Hydrometeorological and biogeochemical observations within 5 embedded catchments (from 0.2 to 14.5 km2). Alpine Mediterranean climate with heavy rainfall and flash floods in automn. The geology is mainly granite. The land use is mainly grassland and forest. More information at http://www.ohmcv.fr

The "Istituto Scientifico Angelo Mosso" research site is located on the watershed between Piedmont and Valle d'Aosta (NW-Italy), in the Municipality of Alagna Valsesia (Monte Rosa massif). The Scientific Laboratories of the "Angelo Mosso Institute" at Col d’Olen (2901 m a.s.l.), the heart of this research site, were built between 1905 and 1907, when it became clear that the Capanna Regina Margherita on Monte Rosa (4554 m a.s.l.), as a high-elevation research centre, had become insufficient to the increasing number of requests for use by the international scientific community. From here the idea promoted by Angelo Mosso (1846-1910), professor of human physiology at the University of Turin, to add an additional structure to the Observatory of the Capanna Regina Margherita for make larger laboratories available to researchers and allow study stays at high elevation. This project soon became a reality thanks to the intervention of Queen Regina Margherita, Ministries of Education and Agriculture, the Italian Alpine Club and various personalities of the time. The research conducted at the Institute did not concern only human physiology, but also other disciplines, including alpine meteorology and glaciology, thanks also to the presence of the Meteorological Observatory that flanked the Institute, directed in the years 1925-40 by Umberto Monterin. It is now home to an automatic snow and weather station, managed by the Alpine Troops-Meteomont service. In addition to the University of Turin, the research groups that operate at the site and contribute to data collection and implementation are currently CNR-IRSA, Alpine Troops Command-Service Meteomont, Monterosa 2000 SpA and Monterosa SpA (Monterosa Ski), Protected areas of Valsesia, ARPA Piemonte, ARPA Valle d'Aosta and Sesia Val Grande Geopark. In addition to the valuable historical series of climate data, a series of research activities are devoted to the study of snow-soil-vegetation interactions, with particular reference to carbon dynamics e soil nitrogen (Magnani et al. 2017a,b; Freppaz et al. 2019). In addition, investigations are performed focusing on the chemical characteristics of high-elevation surface waters, fed by different cryospheric features such as rock glaciers, glaciers, and permafrost (Colombo et al. 2018a,b; 2019a,b; 2020; Vione et al., 2021). New research lines, aimed at investigating the most recent environmental challenges, have been added to the previous ones. For instance, investigations on sources and routes of atmospheric carbon and nitrogen species are ongoing. References: Colombo N. et al. (2018a), https://doi.org/10.1002/esp.4257. Colombo N. et al. (2018b), https://doi.org/10.1016/j.scitotenv.2018.05.098. Colombo N. et al. (2019a), https://doi.org/10.1016/j.scitotenv.2019.06.233. Colombo N. et al. (2019b), https://doi.org/10.1007/s00027-019-0670-z. Colombo N. et al. (2020), https://doi.org/10.1016/j.catena.2020.104700. Freppaz M. et al. (2019), https://doi.org/10.3897/natureconservation.34.30737. Magnani A. et al. (2017a), https://doi.org/10.1657/AAAR0016-037. Magnani A. et al. (2017b), https://doi.org/10.1016/j.catena.2017.03.007. Vione D. et al. (2021), https://doi.org/10.1016/j.scitotenv.2020.143464.

Soil data of LTER Zöbelboden, Austria. Soil inventory is carried out since 1992 on regular positions (approx 65) in the catchment measuring soil chemistry. Soil water chemistry is measured in forest plots (2-3) using lysimeter sampling and analyses on a bi-weekly to monthly basis. Soil hydraulic characterizations exist for the major soil types in the catchment. Soil CO2 and N2O respiration data is available for some years

Waroneu is a 83 ha forested catchment located in the east of Belgium (« Hertogenwald »: Duke's forest) within the municipality of Baelen. In 2011, it was covered with 38% conifers (mainly Picea abies), 45% deciduous trees (Fagus sylvatica, Quercus robur, Betula pendula), and 17% open space. Biogeochemistry (nutrient and organic carbon in throughfall, rainfall, soil solution and outlet) has been studied since 1991. The catchment was limed in 1992 with 3T/ha dolomite and 200 kg/ha potassium sulfate. Since 2013, biogeochemistry and soil microbial parameters (microbial biomass, N mineralization, basal respiration) are studied in 6 intensive plots, reflecting major combinations of vegetation and upper soil caracteristics within the catchment.

Yr Wyddfa/Snowdon is an upland ECN site incorporating the summit of Yr Wyddfa or Snowdon, the highest mountain in England and Wales, 19km south-east of Bangor in North Wales. It is co-located with the Nant Teyrn freshwater site. The altitude ranges from 298-1085m and includes three additional summits over 800m. The bedrock is a mixture of Ordovician acidic and basic volcanic rocks, with localised igneous intrusions. Evidence of glaciation is widespread, with prominent corrie moraines. There are 5 lakes within the site, three of which form a 'staircase'. The soils are varied and include brown podzolic soil, gleys, organic peat soils and humic rankers. The dominant vegetation is acidic grassland with Festuca ovina (sheep's fescue) and Agrostis sp (bent grass) in the drier areas and Nardus stricta (mat grass) in the wetter areas. The site is part of the Yr Wyddfa/Snowdon National Nature Reserve, managed by the Natural Resources Wales under agreement with the owner. The land is unenclosed and grazed by sheep and a small herd of feral goats.

UK Environmental Change Network (ECN) site. The Cairngorms site is located high in the Cairngorms, near Aviemore in Speyside, Scotland. The site lies on the North-Western flank of the Cairngorms encompassing the catchment of the Allt a' Mharcaidh (a site in the ECN freshwater network). It is part of the Invereshie and Inshriach National Nature Reserve, within the Cairngorms National Park, and covers some 10 km2. This is the first ECN site in the UK's sub-arctic zone and is an important link not only to other upland ECN sites but to alpine site in Europe and globally through the GLORIA network, and also to networks across the Arctic (SCANNET and INTERACT). The Cairngorms site has been used intensively for research since the 1970s. An Automatic Weather Station (AWS) has been operating at the site since 1984 and was used in the Surface Water Acidification Programme from 1984 to 1994. CEH and MI have used the site for long-term hydrological and snow studies for about 15 years. From 1997-1999 it was one of the ECOMONT (land use change in mountain areas of Europe) sites. Researchers at several universities and institutes use the site for vegetation, soils and nutrient cycling studies. The site forms part of the larger Feshie catchment in the NICHE programme (National Infrastructure for Catchment Hydrology Experiments). This site is nested within the Cairngorms National Park LTSER site (https://deims.org/1b94503d-285c-4028-a3db-bc78e31dea07).

The site is located in the south-central part of Romania, in the Bucegi and Piatra-Craiului Mts of the Southern Carpathians. Bucegi - Piatra Craiului are located in the Romanian southern Carpathians (Bucegi NP (32.500 ha) and Piatra-Craiului NP (13.800 ha). In 2003, these areas were nominated as two ILTER Sites and in 2008 as LTER - Europe sites (Bucegi - Piatra Craiului). The diversity and vast richness of Bucegi - Piatra Craiului vegetation, with many endemic species and rich fauna which includes endangered species and unique plant communities like chamois, bear, lynx and wolf were the main reasons for the natural and national park designated status of Bucegi - Piatra Craiului.

La Robinette is a 81 ha catchment located in the east of Belgium (« Hertogenwald »: Duke's forest) within the municipality of Baelen. Biogeochemistry (nutrient and organic carbon in throughfall, rainfall, soil solution and outlet) has been studied since 1991 as a reference catchment within the frame of a liming experiment (Waroneu catchment) and critical loads calculations. The catchment, initially covered by Picea abies, was subjected to windthrow, reducing coverage to 46% (1990s) and experimental clearcut of 22 ha (1996), followed by afforestation with deciduous species in 1998. Four 2-ha plots were planted with deciduous species in alternate rows. Alder, rowan, birch and oak were also planted within the catchment. In 2012, the catchment was covered by 8% mature and 41% young conifers (Picea abies), 7% deciduous trees (Fagus sylvatica, Quercus robur, Betula pendula, Alnus glutinosa, Sorbus aucuparia, Salix caprea ), 44% open space. Biogeochemical measurements have been complemented with experiments on litterfall, litter decomposition, soil respiration, N cycle processes. Flux and meteorological data have been collected from 2007 to 2011 (CarboEurope) and from end 2016 (ICOS). In addition, since 2013, biogeochemistry and soil microbial parameters (microbial biomass, N mineralization, basal respiration) are studied in 6 intensive plots, reflecting major combinations of vegetation and upper soil characteristics within the catchment.

The Pürgschachen Moor is located on the bottom of the Styrian Enns valley, about 1.5 km southwest of the village Ardning in the district of Liezen at an altitude of 632 m a.s.l. It is a pine peat bog with a present extent of about 62 ha. Thus, it is the biggest (to a large part) intact valley peat bog of Austria with a closed peat moss cover and a good example of the formerly widely distributed peatlands of inner-alpine valleys. The peat bog site is property of the Benedictine monastery Admont and is leased to the Moorschutzverein Pürgschachen for an indefinite period of time. An EU Life-project were conducted in the years 1995 to 1998. Since 1991, the peat bog is part of the international and intergovernmental treaty of the Ramsar Convention, constituting a convention on wetlands for the conservation and wise use of wetlands and their resources. As a part of the network of nature protection areas Natura 2000 the site is protected as European nature reserve and mentioned as Important Bird Area. Genesis of such valley floor bogs is owed to the incurrence of postglacial lakes on impermeable loamy clay. The open water surfaces silt up due to the sedimentation of dead plant material. Therefore, peat bogs with a peat depth up to 6 meters could evolve from these terrestrialisation mires in the course of time. Mean average temperature of Admont is 6.6°C, annual precipitation is 1400 mm (1971-2000). The typical vegetation of the peat bog is constituted of the three associations of plants Pino mugo-Sphagnetum magellanici (pine peat bog association), Sphagnetum magellanici (coloured bog moss association), and Caricetum limosae (bog sedge association), depending on the prevailing hydrological (local) site conditions. The peat material of the peat bog can be separated into three different peat layers: Muddy-peaty deposits, Carex-rich Sphagnum-Eriophorum-peat, and Ericaceous-poor Sphagnum-Eriophorum-peat. The focus of our research at the study area Pürgschachen Moor is the investigation of carbon fluxes and a full carbon balance measured by eddy covariance technique. Based on the sampling of undisturbed peat cores potential gas releases measured in the laboratory can be compared with the data measured in field. The examination of peat properties, water table measurements, vegetation surveys, and climate data are further important variables. The Pürgschachen Moor is the first peat bog in the Alpine region getting investigated in detail regarding its carbon budget and is supposed to provide extensive information for the assessment and differentiation of alpine peat bogs.

The study plot was established by the Institute of Forest Ecology (Mendel University in Brno) in 1968, namely in connection with the UNESCO International Biological Programme (IBP) and the UNESCO programme "Man and the Biosphere" (MAB). The study plot is carried out in the natural forest region 30 – Drahanská Vrchovina upland (Drahanský bioregion, 1.52) about 1 km west of the village of Němčice in the Czech Republic on the modal oligotrophic Cambisol (KAmd´) of a fir-beech forest vegetation zone (4 FVZ) with forest type 5S1 – Abieto-Fagetum mesotrophicum with Oxalis acetosella (4AB3 – Fageta quercino abietina, union Luzulo-Fagion, association Luzulo-Fagetum) at an a altitude of 600–660 m at sites of autochthonous mixed forests. Research is aimed at ecological aspects of the transformation of spruce monocultures and optimation of management procedures at the application of sustainable management in forests. Recently, research is aimed at possibilities of the adaptation of forest stands on effects of an expected climate change. The main oriented research in present is: (i) study of mesoclimate and microclimate, (ii) evaluation of water balance, (iii) phenology of tree species, (iv) study of biogeochemical cycle (carbon, nitrogen, sulphur), (v) study of decomposition and soil processes, and (vi) evaluation of biodiversity.