Central Germany Research Articles

Monitoring of thermal conditions and snow dynamics at periglacial block accumulations in a low mountain range in central Germany

AbstractThe Rhoen Mountains, a relict periglacial landscape in central Germany, feature a wide range of openwork block accumulations. Although located in a temperate climate, those have characteristics comparable with cold regions of higher altitude or latitude such as arctic‐alpine species, longer lasting snow patches or the discussed existence of summer or even year‐round ice lenses in one of the largest of these landforms in the Central German Uplands. This study aims for a characterization of the microclimatic conditions of two neighbouring block accumulations. Therefore, temperatures were registered by data loggers along profiles, and snow dynamics were monitored using time‐lapse cameras and terrestrial laser scans. These observations are finally compared with geophysical measurements to address the question of potential isolated low‐altitude permafrost occurrences. Mean ground surface temperatures show an inverse thermal gradient along the Schafstein block accumulation. Furrows were identified as the cold spots in winter, whereas snow melt holes are signs of a chimney effect. In summer, cold air flows out at ventilation holes along the front causing temperatures of up to 25°C below air temperatures, although no clear signs of permafrost were detected. Temperature correlations reveal periods indicative of a recurring internal summer air circulation. Coarse blocky substrate also favours ground cooling of the smaller Mathesberg block accumulation compared with its surroundings. Winter temperatures are influenced by a persistent snowbank forming due to drifting and blowing snow at the leeward edge of a plateau as little amounts of snow are sufficient to be redistributed by westerlies. The prolonged melt of the snowbank might have had or still has a local hydrological and geomorphological impact. Uncertainties remain regarding the behaviour of the microclimate of block accumulations in a warming climate. Being ‘cold spots’ of high ecological value further investigations are suggested.

Accuracy assessment of LAI, PAI and FCOVER from Sentinel-2 and GEDI for monitoring forests and their disturbance in Central Germany

ABSTRACT Forest monitoring benefits from biophysical parameters such as Leaf Area Index (LAI), Plant Area Index (PAI) and fractional vegetation cover (FCOVER) and can be obtained from optical and LiDAR remote sensing, such as Sentinel-2 (S2) and the Global Ecosystem Dynamics Investigation (GEDI). While GEDI-derived products consider all phyto-elements, those from S2 refer to green elements only. Apart from individual accuracies, systemic deviations among products are thus expectable. However, products from S2 and GEDI lack inter-comparison. We evaluated S2 and GEDI-derived LAI, PAI and FCOVER with digital hemispherical photography observations (DHP) in a forest disturbance hotspot in Germany across various forest conditions, including vital stands, standing deadwood and clearings. We found moderate to high agreement with in-situ data, with highest accuracy for S2-derived LAI (R2 = 0.54) and GEDI-derived FCOVER (R2 = 0.73). Agreements between S2 and GEDI products were low, which we attribute to systematic influences of woody components, GEDI’s limitations in sloped terrain, and saturation of optical signals in dense canopy. In conclusion, findings suggest that while GEDI is effective in dense canopies, S2 products are beneficial for monitoring forest recovery. We also see potential for synergistic use in monitoring standing deadwood for habitat mapping and fire risk assessment.

Data-Supported Prediction of Surface Settlement Behavior on Opencast Mine Dumps Using Satellite-Based Radar Interferometry Observations

To ensure the safe repurposing of post-mining landscapes, understanding and managing geotechnical risks, particularly ground movements such as settlements on opencast mining dump surfaces, is critical. Satellite-based radar interferometry (InSAR) technology offers highly detailed data on vertical ground movements with a high spatial and temporal resolution. By combining a data-driven approach, using InSAR-generated high-resolution datasets, with model-driven methods such as inverse modeling and classic time–settlement models, the efficient monitoring and prediction of opencast mine dump settlements can be achieved. This dual approach—leveraging advanced data analysis tools and precise modeling—yields valuable insights into spatial settlement behavior. In particular, classic time–settlement models are applied to the InSAR data through least square regression and Taylor approximation. The integration of both approaches enables the more robust, data-validated forecasts of key geotechnical indicators, such as the time to settlement stabilization and the expected maximum settlement over large areas. An application at a mine in central Germany illustrates the method by generating spatial predictions of the settlement behavior over more than 200 ha. In general, the results provide a comprehensive dataset for investigating other factors influencing the settlement behavior of opencast mine dumps.

Local sub‐population dynamics of a central European grey partridge meta‐population support large‐scale conservation approach to halt its ongoing decline

Many farmland birds such as the grey partridge Perdix perdix are experiencing sharp declines across Europe, which can lead to fragmentation and increasing isolation of local populations. Understanding the population dynamics of these local populations is becoming increasingly important for effective conservation efforts. In this study, we used data from grey partridge transect counts with call playback from 2006 to 2023 to investigate the population dynamics of a grey partridge population in central Germany. We employed generalized linear mixed models to model the long‐term meta‐population trend and assessed synchrony between local sub‐populations by calculating the cross‐correlation and the Loreau and de Mazancourt community‐wide synchrony. Additionally, we assessed stability by comparing the extent of yearly fluctuations between sub‐populations and the regional meta‐population by analysing variances. Our analysis revealed that the studied meta‐population remained stable over the course of the study period, despite ongoing declines observed in other regions of Germany. Furthermore, we found that the population dynamics of the sub‐populations were largely asynchronous, and the extent of variance in the sub‐populations was significantly greater than in the meta‐population. The low synchrony between sub‐populations indicates a prevalence of local factors affecting population dynamics, but further research is needed to identify these factors. Our results suggest that asynchrony between sub‐populations may play a role in stabilizing meta‐populations at the landscape level. Based on our results, we argue that large‐scale conservation projects that are able to encompass these population dynamics may help ensure the long‐term persistence of the grey partridge.

Latent classes of learners in people with type 2 diabetes, stratified by educational status: A cross-sectional study

ObjectiveResearch suggests that people with type 2 diabetes (PWT2D) exhibit different approaches to learning about disease-management. This study’s aims to identify distinct learner groups among PWT2D and stratify them by educational status (ES). MethodsCross-sectional data from 227 PWT2D, collected through 46 Likert-scale questions on learning behaviors, preferences, and attitudes, were analyzed using latent class analysis, to identify learner groups. Participants were recruited via healthcare practices in central Germany and a countrywide online survey. Group membership was displayed according to low, medium, and high ES, defined by years of schooling. ResultsFour learner groups were identified: casual, versatile, insecure, and theorist learners. Insecure learners accounted for almost half of all respondents in the low ES group (46 %), casual learners were most prevalent among PWT2D with a medium (27 %), versatile (34 %) and theorist (29 %) learners among those with a high ES. ConclusionThis study sheds light on learner groups among PWT2D, which differ by ES, suggesting social disparities in diabetes care. Further research is needed to validate these findings. Practice ImplicationsUnderstanding individual learning preferences and motivations is crucial for developing effective diabetes self-management trainings, which may involve providing additional background material for theorists and practical applications for insecure learners.

Transforming the feeding regime towards low-input increases the environmental impact of organic milk production on a case study farm in central germany

Abstract Purpose Despite the direct effect of the feeding regime on the environmental impacts of dairy farming systems, its level of intensity, particularly in organic systems, has rarely been investigated. This study compares the environmental impact of a high-input feeding regime with a grassland-based, low-input feeding regime scenario within an organic milk production system conducted on Gladbacherhof, the research farm of Justus Liebig University Giessen, in Central Germany. Methods An integrated Life Cycle Assessment (LCA) analysis was performed from a cradle-to-farm gate perspective to quantify five environmental impacts, namely Global Warming (GW), Non-Renewable Energy Use (NREU), Land Use (LU), Terrestrial Acidification (TA), and Freshwater Eutrophication (FE). All agronomic data of the Gladbacherhof research farm, averaged over the years 2010–2017, were included. When not directly measured on the farm, ecoinvent data were included. Results and discussion Contrary to our hypothesis, the results suggest that a grassland-based low-input system has a higher environmental impact as compared to a high-input system for each of the five impact categories when using fat and protein-corrected milk (FPCM) as the functional unit. A 50% reduction in concentrates and exclusion of maize silage from the feed ration in the modelled low-input production system lead to a 20% drop in milk yield. To balance the energy content in low-input feeding ration, longer grazing period and higher amount of hay, alfalfa, and grass silage are required. This in turn results in higher emissions from enteric fermentation, manure management, and feed production and hence in higher environmental impact, particularly for GW, TA, and FE. Conclusions This study is one of the few that directly explores the environmental impact of feeding intensity in an organic milk production system. Nevertheless, there is a lack of research on consolidated emission factors for several greenhouse gas (GHG) sources in organic livestock and cropping systems to perform more robust carbon footprint calculations that comply with the Intergovernmental Panel on Climate Change (IPCC) Tier 3 GHG reporting guidelines. To generalize the results at the regional or national scale, direct comparisons with a larger number of organic farms representative of high-input and low-input intensities are still essential.

Temporal and spatial variations in the effect-based ecotoxicological assessment of streams

BackgroundWater bodies are affected by chemical contamination, including micropollutants, which is not fully captured by conventional chemical monitoring methods. The inclusion of integrative, effect-based in vivo and in vitro methods in standardized assessment procedures offers the possibility of bridging discrepancies between chemical and biological assessments and has already been proposed in several studies. However, there is a need to develop a comparable ecotoxicological assessment system for surface waters as for chemical and ecological status. This study aims to contribute to this discourse by investigating the temporal and spatial variation of ecotoxicological effects by assessing water grab samples of 15 different sites in central Germany over the course of 1 year using different in vitro assays.ResultsThe level of measured estrogenicity and anti-estrogenicity varied between the four measurement campaigns, while baseline toxicity, dioxin-like effects and mutagenicity showed relatively constant detectable effects over the study period. The impact of conventionally treated wastewater appeared to be one of the strongest influencing stressors, as direct comparisons of ecotoxicity upstream and downstream of wastewater treatment plant dischargers showed a significant increase for most of the conducted bioassays. Comparison of the measured estrogenicity with proposed threshold values showed effects within ecotoxicologically relevant ranges.ConclusionsBioassays record ecotoxicological effects on the basis of specific modes of action, allowing whole groups of substances to be identified as pollutants. Recording ecotoxicological status in this way is a useful complement to water assessment tools and can contribute to successful water management. Although most of the assays in this study were very consistent in detecting strong anthropogenic influences, possible temporal variations of individual assays should be taken into account when planning sampling strategies to improve the comparability of results.

Zircon U–Pb CA–ID–TIMS constraints on the chronology of the Late Carboniferous–early Permian continental Döhlen Basin and its correlation with the Thuringian Forest Basin (Central and Eastern Germany)

We present new zircon U–Pb chemical abrasion–isotope dilution–thermal ionization mass spectrometry (CA–ID–TIMS) ages of two Late Carboniferous–early Permian continental basins in Germany. Three volcanic rocks from the Döhlen Basin (Saxony), and two tuff samples of the Thuringian Forest Basin (Thuringia) were dated. Our data indicate that all four formations of the Döhlen Basin were deposited in the interval of approx. 300 Ma to 298 Ma. The tuff samples of the Thuringian Forest Basin provided ages that overlap with the Döhlen Basin data. The Niederhäslich Formation of the Döhlen Basin and the Manebach and Goldlauter formations of the Thuringian Forest Basin contain fossil-rich lacustrine horizons, which have been correlated to a variety of formations in other European basins through the use of insect, amphibian, or conchostracan assemblage zones. Our new data thus provide new absolute age constraints for different fossil assemblage zones. Furthermore, the data can be considered a strong indication for simultaneous large-scale volcanic activity between 300 and 298 Ma. A relation between volcanic and post-Variscan transtensional tectonic activity is proposed because both the Döhlen Basin and the Thuringian Forest Basin are bound to NW trending strike-slip faults.Graphical abstract

A case study of the regional bioeconomy in Central Germany: construction with renewable resources

In response to global challenges like climate change and resource depletion, national and international policies are increasingly emphasising sustainability. The bioeconomy represents a promising field to reconcile environmental integrity with economic development. The objective of this study is to examine the role of renewable resources in the construction industry within the framework of the bioeconomy, with a particular focus on Sustainable Development Goal 11: ‘Sustainable cities and communities’. The case study analyses the practical challenges and opportunities for innovation in Central Germany through a comprehensive regional analysis of construction practices using renewable resources. The methodology involved monitoring biomass flows by assessing harvest yields, area shares and biomass potentials. It also analysed the importance of the bio-based economy by examining employment data and identifying potential growth sectors. Stakeholder engagement was facilitated through knowledge transfer workshops to encourage collaboration and innovation. The results of the study highlight key trends within the industry, including the increasing prevalence of timber buildings, wood as a renewable carbon source in the chemical industry and the growing demand for wood-based packaging solutions. Policy initiatives are playing a supportive role in driving these developments, taking advantage of the region’s extensive wood resources (14.7 million m3 harvested in 2021) and the significant employment contribution of the forestry, wood and construction industries (2% of total employment, representing no less than 81,506 employees). These figures demonstrate the potential for sustainable construction practices to drive local economic growth and contribute to wider environmental objectives.

Visualizing Hospital Management Data in R Shiny-A Case Study.

There is a demand to make hospital management information beyond basic key performance indicators (KPIs) accessible for clinicians. We developed an interactive application (IAPP) in R Shiny to visualize such information. We provided the IAPP source code online. As a use case, we recorded basic KPIs (numbers of patients (NPs), reimbursed valuation ratios (RVRs), mean length of stay (LOS)), main diagnoses (MDGNs), main procedures (MPRCs), and catchment area (CA) by district from April 2022 to March 2024 at the index department in central Germany, where a neurotrauma and spinal surgery service was resumed on 1 April 2022. Case mix indexes (CMIs) were calculated. We retrieved information about online-reported patient satisfaction (ORPS) from an online physician rating platform between January 2022 and March 2024. Information on longitudes and latitudes of the index department and neighbouring hospitals was collected. We calculated car travelling isochrones (CTIs) of the hospitals as a proxy variable for accessibility. Chi-square and Fisher's exact served as statistical tests. During the observation period, the monthly NPs increased from 26 to 43, the RVR showed a 3.96-fold increase, the CMI showed a 2.41-fold increase, and the LOS reached a steady state in the 2nd year after service resumption. CA (p = 0.03), MDGNs, and MPRCs diversified. ORPS trended towards better overall evaluation after service resumption (p = 0.09). CTI mapping identified a unique market position of the index department. The IAPP makes extended hospital management data accessible to clinicians, can inform other stakeholders in healthcare, and can be tailored to local conditions.

The new bridge “Lahnsteg Nauheim”, Wetzlar: slender, elegant, parametrically designed

AbstractThis paper outlines the planning of a bridge in central Germany. Scheduled for construction in mid‐2024, this new bridge is a replacement for a century‐old pedestrian bridge crossing the Lahn river.The proposed bridge will be an airtight‐welded arch bridge, employing steel cross‐sections in both the arch and tension member. Designed as a single‐span, the arches extend 48.0m over the Lahn. The two arches have a flat rise of 4.65m, supporting the roadway through 9 inclined flat steel hangers.This paper delves into the structural engineering aspects, exploring challenges inherent in the design process. An examination of the parametric design process, facilitated through 3‐D modeling in Rhino® and Grasshopper®, will be presented, along with insights into their interface with the finite element modeling software, RFEM®. This process enables an engineering approach to form‐finding and structure optimisation through iterative design checks for various elements and stages of the structural analysis.

A Possible Depiction of a Woolly Rhino from the Late Magdalenian Hunting Camp of Bad Kösen-Lengefeld in Central Germany

In Central Germany, rhino images were engraved on stone objects during the Magdalenian period, before the global extinction of the woolly rhino around 14,000 cal BP. Our recent excavations, at the Magdalenian open-air settlement site of Bad Kösen-Lengefeld, added to this record, yielding a limestone slab with a presumptive rhino portrait from an exactly stratified, thoroughly documented and well-dated cultural context. Here we present the unique limestone slab with an engraved animal image, unusual because of the head omitted, but — by contrast — aspects of the rear expressed in detail. During the excavation, the limestone slab was found related to a dwelling structure marked by postholes grouped around a central fireplace. Reindeer and horse were hunted close to, and killed at the site, and ice foxes were exploited for their furs. 14C-samples collected from all parts of the settlement attest for a short period of occupation(s) around 15,350 ± 50 cal BP making the rhino portrait one of the latest of its kind, eventually documenting the last sightings of woolly rhino in general, by humans. Moreover, its found context would make this animal portrait a fixture in Magdalenian style chronology.

High-resolution operational soil moisture monitoring for forests in central Germany

Abstract. The forests of central Germany (Saxony, Saxony-Anhalt, and Thuringia) are vital components of the local ecosystems, the economy, and recreation. However, in recent years, these forests have faced significant challenges due to prolonged climate-change-induced droughts, causing water shortages, tree stress, and pest outbreaks. One of the key components of the forests' vitality and productivity is the availability of soil moisture. Given the anticipated increase in the frequency and severity of drought events, there is a growing demand for accurate and real-time soil moisture information. This underscores the need for development of an appropriate monitoring tool to make forest management strategies more effective. The article introduces an operational high-resolution soil moisture monitoring framework for the forests in central Germany. The key components of this system include the advanced LWF-BROOK90 1D water balance model, a large database of the National Federal Forest Inventory, high-resolution forest soil maps, real-time climate data from the German Meteorological Service, and a web information platform for the presentation of daily updated results. This system informs the public and empowers forest managers and other decision-makers to take targeted, local measures for sustainable forest management, aiding in both drought mitigation and long-term forest health in the face of climate change. The validation of the system using soil moisture measurements from 51 stations with various sensor depths (up to 100 cm) showed an overall good agreement (0.76 median Pearson correlation), which was found to be higher for deciduous rather than coniferous forests. Finally, the framework is discussed against the background of the main limitations of existing monitoring systems and how operational soil moisture measurements contribute to better interpretation of simulations.

Soil fertilization with microalgae biomass from municipal wastewater treatment causes no additional leaching of dissolved macronutrients and trace elements in a column experiment.

Microalgae are a promising bio-fertilizer that can be cultivated in municipal wastewater, where the organisms perform water purification by incorporation of nutrients and contaminants. Before bio-fertilization with wastewater-grown microalgae can be put into practice, its impact on the leaching of macronutrients and trace elements needs to be evaluated. Here, we studied the leaching behavior of a microalgae-fertilized soil against a control in column percolation setup. Microalgae were grown in real municipal wastewater supplemented with bromide for the analysis of within-cell Br- accumulation by time-of-flight secondary ion mass spectrometry. Dry biomass (45.0g N kg-1 and 28.9g P kg-1) was added to the topmost layer of the fertilized column at a level of 3g biomass kg-1 on a whole soil basis. Column irrigation was equivalent to 3 years of precipitation in central Germany. The leaching of macronutrients and trace elements from the fertilized and control columns was largely identical. Except for P, depth profiles confirmed very low vertical translocation within the soil. This is held for total element contents as well as for operationally defined pools, suggesting that microalgae cultivated in municipal wastewater provide a slow-release fertilizer largely resistant to leaching. Mass spectrometric imaging gave clear evidence for bromide uptake by the microalgae, and pure cultures of the genus Scenedesmus showed that it was preferentially located in the cell membrane. Therefore, bromide could potentially be employed as a mineralization tracer in future studies on the use of microalgae as a bio-fertilizer.

The Püsterich of Sondershausen: An Explosive Bronze Object between Art, Science and Questions of Human Nature in the 13th Century

Preserved in the Castle Museum at Sondershausen in central Germany is a bronze taking the form of a rotund, kneeling man. The object, nearly 22.5 inches tall and cast in a single piece, is known today as the ‘Püsterich’. Since its archaeological discovery in the 1540s, it has proven to be a subject of intellectual debate: numerous authors have sought to understand either its iconography or, on the basis of its hollow shape and the two openings in its head, its function. The resulting studies have been surprisingly varied in their claims. With a method of approach rooted in ‘object studies’, this article explores both of the aforementioned aspects as well as form-function relations. Starting with a basic art-historical analysis of the bronze—thus far lacking in the scholarship—the article recognizes the work as having been produced in Hildesheim between c. 1220 and 1250, a context in which it can be related closely to the philosophical concerns of the prominent theologian Albertus Magnus. In its function as a ‘sufflator’ (hearth-blower) and its depiction of a ‘pygmeus’, the ‘Püsterich’, along with seven other related figures, can be understood as a ‘Wissensobjekt’, an object or bearer of knowledge. With and through them, viewers/users negotiated complex problems about the nature of living beings; specifically, the bronze thematized the question of what distinguished human beings from animals: in Albertus’s thought, the mastering of science and art. This new understanding of the ‘Püsterich’ allows us to recognize its special position at the origins of ‘philosophical anthropology’ and the history of science.

Linking terrestrial biogeochemical processes and water ages to catchment water quality: A new Damköhler analysis based on coupled modeling of isotope tracers and nitrate dynamics

Catchment-scale nitrate dynamics involve complex coupling of hydrological transport and biogeochemical transformations, imposing challenges for source control of diffuse pollution. The Damköhler number (Da) offers a dimensionless dual-lens concept that integrates the timescales of exposure and processing, but quantifying both timescales in heterogeneous catchments remains methodologically challenging. Here, we propose a novel spatio-temporal framework for catchment-scale quantification of Da based on the ecohydrological modeling platform EcH2O-iso that coupled isotope-aided water age tracking and nitrate modeling. We examined Da variability of soil denitrification in the heterogeneous Selke catchment (456 km2, central Germany). Results showed that warm-season soil denitrification was of catchment-wide significance (Da >1), while its high spatial variations were co-determined by varying exposure times and removal efficiencies (e.g., channel-connected lowland areas are hotspots). Moreover, Da seasonally shifted from processing-dominance to transport-dominance during the wet-spring season (from >1 to <1), implying important linkages between summer terrestrial denitrification and subsequent winter river water quality. Under the prolonged 2018–2019 droughts, denitrification removal generally reduced, resulting in further accumulation in agricultural soils. Moreover, the space-time responses of Da variability indicated important implications for catchment water quality. The older water in lowland areas exhibited extra risks of groundwater contamination, whilst agricultural areas in the hydrologically responsive uplands became sensitive hotspots for export and river water pollution. Importantly, the lowland pixels intersecting river channels exhibited high removal efficiencies, as well as high resilience to the disturbances (wet-spring Da shifted to >1 under drought conditions). The proposed catchment-wide Da framework is implied by mechanistic modeling, which is transferable across various environmental conditions. This could shed light on understanding of catchment N processes, and thus providing site-specific implications of non-point source pollution controls.

Assessing the Volatility of Daily Maximum Temperature across Germany between 1990 and 2022

Climate change causes a global rise in mean air temperature and an increased frequency of temperature extremes. Recent studies link sharp temperature changes between consecutive days to increased mortality, reduced economic growth, and negative effects on ecosystems. This study assesses the variability of the daily maximum air temperature between two consecutive days (i.e., temperature volatility) across Germany from 1990 to 2022. Using observation-based raster data of maximum daily temperature at 0.1° × 0.1° spatial resolution, we assess temperature volatility regarding: (1) magnitude, (2) seasonality, (3) directionality (day-to-day warming vs. cooling), and (4) trends. Further, we analyse land cover changes during the period and examine their correlation to extreme temperature volatility (Tve). The results show that Tve mostly occurred during spring and summer. The magnitude of Tve increased with distance to the coast north-west to south during all seasons and was highest during spring and summer (&gt;10 °C). Overall, Tve was particularly associated with day-to-day cooling (in spring, summer, autumn), while in winter, &gt;60% of days were associated with warming in north and central Germany. Less than 12% of Germany showed significant trends in median Tve associated with warming over the period. Significant trends included increases (&gt;0.26 °C/year) and decreases (−0.09 °C/year) in extreme day-to-day warming during autumn and winter in northeastern Germany. In spring, the majority (&gt;60%) of southern areas showed significant positive trends (up to 0.16 °C/year) in Tve associated with day-to-day cooling. During winter, summer, and autumn, trends in extreme day-to-day cooling were insignificant in over 80% of Germany. Within all land cover types, Tve predominantly varied between 6 °C and 9 °C. Changes in land cover, especially transforming coniferous forests for agricultural purposes, were accompanied by increasing Tve up to 0.49 °C. Understanding rapid temperature changes is crucial for climate change mitigation strategies and limiting the impacts on human health and on the environment.

Further evidence of low infection frequencies of Wolbachia in soil arthropod communities

Endosymbiotic Alphaproteobacteria of the genus Wolbachia are exclusively transferred maternally from mother to offspring, but horizontal transfer across species boundaries seems to be frequent as well. However, the (ecological) mechanisms of how these bacteria are transferred between distantly related arthropod hosts remain unclear. Based on the observation that species that are part of the same ecological community often also share similar Wolbachia strains, host ecology has been hypothesized as an important factor enabling transmission and a key factor in explaining the global distribution of Wolbachia lineages.In this study, we focus on the diversity and abundance of Wolbachia strains in soil arthropods, a so far rather neglected community. We screened 82 arthropod morphotypes collected in the beech forest (dominated by Fagus sp.) soil in the area of Göttingen in central Germany for the presence of Wolbachia. By performing a PCR screen with Wolbachia-MLST markers (coxA, dnaA, fbpA, ftsZ, gatB, and hcpA), we found a rather low infection frequency of 12,2%. Additionally, we performed metagenomic screening of pooled individuals from the same sampling site and could not find evidence that this low infection frequency is an artefact due to PCR-primer bias. Phylogenetic analyses of the recovered Wolbachia strains grouped them in three known supergroups (A, B, and E), with the first report of Wolbachia in Protura (Hexapoda). Moreover, Wolbachia sequences from the pseudoscorpion Neobisium carcinoides cluster outside the currently known supergroup diversity. Our screening supports results from previous studies that the prevalence of Wolbachia infections seems to be lower in soil habitats than in above-ground terrestrial habitats. The reasons for this pattern are not completely understood but might stem from the low opportunity of physical contact and the prevalence of supergroups that are less suited for horizontal transfer.

From single trees to country-wide maps: Modeling mortality rates in Germany based on the Crown Condition Survey

Most years in the period from 2018 to 2022 have been exceptionally dry in Central Europe. In Germany’s forests, this long-lasting drought has caused unprecedented tree mortality. Systematic ground-based surveys, such as the annual Crown Condition Survey, provide information on the vitality status of the different tree species and their mortality rates. However, models are needed to be able to map the spatial patterns of mortality for each tree species based on cause-effect relationships derived from field observations. In this study, logistic regression models were used to identify the most important drivers of mortality for the most important tree species in Germany. For this purpose, the dead and surviving trees from the Crown Condition Survey were combined with a large set of potential predictor variables from the domains of climate, topography, soil, land cover and deposition. After feature selection, the models were evaluated using the area under the curve (AUC) statistic. Norway spruce (Picea abies; AUC = 0.9) showed by far the greatest increase in mortality, with the country-wide average observed and predicted rates approaching almost 10% per year from 2020 to 2022, and much higher predicted rates at the regional level. Much of the spruce mortality was explained by the climatic water balance of the driest summer in previous years. The other main tree species also showed clear mortality responses to the drought conditions. However, in the case of European beech (Fagus sylvatica; AUC = 0.94) and Pedunculate and Sessile oak (Quercus robur and petraea; AUC = 0.88), the peaks in the time series of the country-wide mortality rates stayed below 1%. For these broadleaved species, mortality was more dependent on a range of site conditions, i.e., soil and topography. For Scots pine (Pinus sylvestris; AUC = 0.76), for which the observed mortality rate peaked at 1.2% in 2020, the given drivers could explain mortality only to a lesser degree than for the other species. The regression models were used for spatial prediction to produce country-wide maps of species-specific mortality rates at annual temporal and 100-m spatial resolution, covering all years from 1998 to 2022. The maps visualize the spatial patterns of mortality over time. The regions in western and central Germany, which were most seriously affected by spruce dieback can clearly be identified. The models and maps presented can be used for risk assessment, forest planning, and tree species selection, providing decision support for forest practitioners.

Land use modulates resistance of grasslands against future climate and inter-annual climate variability in a large field experiment.

Climate and land-use change are key drivers of global change. Full-factorial field experiments in which both drivers are manipulated are essential to understand and predict their potentially interactive effects on the structure and functioning of grassland ecosystems. Here, we present 8 years of data on grassland dynamics from the Global Change Experimental Facility in Central Germany. On large experimental plots, temperature and seasonal patterns of precipitation are manipulated by superimposing regional climate model projections onto background climate variability. Climate manipulation is factorially crossed with agricultural land-use scenarios, including intensively used meadows and extensively used (i.e., low-intensity) meadows and pastures. Inter-annual variation of background climate during our study years was high, including three of the driest years on record for our region. The effects of this temporal variability far exceeded the effects of the experimentally imposed climate change on plant species diversity and productivity, especially in the intensively used grasslands sown with only a few grass cultivars. These changes in productivity and diversity in response to alterations in climate were due to immigrant species replacing the target forage cultivars. This shift from forage cultivars to immigrant species may impose additional economic costs in terms of a decreasing forage value and the need for more frequent management measures. In contrast, the extensively used grasslands showed weaker responses to both experimentally manipulated future climate and inter-annual climate variability, suggesting that these diverse grasslands are more resistant to climate change than intensively used, species-poor grasslands. We therefore conclude that a lower management intensity of agricultural grasslands, associated with a higher plant diversity, can stabilize primary productivity under climate change.