3 sites with 10 ha altogether; follow the long-term changes on sand steppe gaps of juniper-poplar forest in order to study the effect of fire

Black Sea site includes three areas: cape Kaliakra, cape Galata and Varna Bay, and Koketrays Sand bank (only for macrozoobenthos). They were chosen on the base of historical data availability and eutrophication/pollution impact. Kaliakra marine area is influenced by eutrophication due to mainly the Danube river inflow. The local anthropogenic impact in the region is insignificant. It is a nature reserve. Cape Galata and Varna Bay sites are under the indirect impact of Varna Bay current and the system Beloslav lake-Varna lake - a cascade introducing nutrients and pollutants of industrial (chemical industry), agricultural, sewage origin and nearby ports. Koketrays Sand bank is an unique benthic habitat. The coordinates of the selected areas are as follow: c. Kaliakra: 28.416667 43.366667 c. Galata: 27.933889 43.186111 Varna Bay: 28.166667 43.166667 Koketrays bank: 27.888889 42.635556

This site is located on the territory of National Park “Rila”, Bulgaria. Parangalitsa has been a reserve since 1933. It is situated on part of the southwestern slopes of Rila mountain, covering 1,509 hectares. It contains some of the oldest pine tree forests in Europe with an average age of over 200 years. The site is a part of the network of bioecological stations of Forest Research Institute – BAS and research is focused on highly productive coniferous forests with unique biomass. In the main experimental plots, long-term complex studies were conducted during the period 1979 - 1998, a large-scale database was created and a number of significant scientific results were obtained. In the period 2000 - 2018, separate targeted studies were carried out - focused on some ecosystem processes, which allows the analysis and evaluation of the functioning of ecosystems to be don

The site, located along the Tyrrhenian coast, north of Rome city, is a Special Protection Area (SPA) for migratory and nesting birds (Anatidae, Ardeidae). The wetland area is one of the last stretches of the Lazio wetlands which have been progressively reclaimed and cultivated during the last century. The flora and the fauna of the site is not only highly specialized but also highly endangered, with a relevant ecological value evidenced in previous studies. The site includes coastal dune habitats of European interest, as the annual vegetation of drift lines, the embryonic shifting dunes, the mobile dunes with Ammophila arenaria and the dune grasslands. There are also habitats related to wet and mud soils, as Mediterranean salt meadows and reed beds dominated by Phragmites australis.

S.C.I IT7228221 Foce Trigno-Marina di Petacciato (Campobasso) S.C.I. IT7140108 Punta Aderci-Punta della Penna S.C.I. IT7140109 Marina di Vasto The site includes 3 Natura 2000 sites along the central Adriatic coast, where the last fragments of natural vegetation zonation on sand coastal dunes occur (shore vegetation, embryo and mobile dune vegetation, annual Mediterranean grasses and wet dune slacks).

SCI IT7222217 Foce Saccione-Bonifica Ramitelli (Campobasso) The site includes 1 Natura 2000 site along the central Adriatic coast, where the last fragments of natural vegetation zonation on sand coastal dunes occur (shore vegetation, embryo and mobile dune vegetation, annual Mediterranean grasses, costa dunes with Juniperus spp and wet dune slacks).

This LTER-site corresponds with a 0.25 ha intensive forest monitoring plot (ICP Forests Level II) including a 0.25 ha buffer zone. The site is located in a homogeneous stand of Corsican pine (Pinus nigra ssp. laricio var. Corsicana Loud.) planted in 1930 on former heathland and is part of Gewestbos Ravels, a landscape (about 1000 ha) with deciduous and coniferous forests, heathland, bogs and pastures in the northern part of the Campine ecoregion of Flanders. The terrain is gently sloping (1-2 %) and the soil is a well-drained sandy soil (Endogleyic Folic Brunic Albic Arenosol (Dystric)). Ground vegetation is dominated by ferns (Dryopteris dilatata and D. carthusiana) and Vaccinium myrtillus. After a storm in February 2007 felled several trees an understorey of Betula pubescens started to develop. Intensive monitoring was started in 1987 with the main objective to study the effects of air pollution on biogeochemical cycling and forest performance (growth, vitality). This yielded a number of long-term data series including on atmospheric deposition, air quality, soil and soil solution chemistry, tree mineral nutrition, ground vegetation and growth. Monitoring will be continued in the future as a statutory task of INBO.

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.

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.

Suserup Skov (19.2 ha) is an old growth temperate forest dominated by beech Fagus sylvatica, pedunculate oak Quercus robur, ash Fraxinus excelsior, wych elm Ulmus glabra, and black alder Alnus glutinosa, admixed with lime Tilia platyphyllos and sycamore maple Acer pseudoplatanus. KU/IGN-SNB, is a 19,2 ha old-growth beech-dominated mixed deciduous forests on western Zealand owned by Sorø Academy. The forest use dates back to 4200 BC. A conservation act was placed on the forest in 1925 for biological and recreational purposes but allowing a minimum odd felling until the act was updated in 1961 to a non-intervention forest. The forest is unique at European level in terms of nonintervention, and the long-term status as non-intervention forest has led to a unique steady state in biomass and accumulation of dead wood, thus serving as an important reference site for unmanaged temperate deciduous forest development. There are long-term data records of e.g. biomass, dead organic matter, soil, forest structure, flora and fungi starting from 1992. The platform is included in a series of paired managed and non-intervention forests for studies of forest structure, biodiversity and biogeochemistry in mature and old beech-dominated forests. Suserup Forest includes an ICP Forests level II plot (2001-). Upgrades: eLTER master sites: soil moisture content (TDR), remote sensing of growth and forest structure, LAI, NDVI (Lidar, camera), continuous plant phenology (web cam),and insect monitoring (optical sensors) as biodiversity measures, ambient air quality and air pollution.