Austrian Alps Research Articles

Living on the edge—Genomic and ecological delineation of cryptic lineages in the high‐elevation specialist Erebia nivalis

Abstract Cold‐adapted species at high elevations may be especially impacted by global warming since they may be limited in their capacity to adapt to changing conditions or may be prevented from shifting their distributions upwards if no suitable habitats are available. The latter may be true for Erebia nivalis, a high‐elevation specialist that mainly occurs in the Austrian Alps and on few mountaintops in Switzerland, where its taxonomic and conservation status remains unclear. We aimed to clarify the relationships among geographically isolated populations of E. nivalis using whole‐genome resequencing data to reconstruct population connectivity and phylogenetic relationships. We inferred current and historical effective population sizes and combined these with tests for ecological differentiation based on available occurrence data to re‐evaluate the conservation status of E. nivalis. Our results confirm that Swiss and Austrian E. nivalis should be considered different evolutionarily significant units for conservation purposes, as they are marked by moderate genomic differentiation, distinct demographic histories and a difference in the abiotic conditions of their habitats. In both Austria and Switzerland, we found rapid uphill range shifts over the last decades, little population connectivity, low current effective population sizes and low genetic diversity. The above, combined with the low dispersal capacity of this 2‐year lifecycle species and its need to overwinter under snow, which is rapidly retreating from several regions of the Alps, leads us to suggest that the status of E. nivalis should be updated to ‘Vulnerable’ or ‘Endangered’ in the European, Swiss and Austrian Red Lists.

Enhancing flood event predictions: Multi-objective calibration using gauge and satellite data

Rainfall-runoff models are widely used for predicting watershed runoff. The accuracy of the predictions heavily relies on effective model calibration, which is majorly influenced by the employed objective functions that measure the agreement between predictions and real-world observations. In this study, we propose a novel multi-objective calibration approach with the aim of improving the flood event predictions of a conceptual rainfall-runoff model applied to a catchment in the Austrian Alps. To achieve this, we include a total of five carefully selected objective functions into calibration. Three of these objective functions can be regarded as more classical and are roughly based on comparing absolute deviations, square of the residuals, as well as bias, correlation and variability of the flow. Another objective function relies on remote observations of the snow covered area, for which the MODIS Terra (MOD10A1.061) and Aqua (MYD10A1.061) datasets are used. The final objective function measures the differences in peak magnitude and timing for the largest events in the observation period. To showcase the proposed approach’s effectiveness, we compare the calibration and validation results with those obtained by a model that was only calibrated for two runoff objective functions and to carefully selected benchmark cases. The presented study reveals that our approach enhances the model’s capacity to depict snow cover dynamics, a crucial factor in accurately predicting snow-driven flooding events. Additionally, the results underscore that incorporating an error metric targeting magnitude and timing errors of large flood events can enhance the model’s ability to predict peak runoff. The results of this study further suggest that in general a more robust model can be obtained by incorporating additional error metrics that specifically target physical states and individual parts of the runoff curve into model calibration.

Analytical computation of local gravitational effects of mountain glacier mass change from polyhedral and prismatic modeling - test case Vernagtferner, Austrian Alps

Gravimetric measurements allow monitoring mass transport in the Earth system and one example is temporal variations in the global water cycle including the cryosphere. Coupling gravity observations to the underlying processes requires modeling of the relevant mass elements. When observing the gravity field from space (i.e., by satellites), point mass models or simple spherical surface layers (mascons) are a reasonable choice. However, for terrestrial observations taken right on the surface of the relevant masses, precise modeling of the geometry of those mass elements and the related gravitational effects becomes crucial for the quality of the modeling and the correct interpretation of the results. In this study, two different modeling techniques are investigated, the right rectangular prism and the general polyhedron. Both approximations provide the possibility to analytically calculate the corresponding gravitational signal. Although modeling in terms of polyhedrons is numerically more complex and less efficient, the representation of the actual surface is superior as the inclined polyhedral surface fits much better to the actual topographic surface than the step function implied by rectangular prisms with horizontal top plane. The case study presented here is related to the gravimetric mass balance of a mountain glacier (Vernagtferner in the Ötz valley, Austria) where on the one hand high resolution digital terrain models (DTM of resolution 1 m × 1 m) are available, while on the other hand, the accuracy requirements are very high (on the level of 10−7 m/s2, i.e., 10 μGal). We evaluate first and second order derivatives of the gravitational potential induced by the melting of ice masses between epochs 2009 and 2016 at gravity sites on and off the actual glacier body. Furthermore, the relation of ground surface slope to the differences between the modeling approaches is investigated for a small part of the DTM, containing a variety of different slope regimes. Besides the original grid spacing, denser and coarser grids are also evaluated in order to examine the relation of the considered DTM resolution to the modeling differences. The modeling choice, the location of the computation points and the morphology of the mass distribution are the main factors that determine the quality of the results. The comparison of the two methods for the original 1 m resolution, provides differences up to 2.9 μGal for the vertical component of the attraction Vz, 9.1 μGal/m for the gradient Vzx, 4.6 μGal/m for Vzy and 17.1 μGal/m for Vzz. Coarser grid resolutions increase these values significantly, up to 500 μGal at specific locations, while grids denser than the 1 m resolution decrease them for about 48%.

Notes on the genus Dictyogenus Klaplek, 1904 (Plecoptera, Perlodidae) in the Austrian, Italian, Slovenian and Swiss Alps, with the description of six new species.

Six new species of Dictyogenus Klaplek, 1904, from the Austrian, Italian, Slovenian, and Swiss Alps, are described and illustrated from adults and nymphs. The species Dictyogenus alpinum (Pictet, 1841) and topotypical Dictyogenus fontium (Ris, 1896) are re-described.

Sex-specific analysis of hiking accidents in the Austrian Alps: a follow-up from 2015 to 2021.

Hiking is one of the most popular leisure sport activities practiced in the Alps during the summer season, but bears the risk of mountain emergencies, accidents, and fatalities. This paper provides an updated analysis of hiking accidents for the years 2015 to 2021 in the Austrian Alps, thereby outlining fatal and non-fatal accident characteristics. For this retrospective analysis, mountain hiking accidents documented by the Austrian Alpine Police during a 7-year period were screened for potential exclusion criteria. The final sample size consisted of 7368 accidents and 7552 victims. The outcome measures were mainly specified by sex, age, injury degree, injury location, pathophysiological characteristics, and cause of injury. The overall annual number of accidents showed a continuous increase from 428 in 2015 to 544 in 2021. In total, 7.1% of the total victims died during the 7-year period, with male hikers being significantly more affected than female hikers (m: 80.8%, f: 19.2%; p ≤ 0.001). The sex specific distribution for non-fatal hiking accidents was 55.9% in women and 44.1% in men. Male victims showed significantly more frequent cardiovascular events (m: 78.5%, f: 21.5%), multiple injuries (m: 60.2%, f: 39.8%), and wounds/blood loss (m: 57.4%, f: 42.6%) than female victims, whereas women showed more fractures (m: 31.5%, f: 68.5%) than men (p ≤ 0.001). Additionally, men were more likely to injure their abdomen/chest (3.7%), head (14.1%), and multiple body parts (26.5%), whereas women were more likely to injure their ankle or foot (42.3%). Finally, men were more likely to have an accident during the ascent (24.1%), whereas women during the descent (69.0%) (p ≤ 0.001). This paper provides the latest data and a deeper insight into sex-specific characteristics of mountain hiking accidents in the Austrian Alps.

Long-unburnt stands of snow gum (Eucalyptus pauciflora Sieber ex Spreng) are exceedingly rare in the Victorian Alps: implications for their conservation and management

The nature of Australia’s high mountains is changing. Recent, repeated landscape-scale fires have burnt much of the subalpine forests dominated by snow gum (Eucalyptus pauciflora). Long-unburnt snow gum forests are important for ecosystem services, have socio-cultural benefits, and conservation values, but they are now exceedingly rare, comprising <1% of snow gum forests in the Victorian Alps. We identify where long-unburnt snow gum stands persist in the Victorian Alps and outline why management intervention is necessary to protect unburnt refuges and, more broadly, to allow mature/adult stands (such as occur on the Baw Baw Plateau) to develop into future old forests.

Sex Differences in Mountain Bike Accidents in Austria from 2006 to 2018: A Retrospective Analysis.

Woyke, Simon, Anja Hütter, Christopher Rugg, Willi Tröger, Bernd Wallner, Mathias Ströhle, and Peter Paal. Sex differences in mountain bike accidents in Austria from 2006 to 2018: a retrospective analysis. High Alt Med Biol. 25:89-93, 2024. Introduction: Mountain biking is becoming increasingly popular, and mountain bike (MTB) accidents are on the rise. The aim of this study was to assess sex differences in mountain biking accidents in the Austrian Alps. Methods: This retrospective study includes all MTB accidents in Austria from 2006 to 2018. Data were collected by Alpine Police officers and recorded in a national digital registry. Results: The accidents involved 5,095 mountain bikers (81% men and 19% women). The number of MTB accidents rose markedly from 208 in 2006 to 725 in 2018. Men wore a helmet more often than did women (95% vs. 92%; p = 0.001). The most common injury category was "wound/bleeding" for both sexes (men 40% and women 41%). Women were more frequently transported by helicopter or terrestrially (p > 0.001). Conclusion: In the Austrian Alps, the number of MTB accidents more than tripled between 2006 and 2018. Women were involved in only one fifth of all accidents. Sex differences in MTB accidents include (1) women wearing helmets less often, (2) women being less frequently injured, (3) women suffering fewer serious injuries, and (4) women being more frequently transported by helicopter or terrestrially, while men more often did not require transportation.

Seasonal Relationships of Alpine Plants and Microbes through a Stoichiometric and Enzymatic Lens

Alpine biomes experience harsh environmental conditions and short growing seasons, which necessitate interspecific and intraspecific interactions to ensure the stability of diversity and ecosystem multifunctionality. The relationship between plants and microbes in this environment is equally dynamic, with seasonal pulses of nutrients and the phenology of plants creating specific "hot moments" of biogeochemical activity. As a crucial zone of interaction between plant roots and microbial communities, the rhizosphere serves as a "hot spot" of biogeochemical cycling where the mineralization of nutrients, such as carbon, nitrogen, and phosphorus, allows for the transfer of nutrients between trophic levels. However, the nature of these interactions depends on edaphic and climatic conditions, potentially leading to cooperation or competition to meet the stoichiometric demands of organisms. Elevation gradients within alpine ecosystems provide dramatic shifts in temperature, precipitation, and soil development that allow for the study of these interactions over short geographical distances. In conjunction with seasonal sampling, this approach can provide a wide environmental context to observe the relationship between specific plants and microbial communities. By investigating the C/N ratios of plants, microbes, and soil, as well as microbial enzymatic potential, we can infer nutrient limitations, temporal niche partitioning, and biological responses to abiotic conditions. Within the Austrian Alps, we studied a selection of herbaceous plants and their associated microbial communities across an elevation gradient spanning 2200-2800 m (Fig. 1). The primary aims of the study were to assess the seasonal changes in C/N stoichiometry from both trophic levels, microbial enzymatic potential, and rhizosphere diversity of bacterial and fungal communities. To fulfill these aims, four locations were selected based on the two present biomes (alpine meadow and sub-nival zone) and the transition between them. Four to five plant species were collected during each season in 2023, including the often-neglected snow-covered winter season, along with rhizosphere and bulk soil for microbial biomass measurements and soil chemistry. Plant leaf tissue samples were analyzed using Isotope-ratio mass spectrometry for plant C/N ratios, while soil and microbial C/N ratios were calculated using chloroform fumigation extraction. Microbial enzymatic potential was assessed using hydrolase enzymatic assays for five fluorophore-labeled substrates. 16S-rRNA and 18S-rRNA genes were sequenced using an Illumina MiSeq platform from the fine roots of collected plant individuals to quantify the relative abundances of bacterial and fungal taxa. The findings of our study indicate that the higher microbial biomass (Cmic) in alpine meadow locations leads to increased enzymatic activity compared to sub-nival zones. However, specific plant species were found to enhance microbial biomass and enzymatic potential in different seasons, suggesting that plants promote microbial interaction and biogeochemical cycling during different seasons as a form of temporal niche partitioning. Most plant species demonstrated an increase in C/N ratios throughout the season, sometimes increasing by more than 200%. However, two Poa spp. showed the highest C/N ratios during the summer, which further correlated with higher microbial C/N ratios. By observing changes in stoichiometric ratios of organisms that interact and share nutrients, we propose that these relationships vary between host plants depending on their temporal niche and abiotic factors (soil and environmental conditions). Furthermore, the positive or negative correlation of plant and microbial C/N ratios may indicate the relative cooperation or competition between trophic levels.

From the Mountain to the Valley - Drivers of Groundwater Prokaryotic Communities along an Alpine River Corridor

Rivers extend into the underlying groundwater which represents the unseen freshwater majority. Understanding microbial community composition and dynamics of shallow groundwater and lotic ecosystems is thus crucial, due to their potential impact on ecosystem processes and functioning. A 300 km section of the Mur river valley, from 2000 m.a.s.l. in the Austrian alps to the flats (200 m.a.s.l.) at the Slovenian border, was followed, analyzing river water from 14 stations and groundwater from 45 wells in early summer and late autumn. The active (RNA derived) and total prokaryotic communities were characterized using high-throughput gene amplicon sequencing. Key physico-chemical parameters and stress indicators were recorded. The groundwater microbiome is analyzed regarding its composition, change with land use, and difference to the river. Community composition and species turnover differed significantly. At high altitudes, dispersal limitation was the main driver of groundwater community assembly, whereas in the lowland, homogeneous selection explained the larger share. Land use was a key determinant of the groundwater microbiome composition. The alpine region was more diverse in prokaryotic taxa, with some early diverging archaeal lineages being highly abundant. This dataset shows a longitudinal change in prokaryotic communities that is dependent on regional differences affected by geomorphology and land use.

Carbon emissions from Australian Sphagnum peatlands increase with feral horse (Equus caballus) presence

Peatlands are globally significant carbon sinks, but when disturbed, have the potential to release carbon back to the atmosphere as greenhouse gases. Feral horse populations in the Australian Alps degrade Sphagnum peatlands, which are highly sensitive to disturbance. However, the link between this degradation and peatland carbon cycling is not understood. Here, we compared the autumn daytime carbon dioxide (CO2) and methane (CH4) fluxes of 12 alpine and subalpine Sphagnum peatlands in Kosciuszko National Park, Australia. The presence of feral horses at these sites was correlated with higher carbon loss: sites with horses were losing carbon to the atmosphere (4.83 and 8.18 g CO2-e m−2 d−1 in areas of Sphagnum moss and bare soil, respectively), whereas sites without horses were removing carbon from the atmosphere (−6.39 g CO2-e m−2 d−1). Sites with feral horses also had higher soil bulk density, temperature, and electrical conductivity (EC), and higher water pH, EC, and turbidity, than sites without horses. Our findings suggest that excluding feral horses from peatland areas could reduce rates of carbon loss to the atmosphere, in addition to improving overall site condition, peat soil condition, and water quality. We discuss potential management applications, further research, and restoration opportunities arising from these results.

Camera-based automated monitoring of flying insects in the wild (Camfi). II. flight behaviour and long-term population monitoring of migratory Bogong moths in Alpine Australia.

The Bogong moth Agrotis infusa is well known for its remarkable annual round-trip migration from its breeding grounds across eastern and southern Australia to its aestivation sites in the Australian Alps, to which it provides an important annual influx of nutrients. Over recent years, we have benefited from a growing understanding of the navigational abilities of the Bogong moth. Meanwhile, the population of Bogong moths has been shrinking. Recently, the ecologically and culturally important Bogong moth was listed as endangered by the IUCN Red List, and the establishment of a program for long-term monitoring of its population has been identified as critical for its conservation. Here, we present the results of two years of monitoring of the Bogong moth population in the Australian Alps using recently developed methods for automated wildlife-camera monitoring of flying insects, named Camfi. While in the Alps, some moths emerge from the caves in the evening to undertake seemingly random flights, filling the air with densities in the dozens per cubic metre. The purpose of these flights is unknown, but they may serve an important role in Bogong moth navigation. We found that these evening flights occur throughout summer and are modulated by daily weather factors. We present a simple heuristic model of the arrival to and departure from aestivation sites by Bogong moths, and confirm results obtained from fox-scat surveys which found that aestivating Bogong moths occupy higher elevations as the summer progresses. Moreover, by placing cameras along two elevational transects below the summit of Mt. Kosciuszko, we found that evening flights were not random, but were systematically oriented in directions relative to the azimuth of the summit of the mountain. Finally, we present the first recorded observations of the impact of bushfire smoke on aestivating Bogong moths - a dramatic reduction in the size of a cluster of aestivating Bogong moths during the fire, and evidence of a large departure from the fire-affected area the day after the fire. Our results highlight the challenges of monitoring Bogong moths in the wild and support the continued use of automated camera-based methods for that purpose.

Using Deep Learning to Detect the Need for Forest Thinning: Application to the Lungau Region, Austria

Timely information about the need to thin forests is vital in forest management to maintain a healthy forest while maximizing income. Currently, very-high-spatial-resolution remote sensing data can provide crucial assistance to experts when evaluating the maturity of thinnings. Nevertheless, this task is still predominantly carried out in the field and demands extensive resources. This paper presents a deep convolutional neural network (DCNN) to detect the necessity and urgency of carrying out thinnings using only remote sensing data. The approach uses very-high-spatial-resolution RGB and near-infrared orthophotos; a canopy height model (CHM); a digital terrain model (DTM); the slope; and reference data, which, in this case, originate from spruce-dominated forests in the Austrian Alps. After tuning, the model achieves an F1 score of 82.23% on our test data, which indicates that the model is usable in a practical setting. We conclude that DCNNs are capable of detecting the need to carry out thinnings in forests. In contrast, attempts to assess the urgency of the need for thinnings with DCNNs proved to be unsuccessful. However, additional data, such as age or yield class, have the potential to improve the results. Our investigation into the influence of each individual input feature shows that orthophotos appear to contain the most relevant information for detecting the need for thinning. Moreover, we observe a gain in performance when adding the CHM and slope, whereas adding the DTM harms the model’s performance.

Rare but not lost: Endemic mountain lizard occupancy following megafire and grazing disturbances

AbstractWildfire and grazing by invasive herbivores can influence habitat suitability for ground‐dwelling fauna, such as reptiles. Australia has a large and diverse reptile fauna, with the Australian Alps bioregion in the southeast of the continent supporting a disproportionately high number of threatened species. In this bioregion, many species are threatened by fire, habitat loss or modification, and invasive species. The range of one such threatened endemic lizard, Cyclodomorphus praealtus (family Scincidae), was impacted by the 2019–20 megafires and is also subject to widespread grazing by invasive species. We investigated the relationship between C. praealtus site occupancy and fire and grazing. We completed 2045 surveys across 120 sites over 4 years, detecting the species at 43% of sites and increasing the species' known geographic range. Using single season detection occupancy models, we found C. praealtus occupancy was not associated with elevation, vegetation height or whether the site was burnt, but was positively associated with grazing activity. Our results indicate that C. praealtus has the capacity to persist following a single fire in some cases, and that habitats with high occupancy probabilities are subject to high grazing pressure. However, our results do not rule out more nuanced impacts associated with these disturbances, which affect a large proportion of C. praealtus' habitat. Our cumulative detection probability calculations revealed that considerable survey effort is often required to determine C. praealtus site occupancy. We therefore recommend that impact assessments assume species presence within areas of suitable habitat within the species' range. Our study improves our understanding of disturbance impacts on C. praealtus' occupancy, while demonstrating the need for sufficiently resourced impact assessments for cryptic and threatened species.

Polyphase rock slope failure controlled by pre-existing geological structures and rock bridges

Even after decades of intensive research, assessing rock slope stability remains a challenge. One reason for this is the spatial variability of rock bridges (RBs) related to non-persistent, pre-existing geological structures, especially as the detection of RBs is generally limited to the post-failure period. Thus, the identification and classification of RBs and their inclusion in numerical studies are demanding, yet essential, since even small quantities of RBs can be decisive for rock slope stability. In our study, we demonstrate how brittle RB failure and pre-existing geological structures control the mechanisms of a polyphase rock slope failure. Therefore, we present a case study in the Austrian Alps, where three rock falls with a failure volume of 30,000 m3 occurred in 2019. Based on detailed process reconstructions, high-resolution terrain models, and comprehensive geological and rock mechanical investigations, we derived high-quality input for our distinct element model (DEM). By applying asymmetric Voronoi tessellation in the DEM, we modelled the coalescence of pre-existing geological structures by brittle RB failure. As a result, we identified toppling as the predominant failure mechanism at the study site. Distinctive geological structures decisively affected the failure mechanism. However, the toppling failure was only reproducible by incorporating RBs in the DEM in their pre-failure position. Finally, we found that joint persistence, and consequently the presence of potential RBs, controls which initial rock fall failure mechanism was developed. In conclusion, we state that the initial toppling failure of the Hüttschlag rock falls is controlled by non-persistent geological structures in interplay with RBs.

Responses of necrophilous beetles to animal mass mortality in the Australian Alps

A diversity of insects can be found at the remains of dead animals (carrion) and they play a vital role in its decomposition and recycling. An emerging global problem with carrion is animal mass mortality events – the sudden, rapid die-off of many animals resulting in a large increase to the localised carrion resource pool. Yet, little is known about how insects respond to sudden and large inputs of carrion. We conducted an experiment in a mountainous alpine region of south-eastern Australia and compared beetle assemblages found at single carcass and mass mortality sites. We also examined the effects of vertebrate exclusion, and decomposition stage on beetles. We found 4,774 beetles representing 146 different species/morphospecies from 17 families. The most abundant species was Saprinus cyaneus cyaneus (Histeridae), and species of Staphylinidae and Silphidae also dominated the fauna, which is typical for necrophilous beetles in Australia. We also found a clear temporal change in beetle assemblages, with abundance and richness peaking during the active decay stage. We found that beetle abundance was greater at single carcasses than mass mortality sites, possibly as an artifact of sampling, and that species richness was similar among these two carcass treatment types. We found no significant effect of vertebrate exclusion on beetles, suggesting that large scavengers in the study system may not influence necrophilous insect communities around carrion.Implications for insect conservation: Our study highlights the diversity of beetles that can be found at carrion and their similar composition to the fauna found in other areas in the south-east of the Australian continent. Beetles may have reduced abundance at mass mortality sites which could affect their ability to contribute to carrion removal relative to smaller carrion quantities. Further research is required to quantify the role of other insects in carrion removal under a range of natural and mass mortality scenarios.

Increases in functional diversity of mountain plant communities is mainly driven by species turnover under climate change

Warming in mountain regions is projected to be three times faster than the global average. Pronounced climate change will likely lead to species reshuffling in mountain plant communities and consequently change ecosystem resilience and functioning. Yet, little is known about the role of inter‐ versus intraspecific changes of plant traits and their consequences for functional richness and evenness of mountain plant communities under climate change. We performed a downslope translocation experiment of intact plant‐soil mesocosms from an alpine pasture and a subalpine grassland in the Swiss and Austrian Alps to simulate an abrupt shift in climate and removal of dispersal barriers. Translocated plant communities experienced warmer and dryer climatic conditions. We found a considerable shift from resource conservative to resource acquisitive leaf‐economy in the two climate change scenarios. However, shifts in leaf‐economy were mainly attributable to species turnover, namely colonization by novel lowland species with trait expressions for a wider range of resource use. We also found an increase in vegetative height of the warmed and drought‐affected alpine plant community, while trait plasticity to warming and drought was limited to few graminoid species of the subalpine plant community. Our results highlight the contrast between the strong competitive potential of novel lowland species in quickly occupying available niche space and native species' lack of both the intraspecific trait variability and the plant functional trait expressions needed to increase functional richness under warming and drought. This is particularly important for the trailing range of many mountain species (i.e. subalpine zone) where upward moving lowland species are becoming more abundant and abiotic climate stressors are likely to become more frequent in the near future. Our study emphasizes mountain plant communities' vulnerability to novel climates and biotic interactions under climate change and highlights graminoid species as potential winners of a warmer and dryer future.Keywords: alpine grassland, functional diversity, invasion, species turnover, traitspace, translocation

Changes in the water retention of mountainous landscapes since the 1820s in the Austrian Alps

Interactions of humans with the environment are strongly related to land use and land cover changes (LULCCs). In the last decades, these changes have led to a degradation of ecosystem services, including water regulation and flood control. In the Alpine areas of Austria, land cover changes have increased flood risk since the middle of the 19th century. In this paper, we assess the influence of these long-term land use changes on the landscape’s ability to retain water using the qualitative Water Retention Index (WRI). The changes are thereby evaluated on the basis of the historical (1826–1859) and present (2016) land cover situation, which is to our knowledge the first high-resolution and regional application of the WRI. The results show that the water retention potential mimics the mountainous characteristic and features. Except for areas strongly dominated by settlement areas, the highest retention potentials are found in valley floors and the lowest values are depicted along the main Alpine complex. In low-lying areas, the retention decreased by over 10%. It was found that this decrease can be mostly attributed to settlement expansion. Above 1,250 m, land use transformations led to slightly increasing water retention values owing to the transformation of wasteland or glaciers to stagnant waters and to the expansion of forest and grassland in high elevations. This examination allows for a holistic and spatially distributed LULCC impact assessment on the landscape’s water regulation capacities and offers valuable high-resolution information for future land use planning and sustainable land development.

First molecular data on the human roundworm Ascaris lumbricoides species complex from the Bronze and Iron Age in Hallstatt, Austria

Palaeoparasitological studies can provide valuable information on the emergence, distribution, and elimination of parasites during a particular time in the past. In the prehistoric salt mines of Hallstatt, located in the Austrian Alps, human faeces have been conserved in salt. The aim of this study was to recover ancient DNA of intestinal parasites from these coprolites. Altogether, 35 coprolites from the Hallstatt salt mines, dating back to the Bronze Age mining phase (1158–1063 BCE) and the Iron Age mining phase (750–662 BCE), respectively, were analysed by microscopy and molecular methods. In 91% of the coprolite samples, eggs of soil-transmitted helminths (STH), namely of Trichuris and/or Ascaris were detected by light microscopy. The Ascaris eggs were exceptionally well preserved. For further analysis, DNA was extracted from the palaeofaecal samples and species-specific primers targeting different genes were designed. While amplification of Trichuris DNA remained unsuccessful, sequence data of A. lumbricoides species complex were successfully obtained from 16 coprolites from three different genes, the mitochondrial cytochrome c oxidase subunit 1 gene (cox1), the mitochondrial cytochrome B gene (cytB) and the mitochondrial NADH dehydrogenase subunit 1 gene (nadh1). Importantly, these included two Ascaris sequences from a coprolite from the Bronze Age, which to the best of our knowledge are the first molecular data of this genus from this period.

The role of thermokarst evolution in debris flow initiation (Hüttekar Rock Glacier, Austrian Alps)

Abstract. A rapid sequence of cascading events involving thermokarst lake outburst, local rock glacier front failure, debris flow development, and river blockage hit Radurschl Valley (Ötztal Alps, Tyrol) on 13 August 2019. Compounding effects from permafrost degradation and drainage network development within the rock glacier initiated the complex process chain. The debris flow dammed the main river of the valley, impounding a water volume of 120 000 m3 that was partly drained by excavation to prevent a potentially catastrophic outburst flood. We present a systematic analysis of destabilizing factors to deduce the failure mechanism. The identification and evaluation of individual factors reveals a critical combination of topographical and sedimentological disposition, climate, and weather patterns driving the evolution of a thermokarst drainage network. Progressively changing groundwater flow and storage patterns within the frozen sediment accumulation governed the slope stability of the rock glacier front. Our results demonstrate the hazard potential of active rock glaciers due to their large amount of mobilizable sediment, dynamically changing internal structure, thermokarst lake development, and substantial water flow along a rapidly evolving channel network.

Identifying mountain permafrost degradation by repeating historical electrical resistivity tomography (ERT) measurements

Abstract. Ongoing global warming intensifies the degradation of permafrost. Permafrost thawing impacts landform evolution, reduces freshwater resources, enhances the potential of natural hazards and thus has significant socio-economic impacts. Electrical resistivity tomography (ERT) has been widely used to map the ice-containing permafrost by its resistivity contrast compared to the surrounding unfrozen medium. This study aims to reveal the effects of ongoing climate warming on mountain permafrost by repeating historical ERT and analyzing the temporal changes in the resistivity distribution. In order to facilitate the measurements, we introduce and discuss the employment of textile electrodes. These newly developed electrodes significantly reduce working effort, are easy to deploy on blocky surfaces and yield sufficiently low contact resistances. We analyze permafrost evolution on three periglacial landforms (two rock glaciers and one talus slope) in the Swiss and Austrian Alps by repeating historical surveys after 10, 12 and 16 years, respectively. The resistivity values have been significantly reduced in ice-poor permafrost landforms at all study sites. Interestingly, resistivity values related to ice-rich permafrost in the studied active rock glacier partly increased during the studied time period. To explain this apparently counterintuitive (in view of increased resistivity) observation, geomorphological circumstances, such as the relief and increased creep velocity of the active rock glacier, are discussed by using additional remote sensing data. The present study highlights ice-poor permafrost degradation in the Alps resulting from ever-accelerating global warming.