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Showing papers by "Swiss Federal Institute for Forest, Snow and Landscape Research published in 2011"


Journal ArticleDOI
TL;DR: This article used repeat photography, long-term ecological monitoring and dendrochronology to document shrub expansion in arctic, high-latitude and alpine tundra.
Abstract: Recent research using repeat photography, long-term ecological monitoring and dendrochronology has documented shrub expansion in arctic, high-latitude and alpine tundra

1,153 citations


Journal ArticleDOI
04 Feb 2011-Science
TL;DR: Reconstruction of tree ring–based reconstructions of central European summer precipitation and temperature variability over the past 2500 years may provide a basis for counteracting the recent political and fiscal reluctance to mitigate projected climate change.
Abstract: Climate variations influenced the agricultural productivity, health risk, and conflict level of preindustrial societies. Discrimination between environmental and anthropogenic impacts on past civilizations, however, remains difficult because of the paucity of high-resolution paleoclimatic evidence. We present tree ring-based reconstructions of central European summer precipitation and temperature variability over the past 2500 years. Recent warming is unprecedented, but modern hydroclimatic variations may have at times been exceeded in magnitude and duration. Wet and warm summers occurred during periods of Roman and medieval prosperity. Increased climate variability from ~250 to 600 C.E. coincided with the demise of the western Roman Empire and the turmoil of the Migration Period. Such historical data may provide a basis for counteracting the recent political and fiscal reluctance to mitigate projected climate change.

1,081 citations


Journal ArticleDOI
23 Sep 2011-Science
TL;DR: This article conducted a standardized sampling in 48 herbaceous-dominated plant communities on five continents and found no clear relationship between productivity and fine-scale (meters−2) richness within sites, within regions, or across the globe.
Abstract: For more than 30 years, the relationship between net primary productivity and species richness has generated intense debate in ecology about the processes regulating local diversity. The original view, which is still widely accepted, holds that the relationship is hump-shaped, with richness first rising and then declining with increasing productivity. Although recent meta-analyses questioned the generality of hump-shaped patterns, these syntheses have been criticized for failing to account for methodological differences among studies. We addressed such concerns by conducting standardized sampling in 48 herbaceous-dominated plant communities on five continents. We found no clear relationship between productivity and fine-scale (meters−2) richness within sites, within regions, or across the globe. Ecologists should focus on fresh, mechanistic approaches to understanding the multivariate links between productivity and richness.

509 citations


Journal ArticleDOI
TL;DR: In this article, an overview of previous and current research on the main topics related to rockfall is provided, covering the onset of rockfall and runout modelling approaches, as well as hazard zoning and protection measures.
Abstract: . Rockfall is an extremely rapid process involving long travel distances. Due to these features, when an event occurs, the ability to take evasive action is practically zero and, thus, the risk of injury or loss of life is high. Damage to buildings and infrastructure is quite likely. In many cases, therefore, suitable protection measures are necessary. This contribution provides an overview of previous and current research on the main topics related to rockfall. It covers the onset of rockfall and runout modelling approaches, as well as hazard zoning and protection measures. It is the aim of this article to provide an in-depth knowledge base for researchers and practitioners involved in projects dealing with the rockfall protection of infrastructures, who may work in the fields of civil or environmental engineering, risk and safety, the earth and natural sciences.

347 citations


Journal ArticleDOI
TL;DR: It is shown that up to 86% of terrestrial and 83% of freshwater ecoregions will be exposed to average monthly temperature patterns >2 SDs (2σ) of the 1961–1990 baseline, including 82% of critically endangered e coregions, and many Global 200 ecoreGions may be under substantial climatic stress by 2100.
Abstract: The current rate of warming due to increases in greenhouse gas (GHG) emissions is very likely unprecedented over the last 10,000 y. Although the majority of countries have adopted the view that global warming must be limited to 600 realizations from climate model ensembles, we show that up to 86% of terrestrial and 83% of freshwater ecoregions will be exposed to average monthly temperature patterns >2 SDs (2σ) of the 1961-1990 baseline, including 82% of critically endangered ecoregions. The entire range of 89 ecoregions will experience extreme monthly temperatures with a local warming of <2 °C. Tropical and subtropical ecoregions, and mangroves, face extreme conditions earliest, some with <1 °C warming. In contrast, few ecoregions within Boreal Forests and Tundra biomes will experience such extremes this century. On average, precipitation regimes do not exceed 2σ of the baseline period, although considerable variability exists across the climate realizations. Further, the strength of the correlation between seasonal temperature and precipitation changes over numerous ecoregions. These results suggest many Global 200 ecoregions may be under substantial climatic stress by 2100.

334 citations


Journal ArticleDOI
TL;DR: Shoot height growth was found to be more sensitive to drought in provenances from northern latitudes than in provenance from southern latitudes, suggesting that genetic factors related to the postglacial immigration history of European oaks might have interfered with selective pressure at provenance origins.
Abstract: Provenance-specific growth responses to experimentally applied drought and air warming were studied in saplings of three European oak species: Quercus robur, Quercus petraea and Quercus pubescens. Four provenances of each species were grown in large open-top chambers and subjected to four climates: control, periodic drought, air warming or their combination in 3 subsequent years. Overall growth responses were found among species and provenances, with drought reducing shoot height growth and stem diameter growth and air warming stimulating shoot height growth but reducing stem diameter growth and root length growth. Differential growth responses in shoots, stems and roots resulted in altered allometric growth relations. Root length growth to shoot height growth increased in response to drought but decreased in response to air warming. Stem diameter growth to shoot height growth decreased in response to air warming. The growth responses in shoots and stems were highly variable among provenances indicating provenance-specific sensitivity to drought and air warming, but this response variability did not reflect local adaptation to climate conditions of provenance origin. Shoot height growth was found to be more sensitive to drought in provenances from northern latitudes than in provenances from southern latitudes, suggesting that genetic factors related to the postglacial immigration history of European oaks might have interfered with selective pressure at provenance origins.

162 citations


Journal ArticleDOI
TL;DR: In this paper, the authors analyzed species richness, diversity and community composition of 63 bird species with reference to major urban environmental gradients at 96 sampling points in three Swiss cities and selected the best explanatory models from candidate models following information theory, and their respective predictions were averaged based on AICc-weights.

160 citations


Journal ArticleDOI
TL;DR: In this paper, the Damma Glacier Critical Zone Observatory was used to study the 150-yr soil chronosequence and evaluate the influence of biological activity on mineral weathering and geochemical cycles.
Abstract: Soils are the product of a complex suite of chemical, biological, and physical processes. In spite of the importance of soils for society and for sustaining life on earth, our knowledge of soil formation rates and of the influence of biological activity on mineral weathering and geochemical cycles is still limited. In this paper we provide a description of the Damma Glacier Critical Zone Observatory and present a first synthesis of our multi disciplinary studies of the 150-yr soil chronosequence. The aim of our research was to improve our understanding of ecosystem development on a barren substrate and the early evolution of soils and to evaluate the influence of biological activity on weathering rates. Soil pH, cation exchange capacity, biomass, bacterial and fungal populations, and soil organic matt er show clear gradients related to soil age, in spite of the extreme heterogeneity of the ecosystem. The bulk mineralogy and inorganic geochemistry of the soils, in contrast, are independent of soil age and only in older soils (>100 yr) is incipient weathering observed, mainly as a decreasing content in albite and biotite by coincidental formation of secondary chlorites in the clay fraction. Further, we document the rapid evolution of microbial and plant communities along the chronosequence.

155 citations


Journal ArticleDOI
TL;DR: In this article, a heuristic model of social capacity building for natural hazards is developed by taking into account a wide range of existing expertise from different fields of research, with particular attention paid to social vulnerability and its assessment, as well as to risk communication and risk education.

151 citations


Journal ArticleDOI
TL;DR: In this paper, the authors propose a methodology to detect surface change and quantify the resultant volumetric errors in areas of complex topography such as channels, where data from multiple scan stations must be combined.
Abstract: Detection of surface change is a fundamental task in geomorphology. Terrestrial laser scanners are increasingly used for monitoring surface change resulting from a variety of geomorphic processes, as they allow the rapid generation of high-resolution digital elevation models. Irrespective of instrument specifics, survey design or data processing, such data are subject to a finite level of ambiguity in position measurement, a consideration of which must be taken into account when deriving change. The propagation of errors is crucial in change detection because even very small uncertainties in elevation can produce large uncertainties in volume when extrapolated over an area of interest. In this study we propose a methodology to detect surface change and to quantify the resultant volumetric errors in areas of complex topography such as channels, where data from multiple scan stations must be combined. We find that a commonly proposed source of error – laser point elongation at low incidence angles – has a negligible effect on the quality of the final registered point cloud. Instead, ambiguities in elevation inherent to registered datasets have a strong effect on our ability to detect and measure surface change. Similarly, we find that changes in surface roughness between surveys also reduce our ability to detect change. Explicit consideration of these ambiguities, when propagated through to volume calculations, allows us to detect volume change of 87 ±5m3, over an area of ∼ ​4900m2, due to passage of a debris flow down a 300m reach of the Illgraben channel in Switzerland.

138 citations


Journal ArticleDOI
TL;DR: In this paper, the authors reviewed 130 papers on climate change impacts on forest ecosystems and species published between 1995 and 2010 and identified key future challenges for nature conservation in forests and ecosystem research.

Journal ArticleDOI
TL;DR: The results indicate that current rates of N deposition in a warmer environment will strongly inhibit C sequestration by Sphagnum-dominated vegetation.
Abstract: Summary • Peatlands in the northern hemisphere have accumulated more atmospheric carbon (C) during the Holocene than any other terrestrial ecosystem, making peatlands long-term C sinks of global importance. Projected increases in nitrogen (N) deposition and temperature make future accumulation rates uncertain. • Here, we assessed the impact of N deposition on peatland C sequestration potential by investigating the effects of experimental N addition on Sphagnum moss. We employed meta-regressions to the results of 107 field experiments, accounting for sampling dependence in the data. • We found that high N loading (comprising N application rate, experiment duration, background N deposition) depressed Sphagnum production relative to untreated controls. The interactive effects of presence of competitive vascular plants and high tissue N concentrations indicated intensified biotic interactions and altered nutrient stochiometry as mechanisms underlying the detrimental N effects. Importantly, a higher summer temperature (mean for July) and increased

Journal ArticleDOI
TL;DR: In this paper, the effects of climate change on plant communities may depend on substrate properties that vary at the scale of individuals (
Abstract: Climate change impacts on vegetation are mediated by soil processes that regulate rhizosphere water balance, nutrient dynamics, and ground-level temperatures. For ecosystems characterized by high fine-scale substrate heterogeneity such as grasslands on poorly developed soils, effects of climate change on plant communities may depend on substrate properties that vary at the scale of individuals (

Journal ArticleDOI
TL;DR: In this paper, the authors evaluated the suitability of HEPS for small-scale basins and quantified the added-value conveyed by the probability information, a reforecast was made for the period June 2007 to December 2009 for the Sihl catchment (336 km2), and concluded that the capacity of the model to provide confident and reliable mid-term probability forecasts for high discharges is limited.
Abstract: . The Sihl River flows through Zurich, Switzerland's most populated city, for which it represents the largest flood threat. To anticipate extreme discharge events and provide decision support in case of flood risk, a hydrometeorological ensemble prediction system (HEPS) was launched operationally in 2008. This model chain relies on limited-area atmospheric forecasts provided by the deterministic model COSMO-7 and the probabilistic model COSMO-LEPS. These atmospheric forecasts are used to force a semi-distributed hydrological model (PREVAH), coupled to a hydraulic model (FLORIS). The resulting hydrological forecasts are eventually communicated to the stakeholders involved in the Sihl discharge management. This fully operational setting provides a real framework with which to compare the potential of deterministic and probabilistic discharge forecasts for flood mitigation. To study the suitability of HEPS for small-scale basins and to quantify the added-value conveyed by the probability information, a reforecast was made for the period June 2007 to December 2009 for the Sihl catchment (336 km2). Several metrics support the conclusion that the performance gain can be of up to 2 days lead time for the catchment considered. Brier skill scores show that overall COSMO-LEPS-based hydrological forecasts outperforms their COSMO-7-based counterparts for all the lead times and event intensities considered. The small size of the Sihl catchment does not prevent skillful discharge forecasts, but makes them particularly dependent on correct precipitation forecasts, as shown by comparisons with a reference run driven by observed meteorological parameters. Our evaluation stresses that the capacity of the model to provide confident and reliable mid-term probability forecasts for high discharges is limited. The two most intense events of the study period are investigated utilising a novel graphical representation of probability forecasts, and are used to generate high discharge scenarios. They highlight challenges for making decisions on the basis of hydrological predictions, and indicate the need for a tool to be used in addition to forecasts to compare the different mitigation actions possible in the Sihl catchment. No definitive conclusion on the model chain capacity to forecast flooding events endangering the city of Zurich could be drawn because of the under-sampling of extreme events. Further research on the form of the reforecasts needed to infer on floods associated to return periods of several decades, centuries, is encouraged.

Journal ArticleDOI
TL;DR: In this article, the authors present a study on three tourism destinations in the Swiss Alps that addressed resource consumption of snowmaking, snow reliability, and future snowmaking potential in a warmer climate.
Abstract: The winter tourism industry is facing considerable challenges with climate change; it is increasingly responding with investments in snowmaking facilities. We present a study on 3 tourism destinations in the Swiss Alps that addressed resource consumption of snowmaking, snow reliability, and future snowmaking potential in a warmer climate. The energy consumption of snowmaking in the ski resorts was in the lower range of what could be expected from literature values. It comprised ∼0.5% of the respective municipality's energy consumption and was moderate compared with other tourism-related activities. Water consumption, however, was in the higher range with regard to what was expected from literature values and was also high compared with other water uses (eg 36% compared with drinking water consumption in one community). Natural snow cover was partly critical for winter sports at low elevations at ∼1200 masl, but uncritical at higher elevations above 2000 masl. Snow cover will become even more crit...

Journal ArticleDOI
TL;DR: The present study identifies a distinct urban arthropod community that enriches landscape (gamma) diversity in Switzerland and illuminates the value of urbanArthropod fauna for overall biodiversity which should be incorporated in planning decisions.

Journal ArticleDOI
TL;DR: Different host and parasite genotypes would be selected under different climatic conditions, affecting the coevolutionary dynamics of the host‐parasite interaction and the course of chestnut blight epidemics.
Abstract: The outcome of host‐parasite interactions may depend not only on the genotypes of the species involved but also on environmental factors. We used the fungus Cryphonectria parasitica, the causal agent of chestnut blight, and its hyperparasitic virus, Cryphonectria hypovirus‐1 (CHV1), to test for genotype‐by‐genotype‐by‐environment interactions in a host‐parasite system. In C. parasitica, infection with CHV1 induces a hypovirulent phenotype with reduced virulence toward the chestnut tree (Castanea spp.) and thus controls chestnut blight in many European regions. In contrast, uninfected virulent C. parasitica have nearly eradicated the American chestnut in North America. We applied a full factorial design and assessed the fungal growth and sporulation of four C. parasitica strains, uninfected and infected with each of the four known CHV1 subtypes, at 12°, 18°, 24°, and 30°C. We found a significant ( \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm...

Journal ArticleDOI
TL;DR: Overall, a substantial number of Mediterranean mammals will be severely threatened by future climate change, particularly endemic species, and existing protected areas will probably be strongly influenced by climate change.
Abstract: The Mediterranean basin is considered a hotspot of biological diversity with a long history of modification of natural ecosystems by human activities, and is one of the regions that will face extensive changes in climate. For 181 terrestrial mammals (68% of all Mediterranean mammals), we used an ensemble forecasting approach to model the future (approx. 2100) potential distribution under climate change considering five climate change model outputs for two climate scenarios. Overall, a substantial number of Mediterranean mammals will be severely threatened by future climate change, particularly endemic species. Moreover, we found important changes in potential species richness owing to climate change, with some areas (e.g. montane region in central Italy) gaining species, while most of the region will be losing species (mainly Spain and North Africa). Existing protected areas (PAs) will probably be strongly influenced by climate change, with most PAs in Africa, the Middle East and Spain losing a substantial number of species, and those PAs gaining species (e.g. central Italy and southern France) will experience a substantial shift in species composition.

Journal ArticleDOI
01 Sep 2011-Geology
TL;DR: In this article, the authors apply terrestrial laser scanning and flow hydrograph analysis to quantify erosion and deposition in a series of debris flows at Illgraben, Switzerland and identify flow depth as an important control on the pattern and magnitude of erosion, whereas deposition is governed more by the geometry of flow margins.
Abstract: Debris flows are among the most hazardous and unpredictable of surface processes in mountainous areas. This is partly because debris-flow erosion and deposition are poorly understood, resulting in major uncertainties in flow behavior, channel stability, and sequential effects of multiple flows. Here we apply terrestrial laser scanning and flow hydrograph analysis to quantify erosion and deposition in a series of debris flows at Illgraben, Switzerland. We identify flow depth as an important control on the pattern and magnitude of erosion, whereas deposition is governed more by the geometry of flow margins. The relationship between flow depth and erosion is visible both at the reach scale and at the scale of the entire fan. Maximum flow depth is a function of debris-flow front discharge and pre-flow channel cross-section geometry, and this dual control gives rise to complex interactions with implications for long-term channel stability, the use of fan stratigraphy for reconstruction of past debris-flow regimes, and the predictability of debris-flow hazards.

Journal ArticleDOI
TL;DR: In this paper, the authors analyzed the impact of climate and human activities on fire occurrence in the most fire-prone regions of Switzerland and found that road and livestock densities had similar influences in the two cantons.

Journal ArticleDOI
TL;DR: In this paper, the congruence between allele-based range boundaries (break zones) in silicicolous alpine plants and species-based break zones in the European Alps was investigated.
Abstract: Aim We test for the congruence between allele-based range boundaries (break zones) in silicicolous alpine plants and species-based break zones in the silicicolous flora of the European Alps We also ask whether such break zones coincide with areas of large elevational variation Location The European Alps Methods On a regular grid laid across the entire Alps, we determined areas of allele- and species-based break zones using respective clustering algorithms, identifying discontinuities in cluster distributions (breaks), and quantifying integrated break densities (break zones) Discontinuities were identified based on the intra-specific genetic variation of 12 species and on the floristic distribution data from 239 species, respectively Coincidence between the two types of break zones was tested using Spearman’s correlation Break zone densities were also regressed on topographical complexity to test for the effect of elevational variation Results We found that two main break zones in the distribution of alleles and species were significantly correlated Furthermore, we show that these break zones are in topographically complex regions, characterized by massive elevational ranges owing to high mountains and deep glacial valleys We detected a third break zone in the distribution of species in the eastern Alps, which is not correlated with topographic complexity, and which is also not evident from allelic distribution patterns Species with the potential for long-distance dispersal tended to show larger distribution ranges than short-distance dispersers Main conclusions We suggest that the history of Pleistocene glaciations is the main driver of the congruence between allele-based and species-based distribution patterns, because occurrences of both species and alleles were subject to the same processes (such as extinction, migration and drift) that shaped the distributions of species and genetic lineages Large elevational ranges have had a profound effect as a dispersal barrier for alleles during post-glacial immigration Because plant species, unlike alleles, cannot spread via pollen but only via seed, and thus disperse less effectively, we conclude that species break zones are maintained over longer time spans and reflect more ancient patterns than allele break zones

Journal ArticleDOI
TL;DR: In this paper, a series of experiments in the laboratory and in the field to study the mechanical response of pulled roots were conducted to systematically quantified the influence of different factors such as root geometry and configuration, soil type, and soil water content considering individual roots and root bundles.
Abstract: [1] Root-soil mechanical interactions are key to soil stability on steep hillslopes. Motivated by new advances and applications of the Root Bundle Model (RBM), we conducted a series of experiments in the laboratory and in the field to study the mechanical response of pulled roots. We systematically quantified the influence of different factors such as root geometry and configuration, soil type, and soil water content considering individual roots and root bundles. We developed a novel pullout apparatus for strain-controlled field and laboratory tests of up to 13 parallel roots measured individually and as a bundle. Results highlight the importance of root tortuosity and root branching points for prediction of individual root pullout behavior. Results also confirm the critical role of root diameter distribution for realistic prediction of global pullout behavior of a root bundle. Friction between root and soil matrix varied with soil type and water content and affected the force-displacement behavior. Friction in sand varied from 1 to 17 kPa, with low values obtained in wet sand at a confining pressure of 2 kPa and high values obtained in dry sand with 4.5 kPa confining pressure. In a silty soil matrix, friction ranged between 3 kPa under wet and low confining pressure (2 kPa) and 6 kPa in dry and higher confining pressure (4.5 kPa). Displacement at maximum pullout force increased with increasing root diameter and with tortuosity. Laboratory experiments were used to calibrate the RBM that was later validated using six field measurements with natural root bundles of Norway spruce (Picea abies L.). These tests demonstrate the progressive nature of root bundle failure under strain-controlled pullout force and provide new insights regarding force-displacement behavior of root reinforcement, highlighting the importance of considering displacement in slope stability models. Results show that the magnitude of maximum root pullout forces (1–5 kPa) are important for slope stability. The force-displacement relations characterized in this study are fundamental inputs for quantifying the resistive force redistribution on vegetated slopes and may provide explanation for abrupt loss of strength during landslide initiation and deformation.

Journal ArticleDOI
TL;DR: The results showed that the zygomyceteous species Mucor hiemalis, Umbelopsis isabellina and Mortierella alpina dissolved the granite powder most efficiently due to the release of a variety of organic acids, mainly citrate, malate and oxalate.
Abstract: Fungi were isolated from fine granitic sediments, which were collected at 15 sampling points within a 20 m x 40 m area in front of the Damma glacier in the central Swiss Alps. From the 45 fungal isolates grown on nutrient-rich agar media at 4 degrees C, 24 isolates were selected for partial sequencing and identification based on the small subunit ribosomal DNA. Sequencing data revealed that the isolated fungi represented three fungal phyla and 15 species. The weathering potential of 10 of the 15 fungal species was tested with dissolution experiments using powdered granite material (< 63 mu m). The results showed that the zygomyceteous species Mucor hiemalis, Umbelopsis isabellina and Mortierella alpina dissolved the granite powder most efficiently due to the release of a variety of organic acids, mainly citrate, malate and oxalate. In particular, the high concentrations of Ca, Fe, Mg and Mn in the solutions clustered well with the high amounts of exuded citrate. This is the first report on fungi that were isolated from a non-vegetated glacier forefield in which the fungi's capabilities to dissolve granite minerals were examined.

Journal ArticleDOI
TL;DR: In this paper, the authors quantified soil organic C pools and fluxes in functional process zones of adjacent channelized and widened sections of the Thur River, NE Switzerland, on a seasonal basis.
Abstract: . Due to their spatial complexity and dynamic nature, floodplains provide a wide range of ecosystem functions. However, because of flow regulation, many riverine floodplains have lost their characteristic heterogeneity. Restoration of floodplain habitats and the rehabilitation of key ecosystem functions, many of them linked to organic carbon (C) dynamics in riparian soils, has therefore become a major goal of environmental policy. The fundamental understanding of the factors that drive the processes involved in C cycling in heterogeneous and dynamic systems such as floodplains is however only fragmentary. We quantified soil organic C pools (microbial C and water extractable organic C) and fluxes (soil respiration and net methane production) in functional process zones of adjacent channelized and widened sections of the Thur River, NE Switzerland, on a seasonal basis. The objective was to assess how spatial heterogeneity and temporal variability of these pools and fluxes relate to physicochemical soil properties on one hand, and to soil environmental conditions and flood disturbance on the other hand. Overall, factors related to seasonality and flooding (temperature, water content, organic matter input) affected soil C dynamics more than soil properties did. Coarse-textured soils on gravel bars in the restored section were characterized by low base-levels of organic C pools due to low TOC contents. However, frequent disturbance by flood pulses led to high heterogeneity with temporarily and locally increased C pools and soil respiration. By contrast, in stable riparian forests, the finer texture of the soils and corresponding higher TOC contents and water retention capacity led to high base-levels of C pools. Spatial heterogeneity was low, but major floods and seasonal differences in temperature had additional impacts on both pools and fluxes. Soil properties and base levels of C pools in the dam foreland of the channelized section were similar to the gravel bars of the restored section. By contrast, spatial heterogeneity, seasonal effects and flood disturbance were similar to the forests, except for indications of high CH4 production that are explained by long travel times of infiltrating water favoring reducing conditions. Overall, the restored section exhibited both a larger range and a higher heterogeneity of organic C pools and fluxes as well as a higher plant biodiversity than the channelized section. This suggests that restoration has indeed led to an increase in functional diversity.

Journal ArticleDOI
TL;DR: In this article, the authors investigated the preferences of non-farmers and farmers for nine landscape scenarios in the Swiss lowlands, which were the result of a photo editing process combining three land-use types (arable crops, grassland and a mixture of both) and three proportions of ecological compensation areas (0, 10% and 30%).

Journal ArticleDOI
TL;DR: In this article, the authors investigated the long-term disturbance history of old protected forest dominated by Norway spruce in the Parangalitsa Reserve, Bulgaria and used aerial photo interpretation and dendroecological methods to reconstruct the history of wind, insect, and fire disturbances across a topographically complex landscape.

Journal ArticleDOI
TL;DR: In this paper, the root bundles are modeled as bundles of heterogeneous fibers pulled along their long axes neglecting root-soil friction, and the root pullout force and corresponding critical displacement are either derived analytically or computed numerically.
Abstract: [1] Roots in soil contribute to the mechanical stability of slopes. Estimation of root reinforcement is challenging because roots form complex biological networks whose geometrical and mechanical characteristics are difficult to characterize. Here we describe an analytical model that builds on simple root descriptors to estimate root reinforcement. Root bundles are modeled as bundles of heterogeneous fibers pulled along their long axes neglecting root-soil friction. Analytical expressions for the pullout force as a function of displacement are derived. The maximum pullout force and corresponding critical displacement are either derived analytically or computed numerically. Key model inputs are a root diameter distribution (uniform, Weibull, or lognormal) and three empirical power law relations describing tensile strength, elastic modulus, and length of roots as functions of root diameter. When a root bundle with root tips anchored in the soil matrix is pulled by a rigid plate, a unique parameter, , that depends only on the exponents of the power law relations, dictates the order in which roots of different diameters break. If 1, large roots break first. When = 1, all fibers break simultaneously, and the maximum tensile force is simply the roots' mean force times the number of roots in the bundle. Based on measurements of root geometry and mechanical properties, the value of is less than 1, usually ranging between 0 and 0.7. Thus, small roots always fail first. The model shows how geometrical and mechanical characteristics of roots and root diameter distribution affect the pullout force, its maximum and corresponding displacement. Comparing bundles of roots that have similar mean diameters, a bundle with a narrow variance in root diameter will result in a larger maximum force and a smaller displacement at maximum force than a bundle with a wide diameter distribution. Increasing the mean root diameter of a bundle without changing the distribution's shape increases both the maximum force and corresponding displacement. Estimates of the maximum pullout forces for bundles of 100 roots with identical diameter distribution for different species range from less than 1 kN for barley (Hordeum vulgare) to almost 16 kN for pistachio (Pistacia lentiscus). The model explains why a commonly used assumption that all roots break simultaneously overpredicts the maximum pullout force by a factor of about 1.6–2. This ratio may exceed 3 for diameter distributions that have a large number of small roots like the exponential distribution.

Journal ArticleDOI
TL;DR: In this article, the advantages and disadvantages of two scan systems used to monitor a recently deglaciated permafrost rock wall at Gemsstock in the central Swiss Alps are analyzed and the optimization of referencing methods and accuracy analyses are discussed.

Journal ArticleDOI
TL;DR: No trend in concentrations and fluxes of BC, SO4–S, and inorganic N were found at most soil depths at five out of the seven sites, which suggests that the soil solution reacted very little to the changes in atmospheric deposition.
Abstract: Trends in atmospheric acid deposition and in soil solution acidity from 1995 or later until 2007 were investigated at several forest sites throughout Switzerland to assess the effects of air pollution abatements on deposition and the response of the soil solution chemistry. Deposition of the major elements was estimated from throughfall and bulk deposition measurements at nine sites of the Swiss Long-Term Forest Ecosystem Research network (LWF) since 1995 or later. Soil solution was measured at seven plots at four soil depths since 1998 or later. Trends in the molar ratio of base cations to aluminum (BC/Al) in soil solutions and in concentrations and fluxes of inorganic N (NO3–N + NH4–N), sulfate (SO4–S), and base cations (BC) were used to detect changes in soil solution chemistry. Acid deposition significantly decreased at three out of the nine study sites due to a decrease in total N deposition. Total SO4–S deposition decreased at the nine sites, but due to the relatively low amount of SO4–S load compared to N deposition, it did not contribute to decrease acid deposition significantly. No trend in total BC deposition was detected. In the soil solution, no trend in concentrations and fluxes of BC, SO4–S, and inorganic N were found at most soil depths at five out of the seven sites. This suggests that the soil solution reacted very little to the changes in atmospheric deposition. A stronger reduction in base cations compared to aluminum was detected at two sites, which might indicate that acidification of the soil solution was proceeding faster at these sites.

Journal ArticleDOI
TL;DR: In this paper, the morphodynamic evolution of the restored reach of the River Thur near Niederneunforn (Switzerland) is studied, in relation to the role of pioneer vegetation roots in stabilizing the alluvial sediment.
Abstract: River restoration has become a common measure to repair anthropogenically-induced alteration of fluvial ecosystems. The inherent complexity of ecohydrologic systems leads to limitations in understanding the response of such systems to restoration over time. Therefore, a significant effort has been dedicated in the recent years worldwide to document the efficiency of restoration actions and to produce new effective guidelines that may help overcoming existing deficiencies. At the same time little attention was paid to illustrate the reasons and the use of certain monitoring and experimental techniques in spite of others, or in relation to the specific ecohydrologic process being investigated. The purpose of this paper is to enrich efforts in this direction by presenting the framework of experimental activities and the related experimental setup that we designed and installed in order to accomplish some of the research tasks of the multidisciplinary scientific project RECORD (Restored Corridor Dynamics). Therein, we studied the morphodynamic evolution of the restored reach of the River Thur near Niederneunforn (Switzerland), also in relation to the role of pioneer vegetation roots in stabilizing the alluvial sediment. In this work we describe the methodology chosen for monitoring the river morphodynamics, the dynamics of riparian and of in-bed vegetation and their mutual interactions, as well as the need of complementing such observations with experiments and with the hydraulic modeling of the site. We also discuss how the designed installation and the experiments integrate with the needs of other research groups within the project, in particular providing data for a number of investigations thereby including surface water and groundwater interactions, soil moisture and vegetation dynamics.