Southeastern Alps Research Articles

3D velocity-depth model from multichannel seismic in the Dinaric foredeep of the Gulf of Trieste (Adriatic Sea), at the NE edge of Adria plate

The Gulf of Trieste (GT), northeastern Adriatic, sits at the rigid edge of the Adria microplate representing the foreland of the adjoining Meso-Cenozoic External Dinarides and Southeastern Alps. The Adria-Eurasia plate boundary extends along the GT eastern coastline, depicted by the Karst Thrust, outer ramp of the SW-verging Dinarides. This separates the Cretaceous-Paleogene carbonates outcropping hundreds of meters on the Karst Plateau (hanging-wall) from their counterparts buried in the eastern gulf. Although the thrust has no evidence of historical and instrumental seismicity, a detailed seismic velocity field is needed to quantify reliable geometries in the foredeep, embedded in a tectonically active area where Adria is moving NNW-ward. Availability of a newly acquired marine multichannel seismic dataset, allowed us to provide the first well-constrained 3D P-wave velocity and depth model in the footwall of the Karst Thrust. Two iterative techniques, traveltime reflection tomography and depth seismic imaging, were applied on the data surveying the Dinaric foredeep. Our findings provide mean velocity values of 1700 m/s for the Quaternary sediments, 2900 m/s for the upper Eocene flysch turbidites, 4500 m/s for the lower flysch, 5000 m/s for the upper carbonates. The maximum flysch unit thickness results in about 1500 m and the top carbonates depth reaches about 1600 m below sea level, 1.7 km offshore Trieste, revealing the thrust is responsible for a minimum 1600–1800 m vertical throw. This study provides benefits for Adria geodynamic models and give new constraints for the geological and tectonic setting assessment, in a region settled over a currently active continental margin.

Phytosociological analysis of acidophytic alpine mat-grass swards in the Julian Alps and the Karawanks

Abstract Acidophytic alpine mat-grass swards are rare in the alpine belt of the predominantly calcareous Southeastern Alps of Slovenia, mostly occurring where limestone is admixed with marlstone or chert. Those for which we were able to make phytosociological relevés can be classified mainly into two syntaxa: Carici curvulae-Nardetum strictae vaccinietosum gaultherioidis and Sieversio-Nardetum strictae vaccinietosum. At slightly lower elevations, in the forest zone of the subalpine plateau Pokljuka, we found similar swards occupying small areas in frost hollows with luvisol on limestone. They include character species of various subalpine-alpine sward and snow bed communities and are classified into the syntaxon Homogyno alpinae-Nardetum scorzoneroidetosum croceae.

Shedding light on species boundaries in small endogeic animals through an integrative approach: species delimitation in the centipedeClinopodes carinthiacus(Chilopoda: Geophilidae) in the south-eastern Alps

AbstractThe investigation of species boundaries in strictly endogeic animals is challenging because they are prone to fine-scale genetic and phenotypic geographical differentiation owing to low dispersal ability. An integrative approach exploiting different sources of information has seldom been adopted in these animals and even more rarely by treating all data sources equally. We investigated species boundaries in the endogeic centipede Clinopodes carinthiacus across the south-eastern Alps by studying genetic and morphological differentiation in a sample of 66 specimens from 27 sites, complemented by the morphological examination of more than 1100 specimens from other sites. Hypotheses of species delimitation were obtained independently from the molecular sequences of three markers (mitochondrial 16S and COI and nuclear 28S) by means of different species discovery methods (automatic barcode gap discovery, assemble species by automatic partitioning, general mixed Yule coalescent and the Poisson tree process) and from ten morphological characters by means of a model-based cluster analysis and Bayesian model selection. We found strong support for the existence of at least two species: C. carinthiacus s.s. and Clinopodes strasseri, which was formerly described as a subspecies of another species, and later placed in synonymy with C. carinthiacus. The two species coexist in syntopy in at least one site.

OH-Defects in Detrital Quartz Grains from the Julian Basin (NE Italy and Slovenia): A Fourier Transform Infrared Study

In this study, we analyzed up to 80 detrital quartz grains from four lithic greywackes along the stratigraphic column of the Julian Basin, a synorogenic basin in the southeastern Alps between Italy and Slovenia. Fourier transform infrared spectroscopy of detrital quartz was used to investigate the sample set with interest to its OH-defect speciation and content of each associated substitution. According to several recent studies, OH-defects in quartz are correlated to petrogenetic conditions of the source material and can be used as a provenance tool. The aim of this study is to compare results based on this method with previous studies that used other methods, to better constrain the palaeogeographical reconstruction of sedimentary fluxes. Detrital quartz within the samples of the basin shows different patterns of OH-defects and water content, indicating substantial petrogenetic differences between the sediment source rocks. For the oldest analyzed sample (ca. 66 Ma), the distribution of OH-defects suggests a mixed source between igneous and non-igneous rocks, with a predominance of metamorphic material supply. Another sample (56 Ma) reveals a great variability of OH-defects and water content, indicating that the magmatic component dominates over the metamorphic component. The distribution of OH-defects in the samples at the top of the sequence (52–53 Ma) suggests an almost solely metamorphic source. These results are in line with previous studies based on heavy minerals and geochemistry.

Topography of the Dolomites modulates range dynamics of narrow endemic plants under climate change

Climate change is expected to threaten endemic plants in the Alps. In this context, the factors that may modulate species responses are rarely investigated at a local scale. We analyzed eight alpine narrow endemics of the Dolomites (southeastern Alps) under different predicted climate change scenarios at fine spatial resolutions. We tested possible differences in elevation, topographic heterogeneity and velocity of climate change among areas of gained, lost, or stable climatic habitat. The negative impact of climate change ranged from moderate to severe, depending on scenario and species. Generally, range loss occurred at the lowest elevations, while gained and stable areas were located at highest elevations. For six of the species, climate change velocity had higher values in stable and gained areas than in lost ones. Our findings support the role of topographic heterogeneity in maintaining climatic microrefugia, however, the peculiar topography of the Dolomites, characterized by high altitude plateaus, resulted in high climate change velocity in areas of projected future climatic suitability. Our study supports the usefulness of multiple predictors of spatio-temporal range dynamics for regional climate-adapted management and eventual assisted colonization planning to not overlook or overestimate the potential impact of climate change locally.

Sava Valley (Posavina) – a heritage of communication Some examples from the Late Bronze Age

Dolina na Savi is a settlement and cemetery dated to the younger phase of the Late Bronze Age and the transition to the Early Iron Age. It is situated across the well-known site of Donja Dolina in northern Bosnia. Ten years of excavations in Dolina yielded numerous traces of communication between the communities along and across the river Sava through the centuries. A similar concentration of Late Bronze Age sites on the Sava can be observed near the settlement of Topolovaca Bregovi, some 70 m downstream. The data collected by archaeological research sheds new light on the role of the River Sava in the communication network of the transitional area between the Carpathian Basin, western Balkans, the Danube, and south-eastern Alps. In contrast to the modern perception of the River Sava as a border, the archaeological record from the Late Bronze Age clearly points to Posavina Region as a coherent cultural territory with a strong communication network both on local and regional scales. The distribution of specific bronze objects found in graves and settlements, but also discovered frequently as single finds along the riverbank, indicate the integration of the Posavina communities from the younger phase of the Late Bronze Age (late 12th – 10th centuries BC) into the communication network spanning eastern Austria, Moravia, Bohemia, and western Hungary. Better knowledge of the local communication heritage on both sides of the river is therefore crucial for the understanding of the wider contexts in a diachronic perspective, especially in the important and dynamic area of the middle Sava valley.

Late la Tène fibulae of the Rakitno-type. Evidence of contacts between the western Balkans and the southern part of the Carpathian basin

Fibulae with a knob on a backward-bent foot, of which different variants of the Picugi type are probably best known, evolved in the eastern Adriatic and its hinterland, and the wider south-eastern Alps during the last two centuries BC. A similar but distinct type of fibula named the Rakitno type has been identified based on its morphological characteristics and distribution. Fibulae of this type have mainly been recorded at sites in Bosnia and Herzegovina, but also in the Sava valley and eastern Slavonia. Similarities in the way they are decorated, with a series of knobs on the backward-bent foot, link fibulae of the Rakitno type with other contemporary forms recorded in the south-eastern part of the Carpathian Basin (fibulae of the Jarak type) and the south-eastern Alps (fibulae of the Mihovo type), indicating that designs were exchanged and then adapted to different communities in local workshops. On the other hand, finds of fibulae of the Rakitno type at sites in eastern Slavonia attest to contacts with communities settled in the western Balkans. Despite the absence of finds from closed associations, documented comparisons allow for fibulae of the Rakitno type to be dated to the latter half of the 2nd and the early 1st centuries BC, with the assumption that this design was typical of female costume.

Climate and Human Impacts Inferred from a 1500-Year Multi-Proxy Record of an Alpine Peat Bog in the South-Eastern Alps

Climate and Human Impacts Inferred from a 1500-Year Multi-Proxy Record of an Alpine Peat Bog in the South-Eastern Alps

Biological Flora of Central Europe: Chondrilla chondrilloides (Ard.) H. Karst

Chondrilla chondrilloides (Asteraceae) is a rare and endangered early-successional plant species endemic to the Eastern European Alps. Its distribution is restricted to near-natural braided rivers and to alluvial fans. The species was common along Alpine gravel rivers, but has declined markedly due to river regulation and degradation in the 19th and 20th century, while some recent restoration projects benefit the plant. Its population declines were caused by habitat fragmentation and destruction as a consequence of extensive hydro-engineering. This paper summarises the published material on taxonomy, morphology, habitat requirements and distribution of the species. The review is complemented by own research data and a phylogenetic assessment of extant and extinct populations within the infrageneric context. A summary on location, size and structure of the remaining populations in the north-eastern and south-eastern Alps is combined with data on seed germination and the habitat niche of the species, with a particular focus on differences between northern and southern populations. Chondrilla chondrilloides forms meta-populations on consolidated gravel bars and older terraces, with extinction and recolonisation due to floodplain dynamics; small populations quickly recover from few founder individuals. Populations in the southern parts of the species’ range are larger with bigger plants and more reproduction, while germination is very high in all populations. Thus, C. chondrilloides has characteristics that allow it to respond rapidly to degradation and restoration of its habitats along gravel rivers in the Eastern Alps.

Speciation of a subterranean amphipod on the glacier margins in South Eastern Alps, Europe

AbstractAimClimatic oscillations altered distributions through migration, extinction, adaptation or speciation. Their joint effect has been rarely studied. Here, we tested how Pleistocene climatic oscillations shaped the evolutionary history and distribution of a subterranean amphipod. We tested four predictions for extant populations: (i) populations of good dispersers moving along the ice‐sheet margin should have homogenous genetic structure and broad tolerance to temperatures; (ii) adaptation to local temperatures evolved in poor dispersers with spatially structured populations; (iii) Pleistocene extinctions in the range of historical glaciers should reflect founder effects and high sensitivity to low temperatures; (iv) para‐ or allopatric speciation could unfold through diverse scenarios as a response to local adaptation and constrained dispersal.LocationNorth‐Western part of the Balkan Peninsula, Europe.TaxonNiphargus stygius, Amphipoda, Crustacea.MethodsWe used time‐calibrated multilocus phylogenies and multilocus delimitations to test independently evolving lineages. For each lineage, separately we assessed historical population dynamics and dispersal potential, modelled climatic niches and mapped them onto palaeoclimatic maps. Additionally, we conducted enzymatic and respiratory tests of thermal tolerance, and reconstructed historical distribution range using phylogeographical diffusion analyses.ResultsWe identified four independently evolving tentative species, dated to the Pleistocene, with no evidence of extinction events. Three main lineages are parapatric with few pairwise syntopies and no traces of hybridization. They evolved in allopatry and possibly maintained constant effective population sizes. The lineages are phylogeographically substructured, indicating low recent dispersal. They differ in their climatic niche envelopes and physiological responses to unfavourable temperatures.Main conclusionsWe infer that periodic drops of groundwater in the Pleistocene caused two vicariant events and the onset of two allopatric speciation events, followed by phases of dispersal leading to secondary contact and occasional overlap of ranges. Speciation was seemingly fostered by eco‐physiologically differentiation due to adaptation to local climates.

Labelling, certification and branding of cheeses in the southeastern Alps (Italy, Slovenia): Montasio, Bovec, Tolminc and Mohant cheese

The paper presents various collective instruments used in the labelling, certification and branding of cheeses in the southeastern Alps of Slovenia and Italy. Based on long term ethnography it discusses four case studies of Montasio, Bovec, Tolminc, and Mohant cheeses, that were awarded protected designation of origin at European Union level. The impact of geographical indications on the local dairy chains is compared to other instruments, ranging from top-down European and national quality schemes and inventories of traditional agricultural products and heritage, to grass-root initiatives such as Slow Food instruments and local brands. The study finds substantial difference in the use and impact of geographical indications in Italy and Slovenia, as well as several ambiguous and dissonant effects in all the identified instruments.

A focal mechanism catalogue of earthquakes that occurred in the southeastern Alps and surrounding areas from 1928–2019

Abstract. We present a focal mechanism catalogue of earthquakes that occurred in the southeastern Alps and surrounding areas from 1928 to 2019. The area involved in the process of convergence between the Adria microplate and Eurasia is one of the most seismically active regions in the Alpine Belt. The seismicity is minor, with the Ms= 6.5 Friuli earthquake being the strongest event recorded in the area, but the seismic risk is relevant because it is a highly populated region. For this reason, numerous studies have been carried out over time to investigate the stress field and the geodynamic characteristics of the region using focal mechanisms. To provide a comprehensive set of revised information, which is challenging to build quickly because the data are dispersed over many papers, we collected and revised the focal mechanisms that were previously published in the literature. Additionally, depending on the data quality and availability, we computed new focal mechanisms by first arrival polarity inversion or seismic moment tensor. Finally, we merged all the fault plane solutions to obtain a catalogue for a selection of 772 earthquakes with 1.8≤M≤6.5. For each earthquake, we reported all the available focal mechanisms obtained by different authors. We also suggested a preferred solution for users who need information provided expeditiously. The catalogue (https://doi.org/10.5281/zenodo.4660412; Saraò et al., 2021) is given as the Supplement of this paper and will be updated periodically (https://doi.org/10.5281/zenodo.4284970).

Evidence for Glacial Refugia of the Forest Understorey Species Helleborus niger (Ranunculaceae) in the Southern as Well as in the Northern Limestone Alps.

Glacial refugia of alpine and subnival biota have been intensively studied in the European Alps but the fate of forests and their understory species in that area remains largely unclear. In order to fill this gap, we aimed at disentangling the spatiotemporal diversification of disjunctly distributed black hellebore Helleborus niger (Ranunculaceae). We applied a set of phylogeographic analyses based on restriction-site associated DNA sequencing (RADseq) data and plastid DNA sequences to a range-wide sampling of populations. These analyses were supplemented with species distribution models generated for the present and the Last Glacial Maximum (LGM). We used exploratory analyses to delimit genomically coherent groups and then employed demographic modeling to reconstruct the history of these groups. We uncovered a deep split between two major genetic groups with western and eastern distribution within the Southern Limestone Alps, likely reflecting divergent evolution since the mid-Pleistocene in two glacial refugia situated along the unglaciated southern margin of the Alps. Long-term presence in the Southern Limestone Alps is also supported by high numbers of private alleles, elevated levels of nucleotide diversity and the species’ modeled distribution at the LGM. The deep genetic divergence, however, is not reflected in leaf shape variation, suggesting that the morphological discrimination of genetically divergent entities within H. niger is questionable. At a shallower level, populations from the Northern Limestone Alps are differentiated from those in the Southern Limestone Alps in both RADseq and plastid DNA data sets, reflecting the North-South disjunction within the Eastern Alps. The underlying split was dated to ca. 0.1 mya, which is well before the LGM. In the same line, explicit tests of demographic models consistently rejected the hypothesis that the partial distribution area in the Northern Limestone Alps is the result of postglacial colonization. Taken together, our results strongly support that forest understory species such as H. niger have survived the LGM in refugia situated along the southern, but also along the northern or northeastern periphery of the Alps. Being a slow migrator, the species has likely survived repeated glacial-interglacial circles in distributional stasis while the composition of the tree canopy changed in the meanwhile.

High-Resolution Crustal S-wave Velocity Model and Moho Geometry Beneath the Southeastern Alps: New Insights From the SWATH-D Experiment

We compiled a dataset of continuous recordings from the temporary and permanent seismic networks to compute the high-resolution 3D S-wave velocity model of the Southeastern Alps, the western part of the external Dinarides, and the Friuli and Venetian plains through ambient noise tomography. Part of the dataset is recorded by the SWATH-D temporary network and permanent networks in Italy, Austria, Slovenia and Croatia between October 2017 and July 2018. We computed 4050 vertical component cross-correlations to obtain the empirical Rayleigh wave Green’s functions. The dataset is complemented by adopting 1804 high-quality correlograms from other studies. The fast-marching method for 2D surface wave tomography is applied to the phase velocity dispersion curves in the 2–30 s period band. The resulting local dispersion curves are inverted for 1D S-wave velocity profiles using the non-perturbational and perturbational inversion methods. We assembled the 1D S-wave velocity profiles into a pseudo-3D S-wave velocity model from the surface down to 60 km depth. A range of iso-velocities, representing the crystalline basement depth and the crustal thickness, are determined. We found the average depth over the 2.8–3.0 and 4.1–4.3 km/s iso-velocity ranges to be reasonable representations of the crystalline basement and Moho depths, respectively. The basement depth map shows that the shallower crystalline basement beneath the Schio-Vicenza fault highlights the boundary between the deeper Venetian and Friuli plains to the east and the Po-plain to the west. The estimated Moho depth map displays a thickened crust along the boundary between the Friuli plain and the external Dinarides. It also reveals a N-S narrow corridor of crustal thinning to the east of the junction of Giudicarie and Periadriatic lines, which was not reported by other seismic imaging studies. This corridor of shallower Moho is located beneath the surface outcrop of the Permian magmatic rocks and seems to be connected to the continuation of the Permian magmatism to the deep-seated crust. We compared the shallow crustal velocities and the hypocentral location of the earthquakes in the Southern foothills of the Alps. It revealed that the seismicity mainly occurs in the S-wave velocity range between ∼3.1 and ∼3.6 km/s.

Slavic Alpine micro-varieties as part of an “Alpensprachbund”?

AbstractThis chapter deals with some characteristics of two more-or-less isolated Slavic varieties in the south-eastern Alps: Resian and Carinthian Slovene, whose nearest relative among the Slavic standard languages is Slovene. Both have been for centuries in situations of total language contact with Romance and Germanic varieties. I will concentrate on thecomepassive. At least in Resian, it developed due to direct Romance influence, which could be claimed to be the overall reason for this grammatical feature in the Alps. The situation in Molise Slavic in southern Italy will serve as a point of comparison.

Evaluating DNA Barcoding for Species Identification and Discovery in European Gracillariid Moths

Gracillariidae is the most species-rich leaf-mining moth family with over 2,000 described species worldwide. In Europe, there are 263 valid named species recognized, many of which are difficult to identify using morphology only. Here we explore the use of DNA barcodes as a tool for identification and species discovery in European gracillariids. We present a barcode library including 6,791 COI sequences representing 242 of the 263 (92%) resident species. Our results indicate high congruence between morphology and barcodes with 91.3% (221/242) of European species forming monophyletic clades that can be identified accurately using barcodes alone. The remaining 8.7% represent cases of non-monophyly making their identification uncertain using barcodes. Species discrimination based on the Barcode Index Number system (BIN) was successful for 93% of species with 7% of species sharing BINs. We discovered as many as 21 undescribed candidate species, of which six were confirmed from an integrative approach; the other 15 require additional material and study to confirm preliminary evidence. Most of these new candidate species are found in mountainous regions of Mediterranean countries, the South-Eastern Alps and the Balkans, with nine candidate species found only on islands. In addition, 13 species were classified as deep conspecific lineages, comprising a total of 27 BINs with no intraspecific morphological differences found, and no known ecological differentiation. Double-digest restriction-site associated DNA sequencing (ddRAD) analysis showed strong mitonuclear discrepancy in four out of five species studied. This discordance is not explained by Wolbachia-mediated genetic sweeps. Finally, 26 species were classified as “unassessed species splits” containing 71 BINs and some involving geographical isolation or ecological specialization that will require further study to test whether they represent new cryptic species.

Investigating the provenance of Egyptian blue pigments in ancient Roman polychromy

Egyptian blue is a copper-based blue pigment that was widely used across the Mediterranean from ca. 3300 BC up to late antiquity and even later. For this case study, we analyzed the provenance of Egyptian blue from a Campana relief from the collection of the Ny Carlsberg Glyptotek, Denmark. Campana reliefs are terracotta plaques, which were named after the Italian collector Gampietro Campana, who published the first collection in 1851. These mould-made plaques were used as ornaments in central Italy from ca. 60 BC to 50 AD – a time when Egyptian blue production is attested at several sites in the Bay of Naples, Italy. The provenance of copper raw materials that were used for producing this pigment could provide clues about the distribution of production centers and trade contacts. A previous investigation of the provenance of a single bulk Egyptian blue sample of this artefact by Rodler et al. (2017) indicated a possible long-distance transport of (Iberian) copper ore or mixing of distant (Iberian) and Italian copper. Our new data are based on the lead isotope analysis of four individual Egyptian blue samples. The refined sampling resolution emphasizes the Italian South-Eastern Alps as the most likely source area of copper raw materials. This copper could have been processed in local Egyptian blue production workshops or brought to the contemporary Egyptian blue production hub in the Bay of Naples and transported from there to the workshop where the artefact was painted.

The disappearing cryosphere in the southeastern Alps: Introduction to special issue

Various ice bodies are an important source of paleoenvironmental data, and their study improves the understanding of present and future environmental conditions. Their changes are an important indicator of climate change. This special issue of Acta geographica Slovenica draws attention to the changing and disappearing cryosphere across the globe, with an emphasis on the southeastern Alps, and the necessity to conduct research in this field before the ice disappears forever. This paper briefly summarizes the current body of knowledge on glaciers, permafrost, cave ice, lake and river ice, and snow in the southeastern Alps, and it presents the contribution of Acta geographica Slovenica to this research and the main highlights of all five papers included in this special issue.

Changes in the Skuta Glacier (southeastern Alps) assessed using non-metric images

The Skuta Glacier in the Kamnik–Savinja Alps (in northern Slovenia) is one of the two remaining glaciers in Slovenia. It is located in a cirque oriented toward the northwest, which shields it from sunlight for most of the year. The glacier lies at an average elevation of 2070m. In recent years, its average area has measured around 1.5 hectares. Monitoring of the glacier has been performed since 1946. In 1962, regular photographing of the glacier with various cameras started from various non-fixed standpoints. Using the single image interactive orientation acquisition method, in which a single photograph is compared with the projection of a modern digital terrain model, seventeen photographs covering the period from 1970 to 2015 were used to acquire the 3D-perimeters of the glacier. The data shows that the elevation of glacier’s upper edge decreased by approximately 40m in the last half-century. Changes in the glacier’s area and average upper edge elevation were compared with average annual temperature and maximum seasonal snow cover depth.

The geochemistry of ice in the southeastern Alps, Slovenia

The Triglav Glacier in the Julian Alps and the Skuta Glacier in the Kamnik-Savinja Alps are among the south-easternmost glaciers in the Alps. Historical data show that ice masses are undergoing mass loss as the overall climate warms. Glacier ice and cave ice contain a wealth of paleoclimatic information, and rapid sampling is needed if any such information is to be saved before the ice is completely melted. We present the first comprehensive geochemical and water isotope data from glacier ice, meltwater, spring water, and cave ice in the Mount Triglav area and glacier ice from the Skuta Glacier. The samples primarily reflect the initial precipitation signal that has been greatly modified by the input of local CaCO3-rich dust with lesser amounts of marine aerosol and vegetation debris.