Central European Mountain Research Articles

Choosing the Optimal Global Digital Elevation Model for Stream Network Delineation: Beyond Vertical Accuracy

AbstractSatellite‐derived global digital elevation models (DEMs) are essential for providing the topographic information needed in a wide range of hydrological applications. However, their use is limited by spatial resolution and vertical bias due to sensor limitations in observing bare terrain. Significant efforts have been made to improve the resolution of global DEMs (e.g., TanDEM‐X) and create bare‐earth DEMs (e.g., FABDEM, MERIT, CEDTM). We evaluated the vertical accuracy of bare‐earth and global DEMs in Central European mountains and submontane regions, and assessed how DEM resolution, vegetation offset removal, land cover, and terrain slope affect stream network delineation. Using lidar‐derived DTM and national stream networks as references, we found that: (a) bare‐earth DEMs outperform global DEMs across all land cover types. RMSEs increased with increasing slope for all DEMs in non‐forest areas. In forests, however, the negative effect of the slope was outweighed by the vegetation offset even for bare‐earth DTMs; (b) the accuracy of derived stream networks was affected by terrain slope and land cover more than by the vertical accuracy of DEMs. Stream network delineation performed poorly in non‐forest areas and relatively well in forests. Increasing slope improved the streams delineation performance; (c) using DEMs with higher resolution (e.g., 12 m TanDEM‐X) improved stream network delineation, but increasing resolution also increased the need for effective vegetation bias removal. Our results indicate that vertical accuracy alone does not reflect how well DEMs perform in stream network delineation. This underscores the need to include stream network performance in DEM quality rankings.

Effects of climate and forest development on habitat specialization and biodiversity in Central European mountain forests

Mountain forests are biodiversity hotspots with competing hypotheses proposed to explain elevational trends in habitat specialization and species richness. The altitudinal-niche-breadth hypothesis suggests decreasing specialization with elevation, which could lead to decreasing species richness and weaker differences in species richness and beta diversity among habitat types with increasing elevation. Testing these predictions for bacteria, fungi, plants, arthropods, and vertebrates, we found decreasing habitat specialization (represented by forest developmental stages) with elevation in mountain forests of the Northern Alps – supporting the altitudinal-niche-breadth hypothesis. Species richness decreased with elevation only for arthropods, whereas changes in beta diversity varied among taxa. Along the forest developmental gradient, species richness mainly followed a U-shaped pattern which remained stable along elevation. This highlights the importance of early and late developmental stages for biodiversity and indicates that climate change may alter community composition not only through distributional shifts along elevation but also across forest developmental stages.

Climate tracking by mountain bumblebees across a century: Distribution retreats, small refugia and elevational shifts

Cold-adapted species endangered by global change are crucial cases for understanding range dynamics and its interface with conservation and environmental decision-making. However, the study of their distribution change is either neglected or conducted at coarse resolutions at continental level, thus having little indicator value for regional and local conservation strategies. In view of climate change, it can be expected that cold-adapted insects should reduce distribution ranges by mainly concentric retreats and moving uphill. To test these hypotheses, we targeted four threatened, high-altitude bumblebees differing in subgenera and elevation ranges, and covering the main central and south European mountains. We performed species distribution models including climate and habitat at a 1 km-resolution, and we estimated elevation uphill and the year of elevation change with broken-line regressions. Results indicate that climate change will likely cause severe future range contractions across large areas, more in the Apennines (80 %–85 % ca) than the Alps and Pyrenees (24–56 % ca), with mostly concentric retreats as future extents will nearly entirely be included in the present ones. Remarkably, since the ‘80 s elevation uplift has started by about 325–535 m, a period coinciding with the beginning of the main warming, and will continue. The size and distribution of climate refugia will challenge conservation: they will be small (2–60 % of current areas) and even vary regionally, but while in the Apennines and Pyrenees they will be nearly entirely within Protected Areas, only a third will be so for the Alps. Such impressive distribution and elevation changes demonstrate that cold-adapted bumblebees can track climate change, reasons for it to be found in the specialist niches mainly requiring narrow temperature ranges and glacier presence. Overall, the distribution changes of cold specialist bumblebees driven by climate change demonstrate that conservation and policy makers should act upon the time dynamics and regional responses because future range contraction, the little availability of new areas and the movement uphill emerge as consistent patterns.

Chloromonas rubrosalmonea sp. nov. (Chlorophyta) causes blooms of salmon-red snow due to high astaxanthin and low chlorophyll content

ABSTRACT Melting snowfields support microbial communities, including blooms of phototrophic psychrophiles. “Watermelon snow” and its flagship species Sanguina nivaloides are mostly found at exposed, alpine or polar sites. Here, we investigated an alga that is morphologically similar but likely less common, thriving in exposed or semi-exposed snowpacks at lower altitudes frequently close to the tree line, and causing characteristic, intensely salmon-red snow surface spots in Central European and Norwegian mountains. Our aim was to illustrate the taxonomic heterogeneity of red snow by performing a cellular and molecular characterization of this species. The phylogenetic analysis placed the alga into the genus Chloromonas, clade “group C”. Single-cell Sanger sequencing enabled us to link the cell morphotype to its genotype. In addition to light microscopy of the snow samples, applying 18S rRNA gene and ITS2 metabarcoding confirmed that this alga dominated the bloom communities. The cysts had multi-layered smooth cell walls, and had a broadly oval to fully spherical shape, in striking contrast to most other Chloromonas species found on snow surfaces. Another remarkable feature was a pronounced astaxanthin accumulation in relation to a low proportion of chlorophylls, occasionally accompanied by a significant reduction of thylakoid membranes. This likely caused the photosynthetic dormancy of mature cysts found in some samples. Based on these data, we describe the snow alga as Chloromonas rubrosalmonea, sp. nov.

Factors controlling Mn and Zn contents in leaves of silver and downy birch in acidified soils of Central Europe and Norway

In Central European mountain forests, foliar element concentrations (FECs) of manganese (Mn) in silver birch (Betula pendula Roth) are occasionally approximately 5000 mg kg−1 and can represent stress for these plants. Factors controlling the Mn FECs in silver birch in Central Europe and downy birch (Betula pubescens Ehrh.) in Norway have not yet been fully deciphered. In this study, the Central European silver birch specimens were sampled in 2022. The samples were analysed by X-ray fluorescence spectroscopy. Norwegian data were obtained from the literature. Mn FECs are commonly negatively correlated with magnesium and, in certain areas, with potassium. Mn FECs are simultaneously elevated with zinc (Zn), likely because of soil acidification and anthropogenic emissions. Mn FECs in birch were previously thought to be related to altitude, which was assigned to (i) downslope washes of Mn or (ii) the historical load of acid emissions. The highest Mn FECs in silver birch were found in the Harz Mountains, Germany, and have been attributed to historical atmospheric contamination and the abundance of soils on felsic silicic rocks poorly buffering acid rains. The historical emission load from iron and steel production was hypothesised to be the cause of elevated Mn and Zn FECs in the Beskid Mountains, Czech Republic. Mn FECs in birch can be used to map historical soil acidification caused by industrial emissions. Zn FECs in birches can reflect soil contamination by this element.

Cut stumps vs broken stumps: Does it make any difference in the maintenance of plant and lichen biodiversity in Central European mountain forests?

Excessive forest exploitation significantly contributes to land degradation and the creation of human-made deadwood. Stumps are sometimes ignored in studies on the biodiversity of coarse woody debris. We investigated whether the type of stump, i.e. broken stumps (naturally created) and cut stumps (formed during forestry operations) had an impact on the species composition and species diversity as well as due to this fact they can be characterized by plant indicators. The research covered 728 spruce stumps (287 broken and 441 cut stumps) that were inhabited by lichens, liverworts, mosses and vascular plants in mountain forest belt (Karkonosze Mts., Poland). The following types of microhabitats were included in the research: the upper surface and the lateral surface of a stump with both bark and wood. There are statistically significant compositional differences between the two types of stumps, which was demonstrated by ordination analyses and indicator species analysis. According to the generalized linear models, the probability of occurrence increases in cut stumps in case of liverworts and vascular plants and also along the decomposition stages. The generalized linear mixed-effects model showed that there was a higher species richness of liverworts, mosses and vascular plants on the cut stumps and less drier but the reverse situation was in lichens. The generalized additive models for their cover showed similar trends. Almost all of the taxonomic groups were affected by altitude both in terms of species composition and total cover on the stumps. We concluded that cut stumps are an important type of deadwood for biodiversity and provide a convenient habitat, especially for many lichens and bryophytes.

Effects of summer desiccation on desmid microflora of ombrogenous pools in central-European mountain peat bogs

Effects of summer desiccation on desmid microflora of ombrogenous pools in central-European mountain peat bogs

Dynamics and variability of microclimate in an unmanaged mountain forest after a bark beetle outbreak

Forest disturbances alter hydrological, energy, and microclimatic characteristics and their extents vary with the landscape characteristics of the terrain. We evaluated changes in evapotranspiration and latent heat rate in an unmanaged, central European mountain forest (Norway spruce) after a bark beetle-induced mortality of >75 % trees, and the spatial variability in microclimate during its natural regeneration. We observed that (1) the annual mean incident solar radiation to the treeless plots was 8.2 MJ m−2 day−1 (95 W m−2), being reduced by ∼45 % compared to its theoretical flux by high average cloudiness (70.6%) and short daily sunshine (4.3 hour day−1). The observed energy input to the forest floor beneath survived canopies (1.2 MJ m−2 day−1) was an order of magnitude lower than solar radiation to the canopy surface. (2) The mean annual evapotranspiration and the average annual latent heat rate decreased by 155 mm yr−1 and 385 MJ m−2 yr−1 (12 W m−2), respectively, after tree dieback. (3) The soil and air temperatures at individual plots correlated positively with the incident solar radiation and negatively with elevation. Mean soil and air temperatures exhibited similar lapse rates of 5.9–8.0 °C km−1 during the growing season (May-October). The energy input (positive relationship) and elevation (negative relationship) explained 74–83 % of the between-plot variability in mean soil and air temperatures and 51–77 % of their daily amplitudes during the growing season. (4) On sunny days, the observed soil and air temperatures were significantly lower (by ∼50 and 15 %, respectively) than ground surface temperature based on thermal satellite data (Landsat-8). The ground surface temperature explained 80–92 % of the observed variability in the soil and air temperatures. (5) The between-plot differences in daily soil and air temperatures and their amplitudes were from 24 to 70 % explained by solar radiation (positive correlation) and relative air humidity and wind speed (negative correlations).

Climate change accelerates ecosystem restoration in the mountain forests of Central Europe

Abstract Restoring degraded forest ecosystems is an important element in the ongoing challenge to sustain the integrity and functioning of the biosphere. However, the evaluation of restoration success is hampered by long lead times of management measures in forests. Moreover, forest change is accelerating also in the absence of management because of ongoing climate change. Yet, because a counterfactual is frequently missing, it remains unclear whether restoration measures are aided or impeded by climate change. Here, we analysed the pace and success of forest restoration under climate change, combining field data and simulation modelling. We focused on the management zone of Berchtesgaden National Park (BGNP), Germany, where restoration aims to restore homogeneous Norway spruce (Picea abies) forests to structurally diverse mixed mountain forests. We evaluated three alternative restoration strategies: Two active strategies focused on planting the currently underrepresented silver fir (Abies alba) and European beech (Fagus sylvatica) but differing in the creation of gap‐cuts, and a third passive restoration strategy without interventions. Strategies were simulated with the forest landscape model iLand from 2020 to 2100 under different climate scenarios (historic, RCP 2.6, 4.5, and 8.5). The forests of BGNP developed into structurally diverse and mixed forests under all evaluated management strategies, and differences between active and passive restoration were generally small. While restoration goals for forest structure were largely met by 2100, forest composition remained far from target in all strategies. Climate change aided restoration by significantly increasing the prevalence of silver fir and European beech (+104.2% to +258.6%). Field data on short‐term restoration effects were in line with simulated long‐term trajectories. Synthesis and applications: We here show that forest restoration efforts in Central European mountain forests will likely be accelerated by climate change. Nonetheless, the slow pace of restoration underscores the need for taking action. Our study highlights that active restoration measures such as tree planting can bring the system closer to restoration targets. However, it also demonstrates that passive restoration (no intervention) is a viable option for management, highlighting the need to evaluate restoration measures against the counterfactual of a no intervention strategy.

Wolf genetic diversity compared across Europe using the yardstick method

Integrating data across studies with traditional microsatellite genetic markers requires careful calibration and represents an obstacle for investigation of wide-ranging species where populations require transboundary management. We used the “yardstick” method to compare results published across Europe since 2002 and new wolf (Canis lupus) genetic profiles from the Carpathian Mountains in Central Europe and the Dinaric Mountains in Southeastern Europe, with the latter as our reference population. We compared each population with Dinaric wolves, considering only shared markers (range 4–17). For each population, we calculated standard genetic diversity indices plus calibrated heterozygosity (Hec) and allelic richness (Ac). Hec and Ac in Dinaric (0.704 and 9.394) and Carpathian wolves (0.695 and 7.023) were comparable to those observed in other large and mid-sized European populations, but smaller than those of northeastern Europe. Major discrepancies in marker choices among some studies made comparisons more difficult. However, the yardstick method, including the new measures of Hec and Ac, provided a direct comparison of genetic diversity values among wolf populations and an intuitive interpretation of the results. The yardstick method thus permitted the integration of diverse sources of publicly available microsatellite data for spatiotemporal genetic monitoring of evolutionary potential.

Effects of understory characteristics on browsing patterns of roe deer in central European mountain forests.

Selective browsing by deer on young trees may impede the management goal of increasing forest resilience against climate change and other disturbances. Deer population density is often considered the main driver of browsing impacts on young trees, however, a range of other variables such as food availability also affect this relationship. In this study, we use browsing survey data from 135 research plots to explore patterns of roe deer (Capreolus capreolus) browsing pressure on woody plants in mountainous forests in central Europe. We fitted species-specific generalised linear mixed models for eight woody taxa, assessing the potential effects of understory characteristics, roe deer abundance and lying deadwood on browsing intensity. Our study reveals conspecific and associational effects for woody taxa that are intermediately browsed by roe deer. Selective browsing pressure was mediated by preferences of plants, in that, browsing of strongly preferred woody taxa as for example mountain ash (Sorbus aucuparia) and of least preferred woody taxa, for example Norway spruce (Picea abies) was not affected by the surrounding understory vegetation, while browsing pressure on intermediately browsed species like for example silver fir (Abies alba) was affected by understory characteristics. Contrary to our expectations, roe deer abundance was only positively associated with browsing pressure on silver fir and bilberry (Vaccinium myrtillus), while all other plants were unaffected by deer abundance. Finally, we did not find an influence of lying deadwood volume on the browsing pressure on any woody-plant species. Overall, our results indicate that patterns in browsing preference and intensity are species-specific processes and are partly affected by the surrounding understory vegetation. Current management strategies that aim to reduce browsing pressure through culling may be inefficient as they do not address other drivers of browsing pressure. However, managers also need to consider the characteristics of the local understory vegetation in addition to deer abundance and design species-specific plans to reduce browsing on woody plant taxa.

Effects of root plates, pits and mounds following windthrow events on the biodiversity of plants and lichens in Central European mountain forests

Windthrows lead to the formation of a characteristic land microtopography and they provide new habitats and substrata for species. The present study is novel, because it concerns different taxonomic groups of organisms and effects of various variables on species composition, richness and abundance within root plate-pit-mound (RPM) complexes. For the first time we studied lichens, liverworts, mosses and vascular plants on RPM complexes across major vegetation types, from deciduous to coniferous forests. We analyzed 164 RPM complexes which included in total 268 components: 115 root plates, 80 pits and 73 mounds. Besides the vegetation types and component types the following variables were also considered: dimensions (area, size), age (decomposition degree), species of the uprooted tree, shade, and elevation. The research revealed that root plates, pits and mounds had their own indicator species, but the key factors for the species composition were the species of uprooted trees and the vegetation type. Furthermore, the type of component and the vegetation type were also the most main variables determining the richness and abundance of the studied taxonomic groups of species. Analyses revealed the greatest species richness and abundance of lichens on root plates, and the highest richness of liverworts and vascular plants in pits. The type of component had no effect on the species richness of mosses. However, they were most abundant on mounds. The response of individual groups to the vegetation types and other variables varied. Findings from the study indicated that the presence of uprooted trees with different features (size and age, species of uprooted tree) is important for the biodiversity of mountain forests. We recommend leaving uprooted trees in forest communities for natural colonization, preferably large objects. Moreover, in managed forests a mosaic of forest communities that mimic the structure of natural unmanaged forests should be supported.

The Prados del Cervunal morainic complex: Evidence of a MIS 2 glaciation in the Iberian Central System synchronous to the global LGM

The area of Prados del Cervunal (PC) is an intra-morainic topographic depression located at 1800 m asl in the divide or interfluve between Garganta de Gredos and Garganta del Pinar valleys (Central Gredos; Iberian Central System, ICS). Both valleys, along with the adjacent Hoya Nevada, were occupied by glaciers during the Upper Pleistocene, leading to the development of the Prados del Cervunal moraine complexes studied in this work. Using cartographic methods and morphostratigraphic analysis, the three main glacial formations established in the Regional Chrono-Evolutionary Pattern for the ICS, Peripheral Deposits (PD), Principal Moraine (PM) and Internal Deposits (ID), have been identified and mapped in this area. The chronology of these formations has been implemented by Cosmic Ray Exposure (CRE) techniques using 10Be (new data) and 26Cl (previous data, recalculated in this work) in samples from morainic boulders. With these data, the following chrono-evolutionary sequence has been established: (stage 1) local-Maximum Ice Extent (MIE), dated in 25.0 ± 1.4 ka and corresponding to the maximum age obtained in these paleoglaciers; (stage 2) period of oscillations around the MIE, corresponding to the development of the PD Formation between ∼25 ka and ∼21 ka; (stage 3) period of readvance and stabilisation, dated after ∼21 ka (average age obtained for the PD moraines attached to PM moraines) and previous to ∼18 (minimum age obtained for a main crest of the PM formation); and (stage 4) onset of deglaciation dated around to ∼18 ka (average of ages obtained for the first main crest of the ID formation). During the stages of maximum ice expansion, these three glaciers formed an Ice field whose tongues were interconnected on the PC flat by an ice transfluence system (stages 1 and 2, Plateau Glacier Period). In later stages, the ice masses were partitioned, giving rise to valley glaciers and large moraines forming morainic complexes like those of PC (stages 2, 3 and 4, Valley Glaciers Period). The local MIE and onset of deglaciation stages in this area show a good fit with the ages stablished to global level for the global Last Glacial Maximum (LGM) and the onset of the Last Glacial Termination (Termination I). They also show good correlation at local (with other areas of the ICS), peninsular (with other Iberian mountains) and continental (some areas of the Alps and mountains of Central Europe) level. Finally, this evolutionary sequence and its correlations allowed us to adjust and validate some units of the Regional Chrono-Evolutionary Pattern model and propose the Gredos-Pinar-Cabeza Nevada glacial system as benchmark for the glaciation of Marine Isotope Stage (MIS) 2 in the Iberian Peninsula.

The impact of natural and anthropogenic factors on the landforms and landscapes of mountains and their forelands

This paper is an introduction to a collection of nine studies that are intended to fill the gap in the literature associated with landform development and landscape changes related to natural forces and human activities in the Central European Mountains and their close forelands. The papers are grouped into four general categories that describe the influence of climate on glacial landforms and snow avalanches, the evolution of slopes in high mountains, the development of mid-mountain relief, and changes in fluvial systems in mountains and their forelands. This paper summarises the contributions of these studies to this special issue and attempts to outline possible avenues of future research on landforms and landscapes in mountainous areas.

A Study of Oribatid Mites as Potential Intermediate Hosts of Anoplocephalid Tapeworms of Tatra chamois and Tatra marmots from the Tatra Mountains, Central Europe, and Report of a New Intermediate Host for Andrya cuniculi, the Parasite of Leporidae.

Tatra chamois (Rupicapra rupicapra tatrica (Blahout 1972)) and Tatra marmot (Marmota marmota latirostris (Kratochvíl 1961)) are significant endemic subspecies of the subalpine and alpine ranges of the Tatra Mountains in Central Europe. In four studied localities in the range of their typical biotopes in Slovakia and Poland, we investigated intestinal parasites of Tatra chamois and Tatra marmots, with an emphasis on anoplocephalid tapeworms. We also studied the occurrence, species diversity, and abundance of oribatid mites as intermediate hosts thereof, and the prevalence of cysticercoid larval stages of anoplocephalid tapeworms in collected oribatids using morphological and molecular methods. Coprological analyses revealed the average positivity of Moniezia spp. in chamois faeces at 23.5% and Ctenotaenia marmotae in marmot samples at 71.1%, with significant differences between the localities under study. Morphological analyses determined the presence of cysticercoids in five oribatid species: Ceratozetes gracilis, Edwardzetes edwardsi, Scheloribates laevigatus, Trichoribates novus, and Tectocepheus velatus sarekensis. This is the first record of T. v. sarekensis as an intermediate host of anoplocephalid tapeworms, as well as the first report of Andrya cuniculi occurrence in the territory of the Tatra Mountains, confirmed also by molecular methods.

Changes in rain-on-snow events in mountain catchments in the rain–snow transition zone

ABSTRACT A shift from snowfall to rain affecting snow storage is expected in future. Consequently, changes in rain-on-snow (ROS) events may occur. We evaluated the frequency and trends in ROS events and their runoff responses at different elevations related to changes in climate variables. We selected 40 central European mountain catchments located in the rain–snow transition zone, and used a conceptual catchment model to simulate runoff components for the period 1965–2019. The results showed large temporal and spatial differences in ROS events and their respective runoff responses across individual study catchments and elevations, with primarily an ROS increase at highest elevations and a decrease at lower elevations during spring. ROS events contributed 3–32% to the total seasonal direct runoff. The detected trends reflect changes in climate and snow variables, with an increase in air temperature resulting in the decrease in snowfall fraction and shorter snow cover period.

Ambient ozone – New threat to birds in mountain ecosystems?

Mountain ecosystems are inhabited by species with specific characteristics enabling survival at high altitudes, which make them at risk from various pressures. In order to study these pressures, birds represent excellent model organisms due to their high diversity and position at the top of food chains. The pressures upon mountain bird populations include climate change, human disturbance, land abandonment, and air pollution, whose impacts are little understood. Ambient ozone (O3) is one of the most important air pollutants occurring in elevated concentrations in mountain conditions. Although laboratory experiments and indirect course-scale evidence suggest its negative effects on birds, population-level impacts remain unknown. To fill this knowledge gap, we analysed a unique 25-years long time series of annual monitoring of bird populations conducted at fixed sites under constant effort in a Central European mountain range, the Giant Mountains, Czechia. We related annual population growth rates of 51 bird species to O3 concentrations measured during the breeding season and hypothesized (i) an overall negative relationship across all species, and (ii) more negative O3 effects at higher altitudes due to increasing O3 concentration along altitudinal gradient. After controlling for the influence of weather conditions on bird population growth rates, we found an indication of the overall negative effect of O3 concentration, but it was insignificant. However, the effect became stronger and significant when we performed a separate analysis of upland species occupying the alpine zone above treeline. In these species, populations growth rates were lower after the years experiencing higher O3 concentration indicating an adverse impact of O3 on bird breeding. This impact corresponds well to O3 behaviour and mountain bird ecology. Our study thus represents the first step towards mechanistic understanding of O3 impacts on animal populations in nature linking the experimental results with indirect indications at the country-level.

Substantial warming of Central European mountain rivers under climate change

Water bodies around the world are currently warming with unprecedented rates since observations started, but warming occurs highly variable among ecoregions. So far, mountain rivers were expected to experience attenuated warming due to cold water input from snow or ice. However, air temperatures in mountain areas are increasing faster than the global average, and therefore warming effects are expected for cold riverine ecosystems. In decomposing multi-decadal water temperature data of two Central European mountain rivers with different discharge and water source regime, this work identified so far unreported (a) long-term warming trends (with river-size dependent rates between +0.24 and +0.44 °C decade−1); but also (b) seasonal shifts with both rivers warming not only during summer, but also in winter months (i.e., up to +0.52 °C decade−1 in November); (c) significantly increasing minimum and maximum temperatures (e.g., temperatures in a larger river no longer reach freezing point since 1996 and maximum temperatures increased at rates between +0.4 and +0.7 °C decade−1); and (d) an expanding of warm-water periods during recent decades in these ecosystems. Our results show a substantial warming effect of mountain rivers with significant month-specific warming rates not only during summer but also in winter, suggesting that mountain river phenology continues to change with ongoing atmospheric warming. Furthermore, this work demonstrates that apart from a general warming, also seasonal shifts, changes in extreme temperatures, and expanding warm periods will play a role for ecological components of mountain rivers and should be considered in climate change assessments and mitigation management.

Anthropogenic impact on erosion, pedogenesis and fluvial processes in the central European landscapes of the eastern Harz mountains forelands (Germany)

The Holocene development of soils and sediments at three sites in the eastern Harz foreland was investigated using field and laboratory methods and integrated into the regional Holocene record of this central European landscape.Apart from early Holocene processes, the history of mid-to late Holocene slope erosion was found to be closely linked to the local land-use history. By c. 1000 BP, soil erosion is a process that is detectable throughout the study area.The studied Chernozemic soils that now cover large areas of the studied landscape are of varying Holocene age. Linear radiocarbon age-depth relations of soil organic matter and indicative changes in soil mineral composition suggest that the Chernozem was formed by long-lasting anecic earthworm cast accumulation at the soil surface. Persistent periods of landscape openness maintained by local preindustrial agriculture explain the promotion of anecic earthworms in naturally forested landscapes of central Europe and act as temporally transgressive drivers of landscape change.An early to mid-Holocene phase of reduced fluvial activity was followed by the onset of Holocene flooding, which correlates with the onset of mining in the Harz Mountains around ca. 3000 BP (e.g. Helme). The onset of flooding of the small streams Zapfenbach and Liethe coincided with the documented medieval and modern mining phases in the eastern Harz. At all sites, present-day flooding frequencies are higher than during the early to mid-Holocene. Shifts in river system behaviour attributable to anthropogenic activities in the Harz Mountains are therefore considered another Anthropocene marker.Based on our observations, we propose that land-use-induced alteration of central European low Mountain rivers and the formation of Holocene Chernozems in subhumid central Europe, in addition to anthropogenic-induced Holocene soil erosion, are included in the cadastre of early Anthropocene processes. These processes have left distinct traces in the continental geologic record. Thus, they would support arguments for long-term time transgressive anthropogenic transformation of Earth surface systems. However, the tipping points for these processes are dated differently (soil erosion - ca. 1000 BP, river activity - ca. 3000 BP, Chernozem formation - diachronous since the Neolithic) and are closely linked to local and regional land use history. Thus, our results are another example that the definition of “golden spikes” remains a critical undertaking, especially for the beginning of the Anthropocene.

Comparison of vertical and horizontal atmospheric deposition of nitrate at Central European mountain-top sites during three consecutive winters

Nitrogen (N) deposition, a key process of atmospheric self-cleaning, represents an important pathway for nutrients and pollutants to ecosystems. Enhanced N deposition flux contributes to acidification, eutrophication and loss of biodiversity. N-NO3− concentrations in rime and snow were measured at 10 Czech plots situated in borderline mountains in 2009–2011 winters. The results were put in context with data-driven geostatistical modelling results of annual wet vertical and horizontal deposition. Our hypotheses were that: (i) rime and snow would be more polluted in the highly industrialized north than in the south, (ii) the N-NO3− concentrations would differ in the three winters studied, and (iii), that N-NO3− rime deposition is not negligible in Central European mountain ranges. Our results indicated that winter N-NO3− concentrations were significantly higher in rime than in snow and that there were much larger between-site differences in N-NO3− concentrations for rime than for snow. Relatively large differences were found between individual years. Atmospheric input of N-NO3− in winter was dominated by vertical deposition, i.e., snow. Modelled results showed that mean winter rime deposition corresponded to about 6–25 %, and mean winter snow deposition made up 25–72.5 % of mean annual N-NO3− wet-only deposition. Model N-NO3−occult deposition estimated from throughfall and total (wet and dry) deposition is highly uncertain, however: N throughfall is not a relevant proxy for estimation of realistic total N deposition due to N exchange between the tree canopy and atmosphere.