Scree Research Articles

A threefold plant specialist – distribution, habitat requirements and nesting biology of the rare leafcutter bee Megachile genalis in the eastern Swiss Alps (Hymenoptera, Megachilidae)

The leafcutter bee Megachile genalis Morawitz, which nests in thick, erect and usually hollow plant stems, is rare and endangered throughout Europe. In Switzerland, it was recorded only six times in the Grisons between 1932 and 2019. In order to create the necessary basis for the conservation of this rare bee, its distribution, habitat requirements and nesting biology were investigated in the eastern Swiss Alps by systematically searching for its nests, by DNA metabarcoding of the cell-building material, by analysing the pollen contained in abandoned brood cells and larval faeces, and by deducing aspects of the species’ nesting biology from collected old nests. A total of 141 new and 64 old nests were discovered at elevations between 600 m and 1270 m in – with decreasing frequency – the Albula Valley, the Lower Engadine, the Domleschg and the Ruinaulta. The nests were exclusively built in living stems of Peucedanum verticillare (Apiaceae), an up to 2–3 m tall umbellifer that grew on fallow land, road and railway embankments, scree slopes, ruderal areas and forest clearings. The leaf fragments used by the females of M. genalis to construct the brood cells in 20 selected nests were largely from shrubs and trees of the Rosaceae (e.g. Rosa, Rubus, Prunus, Sorbus), rarely also from Corylus (Betulaceae). The pollen in 65 brood cells was exclusively collected on thistles (e.g. Arctium, Carduus, Cirsium) and other Asteraceae. The nests were characterised by a surprisingly high variability in their architecture. They consisted of i) an approximately 6 mm x 9 mm large nest opening gnawed by the female bee at a height of 22–217 cm above ground with her mandibles, which are well adapted to penetrate the hard stem walls due to their enlarged base indicating strong adductor muscles and the short and chisel-like shape; ii) a 5–25 mm thick nest plug built 1.5–45 cm below the nest opening from pith particles, leaf fragments and/or grass fibers; iii) 1–14 brood cells usually arranged in one cigar-like series and lying 11–99 cm below the nest opening; and iv) a facultative 4–40 mm thick basal plug consisting of pith particles and/or leaf fragments. Brood mortality was high: at least 56% of 284 brood cells were unsuccessful due to parasites, mould or unknown reasons, and reproduction completely failed in almost half of 46 nests. The most harmful brood parasite was Melittobia acasta Walker (Hymenoptera, Eulophidae), which infested 19% of the brood cells and 28% of the nests. Measures to conserve the population of M. genalis in the eastern Swiss Alps should focus on the conservation and propagation of suitable habitats for P. verticillare in close vicinity to Asteraceae-rich areas and on the promotion of thistles.

Multitemporal Quantification of the Geomorphodynamics on a Slope within the Cratère Dolomieu at the Piton de la Fournaise (La Réunion, Indian Ocean) Using Terrestrial LiDAR Data, Terrestrial Photographs, and Webcam Data

In this study, the geomorphological evolution of an inner flank of the Cratère Dolomieu at Piton de La Fournaise/La Réunion was investigated with the help of terrestrial laser scanning (TLS) data, terrestrial photogrammetric images, and historical webcam photographs. While TLS data and the terrestrial images were recorded during three field surveys, the study was also able to use historical webcam images that were installed for the monitoring of the volcanic activity inside the crater. Although the webcams were originally intended to be used only for visual monitoring of the area, at certain times they captured image pairs that could be analyzed using structure from motion (SfM) and subsequently processed to create digital terrain models (DTMs). With the help of all the data, the geomorphological evolution of selected areas of the crater was investigated in high temporal and spatial resolution. Surface changes were detected and quantified on scree slopes in the upper area of the crater as well as on scree slopes at the transition from the slope to the crater floor. In addition to their quantification, these changes could be assigned to individual geomorphological processes over time. The webcam photographs were a very important additional source of information here, as they allowed the observation period to be extended further into the past. Besides this, the webcam images made it possible to determine the exact dates at which geomorphological processes were active.

Using dendrogeomorphic and lichenometric approaches for rockfall analysis in the high mountains of Central Mexico

Rockfall represents one of the most destructive geomorphic processes for infrastructure and settlements located at the foot of mountain slopes. Furthermore, it poses a hazard for visitors and hikers. Despite the high anthropic activity in these environments, research on the reconstruction of rockfall in the high mountains of Mexico is still scarce. We used dendrochronological, dendrogeomorphological and lichenometric approaches to study the age and rockfall dynamics in a talus slope in central Mexico. Tree- ring chronologies were constructed from 140 samples of 50 Pinus hartwegii trees, 10 Juniperus monticola shrubs and 16 Ribes ciliatum shrubs to determine the age, frequency and rockfall stability at the upper limit of the forest (~4000 m a.s.l.). 52% of the tree samples showed impact scars, 39% callus tissue, 7% growth suppression and 2% corresponded to trees killed by rockfall. The frequency of rockfalls has increased since the second half of the 20th century, with the 1990s being the period of greatest activity. The years with the greatest disturbance were 1991, 1994 and 1998, possibly due to the intense rainfall that accumulated during the summer, as well as the earthquakes recorded in central and southern Mexico with magnitudes ⩾6. For the lichenometric analysis, 231 thalli of Rhizocarpon geographicum were measured in an active rockfall area. The results suggested three areas of rockfall activity. In the first area the ages were from 61 (±5 year) to 322 years (±41 year). In the second area, the ages were from 12 (±3 year) to 50 years (±12 year). The third area corresponds to an active zone with lichen-free blocks, located near the escarpment. The combination of dendrochronological and lichenometric methods allows a better determination of the minimum ages of rockfall, frequency, spatial distribution, and their possible factor triggers.

Comprehensive assessment of rock glaciers in the Himachal Himalayas: Updated inventory and labelling

Rock glaciers are geomorphological features often used as a visible expression of mountain permafrost. These are creeping ice-debris with distinct ridge and furrow structures on the surface with a steep frontal slope. Rock glaciers, being the valuable past permafrost indicators, also have utmost hydrological significance in near future. Therefore, mapping of rock glaciers is an important step in order to understand permafrost regimes better. The Himalayas have large occurrences of these features and this study in Himachal Himalayas complied 789 rock glaciers, covering an area of about 336.2 km2. Different labels based on genesis, location, shape, form, surface relief and activity revealed rock glaciers were mainly derived from talus slopes (239) and exhibited tongue shape (377), primarily found in cirques (531). Most of them were classified as simple units (603) with well-developed surface relief (387), and they were found to be predominantly intact (760). The topographical parameters suggest majority of the rock glaciers are located between 4000 and 4800 m with mean elevation to be 4635 m. These rock glaciers are present at gentle to steep slope gradient (0 to 45°) with curvature ranging between −3.5 and 4.5, and majority showing convex curvature. The slope aspect conducive for formation of rock glaciers in Himachal is northerly (N, NW, NE). Principal geology for these rock glaciers belongs to slate, phyllite, quartzarenite, limestone and meta basics. The climatic parameters and indices also affect the rock glaciers occurrence significantly. The mean land surface temperature (LST) for majority rock glaciers lies between 0 and −15°C. While, the mean NDSI of all the rock glaciers varies from 0.04 to 0.68 and mean NDVI varies from −0.06 to 0.08. Overall, the inventory along with labels is a valuable database for understanding the distribution and characteristics of rock glaciers in the Himachal Himalayas.

Orobanche dagestanica (Orobanchaceae): a new species from the Greater Caucasus

A new, probably endemic species, Orobanche dagestanica is described from Dagestan in Russia (the Greater Caucasus). The species grows in alpine shale scree slopes, and is a parasite of the roots of species from the genus Lophiolepis (Asteraceae). Based on morphological and phylogenetic data, the newly-described species belongs to Orobanche subsect. Curvatae, and specifically to O. ser. Krylowianae, however it is distinct from all other taxa in this group. A detailed description, diagnosis, illustrations, a comparison with related species, as well as phylogenetic analysis are provided.

Geoecology of limestone-hosted dryland calcicolous plants, North Otago, New Zealand

ABSTRACT Dryland calcicolous plants are drought-tolerant species that are adapted to survive on alkaline low-nutrient bare substrates derived from limestone around the world. Outcrops of the Otekaike Limestone of North Otago host some rare low-growing (<10 cm) endemic calcicoles, and conservation reserves have been created at some localities. The calcicoles occupy microhabitats in solution cavities in limestone outcrops, growing in thin (<10 cm) limestone debris accumulations, including detrital sand and silt. Calcicoles also grow in coarse and fine disaggregated limestone talus deposits at tops and bottoms of outcrops, commonly with the low-growing exotic hawkweed but the calcicoles are displaced by taller species, especially grasses. Calcicole substrates have pH 8 to 9, with a balance between calcite dissolution and calcite re-precipitation. Electrical conductivity is typically <500 µS/cm, but can be as high as 7 mS/cm with evaporative salts and salt weathering enhancing porosity. The limestone contains variably oxidised authigenic glaucony and pyrite, which provide some plant nutrients (K, Mg, Fe, S, N) as roots penetrate porous limestone, with apatite providing phosphate. Persistence of these rare calcicolous communities in soil-free settings is strongly affected by the underlying mineralogy and geochemistry, and some similar microhabitats may occur on other rock types.

Application of the Schmidt-hammer for relative-age dating of glacial and periglacial landforms in the Cantabrian Mountains (NW Spain)

A Schmidt hammer was applied for relative-age dating to 48 sites in 5 different massifs of the Cantabrian Mountains (NW Spain). The sample included glacial (moraines, erratics, and polished bedrock) and periglacial (rock glaciers, blockfields, and talus slopes) sites from the last glaciation to the present in different geomorphological contexts. The rebound (R) values agree with the morphostratigraphic reconstructions, showing progressively lower values for older deposits. Six stages from the Last Glacial Maximum to the present are inferred. The results differ according to the lithology: i) the quartzites showed higher R-values and very low weathering rates; ii) the granodiorites showed larger differences in R-values reflecting clearly age differences; iii) sandstones appear to be unsuitable for Schmidt hammer measurements in some areas; however, quartzite sandstones provide better results. The rock glaciers formed in different periods after deglaciation (i.e. just after the Last Glacial Maximum, Bölling/Allerød, Holocene), indicate a paraglacial dependence rather than climate-driven landforms. The sampled blockfields stabilized after the (almost) total deglaciation of the cirques, but their origin and significance in this mountainous area remain poorly understood.

Can tree rings indicate deformation of talus slope in the cold region?

Can tree rings indicate deformation of talus slope in the cold region?

Sustainable Retaining Wall Solution as a Mitigation Strategy on Steep Slopes in Soft Rock Mass

Steep slopes in soft rock are characterized by their susceptibility to instability (rockfall, rockslide) due to weathering and erosion of the slope surface. This article deals with the problem of adapting to the increasing height of the scree slope. The construction of a retaining wall in a scree slope in front of a slope of soft rock with a steep face, where a very rapid weathering and erosion process of weathered material takes place, and the simultaneous deposition of material in front of the steep slope is a common solution. Changes in the geometry of the slope and the front scree are taken into account, and at the same time, sufficient safety against rockfall must be ensured. The analysis is shown on a specific example of a steep flysch slope near Split, Dalmatia. The retaining wall solutions are compared in terms of function, cost and sustainability. The construction of a single colossal, reinforced concrete retaining wall shows that this solution is not feasible due to the high construction costs and CO2 emissions of the retaining wall. A model was therefore developed to determine the height of the retaining walls for different construction time intervals and distances from the original rock face. The critical failure modes were investigated for various retaining wall solutions with regard to the highest degree of utilization of the resistance, which also allows the cost-optimized solutions to be determined. By building two or more successive retaining walls at suitable intervals and at an appropriate distance from the original rock face, construction costs and CO2 emissions can be significantly reduced.

Modeling the Link Between Air Convection and the Occurrence of Short‐Term Permafrost in a Low‐Altitude Cold Talus Slope

ABSTRACTWe extend a numerical modeling approach developed to explicitly model convective heat transfer in periglacial landforms to represent the ground thermal regime of low‐altitude talus slopes. Our model solves for heat conduction and accounts explicitly for air convection adopting a Darcy term with a Boussinesq approximation for air circulation in the porous ground. Numerical model experiments for the low‐altitude talus slope Dreveneuse, Switzerland, confirm that air convection is the key to forming and maintaining ground ice. In the model, the porous talus slope is underlain by a layer of water‐bearing morainic material. In years, where the gradient between air and talus temperature is sufficiently large to result in increased convection and therefore cooling, ground ice forms due to air convection within the porous material and lasts for more than a year. It is only by considering convection that the model is able to represent the occurrences of ground ice, in accordance with temperature observations on‐site. These findings are important, as they confirm that ground ice can be formed and maintained in landforms with a mean annual air temperature &gt; 0°C if ground air convection is present combined with the presence of water.

Comprehensive observations and geostatistics of slope streaks within the Olympus Mons aureole

Slope streaks (SS) are enigmatic linear features characterized by relatively low-albedo features that appear and fade on high-albedo slopes on Mars. Despite numerous hypotheses proposed to explain their formation, the primary mechanism behind SS remains elusive. Here, we examine 702 SS features using 32 multitemporal Context Imager (CTX) images and mesoscale modeling data obtained from a site (centered at 31.230°N, 216.281°E) in the Olympus Mons Aureole region. Our investigation revealed several key findings that shed light on the dynamics of SS formation and fading. We discovered a significant preference for SS formation on south-facing (equator-facing) slopes compared to north-facing slopes, with SS being over seven times more likely to occur on the former. Furthermore, SS formation was found to be seasonal with significantly enhanced by a factor of ∼6 near the equinoxes (from solar longitude Ls 337°-42° and 136°-227°) compared to other times of the year. Our analysis also revealed a correlation between the rates of SS formation and fading, with scree slopes exhibited the fastest-fading SS also experiencing the highest rates of newly-formed SS. Additionally, we measured the median starting and stopping slopes of SS to be 23.4° and 14.9°, respectively, significantly below the angle of repose of sand. These low slopes suggest the necessity for an energetic trigger mechanism to initiate SS formation. Infrared spectroscopy revealed that the principal distinction between the material inside and outside of a SS lies in the reduced abundance of dust within the streak. Notably, this site demonstrates the highest rates of SS formation (a 29.6% increase in new SS per Mars year) and fading (a 12% fading of SS per Mars year) ever quantified. These elevated rates may be attributed to the site's topography, which facilitates calm surficial nighttime winds throughout the year, leading to widespread dust deposition. Daytime downhill winds near the ridgelines of S-facing slopes may then trigger movement of newly deposited dust aggregates or alternatively, a Knudsen pump phenomenon could serve as a potential trigger for SS. We propose that SS is inhibited during the northern summer solstice season due to the relatively clear aphelion atmosphere, which limits dust deposition. Similarly, the lack of triggering activity during the winter solstice is likely due to more moderate daytime winds. Overall, our findings are consistent with the wind-triggered dry avalanche hypothesis as a plausible explanation for SS formation.

An overcooled coarse‐grained talus slope at low elevation: New insights on air circulation and environmental impacts, Cannon Cliff, New Hampshire, USA

AbstractOvercooled talus slopes are generally described as islands of sporadic permafrost below the lower alpine limit of permafrost. The negative thermal anomaly of the ground is mainly consecutive to the internal ventilation of the deposit, but it is also conditioned by multiple factors as topography, slope aspect and incline, openwork structure and coarseness of the deposit, air temperature, solar radiation and wind regime. Therefore, the study of the spatiotemporal dynamics of ventilation processes allows a better understanding of the phenomenon. At Cannon Cliff, New Hampshire (USA), several field visits and environmental monitoring allowed us to describe the varying nature and significance of the ventilation mechanisms that can be observed at the ground surface and associated with both the intensity and direction of the airflows in a talus debris accumulation/protalus rampart system. The thermal negative anomalies are strong enough to lower the ground temperature to the point of preserving ice during the late spring and summer seasons. The monitoring of the gradient between external (air) and internal (talus) temperatures coupled with several dendroecological and geomorphological analyses provided a complete environmental picture of the impacts, feedback and extent of the phenomenon.

Triggers of present-day rockfalls in the zone of sporadic permafrost in non-glaciated mountain region: the case study of Turnia Kurczaba (the Tatra Mts., Poland)

In recent decades there has been growing evidence of the impact of ongoing climate warming on the frequency of rockfalls. However, these are not adequately documented, especially in non-glaciated, high mountain regions of middle latitude. This study comprehensively documents the Turnia Kurczaba rockfall, one of the most significant rockfalls recorded in recent decades in the Tatra Mountains. The precise projections of the volumes and distribution of rock losses and deposits, the determination of the trajectories, modes and speeds of movement of rock material, as well as information on the geological, morphological, and meteorological conditions behind the Turnia Kurczaba rockfall form a unique dataset. The data documents a spectacular episode in the contemporary development of a complex slope system in the Tatras in an all-encompassing way and can be used to validate and calibrate existing models and improve numerical simulations of other rockfalls, both for hazard and risk assessment and slope evolution studies. Moreover, in the context of archival data, they demonstrate that in the Tatra sporadic permafrost zone, only relatively small rockfalls have been recorded in recent decades. Their cause was not the degradation of permafrost but freeze-thaw processes with the co-participation of rainwater and meltwater. The largest of these occur within densely fractured cataclysites, mylonites, and fault breccias. The impact of rockfalls on the morphodynamics of talus slopes is uneven in the storied arranged rock-talus slope systems. Even colluviums belonging to the same slope system can differ in their development rate and regime, and different thermal and wetness drivers can control their evolution.

Complex Methodology for Spatial Documentation of Geomorphological Changes and Geohazards in the Alpine Environment

The alpine environment with a high degree of nature protection is characterized by complete non-intervention. The processes and phenomena occurring in it are exclusively of a natural origin. Related geohazards are threatening the safety of people’s movement. They arise as a result of a combination of meteorological, hydrological, and geological–morphological factors permanently operating in the country. Therefore, the prevention of fatal events is limited to monitoring and predicting changes in selected objects where we expect change. Changes in the shape and dimension, or the object’s deformation, can be documented using geodetic and photogrammetric measurements. Our research focuses on monitoring a rock talus cone in High Tatras, Slovakia, at an altitude of 1700 m above sea level (ASL), created mainly due to erosion and seasonal torrential rains. To monitor changes in selected objects, we used mass non-contact methods of terrestrial laser scanning (TLS), UAS photogrammetry based on the principle of structure-from-motion–multi-view stereo (SfM–MVS), and airborne laser scanning (ALS). From the selective measurement methods, spatial measurement by a total station (TS) and height measurement based on the principle of precise leveling were used in the monitoring deformation network on a stand-alone boulder. The research results so far analyze and evaluate the possibilities, limits, effectiveness, and accuracy of the measurement and data processing methods used. As a result, we propose a complex methodology for monitoring similar phenomena in alpine environments.

Multiclavula mucida (Basidiomycota) and other cryptogamic taxa in the Hungarian flora

The paper deals with the species found during cryptogamic flora mapping in 2023 that are remarkable from a floristic, taxonomic or conservational point of view. We present data from the Bükk Mts of two Trapeliopsis species which appear to be rare in Hungary. Multiclavula mucida, which is ap­parently a rare basidiomycete lichen species in Europe that prefers humid, montane habitats was dis­covered in the Mecsek Mts as a new species for the Hungarian flora. Of the knothole moss, Anacampto­don splachnoides, which is now thought to be entomophilic, we communicate the only extant popula­tion from Southern Transdanubia. We report the first occurrence of the atlantic-mediterranean Lepto­don smithii from the Hungarian side of the Great Hungarian Plain. Numerous data of the corticole Neck­era pennata indicate that in Hungary the distributional centre of this species is situated in the county of Baranya in the lowlands. New data from the Bükk Mts underline that in the Pannonian region Buxbaumia viridis is primarily a terricole species of acidophilous beech forests. We communicate the first occurrence from the lowlands of the alien lignicolous Sematophyllum adnatum which is danger­ous­ly spreading in Europe, at the same time one of the most vigorous populations in the Pannonian region. The third Hungarian occurrence of Callicladium haldanianum, a species that seems to spread in bogs, as well as the second occurrence of Racomitrium lanuginosum, growing abundantly on an ande­site boulder scree in Mátra Mts, are also reported here. Of Phegopteris connectilis we present in photo­graphic docu­mentation the first extant population from Southern Transdanubia, and we discuss whether the first publication from Mecsek Mts is correct or exact. In addition to listing the floristic data, we also briefly discuss the (mis)use of distribution data in the context of climate change, the difficulties of distinguish­ing the microtaxa of some pteridophytes, e.g. Asplenium adiantum-nigrum agg. and Dryop­teris affinis agg., and we correct one of our previously published, erroneous Hedwigia stellata data. Some interest­ing data of other taxa (such as Leucobryum glaucum, Palustriella commutata, Tetraphis pellucida, Gym­nocarpium robertianum, Ophioglossum vulgatum) are also mentioned in the paper.

Měkkýši přírodní rezervace Jedlový důl v CHKO Jizerské hory (Česká republika) [Molluscs of the Jedlový důl Nature Reserve in the Jizerské hory Protected Landscape Area (Czech Republic)

The Jedlový důl Nature Reserve is located in the central part of the Jizerské hory PLA near the village of Josefův Důl in northern Bohemia. The reserve protects a geomorphologically important mountain valley with rocks, waterfalls, semi-natural forests on talus slopes, and rare montane plant and animal species. The local mountain biotopes are quite acidophilic, represented by a few springs, mountain brook, beech woods, and mixed talus slope forests with the predominance of spruce. Thus the surveyed malacofauna with 18 species (17 terrestrial gastropods and 1 bivalve) is relatively poor. Currently, forest and ubiquitous species are dominant there and are widespread in the Jizerské hory PLA.

Multiclavula mucida (Basidiomycota) and other cryptogamic taxa in the Hungarian flora

The paper deals with the species found during cryptogamic flora mapping in 2023 that are remarkable from a floristic, taxonomic or conservational point of view. We present data from the Bükk Mts of two Trapeliopsis species which appear to be rare in Hungary. Multiclavula mucida, which is ap­parently a rare basidiomycete lichen species in Europe that prefers humid, montane habitats was dis­covered in the Mecsek Mts as a new species for the Hungarian flora. Of the knothole moss, Anacampto­don splachnoides, which is now thought to be entomophilic, we communicate the only extant popula­tion from Southern Transdanubia. We report the first occurrence of the atlantic-mediterranean Lepto­don smithii from the Hungarian side of the Great Hungarian Plain. Numerous data of the corticole Neck­era pennata indicate that in Hungary the distributional centre of this species is situated in the county of Baranya in the lowlands. New data from the Bükk Mts underline that in the Pannonian region Buxbaumia viridis is primarily a terricole species of acidophilous beech forests. We communicate the first occurrence from the lowlands of the alien lignicolous Sematophyllum adnatum which is danger­ous­ly spreading in Europe, at the same time one of the most vigorous populations in the Pannonian region. The third Hungarian occurrence of Callicladium haldanianum, a species that seems to spread in bogs, as well as the second occurrence of Racomitrium lanuginosum, growing abundantly on an ande­site boulder scree in Mátra Mts, are also reported here. Of Phegopteris connectilis we present in photo­graphic docu­mentation the first extant population from Southern Transdanubia, and we discuss whether the first publication from Mecsek Mts is correct or exact. In addition to listing the floristic data, we also briefly discuss the (mis)use of distribution data in the context of climate change, the difficulties of distinguish­ing the microtaxa of some pteridophytes, e.g. Asplenium adiantum-nigrum agg. and Dryop­teris affinis agg., and we correct one of our previously published, erroneous Hedwigia stellata data. Some interest­ing data of other taxa (such as Leucobryum glaucum, Palustriella commutata, Tetraphis pellucida, Gym­nocarpium robertianum, Ophioglossum vulgatum) are also mentioned in the paper.

Woodstock Rocks: From Acheulean to Iron Age in the Waterberg, Limpopo Province, South Africa

The cliff terrace site, Woodstock Rocks, was exploited occasionally by hominins from the Earlier Stone Age to the Iron Age. A small excavation uncovered an Acheulean quartzite workshop with many flakes, but lacking large cutting tools and without organic preservation. Below the workshop site, a ferricrete river terrace cements Acheulean lithics that include large cutting tools, giant flakes and heavy-duty scrapers. A palaeomagnetic study reveals reversed polarity, implying that the ferricrete formation likely took place during the Matuyama Chron and that the lithic assemblage is older than 780 000 years. The cliff face was painted expansively, but both the Bushman and Iron Age farmer art is faded. There are some rare images including a wild dog, a bird and a possible genet. The southern edge of the cliff terrace has Middle and Later Stone Age lithics on the surface and talus slope, as well as grindstones, and ceramics that include Bambata sherds from six vessels. The proximity to the Mokolo River and sources of rocks for knapping, as well as smooth rock walls for painting ensured repeated Woodstock Rocks visits (not necessarily occupation) for generations of Homo sapiens visitors, as well as earlier hominins.

UAV-mounted Ground Penetrating Radar: an example for the stability analysis of a mountain rock debris slope

This paper describes scientific research conducted to highlight the potential of an integrated GPR-UAV system in engineering-geological applications. The analysis focused on the stability of a natural scree slope in the Germanasca Valley, in the western Italian Alps. As a consequence of its steep shape and the related geological hazard, the study used different remote sensed methodologies such as UAV photogrammetry and geophysics survey by a GPR-drone integrated system. Furthermore, conventional in-situ surveys led to the collection of geological and geomorphological data. The use of the UAV-mounted GPR allowed us to investigate the bedrock depth under the detrital slope deposit, using a non-invasive technique able to conduct surveys on inaccessible areas prone to hazardous conditions for operators. The collected evidence and the results of the analysis highlighted the stability of the slope with Factors of Safety, verified in static conditions (i.e., natural static condition and static condition with snow cover), slightly above the stability limit value of 1. On the contrary, the dynamic loading conditions (i.e., seismic action applied) showed a Factor of Safety below the stability limit value. The UAV-mounted GPR represented an essential contribution to the surveys allowing the definition of the interface debris deposit-bedrock, which are useful to design the slope model and to evaluate the scree slope stability in different conditions.

Apparent annual survival of female eastern small-footed bats (Myotis leibii) roosting in Arkansas bridges

Abstract The Eastern Small-footed Bat (Myotis leibii) inhabits mountainous areas of the eastern United States and generally roosts in cliff faces and talus slopes. However, the difficulty of accessing these sites has limited research on this species. We studied survival rates of eastern small-footed bats by capturing bats roosting in crevices between sections of concrete guardrails on bridges in the Ozark mountains of northern Arkansas from 2014 to 2021. We accumulated 1,413 bat captures (1,050F; 363M) of 283 individual females and 198 individual males sampled over 8 years and determined apparent annual survival of female bats using Cormack–Jolly–Seber survival models. Only 1 of 30 bats tested positive for the presence of Pseduogymnoascus destructans, a fungus causing white-nose syndrome (WNS) which is responsible for significant declines in populations of some North American bat species, when all maternity colonies were sampled in the spring of 2019. Overall apparent annual survival of all females was 0.643, with first-year juvenile survival of 0.472 and adult (ages 1–6) survival of 0.744, approximately 58% greater than first-year survival. Apparent annual survival did not differ greatly among the sites or among years. We found no significant decline or increase in overall number of bats among all sites during the 8 years of study. Stability in both the number of bats encountered and their survival rates suggests that the impact of WNS on these colonies has been marginal.