduction. The recent data confirmed the lake's water quality has recovered, i.e. returned to a pre-pollution chemical state. Lake water values of pH and concentrations of ammonium, sulphate and base cations have stabilized. Alkalinity and nitrate concentrations are also expected to reach stable level in the next few years. Levels of nitrate, reactive silica, and phosphorus compounds are now regulated by algal uptake, providing indirect evidence of a partial biological recovery. For instance, both the inter-annual average decline and the reappearance of a seasonal signal in silica confirmed the presence of a stable diatom community. The lake is presently oligotrophic, and concentrations of both N and P compounds are steady and low throughout the year. However, a monthly check of nutrient levels of the lake and inflowing waters is recommended. The monitoring of base chemical variables, major ions and trace metals should be maintained to assess the overall status of the ecosystem in response to various drivers, including climate change

Indicators for the Assessment of Thresholds and Points of Non-Return

Ecological indicators are used increasingly to assess the conditions and/or status of ecosystems. Historically, the first approach was to develop indices based on a particular species or components, e.g. macrophytes, zooplankton, etc. In general, such indices are not broad enough to reflect the complexity of the ecosystem, as they do not include information at the structural, functional and system levels. To cope with these aspects new indices have been develop (for recent reviews see Rapport, 1995; Jørgensen et al., 2005) that try to synthesyze information at all ecosystem levels. In this project we are interested in evaluating indicators in terms of their potential to detect thresholds and point of non-return in coastal ecosystem.JRC.H.5-Rural, water and ecosystem resource

Temporal evolution of lake level fluctuations under flood conditions and impacts on the littoral ecosystems

Lake levels fluctuations are conditioned by seasonal variability, water resources management and climate change. Recent studies have shown that global warming potentially affects the risk of flooding and that the decisive factor for flood events is not temperature, but precipitation characteristics and hydrological conditions. Flood events have numerous impacts on social, economic and environmental aspects depending on how humans have altered lands, natural rivers and lake dynamics. Flood protection measures can cause conflicts with conservation measures and with ecosystem services because natural capital is not considered able to control floods and to contribute control floods and that it can contribute to human health and safety. In this paper we analysed the flood events in Lake Maggiore for return time periods of 3 – 5 – 10 – 25 – 50 – 100 – 250 – 500 years, considering the flood frequency in the last ten years using 1868-2021 as a reference period. We discussed the probability distribution of flood peaks, the correlation and linear regression between the lake level fluctuations and macroinvertebrates occurrence. We also presented lake coasts flood hazard mapping. The probability distribution that better describes the annual peak level is the Gumbel function, while for spring and autumn flood events the better distribution is the Log-Pearson type III. One of the historical flood events in terms of magnitude was in 2000, characterized by a return time of about 50 years. The last flood event in 2020, was characterized by a return period of about 10 years. Considering the seasonal frequency of flood, the autumn magnitude was higher than the spring one, and the differences between seasonal flood events progressively increased. The results suggested a high probability of a flood event every three years and also a forecast of a flood of about 197 m asl (3.14 m above the average lake level) every 10 years. Raising the lake level will affect the reed bed area from 193 m asl, and it will be more effective at 194.5 m (up to a 10% reduction). During flood events, the whole reed bed area is submerged. As regard macroinvertebrates composition and abundance, the first results show significant negative relationships between all sampling stations altogether vs the abundance of Cladotanytarsus sp. (Chironominae) and nearly significant positive relationships between water levels at Magadino vs Pscectrocladius sordidellus (Orthocladiinae) abundances. These few results are perhaps due to the current limited data availability

Establishment of Corbicula fluminea (O.F. M?ller, 1774) in Lake Maggiore: a spatial approach to trace the invasion dynamics

We analysed the dynamics of the invasive Asian basket clam Corbicula fluminea in Lake Maggiore (Italy), recorded for the first time in August 2010. In order to reveal the extent of its dispersal, we monitored 30 locations along the lake for presence/absence of clams. This assessment of population structure, density and biomass is based on quantitative samples collected along the southern shoreline at four sites with diverse types of habitats. In the present study, the on-going process of Corbicula invasion was analysed from a spatial and temporal perspective. We compared density and size structure of the population among the sites (spatial distribution). We attempted to trace the colonization dynamics of the clams, so the invasion dynamics were tentatively reconstructed from spatial distribution of size /age groups and the contribution of the last recruited cohort to total population density along the lake littoral zone. Results from our surveys conducted in 2010-2011 have demonstrated that the Asian clam was well-established in the lake, thus about one-third of the lake (i.e. the southern basin) was already colonized by C. fluminea in 2011. Size frequency distribution in autumn 2011 further illustrated reproduction events and new recruitments. Population densities in Lake Maggiore were among the highest ever recorded in an Italian lake. Both the rapid spread of Corbicula in the littoral area and the relatively high densities, even at the most recently invaded sites, infer the potential ecosystem impacts associated with a dominant invasive species. Data reported here are not intended to be exhaustive since they concern only two years of investigations, so more detailed studies on both the ecology and invasive habits of this new alien species in Lake Maggiore are planned. The spatial approach used in the present study may clarify the dynamics of this invasion. Future monitoring might help us to disentangle the effects of spatial variability versus temporal succession during the establishment of the invasive species

Synoptic results on the potential impacts of the Lake Maggiore water management strategy on freshwater littoral ecosystems and invertebrate biocoenosis (NW, Italy)

The first results of the application of the integrated multidisciplinary protocol to study the effects of water level management on the Lake Maggiore littoral habitats and biocoenosis are presented. The "Parchi Verbano Ticino" project (2019-2021, ID: 481668) was the driving force to fine-tune the monitoring and management system of multidisciplinary information (chemistry, hydro-morphology, macro- and meio-fauna monitoring). The study reveals that water level fluctuations in Lake Maggiore, sometimes characterized by measurable changes in water levels, have remarkable effects on littoral habitats and on the structure and function of macro- and meiofaunal assemblages living there. Overall, this study provides insights into the potential impacts of Lake Maggiore water management strategy on freshwater littoral ecosystems during late spring-early summer, and emphasizes the need for a comprehensive understanding of the lake ecosystem dynamics. Thanks to the results achieved, publicly endorsed water management rules will be stated, for the late spring-early summer period, considering frequency and amplitude of water level fluctuations as crucial factors in management plans to mitigate their impacts. The endorsed rules turn out to be a negotiated compromise between the maintenance of ecosystem services and the protection of littoral life below water

Biological survey of lakes and reservoirs from Sardinia and Piedmont (Italy), a georeferenced dataset from the project LIFE INHABIT

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)

A basin-wide Black Sea Mnemiopsis leidyi database

A specific marine biological data management tool, the Black Sea Mnemiopsis leidyi database system was created within the European Commission 6th framework Black Sea SCENE project for the Black Sea region and is now being supported by the Permanent Secretariat of the Black Sea Commission. The core team of scientists studying M. leidyi in the Black Sea was brought together and all their available M. leidyi data and metadata were loaded into the common database. This works on the Internet and has a simple user interface. It gives Black Sea scientists the option to load all their corresponding data on the database and to use it as an effective tool to work both with M. leidyi and, in future, with other gelatinous organisms’ data, including another invasive ctenophore Beroe ovata. All loaded metadata and historical data are available to the entire scientific community. More recent data are available to the team members and with some restrictions to other scientists.JRC.H.5-Land Resources Managemen

Ocean current connectivity propelling the secondary spread of a marine invasive comb jelly across western Eurasia

Publication history: Accepted - 15 February 2018; Published - 16 May 2018.Aim: Invasive species are of increasing global concern. Nevertheless, the mechanisms driving further distribution after the initial establishment of non-native species remain largely unresolved, especially in marine systems. Ocean currents can be a major driver governing range occupancy, but this has not been accounted for in most invasion ecology studies so far. We investigate how well initial establishment areas are interconnected to later occupancy regions to test for the potential role of ocean currents driving secondary spread dynamics in order to infer invasion corridors and the source–sink dynamics of a non-native holoplanktonic biological probe species on a continental scale. Location: Western Eurasia. Time period: 1980s–2016. Major taxa studied: ‘Comb jelly’ Mnemiopsis leidyi. Methods: Based on 12,400 geo-referenced occurrence data, we reconstruct the invasion history of M. leidyi in western Eurasia. We model ocean currents and calculate their stability to match the temporal and spatial spread dynamics with large-scale connectivity patterns via ocean currents. Additionally, genetic markers are used to test the predicted connectivity between subpopulations. Results: Ocean currents can explain secondary spread dynamics, matching observed range expansions and the timing of first occurrence of our holoplanktonic non-native biological probe species, leading to invasion corridors in western Eurasia. In northern Europe, regional extinctions after cold winters were followed by rapid recolonizations at a speed of up to 2,000 km per season. Source areas hosting year-round populations in highly interconnected regions can re-seed genotypes over large distances after local extinctions. Main conclusions: Although the release of ballast water from container ships may contribute to the dispersal of non-native species, our results highlight the importance of ocean currents driving secondary spread dynamics. Highly interconnected areas hosting invasive species are crucial for secondary spread dynamics on a continental scale. Invasion risk assessments should consider large-scale connectivity patterns and the potential source regions of non-native marine species.Danish Council for Independent Research; Grant/Award Number: DFF-1325-00102B; FP7 People: Marie-Curie Actions, Grant/Award Number: MOBILEX, DFF - 1325-00025; EU, BONUS, BMBF, Grant/ Award Number: 03F0682; Excellence Cluster “Future Ocean”, Grant/Award Number: CP153