In order to combat the eutrophication of Lake Balaton, the Kis-Balaton Water Protection System (KBWPS) was initiated in the early 1980s. Originally, the KBWPS consisted of an 18 km2 shallow (less than 1.3 m) artificial lake system (Lake Hídvégi) and a 16 km2 wetland, which were constructed on the site of the former Kis-Balaton wetland in the mid-1980s. Later, the wetland part of the KBWPS was significantly enlarged (over 50 km2). Lake Hídvégi was designed to retain nutrients and provide ideal conditions for algae growth, while the wetland component of the KBWPS prevented these algae from entering Lake Balaton. Regular limnological, ornithological, ichthyological and plant ecological measurements are carried out in both Lake Hídvég and the wetland part of the KBWPS.

Coniferous forests and mire.

The McMurdo Dry Valleys (MDVs) (78°S, 162°E) represent the largest (4500 km^2) ice-free area on the Antarctic continent. The MDV landscape is a mosaic of glaciers, soil and exposed bedrock, and stream channels that connect glaciers to closed-basin, permanently ice-covered lakes on the valley floors. Mean annual air temperatures are cold (ranging from -15 to -30°C on the valley floors), and precipitation is low (~50 mm annual water equivalent as snow). Summer air temperatures typically hover around freezing and winter air temperatures are commonly < -40°C. While the water columns of the lakes are liquid and biologically active year round, glacial meltwater streams flow and soils thaw only during the austral summer. There are no vascular plants, but microbial mats are abundant in lakes and streams. Mat organisms are transported by wind onto glacier and lake ice surfaces where they actively metabolize in liquid water pockets (cryoconites) that form during the summer months. In the streams, which desiccate for ~10 months each year, cyanobacterial mats host extensive diatom and soil invertebrate communities. Lakes provide a habitat for diverse phototrophic and heterotrophic plankton communities that are adapted to annual light-dark cycles and temperatures near 0°C. Soils are inhabited by nematodes, rotifers, and tardigrades, all of which are metabolically active during summer. The McMurdo Dry Valleys LTER (MCM) began studying this cold desert ecosystem in 1993 and showed that its biocomplexity is inextricably linked to past and present climate drivers. In the fifth iteration of the MCM LTER program, we are working to determine how the MDVs respond to amplified landscape connectivity resulting from contemporary climate variation.

The Sonnblick Observatory is located in the Austrian Central Alps at an elevation of 3100 m a.s.l. It is situated at the alpine main divide, which is a clear climatological border. It also lies in the “Nationalpark Hohe Tauern” which covers 1856 km2 of the Austrian Alps. Research of the Sonnblick Observatory is currently formulated in the research programme ENVISON. It covers three main topics (the atmosphere, the cryosphere, and the biosphere) in an extensive monitoring programme and with many research projects.The Sonnblick Observatory is outstanding with respect to its long-term climate observations and studies on glacier changes. Thus, the impact of Climate Change on the cryosphere is a major research topic at the Sonnblick Observatory. Since 1886, the observatory is also involved in many international projects on atmospheric chemistry and atmospheric physics. The research is described on www.sonnblick.net. The Sonnblick Observatory cooperates with several Austrian and international universities/research institutions. Within the frame of the GAW-DACH cooperation, Sonnblick has a special partnership with the observatories Jungfraujoch (in Switzerland), Zugspitze and Hohenpeissenberg (both Germany) for common research on atmospheric processes and Climate Change. The Sonnblick observatory ist part of the BSRN-Network, LTER Austria, ACTRIS, etc. Data are available via the SBO Data Portal. In the frame of eLTER the SBO will be part of the eLTSER Cluster NPHT.

The site Klausen-Leopoldsdorf is part of the European Level II Forest Monitoring System in the frame of the International Co-operative Programme on Assessment and Monitoring of Air Pollution Effects on Forests (ICP Forests). The site was established in 1995 and is, since 2006, part of the LTER Austria network. It is situated in a homogenous 80 years-old managed beech stand about 20km west of Vienna. The LTER-CWN research area in Klausenleopoldsdorf is divided into 3 subplots: a measuring weir, a dendrometer/sapflow measuring facility and GHG-chambers for measuring the fluxes of CO2 and other relevant GHG´s. All 3 subplots were installed in 2019 to collect high-resolution data. The measuring weir is located at about 475m a.s.l and the other subplots (denrometer/sapflow, GHG measuring chambers) are located at about 510m a.s.l. The observed catchment of the measuring weir has an area of 46 hectares. The dominating soil types in the catchment are Planosoils and Stagnosols. The subplots are situated in the near vicinity of the ICP-forest plot.

The Ploemeur-Guidel observatory (Britanny, France) is focusing on surface-depth relationships in a fractured crystalline geological context and oceanic climate. It is built on 2 sub-sites, one highly anthropized, the other in natural state. In Ploemeur, groundwater has been pumped since 1991, supplying more than 1 million m3 of clean drinking water annual at a sustainable rate. Such high productivity is explained the specific fractured network in granite and micaschists, draining deep geological layers (~400 m). Extracted water quality is very good, with limited nitrate concentration, in a region that has been strongly affected by widespread pollution. Guidel site is in a similar, but natural context. Deep iron-rich groundwater is upflowing, creating surface and deep groundwater-dependent ecosystems, and feeding a classified coastal wetland. Both sites have a very dense equipment to study rapid to long-term surface-depth exchanges: a flux tower, unsaturated zone monitoring, a network of ~50 shallow (<10m) and deep boreholes (>80m), hydrochemical, temperature and deformation. An well-characterized fractured experimental site offers the possibility to conduct experiments to test innovative instruments and develop new methodologies

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).

The site is located at the main Alpine ridge in Silvretta group right at the border between Austria and Switzerland. Jamtalferner glacier and it's forefield is subject to scientific reseach for more than 100 years. Current monitoring includes climate, hydrology, glacier mass balance, permafrost, paleoglaciology, society and biotic succession in the periglacial area. In addition to that, several short time research projects are carried out, e.g. concerning glacier albedo. The site inlcudes the are from the highest peaks at 3384 m a.s.l. and the valley further down to the communities of Galtür and Ischgl (1263 m a.s.l.). More information can be found at the website of the environmental education program Jamtal www.umweltbildung-jamtal.info.

The LTSER platform Oberes Paznaun includes the communities of Ischgl and Galtür (225 km²), and covers an elevation range from 1263 to 3384 m.a.sl.. The village of Galtür is one of the highest permanently inhabited places in the Alps. Fluchthorn, the highest peak of the largely glacier-covered Silvretta, was taken down by about 30m in 2023, when a major rock fall occurred as a result of reducing permafrost. Both the effects of climate and those of land use change affect the very sensitive livelihoods in the are, exposed as they are to natural hazards, such as avalanches, rock fall and floods. The region was economically weak until winter tourism boomed from the 1970s. Skiing as dominant source of income now has an impact on land use as well as on social and economic structures in the region. Management issues arise from the high number of incoming tourists. Local stakeholder networks involved in spatial planning and hazard management are also part of the LTSER Platform. The local Alpinarium museum is dedicated to presenting the livelihoods of mountain communities and acts as a local hub for linking science and society. Apart from the long-term monitoring of the environmental parameters, initiated in 1895 with glacier length changes, the socio-economic research in the Paznaun area dates back to the 1960s. Socio-economic and socio-ecological research in the region focuses on the multiple feedbacks between environmental and socio-economic changes in the region. The avalanche disaster of Ischgl and Galtür in 1999 affected disaster management and related structures in many ways, not only for the region, but for all of Austria, for instance leading to the foundation of crisis intervention teams. The question of how to deal with impacts of climate change, for example on hydrology and water management, is part of research projects in the area connecting stakeholders and scientists. The overarching aim of the platform Oberes Paznaun is linking up geosphere, atmosphere, hydrosphere and biosphere research with local political and administrative processes for sustainable development in a warming future.

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.