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The holistic ecosystem research approach of eLTER and practical implications for building a Research Infrastructure
No full textDriven by the increasing awareness that innovative approaches to solving the problems at hand in our complex human-environment interactions require closer collaboration among scientific disciplines and communities, inter- and transdisciplinary integration is continuously gaining importance in R&D agendas and Research Infrastructure (RI) development strategies. In addition, the complexity and costs of RIs have substantially increased in many realms triggered by technological developments and the need to organize beyond national and continental boundaries. This suggests multi-, inter- and transdisciplinary collaborations, sharing and multiple usage of infrastructures. Alignments of infrastructure developments needed for this purpose require a conceptual framework for disciplinary integration suited for identifying common approaches and resulting infrastructure design and service components. The talk reports recent advancements in building a common theoretical base between major communities that is - inter alia - underlying the ongoing implementation of the Integrated European Ecosystem, critical zone and socio-ecological Research Infrastructure (eLTER RI). An overview of considered theories on within- and cross-scale interactions and feedback loops will be given and the pathway to the eLTER "Whole System Approach” will be presented. We will also expand on the potential of such a unifying approach in theory-guided integration and division of tasks amongst related environmental RIs. Expected practical implications are answers to questions like where concretely existing and planned European environmental RIs are challenged to interact in response to common overarching questions, and what practical fora and mechanisms (across RIs) would be needed to bridge the gap between research teams driven (bottom-up) efforts and the centralistic RI design and operations
A two-decades mountain forest Carbon sink affected by increased disturbance and drought
No full textTemperate mountain forests are critical to global carbon (C) cycling, acting as significant sinks for atmospheric CO₂. This study investigates two decades of stem C sequestration dynamics in a 90-ha forest in the Northern Limestone Alps in Austria, a region subjected to intensifying climate disturbances, including storms, droughts, and spruce bark beetle outbreaks. Utilizing a high-resolution, long-term dataset, the analysis reveals that disturbances reduced stand density, increased the proportion of deciduous tree species, and drove a decline in Norway spruce populations. Stem C sequestration decreased significantly during disturbance-intensive periods, particularly in conifer-dominated stands, while mixed forests exhibited higher resilience and recovery. Drought effects were limited to the extreme events, such as the 2003 drought, which caused transient reductions in C sequestration, likely due to cumulative pre-drought stress. Conversely, other drought years, that affected forest’s C sink whole over Europe, showed minimal impact, attributed to the humid mountain climate. Warming trends, marked by increasing minimum temperatures, enhanced C sequestration in beech-dominated stands, demonstrating the species' adaptability to higher temperatures and extended growing seasons. These findings underscore the influence of forest composition, soil properties, and climatic trends on landscape-scale C sink dynamics and provide valuable insights for adaptive forest management and climate resilience in temperate mountain ecosystems
Groundwater – surface water interactions revisited
No full textInteractions between groundwater (GW) and surface water (SW) have been a focus of hydrologic research for some time. Seminal early work by Toth (1963) and later Winter (1999) had shown the existence of nested GW flow systems and stressed that surface water bodies are integral parts of these flow systems. Despite this early, integral perspective, a simpler perception of GW and SW as two distinct compartments, which interact via some often loosely defined transfer mechanisms, still prevails. This perception can be found in many hydrologic models, but can be misleading, as it implies the existence to two clearly separable compartments, while in fact GW and SW are part of a hydrologic continuum (as a part of the terrestrial hydrologic cycle), in which water dynamically transitions back and forth between surface water bodies (rivers, lakes, wetlands) and shallow aquifers. For example, shallow riparian groundwater may become stream water in one moment and return back to the alluvial aquifer in the next with implications for water and solute exchange and biogeochemical turnover. While simplified conceptualizations of the GW-SW hydrologic continuum may be acceptable for the simulation of catchment streamflow response, they usually fall short, when trying to represent fluxes and dynamics of nutrients and other solutes, which are typically controlled by hydrological and biogeochemical processes in the transition zone between GW and SW. I argue that in our quest to understand coupled hydrological and biogeochemical processes and GW dependent ecosystems at the catchment and landscape scales, we needed to revisit the perception of GW and SW as a hydrologic continuum. I will use the example of dissolved organic carbon (DOC) export from a headwater catchment to stress this point and illustrate how rich field data and an integral numerical model can help to refine and improve a simplified conceptual model for catchment-scale DOC export. Finally an outlook will be given on future requirements for adequate monitoring and modeling of coupled GW-SW ecosystems
Long-term socio-ecological research at Poloniny National Park LTSER platform
No full textThe Poloniny National Park LTSER platform (https://deims.org/4a954f2b-7d18-4992-a860-adb7268f9dc7) is located in the northeast of Slovakia, on the border with Poland and Ukraine, in the Carpathian mountain range. The area is about 34,000 hectares. The area has a highland to upland character and is part of the Eastern Carpathians Biosphere Reserve. Forests dominate (approximately 85% in 2013), with transitional woodland covering 3–4%, the agricultural part is represented mainly by grasslands (8–9%), while arable land with agricultural mosaics covers less than 2%.The territory is a remote, peripheral part of Slovakia with significant specificities - characteristic mountain meadows, a high level of forestation, a low share of arable land, the absence of a larger industrial center, low employment opportunities for the local population, long-term population decline, and limited accessibility to the territory.During the last decades, the territory has undergone several political and socioeconomic changes, the most significant are: collectivization and the establishment of two large agricultural cooperatives in the early 1970s; the eviction of seven municipalities because of construction of Starina water reservoir for drinking water (1980–1987); the transition to a market economy and a deeper decline in agriculture after 1989; and the partial restoration of agricultural support after Slovakia's accession to the EU in 2004 (Bezák and Mitchley 2014).The research project "Socio-ecological research of landscape and biodiversity change in mountain area of the NP Poloniny in context of global changes (VEGA 2/0184/11)" also included an assessment of changes in landscape management. The socio-economic research in 2011–2014 revised and adjusted the basic milestones of landscape and biodiversity change of the Poloniny NP, summarizing knowledge from previous research, literary sources, and using a questionnaire survey with the main actors in the area (farmers, mayors, nature conservation representatives, etc.). The management of the landscape moved from small-scale farming on narrow-strip fields and extensive meadow management to large-block and machine-based farming of permanent grasslands around municipalities to the abandonment and overgrowing of distant and smaller plots. Succession processes formed up to 20% of the territory, and the landscape became homogeneous. The region recorded a permanent decrease in the number of inhabitants. Remoteness, unfavourable economic and living conditions were other factors that caused the overall decline of agriculture. Slovakia's entry into the EU (2004) was associated with the renewal of agricultural and environmental support (application of the agri-environmental schemes), which caused the clearing and regular mowing of many previously overgrown agricultural plots. However, the focus of this scheme rather supported large-block intensive farming. Smaller or badly accessible locations (e.g., meadows at higher altitudes, wetlands) continued to change into a shrub-forest ecosystem (Bezák et al. 2016).Based on the sustainability appraisal of Poloniny in 2005 under the BioScene project (Scenarios for Reconciling Biodiversity Conservation with Declining Agriculture Use in Mountain Areas in Europe), three scenarios of agricultural landscape development were outlined:Business as Usual,Agricultural Liberalisation, andManaged Change for Biodiversity.Our research in 2020-2021 assessed the trajectories of these scenarios after 15 years, considering the socio-ecological context and achievement of selected sustainable objectives. Tourism, assumed to be the recent key factor in Poloniny’s rural development, was also analysed. The assessment employed data on demography, changes in agricultural area, changes based on geo-tagged photos, and two questionnaire surveys with local stakeholders. A mixed impact on biodiversity and natural resources and a negative or stagnant trend for most social and economic aspects were found. Improvements were expected primarily in avoiding depopulation and maintaining a young generation, support for social infrastructure, and local job creation. A key factor in stimulating multi-functional and sustainable landscape management is surely ecotourism, which has significantly expanded in the last few years, especially due to local initiatives. However, its long-term maintenance is uncertain since its linkage to the well-being of the local community is absent. Achieving this objective requires a systematic design of targeted rural policy that respects the needs and character of peripheral mountain regions, provides better conditions for sustainable farming, especially in connection with non-production benefits from agricultural landscape such as recreation and biodiversity, and considers local actions and knowledge (Bezáková and Bezák 2022)
REWET (REstoration of WETlands to minimise emissions and maximise carbon uptake – a strategy for long term climate mitigation) – Water level and quality in a minerotrophic open mire Ylpässuo in Kiuruvesi, Finland
No full textWetlands store 33% of the world's terrestrial carbon although they occupy only 7% of the earth's surface. Especially peatlands contain great amounts of carbon locked in the submerged soil or as waterlogged undecomposed organic material. When these ecosystems are drained to be converted into agricultural or forestry exploitations or for peat extraction, they release greenhouse gas (GHG) emissions, which accelerate climate change. Also, leaching of dissolved organic carbon (DOC) and nitrogen (N) into aquatic ecosystems may increase (Nieminen 2004).The REWET/EU-Horizon project (2022-2026) aims to improve knowledge on the status of EU wetlands to understand their capacity as carbon sinks or GHG sources for climate mitigation, and improve assessment of the added value of wetland, peatland and floodplain restoration approaches under different scenarios and monitor their benefits and trade-offs in terms of GHG emissions, climate change adaptation and disaster risk reduction. The project has seven Open Labs across Europe. In the Finnish Open Lab (OL3), coordinated by University of Eastern Finland (UEF), the carbon sink strength and biodiversity of Ylpässuo (Kiuruvesi, Finland) is being investigated. The area is conserved by The Natural Heritage Foundation after donation by UEF but has been affected by edge drains and forest ditching in the surrounding area.In this poster presentation, water level and quality measurements in OL3 are presented. The data has been collected for water quality (nutrients, other ions, conductivity, pH, temperature, turbidity, DOC, elements, alkalinity) and water level by University of Oulu once a month from June to October in 2023 and from May to October in 2024. Water quality samples were collected from three sample points through perforated pipes installed into the wet ground. Samples for analysing nutrients, other ions, DOC and elements were filtered through 0.2 µm polyethersulfone filters. Water level data was collected from two samples points with water level HOBO logger (HOBO U20L-04 water level). Also, pH and temperature were detected with HOBO logger (Onset Hobo MX2501) from the sample point right next to the weather station. Air pressure and temperature were measured on this point as well.The water at OL3 was detected to be moderately acidic (pH 4–5; based on grab samples) and low in alkalinity (< 0.08 mmol/L) and conductivity (< 40 µS/cm). DOC and total N were remarkably higher (30–50 mg/L and 400–1400 µg/L, respectively) during the sampling period 2023, which was rainier than the sampling period 2024 (15–20 mg/L DOC, 400–700 µg/L TN). During both sampling periods, DOC also decreased from spring to autumn. In the concentration of phosphorus (P), there was not that clear difference between the two sampling periods. However, during both periods, P concentration was the highest on the first sampling date in the spring. The results are in correlation with the fact that in boreal and temperate freshwater ecosystems, the increased concentrations and leaching of DOC and N from peatlands have been connected to increased rainy periods and changes in soil frost periodicity and moisture conditions related to the climate change (Raymond and Saiers 2010, Mattsson et al. 2015, Lepistö et al. 2014), whereas leaching of P is usually less affected (Kløve 2001).Water temperature stayed quite stable during the measurement period being between 12–24 Celsius degrees. The pH of water varied between 4.5 – 5.5 based on the online pH readings. Water levels were compared to the air pressure and during the rainy season water levels were higher as well as in the beginning of the summer period (Rocchio et al. 2021). During the warm summertime the water levels dropped. Differences in the water levels were 45.9 cmH20 in maximum
Intra-annual tree growth patterns in eLTER sites in Romania based on dendrometer data
No full textLong-term monitoring of tree growth represents a valuable source of information about tree’s capacity to react and adapt to environmental changes. As climate change has already affected forest ecosystems, continuous measurements of tree reactions to environmental factors need to be considered in sustainable forest management. In this study, we investigate intra-annual tree growth patterns of the most common tree species (Picea abies, Fagus sylvatica, Quercus robur, Quercus petraea, Abies alba, and Pinus cembra) in Romanian forests based on 10 years of dendrometer data with hour-resolution. These measurements were conducted in 7 eLTER plots in Romania. The cumulative radial increments were modeled using the Gompertz function, which allowed for the estimation of the period with the highest growth rate through the function's first derivative. Growth parameters were derived from the Gompertz model, i.e., the maximum radial increment (A parameter of the function) and the growth vigor (k parameter of the function). Climatic factors most contributing to tree growth were identified using Random Forest Analysis, which highlighted the variable importance using changes in Mean Square Error. The onset and cessation of the growing season were defined by determining thresholds of 5% and 95% of the maximum growth rate. Periods with increased Tree Water Deficit were determined using the zero-growth concept. Preliminary findings indicate that Quercus robur initiates radial growth earlier than other species, while Fagus sylvatica has the latest onset of growth. Furthermore, Fagus sylvatica reaches the peak of daily growth rate later in the growing season compared to other species. In terms of maximum radial growth, Picea abies exhibited the highest values among the studied species. The results also revealed that spring precipitation strongly influences the growth of Quercus species, whereas Fagus sylvatica growth is constrained by spring-summer temperatures. Preliminary results significantly enhance our understanding of the intra-annual growth dynamics of Romanian main tree species
Integrating Phenological Data from observational networks, Citizen Science, and a Land Surface Model in Central European Forests
No full textPhenology plays an important role in mediating ecosystem responses to global change, linking plant physiology and ecosystem processes. However there is not one single data source that has both the temporal and spatial coverage needed to fully capture phenology at regional and global scales. This influences the accuracy of our future predictions of phenology and implicitly the carbon cycle, as the performance of the model relies on the type and quality of data used for validation. Given that accurate representation of phenological processes in land surface models (LSMs) is crucial for predicting ecosystem responses to environmental changes, integrating data across multiple scales and sources is essential for improving model accuracy and reliability. Focusing on central European forest sites, we combine the growing season simulated with the QUINCY LSM with phenological information from eddy covariance tower networks (Fluxnet, ICOS, European Eddy Fluxes Database Cluster), phenocam imagery from the Phenocam network, and remote sensing products.For the first time, we include citizen science observations collected through the Flora Incognita app, complemented with observations from the GBIF and iNaturalist platforms. We compare growing season metrics derived from these datasets to i) evaluate the advantages and limitations of each individual data source for data-model integration and ii) determine how data sources can be integrated to better represent phenological stages in temperate deciduous forests. This work underscores the importance of network efforts to provide datasets useful for bridging information gaps, and highlights how citizen science participation can meaningfully contribute to traditional datasets and foster a broader understanding of ecosystem dynamics in the face of global change
Exploring litter decomposition dynamics in Mediterranean pine forests
No full textForests’ global carbon stock is estimated at 662 Gt, with 45% of it being soil organic matter (FAO 2020). Mediterranean forests, while crucial for long-term carbon storage in their soils (with a reported 25% of CO2 assimilated through photosynthesis being stored in the ecosystems’ soils (Luyssaert et al. 2007), face growing threats from climate change-induced xerothermic conditions and ongoing anthropogenic disturbances. Even though climate change mitigation strategies in forestry have been developed, they mostly concern wood and biomass production, and less attention has been given to mitigation strategies regarding forests’ soil carbon stocks in Europe. PineOptim project attempts to investigate the impact of different management practices on water and carbon budgets in pine forests, across an established monitoring network of Pinus brutia and P. halepensis forests distributed across Sani, Xanthi and Lesvos Island in Greece. This study, as part of the PineOptim project aims to enhance current knowledge on decomposition dynamics in Mediterranean forests and the effects of abiotic factors involved under different management regimes, vegetation status and climatic regions. The study areas in Sani (P. halepensis with evergreen understory vegetation) and Xanthi (P. brutia with broadleaf tree understory) have been subjected to various management practices (understory removal in Sani and different overstory thinning intensities in the peri-urban forest of Xanthi), while on Lesvos the study area consists of unmanaged P. brutia stands varying in post-fire age and stand structure density. Decomposition dynamics have been studied by a parallel implementation protocol of the litterbag method and a standard materials method (paper sheets and wood sticks) (Kurz-Besson et al. 2005; Joly et al. 2017) for evaluating site-specific physicochemical litter characteristics drivers along with micro-environmental factors. Analysis was conducted using generalized linear and non-linear mixed effects models, to explore the importance of each factor involved in decomposition dynamics across and among the various study sites. Preliminary results suggest a significant influence of atmospheric and soil climatic parameters (air relative humidity, soil temperature and water content) and their interaction, along with Leaf Area Index (LAI) to decomposition rates and the remaining organic mass. Regional deviations are highlighted, giving us insight into the rates of organic matter assimilation under each management practice and climatic region. These findings underscore the potential of tailored forest management strategies to optimize litter decomposition and soil carbon stocks, in mediterranean pine forests. In addition, our results support the integration of decomposition dynamics into climate change mitigation strategies on the forestry sector
Developing a Robust SDM Pipeline for Predicting Climate-Driven Shifts in Freshwater Fish Distributions
No full textUnderstanding climate-induced shifts in freshwater biodiversity requires rigorous modeling approaches. This study applies a spatially explicit species distribution modeling (SDM) framework, incorporating high-resolution (1 km) environmental predictors and 3,307 field survey sites collected between 2016 and 2022 in South Korea. Using Maxent modeling, we assessed the potential distribution shifts of 130 freshwater fish species under three climate scenarios (SSP1-2.6, SSP3-7.0 and SSP5-8.5). To enhance model accuracy and applicability across regions, we implemented a robust preprocessing pipeline, including spatial filtering to correct sampling bias, multicollinearity reduction (Pearson correlation and variance inflation factor), pseudo-absence generation, and ensemble modeling to minimize uncertainty. Model performance was validated using AUC and TSS metrics, ensuring reliable predictions for conservation planning. Our results indicate that 48 species are at risk of significant range loss by 2080, with climate-driven contractions disproportionately affecting endemic and endangered species, in addition to cold-water taxa. Specifically, 17 endemic species and 6 nationally endangered species, including Coreoleuciscus splendidus and Cottus koreanus, were identified as highly vulnerable, highlighting the urgent need for conservation interventions. Regional projections pinpointed biodiversity loss hotspots, particularly in the Yeongsan and Nakdong River basins. This study demonstrates how a reproducible SDM pipeline, combining rigorous preprocessing and climate scenario analysis, can provide actionable insights for freshwater conservation planning. Our approach is adaptable to other regions, offering a transferable framework for assessing climate-driven biodiversity shifts in freshwater ecosystems
Assessing biogeochemical anomalies in 2024 at an eLTER Site in the Northern Adriatic Sea: the Senigallia-Susak transect and TeleSenigallia pylon
No full textThe year 2024 presented a series of environmental conditions that attracted the interest of the scientific community, particularly concerning alterations in the biogeochemical parameters of the Adriatic Sea. In particular, the northern Adriatic Sea experienced record-high surface temperatures, reaching 30°C near the coast of Ancona (Italy). This rise in temperature could be linked to multiple factors, including marine heatwaves and the increased occurrence of African anticyclones.The impacts of this warming are numerous, causing significant stress on the marine ecosystem, with certain fish species struggling to survive under such extreme conditions. Furthermore, a warmer sea leads to increased evaporation, raising atmospheric humidity and potentially triggering intense rainfall when cold air masses collide with the warm, humid air. In addition, in 2024, the phenomenon of mucilage was observed again along the western coast of the Adriatic Sea, something that had not been seen on such a large scale since the early 2000s.The European network of eLTER (Long-Term Ecosystem Research: https://elter-ri.eu/) stations provides long-term data that allow for the analysis of environmental variations and the identification of potential anomalies compared to historical averages.The long-term data series (1988–2024) of physical, chemical and biological parameters were analyzed to assess trends and variability in oceanographic conditions at the coastal station of the eLTER Senigallia transect and TeleSenigallia pylon, located in the northern Adriatic Sea within the Mediterranean Sea. This transect is an important monitoring site due to its distance from the Po Delta and its location within an area where the dense water mass, known as the North Adriatic Dense Water (NAdDW), forms during winter and crosses the region as a bottom current. This analysis aimed to highlight and enhance our understanding of anomalies in biogeochemical processes, including seasonal and interannual changes (i.e., temperature, salinity, nutrients, chlorophyll-a and phytoplankton abundance).In this study, data from the coastal station (SG1) and the TeleSenigallia pylon were analyzed to assess whether 2024 exhibited significantly different biogeochemical characteristics compared to previous years (1988–2023) through the analysis of key parameters such as physical parameters (temperature, salinity), chemical parameters (dissolved oxygen, nitrites, nitrates, ammonium, orthophosphates, and orthosilicates), and biological (chlorophyll-a derived from fluorescence sensor and phytoplankton abundance).For data processing, the database was divided into seasons. The temporal assessment of temperature (T) and salinity (S) shows a strong difference between the bottom layer and the surface layer in summer, when stratification is at its maximum. In winter, the two layers are more homogeneous, as expected. Along the western Adriatic coast, the impact of river plumes with freshwater is evident, varying depending on the season.The trend analysis of temperature and salinity data for the period 1988–2023 has shown a general increase in both temperature and salinity in the majority of the analyzed datasets. In particular, it has been observed that SG1 exhibits a significant increase in temperature both at the surface and at the bottom in all seasons except for summer. The increases range from 0.22% yr⁻¹ (winter, surface) to 0.66% yr⁻¹ (winter, bottom). Salinity shows a significant decrease only in spring (0.06–0.09% yr⁻¹) and increases in other seasons within a range of 0.06% yr⁻¹ (autumn, bottom) to 0.11% yr⁻¹ (autumn, surface; winter, surface). Phytoplankton trend confirmed the increase of small sized taxa reflecting the tendency to oligotrophication.Correlation analyses between nutrients (NO₃ and Si(OH)₄) and salinity carried out in different seasons have highlighted the impact of river inputs along the coast. Station SG1 shows a significant correlation with salinity in winter (surface and bottom) and autumn (surface) for both analyzed nutrients. In spring, only nitrates show a significant correlation.The preliminary temporal analysis of temperature and salinity has clearly highlighted how, over 35 years, the investigated area has undergone a marked increase in both temperature and salinity.The effects of climate change during 1988–2023 seem to impact the increase in temperature in all seasons except summer. It should be noted that sampling carried out during the summer period was often missing in August (summer holiday), when sea warming is at its maximum. Salinity has shown a significantly increasing trend in the area, except for spring, where a significant decrease has been observed near the coast. These observations seem to indicate that coastal inputs have decreased over the years due to lower precipitation. On the other hand, spring has often been characterized by extreme rainfall events and river floods.The 2024 recorded temperatures were approximately 1°C above the historical average, with anomalous summer peaks (about 30°C recorded at the end of July). The anomalies observed in 2024 could be attributed to exceptional climatic factors, such as rising atmospheric temperatures, changes in water mass circulation patterns, and variations in the rainfall regime. The preliminary results suggest that 2024 was an anomalous year compared to historical conditions, with significant ecological implications for the Northern Adriatic ecosystem. It will be crucial to continue long-term monitoring to understand whether these variations represent a new trend or a temporary fluctuation