Valais Region Research Articles

From risk to reward: the strategic advantages of diversifying grape varietals

PurposeThe purpose of this study is to evaluate whether a diversification by grape varieties may help wine producers reduce uncertainty in quantity and quality variations due to increasingly erratic climate conditions.Design/methodology/approachThis study hand-collects granular quantity and quality data from wine harvest reports for vintages 2003 to 2017 for the Valais region in Switzerland. The data allows us to obtain detailed data on harvested kilograms/liters and Oechsle/Brix degrees. It is then merged with precise meteorological data over the same sample period. The authors use this data set to capture weather conditions and their impact on harvested quantities and quality. Finally, they build portfolios including different grape varieties to evaluate whether this reduces variations in quality and quantity over vintages.FindingsThe findings highlight that the weather varies relatively strongly over the sample period and that climate hazards such as hail, frost or ensuing vine diseases effectively occur. These strongly impact the harvested quantities but less the quality of the wine. The authors further show that planting different grape varieties allows for a significant reduction in the variation of harvested quantities over time and thus acts as a good solution against climate risk.Originality/valueThe effect of climate change on viticulture is becoming increasingly important and felt and bears real economic and social consequences. This study transposes portfolio diversification which is central to reducing risk in the finance industry, into the wine industry and shows that the same principle holds. The authors thus propose a novel idea on how to mitigate climate risk.

Tracking Alpine copper—analysis of Late Bronze Age copper ingot hoard from South Bohemia

We present the results of a complex archaeometric study of Late Bronze Age copper ingots from the Stare Hodějovice hoard (South Bohemia). In order to understand the origin of the copper and describe the metallurgical process, we use modern analytical methods (metallography analyses, major/trace element and lead isotope analyses) to describe the samples. Within this study, a representative dataset of trace element composition and lead isotope ratios of non-alloyed and non-recycled corpus of copper ingots from the Late Bronze Age was created. We assume that most of the ingots were not altered by alloying, mixing or recycling. Based on lead isotope ratios and major/trace element composition, we suppose that the origin of the copper could be mostly Alpine ores from the Trentino and Mitterberg regions and possibly the Valais region. By this study, it was proved that copper smelted by a matte smelting process was transported in the form of flat or plano-convex ingots from multiple sources to South Bohemia, where it was subsequently refined and alloyed. Obtained analytical results refute the idea of prevailing copper recycling in the Late Bronze Age.

A study of the Würm glaciation focused on the Valais region (Alps)

Abstract. During the Last Glacial Maximum (LGM), the glaciation in the European Alps reached maximum ice extent. We already simulated the steady states of the Alpine ice coverage for several climate drivers in Becker et al. (2016) and heighten in this article such studies for the Swiss Valais region. To this end, we employ the Parallel Ice Sheet Model (PISM), which combines the shallow ice approximation (SIA) with basal sliding elements of the shallow shelf approximation (SSA), and subject this model to various external driving mechanisms. We further test the sensitivity of this kind of the ice coverage in the Valais region to a temporally constant climate and to monotonic ice sheet build-up from inception to steady state as well as to the Dye 3 temperature driving during the past 120 000 years. We also test differences in the precipitation patterns exerted to the northern and southern catchment areas of the Rhone and Toce rivers to possible transfluence changes in ice from the northern to the southern catchment areas and vice versa. Moreover, we study the effect of the ice deformability and estimate the removal up to 1000 m of sediment in the Rhone Valley and study the removal of rock hindering the flow through the valley cross section at the knee of Martigny. All these studies took place because of a discrepancy in the ice height prediction of the modelled ice sheet with its geomorphologically reconstructed counterpart with proxy data obtained by Bini et al. (2009) as well as a difference in ice height between the two of up to 800 m. Unfortunately, all the scenarios in the model do not sufficiently reduce this discrepancy in the height prediction and the geomorphological reconstruction. The model results have discovered an ice dynamical discrepancy with the land map in Bini et al. (2009).

Migratory trajectory and recomposing of Alpine societies

In 2011 and 2012, we carried out a multi-disciplinary field study in the lower Valais region. The goal of this study was to account for the immigration and integration mechanisms at a very local level, as close as possible to the experience of our acting participants, who were immigrants. The project comprised an anthropological section, which led to the content of this article, and a historical part that makes visible the continuities and disruptions of migratory movements.This anthropological research, which essentially has a qualitative nature, comprised two inseparable aspects. On the one hand, we questioned the motivations behind the ever-increasing number of migrants settling over the past two or three decades in 14 villages situated in the Bagnes and Entremont valleys, as well as a commune in the Rhone plain, and the way in which they have managed to become “social actors” and put down roots in their respective communities. On the other hand, our study raises the issue of the perpetual recomposing of mountain societies, still often perceived – or promoted – as entities that are rather homogeneous, authentic and specific. In other words, our survey is situated at the intersection between individual and collective identities.

Characterization and dynamic behavior of wild yeast during spontaneous wine fermentation in steel tanks and amphorae.

We studied the dynamic behavior of wild yeasts during spontaneous wine fermentation at a winery in the Valais region of Switzerland. Wild yeasts in the winery environment were characterized using a PCR-RFLP method. Up to 11 different yeast species were isolated from the vineyard air, whereas only seven were recovered from the grapes surface. We initially investigated a cultureindependent method in pilot-scale steel fermentation tanks and found a greater diversity of yeasts in the musts from two red grape varieties compared to three white grape varieties. We found that the yeasts Metschnikowia pulcherrima, Rhodotorula mucilaginosa, Pichia kluyveri, P. membranifaciens and Saccharomyces cerevisiae remained active at the end of the fermentation. We also studied the dynamic behavior of yeasts in Qvevris for the first time using a novel, highlysensitive quantitative real-time PCR method. We found that non-Saccharomyces yeasts were present during the entire fermentation process, with R. mucilaginosa and P. anomala the most prominent species. We studied the relationship between the predominance of different species and the output of the fermentation process. We identified so-called spoilage yeasts in all the fermentations, but high levels of acetic acid accumulated only in those fermentations with an extended lag phase.

Provenance of Early Bronze Age metal artefacts in Western Switzerland using elemental and lead isotopic compositions and their possible relation with copper minerals of the nearby Valais

Ten Early Bronze Age (BzA1, 2200–2000 BC) copper artefacts from the central Valais region from Switzerland were studied for their elemental composition and lead isotope ratios. In order to answer the archaeological question of a local copper supply, a database for copper minerals across the Valais (Switzerland) has been established. This database contains 69 data on lead isotope ratios as well as additional information on the minerals and geochemical associations for copper minerals from 38 locations in the Valais. Comparisons of the artefacts were also made with data pertaining to minerals from various deposits from Europe and Anatolia taken from the literature. The provenance of the materials is very diverse. Some of the data are compatible with the data from the copper mineral deposits of the Valais region. Moreover, three copper lunulae were identified as possibly Tuscan, which suggests contacts between Italy and the Valais region. This pattern also establishes a multiplicity of provenances for the metal and cultural influences in the Alpine environment of the Rhone Valley of Switzerland at the beginning of the Early Bronze Age.

The 1946 magnitude 6.1 earthquake in the Valais: site-effects as contributor to the damage

The January 25, 1946 earthquake in the central Valais region in southwest Switzerland was the strongest for the last 150 years. It reached an epicentral intensity Io of VIII in the area of Sierre. The Swiss Earthquake Catalogue (ECOS 2002) assigns a moment magnitude of Mw = 6.1 to the event. Assessment of recordings from European stations resulted in a moment magnitude of 5.8 (Bernardi et al. 2005). The earthquake caused moderate to high damage within a circle of about a 25 kilometer radius. Slight damage occurred up to a distance of 200 kilometers from the epicenter. The goal of this study was to reconstruct the damage field and consider its possible site-effects. We used an approach combining historical research with seismo-/geological investigation including a large number of experiments measuring the fundamental frequency of resonance and the shear-wave velocities of the sedimentary layers, using the characteristics of ambient vibration. This kind of research is relevant, since a huge alpine valley characterizes the Valais region, showing ground conditions that make site-effects likely for earthquakes. While we searched for damage in an unlimited area, our investigation of site-effects was limited to the Rhone valley and to Sion and Sierre in the central Valais region in particular. Since a contemporary damage assessment has survived in fragments only, the results of our historical investigation are incomplete. Nevertheless, it was possible to describe the losses within the epicentral region adequately enough to discuss possible site-effects. Our results show that Valaisan districts with a high percentage of settlement on the lacustrine and fluviatile deposits of the Rhone valley show higher losses than other districts. The villages of Sierre and Sion we investigated in more detail. Sion is located on compacted sediments with relatively high shear-wave velocities. The city suffered only moderate damage, rather regularly distributed. In Sierre, on the other hand, we identified two zones of significantly increased damage, in which site-effects appear a very probable contributor. Local two- or three-dimensional resonance phenomena play an important role in explaining this feature.

Microsatellites reveal genetic differentiation among populations in an insect species with high genetic variability in dispersal, the codling moth,Cydia pomonella(L.) (Lepidoptera: Tortricidae)

Little is known about genetic differentiation and gene flow in populations of insect species that have a high genetic variability in dispersal but lack morphologically visible morphs that disperse. These characteristics apply to the codling moth, Cydia pomonella L. (Lepidoptera: Tortricidae), a major pest of fruits and nuts. Larvae were collected from three orchards each of pome fruits, stone fruits and nut trees in a major fruit growing area of Switzerland (Valais) and from six further (mainly apple) orchards throughout this country. Nine microsatellite loci were used to investigate genetic differentiation and the amount of gene flow among the sampled populations. All the loci were shown to be polymorphic in all populations. The number of alleles ranged from five to 15 over nine loci for the 15 populations. Significant genetic differentiation was noted among the populations from apple, apricot and walnut in the Valais region. Furthermore, among the eight populations sampled from apple in different geographic regions throughout Switzerland, AMOVA and pairwise FST analysis revealed significant population genetic differentiation even between populations collected from orchards 10 km apart. These results indicate that a distinct prevailing characteristic, in the present case the sedentary behaviour of the moth, can shape population architecture.

Harmonisation et définition des unités lithostratigraphiques briançonnaises dans les nappes penniques du Valais

The Brianconnais lithostratigraphic units in the Valais region consist of pre-Triassic basements and metamorphic Mesozoic–Cenozoic covers. Structurally they constitute the «Grand St-Bernard nappe» and partly the «Combin zone» of Argand (1908, 1909), now considered as middle and upper Penninic nappes. Successively the tectonic and lithostratigraphic models were refined (fig. 1; Bearth 1963, Escher 1988, Steck et al. 1999). Stratigraphic as well as structural links were established with the nappes of the Prealpes representing the nonmetamorphic sedimentary cover pushed into a more external position.

400 Years of Debris-Flow Activity and Triggering Weather Conditions: Ritigraben, Valais, Switzerland

Three major rainfall events have caused considerable damage in the Valais region (Swiss Alps) since 1987. Substantial debris flows originating from periglacial environments were recorded during the August 1987 and September 1993 rainfall events, whereas no debris flows occurred in October 2000. This paper aims at putting these large-area events and the apparent increase in debris-flow frequency into a wider context by reconstructing the past debris-flow activity in the Ritigraben torrent (Mattertal, Valais) with dendrogeomorphological methods. Tree-ring analysis allowed the reconstruction of 53 events, going back to the year 1605. Previously, only 10 debris flows had been known for the torrent, and these were limited to the period between 1922 and 2002. Results further show that the apparently above-average concentration of events since 1987 was mainly caused by insufficient and short archival data. In fact, debris flows occurred even more frequently in the nineteenth century than they do today. The spatial distribution of injured trees in particular years further indicates that significant events, like the one in 1993, always occurred in the torrent. Finally, reconstructed event years were compared with archival data on flooding in neighboring catchments. The comparisons prove that large-area events like those in 1987, 1993, or 2000 have at least been as common in the past as they are today.

Local re-appropriation of tourism : The case of Verbier (Switzerland)

Abstract : The article endeavours to analyse the representations of the local population of a mountain area affected tourism development by examining the discourse of the inhabitants. Using the example of Verbier in the Valais region of the Swiss Alps, we attempt to show that the relations between the resident population and the local area depend on a tourism-based productive system and that these relations are strongly influenced by tourism-based representations of both the local area and the landscape. Going beyond this observation, our analysis reveals that the touristic places and the landscape, originating a priori in their perception by people from outside the area, become transformed into identity attributes that are used by die resident population to define the relationship that they have with their local area. The representation of certain places in the Verbier local area is examined. These are found to be subjected, in varying degrees, to this process of identification.

The Valais earthquake of December 9, 1755

The earthquake on December 9, 1755 is one of the major events in the Valais region, having an important influence on the seismic hazard assessment of the area. The re-evaluation of the event was undertaken in the course of upgrading the Earthquake Catalog of Switzerland (ECOS). It is now based on a newly investigated and reliable database created through research in archives and libraries. Using the data made available by the historical information, we assigned site intensities according to the criteria established by the European macroseismic scale EMS 98 (Grunthal 1998). Based on the broad spectrum of the available information, we assigned minimum and maximum possible values (Imin; Imax) and determined a most probable intensity value (Iw) for each site. The maximum observed intensity, Ix, is the largest intensity for each quake. Epicentral intensity, I0, is equal to the maximum observed intensity Ix, if at least two data points are assigned an intensity of Ix. We obtained maximum Ix = I0 = VIII at Brig/VS (46.3/8.0) and moment magnitude Mw = 6.1.

The instrumental seismicity of the western Alps: spatio-temporal patterns analysed with the wavelet transform

We perform a spatial and temporal analysis of the instrumental seismicity of the Western Alps, between latitude 41°–48° N and longitude 5°–10° E, using a recently revised catalogue available for the period 1962–1995 containing 7500 events in the magnitude range 2–5.9. Taking into account the fact that the major difficulty of such an analysis in an area of moderate seismicity is the long return period of the events and the diffusive character of the seismic swarms, we first carry out a statistical analysis of the 3-D distribution of the foci with the help of a 3-D wavelet transform. This smooths the location errors, which are estimated to be 1 km in epicentral coordinates and 5 km for the depth for recent years, whereas they are more than 10 km in epicentral coordinates for the oldest events. The good agreement between the shape of the filtered volumes and geological/tectonic features supports this new methodology for defining seismogenic zones, which are outlined better than by simple observations of the seismicity map. The study of seismic energy release shows the major heterogeneity in the mechanical behaviour of these seismogenic zones. An evaluation of seismic deformation has been carried out for some of these regions and compared with published geodetic results. The cumulative slip estimated for the Durance fault is 0.01 mm yr−1 (1° per cent of the geodetic estimation), and for the Vuache fault it is 0.19 mm yr−1, whereas historical triangulation yields horizontal movements of up to 5 mm yr−1 in the neighbourhood of the Vuache fault. In the Valais region, the ‘seismic’ shear strain rate has been evaluated to be 5 × 10−4μrad yr−1 (0.5 per cent of the geodetic deformation); in the Ligurian Sea, the shortening rate deduced from seismological data is 1.1 mm yr−1 (20 per cent of the geodetic evaluation). The paradoxical result of this study is that areas where instrumental seismicity is low correspond to the location of strong historical seismicity or to regions of high geodetic deformation. Only two regions (Valais and the Ligurian Sea) seem to correspond in historical and present seismicity. These results show the difficulty of predicting seismic activity in such areas. The discrepancy between low seismic activity, high local deformation rate, and the moderate average velocity between Africa and Europe in the western Alpine region needs to be explained by any tectonic theory of the western Alps.

Predicting the potential distribution of plant species in an alpine environment

Abstract. The relationships between the distribution of alpine species and selected environmental variables are investigated by using two types of generalized linear models (GLMs) in a limited study area in the Valais region (Switzerland). The empirical relationships are used in a predictive sense to mimic the potential abundances of alpine species over a regular grid. Here, we present the results for the alpine sedge Carex curvula ssp. curvula. The modelling approach consists of (1) a binomial GLM, including only the mean annual temperature as explanatory variable, which is adjusted to species presence/absence data in the entire study area; (2) a logistic model restricted to stands occurring within the a priori defined temperature range for the species ‐ which allows ordinal abundance data to be adjusted; (3) the two species‐response functions combined in a GIS to generate a map of the species' potential abundance in the study area; (4) model predictions filtered by the classes of the qualitative variables under which the species never occur.Such a stratified approach used to better fit the variability within the optimal altitudinal zone for the species. Removing stand descriptions from altitudes too high or too low, where the species is unlikely to occur, enhances the global modelling performance by allowing the identification of important environmental variables only retained in the second model.The model evaluation is finally carried out with the γ‐measure of association in an ordinal contingency table. It shows that abundance is satisfactorily predicted for C. curvula.

Influence of water abstraction on the macroinvertebrate community gradient within a glacial stream system: La Borgne d'Arolla, Valais, Switzerland

SUMMARY1. Water abstraction from glacial rivers is an important characteristic of hydroelectric power schemes in Alpine regions. Streams in the Valais region of Switzerland have been particularly affected.2. Invertebrate distributions are described in La Borgne d'Arolla, a glacial stream with icemelt‐, snowmelt‐ and groundwater‐dominated tributaries. The icemelt‐dominated streams have been affected by abstractions for more than 30 years.3. The glacial streams contain only Chironomidae (Diamesa), and are devoid of fauna for between 200 and 500 m below the glacier snouts.4. Immediately below the water intakes the streams are intermittent, flowing only during system purges and high floods, and are devoid of fauna for short distances (<1.5km).5. Further downstream, abstraction of glacial meltwater increases the importance of snowmelt and groundwater, increasing water temperatures, improving water clarity and increasing the length of krenal/rhithral streams at the expense of kryal streams.6. A community including Chironomidae, Simuliidae, Baetidae, Nemouridae, Limnephilidae and Chloroperlidae occurs as soon as a permanent flow is maintained by tributary runoff, and the channel becomes stable.7. A wide range of taxa inhabit snowmelt‐ and groundwater‐dominated tributary streams with stable channels, often at much higher altitudes than the main river. The tributaries provide sources for rapid colonization of the main channel following ice retreat or physical disturbance.8. Purges and high floods are important disturbances within the main channel. Recovery may be rapid because of drift from tributaries, but sites influenced by frequent disturbances have reduced faunas in comparison to stable channel sites.9. This study supports the model proposed by Milner & Petts (1994) and shows that deterministic responses of macroinvertebrate communities may be observed to changes of temperature, turbidity, flow regime and channel stability.

Remarques sur la correlation des unites penniques externes entre la Savoie et le Valais et sur l'origine des nappes prealpines

Abstract Discusses the tectonic relationships of Pennine structural elements and the sources of Prealpine nappes in the Savoy (France)-Valais (Switzerland) region. The source of the central Prealpine nappe seems to have been in the Subbrianconnais-outer Brianconnais zone. Plastic elements were thrust along Carnic (Triassic) gypsum beds, whereas rigid elements were dislocated along Werfenian (Triassic) gypsum. Between the Ultradauphinois- Ultrahelvetic and the Subbrianconnais zones, north of the Arc river, lies the Valais zone which had an independent paleogeographic history. The source of the upper Prealpine nappes is still uncertain.

Infrastructure des Alpes et tremblement de terre du 25 janvier 1946 [with discussion

Abstract Distinguishes four structural complexes in the Alps, noting in particular that the crystalline basement is composed not only of Hercynian (late Paleozoic) masses but also of recrystallized material which had been subjected to extensive folding prior to emplacement of Hercynian granite massifs, probably during the Caledonian (early Paleozoic) orogeny rather than in an early stage of the Hercynian orogeny. The earthquake in the Valais region, Switzerland, was undoubtedly tectonic in origin, but whether it represented a continuation of Alpine movements or was caused by subsidence associated with isostatic readjustment of crustal blocks cannot yet be determined.