Bidighinzu Lake is a warm monomitic and hypereutrophic reservoir located in northwestern Sardinia at 334 m a.s.l. Built in 1956, it is mainly used for drinking water for a population of about 160,000 users. Bidighinzu Lake covers a surface area of 1.7 × 10⁶ m² and has a maximum volume of 12.2×10⁶ m³ and a mean depth of 7.3 m. According to ECOSTAT, it belongs to the LM7 category (altitudes <800 m a.s.l., mean depths >15 m, conductivity <2.5 mS cm−1). Its watershed has a surface area of 52 km² with a geological substrate consisting of basalt, limestone, and shale. The supplies of water from the catchment to the lake are insufficient to make up for the losses and human demands. Consequently, the lake receives additional water from Temo Lake and Rio Mannu-Su Tulis river lock, localized in different watersheds. Problems of potabilization have arisen since the early years of the reservoir’s use, particularly in summer-autumn, because of hypolimnic deoxygenation and the excessive presence of algae in the epilimnion. To face this situation, different restoration actions were carried out in Bidighinzu Lake. Among the most important: the installation in 1966 of an aeration system in the area around the water intake tower and in 1987 the reduction of nutrient loads from the watershed by the diversion of civil and industrial wastewater downstream of the dam. A comparison among data collected from just before to about 10 years after this last action the site did not show any improvement in the trophic status. Since 2006, the lake is managed by the Sardinia Water Authority (ENAS) and is part of LTER-Italy. The site has real-time remote monitoring station equipped with a multiparameter probe housed on floating platform. The main scientific purposes at present concern the relationships between trophic status, abundance of cyanobacteria and the presence of toxins; the assessment of climate change and local factors on the phytoplankton dynamics; the development of territorial indicators related to the trophic conditions based on the land cover and use of catchment areas. Recently in Lake Bidighinzu it was conducted an experimental activity, with an aeration system with micro-bubbles. The aim was to maintain sufficient oxygen in the hypolimnetic waters, especially in the summer months, in order to improve the purification process, prevent phosphorus release from sediments and mitigate eutrophication. Available data sets include information on phytoplankton and limnological variables since the last 70.

The Hölstein site is located in in the eastern part of the Swiss Jura mountains (47°26’16.4’’, 7°46’31.1’’; 540 m a.s.l.), in a mixed, temperate forest with an exceptionally high biodiversity and a vigorous tree regeneration. The research plot has a size of 1.6 ha and comprises 540 mature trees. The main tree species are Fagus sylvatica and Picea abies with an admixture of Abies alba, Quercus petraea, Pinus sylvestris, Acer pseudoplatanus, Carpinus betulus, Fraxinus excelsior and Sorbus torminalis. A canopy crane is installed in the center of the research area to access the tree canopies for in situ measurements and for sampling of leaf material. Rainout shelters will be installed in 2019 for conducting a long-term throughfall exclusion experiment.

The BLE LTER program (https://ble.lternet.edu/) focuses on productivity, trophic relationships, and biogeochemical cycling in the network of lagoons that span Alaska’s northernmost coastline. BLE is examining factors that affect the stability and resilience of microbial and metazoan food webs, including drivers and forms of primary production, in these highly dynamic ecosystems.

The WelFin LTER-site is located at the Hanko peninsula, at the entrance to the Gulf of Finland. The activities are largely focused to the coastal areas surrounding Tvärminne Zoological Station (University of Helsinki); a marine station established in 1902. The site is well equipped to meet the research demands, offering differently sized research vessels, field equipment, a range of climate chambers, and modern analytical instrumentation. A large part of the surrounding area is a nature reserve, to be used only for science and education. Many of the partners of this site have a long history of scientific collaboration. Although high-quality basic research continues to be at the heart of the site’s activities, many of the research questions nowadays include aspects of human induced long-term change.

The coastal marine observatory site Gulf of Trieste lies within the Marine Protected Area (MPA) of Miramare and includes the biological time-series station “C1”, part of the Italian Long-Term Ecological Research (LTER) network, and the in situ continuous MAMBO meteo-oceanographic buoy. Marine Protected Areas represent one of the most effective systems for marine biodiversity preservation and management. Since 1986, the time-series station “C1” in the Gulf of Trieste (GoTTs, Gulf of Trieste Time series) represents a crucial site for marine ecological research, as it is subject to the interaction among several natural forcing (river, groundwater discharge, tides, general circulation, intense meteorological) and numerous anthropogenic activities (maritime transport, harbours of Trieste and Monfalcone, urban waste discharge, mussel- and fish-farming, fishing and recreational activities). In 1999, the ecological research site has been equipped with a meteo oceanographic buoy (MAMBO) in order to acquire continuous data on meteorological conditions at sea and on seawater physical and biogeochemical properties. Due to the high temporal dynamics of ecological processes in coastal ecosystems, continuous and real-time data of the main meteorological, physical and biogeochemical properties are fundamental for a better understanding of marine ecosystem functioning.

The Seine estuary is a megatidal estuary located in northern France. It is the third largest estuarine ecosystem in the country after the Gironde and Loire along the French Atlantic coast; its waters flow into the English Channel. The geographical zone of influence of the Seine estuary runs from just upstream of the Poses dam, at the limit of the tidal penetration into the estuary — 160 km upstream of Le Havre —to the eastern part of the Bay of Seine. It can be divided into three sections: the fresh water upstream section (125 km), the mixing zone characterized by varying salinity levels (35 km), and the marine downstream section under the influence of the Seine River. The megatidal regime generates a turbidity maximum in the mixing zone (middle estuary) between the marine and fluvial sections of the estuary. The Seine estuary is a typical estuarine ecosystem: highly stressed by natural fluctuations and anthropogenic pressures, and hosting a rich ecological system. The Seine valley and its estuary are of major economic importance for France, with the presence of two maritime ports. It’s watershed (79,000 km2) is the home to 17 million people, and accounts for 50 % of the river traffic in France, 40 % of the country's economic activity, and 30 % of its agricultural activities. In addition to the Greater Paris area (> 11 million inhabitants), which contributes heavily to the Seine estuary's upstream inputs, two other major river settlements — Rouen (500,000 inhabitants) and Le Havre (300,000 inhabitants) — are maritime ports of international importance. Due to economic development, the Seine estuary has been subjected to major hydrodynamic, ecological, biogeomorphological and biogeochemical changes. The importance of studying the effects of anthropogenic impacts on estuarine ecosystems has increased in the last decade, especially under the Water Framework Directive, which aims to achieve “good environmental status” of all European water bodies.

The ZA PYGAR covers the whole Garonne river basin up to the upper part of the Gironde estuary (La Reole station). Within this territory, research is structured around 4 main sites: the Pyrénées mountains, covering the upstream part of the Garonne river basin (PYRénées site), the farmland of the foothills of the Pyrénées (Vallées et Coteaux de Gascogne site), the Garonne river (Axe Fluvial Garonne site) and the basin of two tributaries of the Garonne river in the Massif Central moutains (Aveyron-Viaur site).

Designation: Ecosystem research and management under land-use and climate change. Climate: Mean annual precipitation 150-200mm between November and April; mean maximum summer temperature 34° C, mean minimum winter temperature 6° C. (Data avialable for 15-min interval meteorological measurements and daily summaries for rainfall, air and soil humidity and temperature, wind velocity and direction, from 1997 to the present.) Principal biomes: Semiarid shrub land (shrub-grass steppe), rocky and loessial watersheds, ephemeral streams. Vegetation is dominated by patch-forming dwarf shrubs (Noaea mucronata, Atractylis serratuloides and Thymelea hirsuta) with species-rich annual winter vegetation in the inter shrub (dominated by Stipa capensis and other grasses) and shrub patch understory (dominated by Anagallis arvensis and other forbs). As a result of drought there are also two new sub biomes: crust land and grass land. Management: Livestock grazing excluded in central watershed (20 ha) since 1987; restricted/controlled grazing by Bedouin sheep herds in surroundings; in the outer parts of the area native and exotic trees were planted in 1985-87 in contour dykes (‘shikhim’) on the slopes and in terraces in the riverbed. Research: 1. Long-term experiments (up to 20 years) for monitoring changes in abundance, diversity, species composition and distribution, and development of biological soil crusts (BSC), perennial plants (dwarf shrubs) and winter annuals in relation to rainfall, soil disturbance, patch distribution, and livestock grazing. 2. long term hydrological studies on rainfall-runoff relationship under natural and manipulation experiments. 3. Short-term experiments and surveys (1 to 5 years) A. for testing hypotheses about the detailed processes, mechanisms and interactions involved in the development, dynamics and stability of shrub- and BSC-dominated patches, their landscape mosaic patterns and their feed-back relationships with flows of materials through the landscape; B. for testing hypothesis on the effect of geodiversity on the stability of shrub land to extreme drought and understanding state changes in drylands. 4. Long term studies on cross scale-cross level interactions in natural and human modified landscape. 5. Network-related research including regional comparisons of herbaceous plant productivity in open rangeland along the Israeli North-South rainfall gradient, and global comparison of woody plant diversity effects on ecosystem functionality of most dryland regions of the world.

Monitoring stations in Aukštaitija NP started functioning in 1993. Aukstaitija station (LT01) was founded in strict reserve zone of Aukstaitija national park in Ažvinčių old forest, Versminis river closed basin. The area of the basin is 101.5 ha. The lowest place is at 159.5 m, the highest - 188.6 m above sea level. Geographical co-ordinates of the basin are: longitude - 26*03*20* - 26*04*50*, latitude - 55*26*00* - 55*26*53*. The climate is characterised as average cold with high humidity and abundant precipitation. The average air temperature is 5.8 C, average precipitation - 682 mm. Length of vegetation period - 189 days. Side glavioacvalic accumulation forms with sand, gravel and stones are typical for river basin and in the western part of the basin, with the decrease of surface altitude transfers into fliuvioglacial terrace delta plain with fine sand, and at the source- into marsh accumulation forms with organic sediments. At the eastern side of the basin, which has higher altitudes, the typical for this basin glavioacvalic accumulation forms transfer into gravel sand. Carbonates start foaming at 45 cm depth (Gulbinas et al., 1996). The saturation of the river water with the oxygen is very weak. The average yearly oxygen concentration equals to 2.9 mg/l (minimal allowable concentration – 6 mg/l). The pH value of the water fluctuates from 7.10-7.75 mg/l, which indicates the alkalisation of the water. Concentration of hydro-carbonate ions varies in the intervals of 148-224 mg/l. Concentrations of sulphates and chlorides are very small. Calcium and magnesium ions are dominating in the media of cations. Concentration of natrium ions is insignificant – 2 mg/l 9DLK=120 mg/l), concentration of kalium ions reaches only tenths of mg/l (DLK=50 mg/l). According to the size of mineralisation the river water could be described as having average mineralisation levels. Concentrations of nitrogen materials (ammonium nitrogen, nitrates) are small, compared to maximum allowable concentrations (DLK) set for surface waters. Concentrations of phosphates are small. Silicium concentrations fluctuate from 2 mg/l to 9 mg/l (Čeponienė, 1997). Main ecosystems Coniferous multi-layered forest stands are prevailing in the basin, which are mainly pine trees with a mixture of spruce. Those stands usually have a second and third tree layer with abundant under layer vegetation. Spruce stands are also of complicated structure. The second and third spruce layer with abundant under layer vegetation are common. Remarkable amounts of territory are occupied by mixed conifer-deciduous or mixed conifer forests. Pure birch stands in more wet habitats in the vicinity of Versminis river source can also be found. According to the forest stand age they are old pure overmature or with accompanying forest stands of several age classes. It is mainly multi-aged and multi-layered over mature pine and spruce stands. In addition The study was based on monitoring data on crown defoliation of more than 3000 Scots pine (Pinus sylvestris L.) trees from 20 permanent observation stands (POS) annually obtained between 1994 and 2009 in Aukstaitija national park (ANP), located in the eastern part of Lithuania (Fig. 1). Over 16yr period mean values of crown defoliation of every sample pine stand were computed annually. Therefore the total number of treatments made N=320. These stands were classified according to stand maturity: 4 sapling stands (45 to 50 years – Table 1, section “Stand maturity”, group 1), 5 middle aged stands (61 – 80 years – group 2), 4 premature stands (81-100 years – group 3), 3 mature stands (101-120 years – group 4) and 4 over mature stands (> 121 years – group 5). Main characteristics of the considered stands are compiled in table 1. All stands represent the prevailing in Lithuania Pinetum vaccinio-myrtilosum forest type.

Small agricultural catchment (320 ha) with 30 years of data to study impact of climate change and agricultural practices on soil erosion, weathering rate and river fluxes. Continuous measurements with sensor: river discharge, Temperature, pH, conductivity, turbidity, dissolved oxygen, nitrate Weekly samples and high resolution sampling during storm runoff: major cations and anions, alkalinity, pH, dissolved silica, conductivity, total suspended solids, stable isotopes (13C of DIC, 2H and 18O of H2O, 15N of nitrates), heavy metals, some pesticide molecules Climatological station, rain collector for precipitation chemistry, soil solution station with lysimetric plate at different depths. Continuous measurement since 2004 of CO2, N2O, water vapor, energy exchange in the soil-vegetation-atmosphere continuum thanks to Eddycovariance and closed chamber methodologies (see OZCAR-RI Regional Spatial Observatory in the South West France contribution) Collaboration with the Aurade farmer association for fertilizer and pesticide inputs, cultivation, agricultural practices... Aurade experimental catchment and flux site are an international field site of the Critical Zone Exploration Network CZEN and of ICOS network, a field site of the French Research Infrastructure OZCAR and it is also a site of the French LTSER ZA PYGAR "Zone Atelier Pyrénées-Garonne". and a regional Platform of Research and Innovation-Midi Pyrénées.