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Ganthaler A.,University of Innsbruck | Ganthaler A.,Alpnter for Climate Change Adaptation | Mayr S.,University of Innsbruck
Forest Pathology | Year: 2015

The fungal pathogen Chrysomyxa rhododendri undergoes a host shift between Rhododendron spp. and Picea abies and has a considerable negative impact on the latter by infecting the new sprouting needles and reducing photosynthesis, growth and seedling survival. Repeated high infection rates in the Central European Alps were reported in recent years, and although the life cycle of the pathogen is well understood, knowledge on temporal patterns of host infection, spore dispersal and influence of weather conditions is limited. We analysed the period of needle infection by a staggered application of fungicide on twigs of Norway spruce. Seasonal and diurnal patterns of spore dispersal were investigated using a Burkard volumetric spore trap, and airborne spore concentrations were correlated with several weather parameters. Needle infection occurred within 3 weeks (19 June-9 July). Basidiospores (infecting Norway spruce) were trapped from May to July, and airborne spore concentration was positively correlated with air temperature, global radiation and wind speed, and negatively with air humidity and precipitation. Aeciospores (infecting rhododendrons) appeared from August to October, and high concentrations were significantly associated with rain events. Needle infection started with bud sprouting and was limited either by decreasing spore concentrations or morphological and chemical differentiation of the needles, which prevented infection. Both spore types showed distinct periods of dispersal based on the life cycle of the pathogen, and the variability in concentration within these periods was explained by local weather conditions. The correlation analysis indicated different mechanisms of spore dispersal for both spore types and, with respect to global warming, more favourable conditions for the pathogen in future. The results can explain the high year- and site-specific variation in Chrysomyxa infection intensities of P. abies and may be helpful for developing successful strategies to control the pathogen and protect alpine spruce forests. © 2015 Blackwell Verlag GmbH.

Theuretzbacher F.,University of Natural Resources and Life Sciences, Vienna | Lizasoain J.,University of Natural Resources and Life Sciences, Vienna | Lizasoain J.,Alpnter for Climate Change Adaptation | Lefever C.,University of Natural Resources and Life Sciences, Vienna | And 5 more authors.
Bioresource Technology | Year: 2015

Wheat straw can serve as a low-cost substrate for energy production without competing with food or feed production. This study investigated the effect of steam explosion pretreatment on the biological methane potential and the degradation kinetics of wheat straw during anaerobic digestion. It was observed that the biological methane potential of the non steam exploded, ground wheat straw (276lNkgVS-1) did not significantly differ from the best steam explosion treated sample (286lNkgVS-1) which was achieved at a pretreatment temperature of 140°C and a retention time of 60min. Nevertheless degradation speed was improved by the pretreatment. Furthermore it was observed that compounds resulting from chemical reactions during the pretreatment and classified as pseudo-lignin were also degraded during the anaerobic batch experiments. Based on the rumen simulation technique, a model was developed to characterise the degradation process. © 2014 Elsevier Ltd.

Wyss R.,University of Applied science Chur | Wyss R.,Catholic University of Eichstatt-Ingolstadt | Luthe T.,University of Applied science Chur | Abegg B.,University of Innsbruck | Abegg B.,Alpnter for Climate Change Adaptation
Local Environment | Year: 2014

While there is ample - though partially contradictory - evidence regarding the effects climate change will have on various regions of the world, there is only very limited work dedicated to the analysis of different governance structures, and how these structures are likely to influence the resilience of alpine tourism systems in the face of climate change. We present an analytical framework based on network theory, and apply this to the Swiss case study destination of Engelberg, in order to deduct a number of insights for the future assessment of resilience based on the cooperation of local actors. The main aim of the paper is to come up with comparable resilience metrics based on social network analysis in order to assess the structural strengths and weaknesses of a geographically delimited tourism system in the face of climate change. Together with the action potential of the individual actors these structural properties influence the adaptive capacity of both individual actors, and the tourism system as a whole. In line with comparable studies, we identify structural strengths and weaknesses around the core-periphery distribution (centrality), subgroups (modularity) and information flows (path length). We find that the Engelberg network follows an almost ideal-typical scale-free structure and the overall cooperation rate (density) is comparable to other tourism networks. The main weaknesses of the network with regard to climate change resilience are the lacking integration of public sector actors and the relatively high number of actors in the periphery of the network. © 2014 © 2014 Taylor & Francis.

Zerlauth M.,Alpnter for Climate Change Adaptation | Zerlauth M.,University of Innsbruck | Ortner H.,University of Innsbruck | Pomella H.,University of Innsbruck | And 2 more authors.
Swiss Journal of Geosciences | Year: 2014

Based upon tectonic as well as facies arguments, two different Helvetic nappes can be distinguished in western Austria (Vorarlberg) and in southwestern Germany (Upper Allgäu): the Hohenems nappe and the overlying Vorarlberg Säntis nappe. Both encompass Middle Jurassic to Eocene strata deposited on the internal to external shelf of the southward deepening European margin of the Eurasian plate. Synsedimentary normal faults caused changes in thickness and facies of the various strata, which play a crucial role in deformation behavior. Arcuate fold axes in map view and an almost 3 km thick sequence of stacked Middle Jurassic shales and sandstones drilled below a Jurassic anticlinorium in the southern part of the Bregenzerwald are thought to be indicative of an inverted Jurassic basin. Inversion occurred during the Cenozoic Alpine nappe formation along synsedimentary normal faults, reactivated as ramps and tear faults. A lateral ramp, segmented by tear faults, running along the Iller Valley, and a supposed lateral ramp in the subsurface of the Rhine Valley mark the extension of the inverted former basin. Fault deformation style changes across the Rhine Valley. East of it, i.e. in Vorarlberg, the Vorarlberg Säntis nappe comprises a coherent succession of Jurassic and Cretaceous strata detached along Middle Jurassic sediments. In the west, on the other hand, Cretaceous strata of the Swiss Säntis nappe were largely detached from their Jurassic substrate (Gonzen-Walenstadt imbricates) along the Säntis thrust. This allows to correlate the Helvetic nappe stack of eastern Switzerland, comprising the Swiss Säntis nappe (together with the Gonzen-Walenstadt imbricates) and the underlying Mürtschen nappe, with the Vorarlberg Säntis nappe and the Hohenems nappe of Austria. © 2014, Swiss Geological Society.

The hydrogeology of the deep-seated, slowly creeping Klasgarten rockslide in Austria is investigated in this study based on detailed surface and subsurface field data, laboratory analyses, and analytical and numerical simulations. Field data are derived from several deep exploration and monitoring boreholes, an exploration drift located within the rockslide, and geological and geomorphological mapping. Particular attention is given to the pore pressure measurements and their temporal and spatial variability. These pore pressure variations are controlled by a thin layer of clayey fault gouge (representing the basal shear zone of the rockslide), a high-permeability rockslide mass, and moderately fractured paragneissic bedrock. Variably saturated equivalent-continuum hydraulic conductivities and storage properties are derived from packer tests, laboratory tests and optical televiewer images. These data sets are used for two-dimensional numerical groundwater models to study the flow-field and pore-pressure variations caused by the reservoir water-level fluctuations, the transient groundwater infiltration from snowmelt and precipitation along the slope, and the exploration drift. The strongest pressure transients in the rockslide are caused by reservoir level fluctuations and not the natural groundwater recharge, even at substantial distances from the reservoir. The response times are very short and only a minor distance-dependent attenuation is observed. The results of this study are essential to analyse the hydromechanical control of the deformation behaviour of rockslides adjacent to hydropower reservoirs. Further, it helps to understand how the formation of a rockslide can change the original bedrock aquifer. © 2015, Springer-Verlag Berlin Heidelberg.

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