Swiss Alpine Region Research Articles

How farmers’ self-identities affect agri-environmental transition in Grassland Use: a mixed method study in the Swiss Alpine Region

How farmers’ self-identities affect agri-environmental transition in Grassland Use: a mixed method study in the Swiss Alpine Region

A quest for precipitation attractors in weather radar archives

Abstract. Archives of composite weather radar images represent an invaluable resource to study the predictability of precipitation. In this paper, we compare two distinct approaches to construct empirical low-dimensional attractors from radar precipitation fields. In the first approach, the phase space variables of the attractor are defined using the domain-scale statistics of precipitation fields, such as the mean precipitation, fraction of rain, and spatial and temporal correlations. The second type of attractor considers the spatial distribution of precipitation and is built by principal component analysis (PCA). For both attractors, we investigate the density of trajectories in phase space, growth of errors from analogue states, and fractal properties. To represent different scales and climatic and orographic conditions, the analyses are done using multi-year radar archives over the continental United States (≈4000×4000 km2, 21 years) and the Swiss Alpine region (≈500×500 km2, 6 years).

Supercell Thunderstorms in Complex Topography—How Mountain Valleys with Lakes Can Increase Occurrence Frequency

Abstract This study investigates the effects of lakes in mountainous terrain on the evolution of supercell thunderstorms. With a newly developed radar-based, mesocyclone-detection algorithm, a recent study has characterized the occurrence and evolution of supercell thunderstorms in the Swiss Alpine region. That study highlights the influence of orography on both storm intensity and occurrence frequency. To disentangle the different influential factors, an idealized modeling framework is established here using the mesoscale model CM1. The modeling scenarios are based on a high-CAPE environment with unidirectional shear, where a warm bubble serves to initiate the convection. Mimicking the environment of the southern Prealps in central Europe, scenarios with a high mountain ridge, valleys, and lakes are explored. The effect on the supercells of the slopes, high-altitude terrain, and moisture sources emphasizes the highly localized nature of terrain effects, leading to a heterogeneous intensity life cycle with transitory enhancement and weakening of the supercell. The dynamic and thermodynamic impact of mountain valleys with lakes increases the range of atmospheric conditions that supports supercellular development through horizontal vorticity production, increased storm relative helicity, and higher moisture content. This influence results in a systematic location dependence of the frequency, intensity, and lifetime of supercells, as also found in observations.

Perceived feasibility of sward management options in permanent grassland of Alpine regions and expected effects on delivery of ecosystem services

Agriculture in Alpine regions plays an important role for multiple ecosystem services (ES) supplied from permanent grassland (PG). This paper investigates the feasibility of sward renewal, overseeding, and rising plate meters on PG for the Swiss Alpine region and analyses their expected effects on ES supply. Sward renewal and overseeding are management options implemented in response to a decline of grassland yields and nutritive value or sward damage. Rising plate meters focus on increased grass utilisation for improving profitability of grassland farms in a sustainable manner. The aim was to improve the understanding which of these three PG management practices could be promoted to deliver a wide range of agricultural and non-agricultural ESs in the Swiss Alpine region. Through interviews with 75 farmers (including organic and intensive/extensive non-organic farmers) and a Delphi-methodology on a panel of experts (N = 10 experts with different expertise), we found that sward renewal is perceived to have negative effects on biodiversity, carbon storage, flood control, prevention of soil erosion, and prevention of loss of organic matter in Alpine regions. Therefore, sward renewal should not be promoted, although about half of the farmers interviewed had already carried out the practice on plots following severe sward damage in Alpine regions. Overseeding is perceived to have positive effects on biodiversity, prevention of soil erosion, and grass production. Thus, the high level of overseeding that is currently practiced in the Swiss Alpine region is probably sustainable. Rising plate meters do not play a significant role in PG management in the Alpine region because calibration in PG with diverse grassland botanical composition in the Alpine region is too difficult.

Assessment of the stream invertebrate -diversity along an elevation gradient using a bidimensional null model analysis.

β‐Diversity, commonly defined as the compositional variation among localities that links local diversity (α‐diversity) and regional diversity (γ‐diversity), can arise from two different ecological phenomena, namely the spatial species turnover (i.e., species replacement) and the nestedness of assemblages (i.e., species loss). However, any assessment that does not account for stochasticity in community assembly could be biased and misinform conservation management. In this study, we aimed to provide a better understanding of the overall ecological phenomena underlying stream β‐diversity along elevation gradients and to contribute to the rich debate on null model approaches to identify nonrandom patterns in the distribution of taxa. Based on presence‐absence data of 78 stream invertebrate families from 309 sites located in the Swiss Alpine region, we analyzed the effect size of nonrandom spatial distribution of stream invertebrates on the β‐diversity and its two components (i.e., turnover and nestedness). We used a modeling framework that allows exploring the complete range of existing algorithms used in null model analysis and assessing how distribution patterns vary according to an array of possible ecological assumptions. Overall, the turnover of stream invertebrates and the nestedness of assemblages were significantly lower and higher, respectively, than the ones expected by chance. This pattern increased with elevation, and the consistent trend observed along the altitudinal gradient, even in the most conservative analysis, strengthened our findings. Our study suggests that deterministic distribution of stream invertebrates in the Swiss Alpine region is significantly driven by differential dispersal capacity and environmental stress gradients. As long as the ecological assumptions for constructing the null models and their implications are acknowledged, we believe that they still represent useful tools to measure the effect size of nonrandom spatial distribution of taxa on β‐diversity.

Heat and Moisture Relevant In Situ Measurements in a Railway Passenger Vehicle Driving through the Swiss Alpine Region

Transportation is a major sector of energy consumption in most, if not in all, European countries. Besides the energy used for traction, energy is also consumed for ventilation, heating, and cooling inside the vehicles to assure traveler comfort. This issue gains increasing importance as the demand for public transport increases in the future. There is a need for retrofit to improve the thermal resistance of the envelope of existing vehicles to reduce the heat loss to the environment during the cold period of the year, especially in the Alpine region. A major concern in adding insulation material to the envelope is the possibility of convective moisture transfer due to air circulation in the vehicle, which would cause condensation accumulation on the cold surfaces. The present investigation addresses this topic by measuring surface and air temperature, air moisture, air flow, and heat flow at several critical locations of a vehicle during its travel in the Swiss Alpine region over several months during the cold period of the year. Temperature measurements showed the potential of reducing the heat losses in some parts of the vehicle. The level and duration of the moisture exposure did not suggest a relevant formation of condensation in the cross-section of the vehicle wall. The observed increase in relative humidity when driving through tunnels is too short to cause relevant condensation in the vehicle shell. The measured low air flow justifies the assumption that no forced convection occurs in the envelope cavities.

Heat and Moisture Relevant In-Situ Measurements in a Railway Passenger Vehicle Driving Through the Swiss Alpine Region

Heat and Moisture Relevant In-Situ Measurements in a Railway Passenger Vehicle Driving Through the Swiss Alpine Region

Time-dependent source apportionment of submicron organic aerosol for a rural site in an alpine valley using a rolling positive matrix factorisation (PMF) window

Abstract. We collected 1 year of aerosol chemical speciation monitor (ACSM) data in Magadino, a village located in the south of the Swiss Alpine region, one of Switzerland's most polluted areas. We analysed the mass spectra of organic aerosol (OA) by positive matrix factorisation (PMF) using Source Finder Professional (SoFi Pro) to retrieve the origins of OA. Therein, we deployed a rolling algorithm, which is closer to the measurement, to account for the temporal changes in the source profiles. As the first-ever application of rolling PMF with multilinear engine (ME-2) analysis on a yearlong dataset that was collected from a rural site, we resolved two primary OA factors (traffic-related hydrocarbon-like OA (HOA) and biomass burning OA (BBOA)), one mass-to-charge ratio (m/z) 58-related OA (58-OA) factor, a less oxidised oxygenated OA (LO-OOA) factor, and a more oxidised oxygenated OA (MO-OOA) factor. HOA showed stable contributions to the total OA through the whole year ranging from 8.1 % to 10.1 %, while the contribution of BBOA showed an apparent seasonal variation with a range of 8.3 %–27.4 % (highest during winter, lowest during summer) and a yearly average of 17.1 %. OOA (sum of LO-OOA and MO-OOA) contributed 71.6 % of the OA mass, varying from 62.5 % (in winter) to 78 % (in spring and summer). The 58-OA factor mainly contained nitrogen-related variables which appeared to be pronounced only after the filament switched. However, since the contribution of this factor was insignificant (2.1 %), we did not attempt to interpolate its potential source in this work. The uncertainties (σ) for the modelled OA factors (i.e. rotational uncertainty and statistical variability in the sources) varied from ±4 % (58-OA) to a maximum of ±40 % (LO-OOA). Considering that BBOA and LO-OOA (showing influences of biomass burning in winter) had significant contributions to the total OA mass, we suggest reducing and controlling biomass-burning-related residential heating as a mitigation strategy for better air quality and lower PM levels in this region or similar locations. In Appendix A, we conduct a head-to-head comparison between the conventional seasonal PMF analysis and the rolling mechanism. We find similar or slightly improved results in terms of mass concentrations, correlations with external tracers, and factor profiles of the constrained POA factors. The rolling results show smaller scaled residuals and enhanced correlations between OOA factors and corresponding inorganic salts compared to those of the seasonal solutions, which was most likely because the rolling PMF analysis can capture the temporal variations in the oxidation processes for OOA components. Specifically, the time-dependent factor profiles of MO-OOA and LO-OOA can well explain the temporal viabilities of two main ions for OOA factors, m/z 44 (CO2+) and m/z 43 (mostly C2H3O+). Therefore, this rolling PMF analysis provides a more realistic source apportionment (SA) solution with time-dependent OA sources. The rolling results also show good agreement with offline Aerodyne aerosol mass spectrometer (AMS) SA results from filter samples, except for in winter. The latter discrepancy is likely because the online measurement can capture the fast oxidation processes of biomass burning sources, in contrast to the 24 h filter samples. This study demonstrates the strengths of the rolling mechanism, provides a comprehensive criterion list for ACSM users to obtain reproducible SA results, and is a role model for similar analyses of such worldwide available data.

Finding shared solutions in landscape or natural resource management through social learning: A quasi-experimental evaluation in an Alpine region

ContextThe implementation of landscape-management decisions is often blocked because actors disagree in their perception of the problem at hand. These conflicts can be explained with the concept of problem framing, which argues that actors’ problem perspectives are shaped by their interests. Recent literature suggests that social learning through deliberative processes among actors enables shared solutions to complex landscape-management conflicts.MethodsTo examine these assumptions, a participatory process on integrated water-resource-management in a Swiss Alpine region was systematically evaluated using a quasi-experimental intervention-research design. The involved actors’ problem perspectives were elicited before and after the participatory processes using qualitative interviews and standardized questionnaires. Furthermore, a standardized survey was sent to a sample of regional residents (N = 2000) after the participatory process to measure the diffusion of actors’ social learning to the wider public.ResultsThe data analysis provided systematic evidence that a convergence of involved actors’ problem perspectives, which were found to differ considerably before the intervention, had taken place during the participatory process. Furthermore, it determined diffusion effects of actors’ social learning to the wider public in terms of its attitude towards participatory regional planning.ConclusionsThe findings confirm the expected mechanism of social learning through deliberative processes and demonstrate it as a promising approach to implementing landscape-management decisions successfully. The catalyzing role of shared interests among actors suggests that landscape-management decisions should be implemented by participatory integrated planning on the regional level, which would require a new, strategic role of regional institutions.

Economic assessment of potential efficiency gains in typical lamb production systems in the alpine region by using local resources

Abstract The alpine region is very suitable for sheep farming, which keeps the landscape open and produces meat by using local resources. However, the market has more potential than currently realised, but the profitability of lamb production needs to be improved. Management changes would allow efficiency gains and could be implemented on farms in the short or medium term. Thus, based on traditional high-quality forage management in the Swiss alpine region, we analysed the profitability of lamb production systems by full-cost accounting and by examining the economic impact of variables such as productivity, live weight and fattening management for two typical (standardised) farms: 1) farm with 200 sheep (Hill-200) in a hilly area with accelerated lambing and 2) farm with 140 sheep (Mount-140) in a mountainous area with seasonal lambing once per year. In both farm types, conventional breed types resulting from displacement crossing were kept on a constant forage area. The analyses were based on accountancy data and face-to-face interviews with farmers on 15 single farms in different regions. For Hill-200, next to other simulated management interventions the most promising was shortening the lambing interval to 240 days (3 lambings in 2 years), resulting in a substantial increase in gross margin (+44 %), return on labour (+27 %) and income per hectare (+57 %) compared with the baseline scenario. The carcass weight per hectare increased from 202 to 265 kg. A lambing interval of 240 days compared with seasonal lambing (365 days) increased the income per hectare by 82 %. For Mount-140, the most promising simulated management interventions were increasing the litter size, reducing concentrate input and extending the fattening period. When combined, these interventions resulted in a substantial increase in gross margin (+58 %), return on labour (+38) and income per hectare (+63 %) compared with the baseline scenario. The carcass weight per hectare increased from 153 to 194 kg. The improvements based on our model calculations are practicable by changing the ewe flock to original genetics characterised by higher prolificacy, less weight and greater hardiness. When crossed with rams of meaty breeds, these ewes can be expected to produce vigorous hybrid lambs with a similar growth rate and carcass quality compared with lambs of ewes in the current (baseline) systems.

Morphological and Molecular Characterization of a New Mycobacterium avium Subsp. paratuberculosis S-Type Strain Genotype in Goats.

Paratuberculosis is a chronic bacterial disease of global importance mainly in domestic and wild ruminants, caused by Mycobacterium avium subsp. paratuberculosis (MAP). In goats, paratuberculosis is mostly caused by the “C-type” (cattle) and in a few cases by the “S-type” (sheep) strain of MAP. In 2017, a caprine S-type III isolate with a new VNTR profile was identified in a Swiss alpine region. In 2018, new caprine isolates with the same novel VNTR profile originating from a farm of a close by neighboring valley were analyzed. Here we report on this MAP S-type III outbreak in a Swiss dairy goat farm in which we investigated the pathological changes, distribution and genotype of MAP tissue homogenates. Full necropsy and histological examination were undertaken on two female adult goats with a history of weight loss and intermitting diarrhea. Routine and special stains were applied to characterize the morphological changes. DNA was extracted from 33 different tissue samples and tested for MAP by qPCR targeting IS900 and F57. Subtyping was performed, using the variable number tandem repeats (VNTR) and mycobacterial interspersed repetitive units (MIRU) approach. The goats showed moderate to marked emaciation and displayed typical clinical features of paratuberculosis. A moderate granulomatous enteritis and regional lymphadenitis with a small to moderate number of acid-fast bacteria within macrophages was detected. MAP detection was mainly restricted to the gastrointestinal tract, mesenteric and hepatic lymph nodes. Subtyping the S-type isolates using a panel of eight established MIRU-VNTR loci identified a new genotype, INMV 218.

A 10‐year radar‐based analysis of orographic precipitation growth and decay patterns over the Swiss Alpine region

The dependence of precipitation growth and decay on the orientation of orographic features, mesoscale flow and freezing‐level height is quantified using a 10‐year archive of composite weather radar images over the Swiss Alpine region. The mesoscale flow is described by the motion of radar precipitation echoes, computed through variational echo tracking, while the freezing‐level height is extracted from the analyses of the numerical weather prediction model COSMO. On the northern side of the Alps, the areas of growth are generally observed on the upwind slopes of the Alpine chain, while on the southern side their location also depends on factors other than the motion of precipitation, such as the convergence of low‐level flows. On the other hand, the decay of precipitation is generally found in the inner Alpine valleys and on the downwind slopes of the Alpine chain. Compared to situations characterized by low freezing level, the areas of precipitation growth penetrate more into the mountain range with high‐freezing‐level conditions. When considering a time lag of 1 h and specific flow conditions, the systematic growth and decay of precipitation can explain up to 30–40% of its total variability over the orography. The relative contribution to the total variability is lower with high freezing level because the non‐systematic variability is larger. The statistical analysis of precipitation growth and decay using large archives of composite radar images highlights the mesoscale flow conditions and geographical locations most prone to orographic precipitation enhancement, but also has potential to improve existing precipitation nowcasting systems in mountainous regions and to provide a basis for the verification of systematic biases of numerical weather prediction models.

Design and Evaluation of a Low-Power Sensor Device for Induced Rockfall Experiments

Rockfalls have over the last decades become a serious and frequent hazard, especially due to larger variations in precipitation and temperatures, destabilizing rocky slopes in mountainous regions. Hence, civil engineers are applying the latest simulation tools to perform risk assessments and plan mitigation strategies. These tools are based on various models with many parameters that should be calibrated and evaluated with real-world in-field measurement data. In this paper, we present a rugged low-power multisensor node termed StoneNode that has been designed to acquire and log accurate inertial sensor measurements during induced in-field experiments with falling rocks. The node hosts low-power microelectromechanical system sensors with high dynamic ranges sampled up to 1 kHz, and provides a long battery lifetime of up to 56 h, enabling long-lasting field studies with a duration of several working days. Exhaustive in-field experiments have been carried out with several differently shaped rocks on typical terrain in the Swiss alpine region. The experiments comprise more than 100 induced tests with several heavy impacts of >400 g. This paper gives a detailed summary of these results, including unprecedented in situ data of rockfall trajectories and postexperimental validation where we compare simulated rockfall deposition distributions and motion traces with in-field measurements after calibration of the simulation module. Our results and experience gained in-field confirm that the StoneNode is a reliable easy-to-use device, which greatly facilitates the data acquisition process. Further, the results obtained with the calibrated simulation tool show good quantitative and qualitative congruence with the experiments, further reaffirming our methodological approach.

A bioarchaeological approach to the Iron Age in Switzerland: stable isotope analyses (\u03b413C, \u03b415N, \u03b434S) of human remains

In Switzerland, a large number of Iron Age burial sites were found in the last century. Changes in living conditions and socio-cultural behavior may have occurred over time and space and could be reflected in the dietary habits, social stratigraphy within populations and migration patterns. This study attempts to shed light on these aspects with the application of stable isotope analyses. Human remains from 11 different burial sites (n = 164) in the area of today’s Swiss Plateau and Swiss Alpine regions were investigated. Temporal and geographical variations as well as sex and age-related dietary differences were analyzed through isotopic studies (δ13C, δ15N, and δ34S). In total, the data of 129 individuals could be evaluated. Highly significant differences between the burial sites were found, with higher δ13C and δ15N values in the Alpine regions. Cultural and/or climatic changes as well as the different geological conditions might have led to distinct patterns of crop cultivation and animal husbandry and consequently to significantly different dietary habits in the Plateau and the Alpine regions. The data indicate a higher intake of millet and animal protein including early dairy production in the southern regions, probably influenced by the Mediterranean world. Cultural exchange between geographical regions might have been facilitated by migration during the Iron Age as suggested by the δ34S.

Peucedanum ostruthium (L.) Koch: Morphological and phytochemical variability of twelve accessions from the Swiss alpine region

Ostruthin, a natural bioactive compound mainly occurring in the roots of Peucedanum ostruthium , is the focus of this study. P. ostruthium was collected from twelve locations in the Swiss alpine region and reared in an experimental field, subdivided into twelve lots over two years. In the spring and fall, a portion of each of the twelve accessions was harvested and separated into above and below ground plant parts. The dried plants were then extracted with 60 % ethanol using accelerated solvent extraction (ASE) and analyzed using high pressure liquid chromatography (HPLC).The above and below ground plant parts were then analyzed concerning their dry matter yield (DMY), their ostruthin concentration and their ostruthin yield. Focusing on ostruthin, it was found that the below ground plant parts harvested in the fall rendered the highest ostruthin yield. Furthermore, a variability concerning ostruthin among the twelve accessions was found. This variability among the accessions is of interest with regards to a breeding program used to develop a cultivar with a high ostruthin yield.

Future acceptance of wind energy production: Exploring future local acceptance of wind energy production in a Swiss alpine region

Future sustainable energy systems strongly rely on new renewable energies. Wind energy production has become an interesting option for alpine regions. In addition to grid reliability, public acceptance is an important factor that currently limits wind energy's market penetration.An interdisciplinary research team explored, through socio-economic and technical approaches, the current and future acceptance of wind energy production in the Swiss energy region of Goms, an alpine valley at 1300m above sea level. The focus of this paper is on research questions comprising future societal challenges for the local population. For this purpose, the focus-group discussion has proven to be a valuable participatory method.Concerning future development of wind energy in the Alps, regional value creation (including workplaces) and the placement of systems where man-made infrastructure is already present were the main visions mentioned by workshop participants.So far, wind energy as implemented in the valley of Goms has not been perceived as a topic of conflict by the local community. Crucial components towards local acceptance of wind turbines are questions of aesthetics, technical performance and economic feasibility.

Implementation and validation of a Wilks-type multi-site daily precipitation generator over a typical Alpine river catchment

Abstract. Many climate impact assessments require high-resolution precipitation time series that have a spatio-temporal correlation structure consistent with observations, for simulating either current or future climate conditions. In this respect, weather generators (WGs) designed and calibrated for multiple sites are an appealing statistical downscaling technique to stochastically simulate multiple realisations of possible future time series consistent with the local precipitation characteristics and their expected future changes. In this study, we present the implementation and validation of a multi-site daily precipitation generator re-built after the methodology described in Wilks (1998). The generator consists of several Richardson-type WGs run with spatially correlated random number streams. This study aims at investigating the capabilities, the added value and the limitations of the precipitation generator for a typical Alpine river catchment in the Swiss Alpine region under current climate. The calibrated multi-site WG is skilful at individual sites in representing the annual cycle of the precipitation statistics, such as mean wet day frequency and intensity as well as monthly precipitation sums. It reproduces realistically the multi-day statistics such as the frequencies of dry and wet spell lengths and precipitation sums over consecutive wet days. Substantial added value is demonstrated in simulating daily areal precipitation sums in comparison to multiple WGs that lack the spatial dependency in the stochastic process. Limitations are seen in reproducing daily and multi-day extreme precipitation sums, observed variability from year to year and in reproducing long dry spell lengths. Given the performance of the presented generator, we conclude that it is a useful tool to generate precipitation series consistent with the mean climatic aspects and likely helpful to be used as a downscaling technique for climate change scenarios.

Renewable Energy, Authenticity, and Tourism: Social Acceptance of Photovoltaic Installations in a Swiss Alpine Region

With the increasing emergence of renewable energy sites in Switzerland, new impacts on the landscape can be observed. Above the Alpine village of Bellwald, a pilot project testing avalanche barriers as a possible site for photovoltaic installations was inaugurated in 2012. This study focused on social aspects of the project and asked questions about local residents' and tourists' perceptions of and attitudes toward the installations. Its findings reveal that the new elements are not perceived as a drastic intrusion into the landscape, because the view was already affected by the avalanche barriers, which are accepted because of their vital protective function. No significant difference was found between residents' and tourists' evaluation of the new photovoltaic installations. However, different factors influenced the perceptions of these 2 groups. In both groups, conceptions related to place played an important role in the evaluation of possible photovoltaic sites.

A case of rapidly progressing primary thyroid angiosarcoma in a Japanese man

Primary thyroid angiosarcoma is a very rare and aggressive disease, originally reported in patients from the Swiss Alpine region, but is rare in other parts of the world. We describe a Japanese case of primary angiosarcoma of the thyroid in a 64-year-old man, who presented with a rapidly enlarging painful neck mass. Fine-needle aspiration biopsy was performed, and the results were interpreted as malignant. FDG-PET-CT demonstrated a necrotic lesion on the right side of the neck with high FDG uptake. The patient underwent a total thyroidectomy. Pathological findings revealed a proliferation of atypical cells lined vascular spaces. Immunohistochemistry staining (IHCS) was positive for factor VIII, and CD31, but not CD34, and negative for CK 5, CK 7, and CK 20. From these findings, it was diagnosed as an epithelioid angiosarcoma. Two weeks after the operation, bilateral bloody pleural effusion was observed, and he died 3 months after the surgery.

Analysis of Swiss honeys for pyrrolizidine alkaloids

SummaryVarious studies have shown that honey may contain pyrrolizidine alkaloids (PAs) and thus can pose a potential health risk for consumers. It seems that the level of contamination depends on the geographical and botanical origin of the honey. The geographically central location of Switzerland within Europe accounts for various different climate zones, and therefore can serve as a model to study PA contamination in honeys. We analysed 71 honeys between 2009 and 2011. Honeys from various botanical origins were collected from regions north and south of the Alps as well as the alpine regions. The PA concentration of the honeys was determined by target analysis using an HPLC-MS/MS-system, allowing the detection of 18 different PAs and PA-N-oxides found in the genera Echium, Eupatoriumand Senecio. 54% of the honeys contained PAs, while in 46% of the honeys PA concentrations were below the limit of quantitation (LOQ). The LOQs ranged from 1 μg/kg to 3 μg/kg, depending on the PA. The mean PA concentration of the positive samples was 6.7 μg/kg. The highest concentration of PAs (55 μg/kg) was found in a honey from Ticino, an area of the southern flank of the Alps. All the other positive honeys contained PAs at concentrations below 18 μg/kg. Therefore Swiss honey usually does not pose a risk for consumers. In the investigated honeys, honeys from the Swiss alpine regions (29 out of 37) tested more frequently positive for PAs compared to honeys from areas north of the Alps (9 out of 34). This probably reflects the different botanical settings of the central European and the alpine climate regions.