Swiss Federal Institute for Forest, Snow and Landscape Research

About: Swiss Federal Institute for Forest, Snow and Landscape Research is a facility organization based out in Birmensdorf, Switzerland. It is known for research contribution in the topics: Climate change & Soil water. The organization has 1256 authors who have published 3222 publications receiving 161639 citations. The organization is also known as: WSL.

Discovering the True Chrysoperla carnea (Insecta: Neuroptera: Chrysopidae) Using Song Analysis, Morphology, and Ecology

Abstract: What was once considered a single Holarctic species of green lacewing, Chrysoperla carnea (Stephens), has recently been shown to be a complex of many cryptic, sibling species, the carnea species group, whose members are reproductively isolated by their substrate-borne vibrational songs. Because species in the complex are diagnosed by their song phenotypes and not by morphology, the current systematic status of the type species has become a problem. Here, we attempt to determine which song species corresponds to Stephens’ 1835 concept of C. carnea, originally based on a small series of specimens collected in or near London and currently housed in The Natural History Museum. With six European members of the complex from which to choose, we narrow the field to just three that have been collected in England: C. lucasina (Lacroix), Cc2 ‘slow-motorboat’, and Cc4 ‘motorboat’. Ecophysiology eliminates C. lucasina, because that species remains green during adult winter diapause, while Cc2 and Cc4 share wi...

Exudation of organic acid anions from poplar roots after exposure to Al, Cu and Zn

Abstract: We studied the effects of a 2-day exposure to aluminum (Al), copper (Cu) and zinc (Zn) stress on root exudates and root apices of aseptically grown poplar (Populus tremula L.) cuttings. Aluminum induced root exudation of oxalate and citrate, Cu induced root exudation of oxalate, malate and formate, and Zn induced root exudation of formate. The threshold treatment concentrations were 100 microM for Cu and 500 microM for Al and Zn, corresponding to about 30 microM Cu2+, 140 microM Al3+ and 290 microM Zn2+. Simultaneous with the increase in organic acid anion exudation, sulfate and the nutrient cations K+, Ca2+ and Mg2+ were released into the solutions. Significant positive correlations between the organic acid anions and the cations indicate possible co-release. Toxicity symptoms of the poplar roots included browning of the root apices, which occurred at Cu concentrations of 50 microM and above, at Zn concentrations of 500 microM and above, and at an Al concentration of 1000 microM, and callose formation, which was observed solely in response to Al concentrations of 500 microM or higher. The results indicate that the composition of the exuded organic acid anions from poplar roots and the toxicity symptoms are specific to each of the applied heavy metals.

Evidence of response of vegetation to environmental change on high-elevation sites in the Swiss Alps

Abstract: Climate change has in the past led to shifts in vegetation patterns; in a future, warmer climate due to enhanced greenhouse-gas concentrations, vegetation is also likely to be highly responsive to such warming. Mountain regions are considered to be particularly sensitive to such changes. In this paper we present an approach to assess the impact of climate change on long-term vegetation plots at the high-elevation site of the Schynige Platte, 2000 m above sea level, in the Bernese Alps (Switzerland). Records of vegetation spanning the period from 1928 to today at two different sites, each with several plots, were considered. The observed change in the species composition was then related to changes in land use and climate. We used daily values of temperature, snow and precipitation from several high-elevation weather stations to conduct these analyses. The correlation between climate and vegetation patterns revealed that species that prefer low thermal conditions move out of the plots, i.e., their frequency of occurrence is negatively correlated with the average number of degree-days over the last six decades. On the other hand, species with higher thermal demands are seen to be invading the plots, i.e., their frequency of occurrence is positively correlated to the average number of degree-days. Nutrient changes – though independent from climate – also play an important role in the observed shifts in species.

Monitoring and prediction in early warning systems for rapid mass movements

Abstract: . Rapid mass movements (RMM) pose a substantial risk to people and infrastructure. Reliable and cost-efficient measures have to be taken to reduce this risk. One of these measures includes establishing and advancing the state of practice in the application of early warning systems (EWSs). EWSs have been developed during the past decades and are rapidly increasing. In this paper, we focus on the technical part of EWSs, i.e., the prediction and timely recognition of imminent hazards, as well as on monitoring slopes at risk and released mass movements. Recent innovations in assessing spatial precipitation, monitoring and precursors of the triggering and deformation of RMM offer new opportunities for next-generation EWSs. However, technical advancement can only be transferred into more reliable, operational EWSs with an adequate well-instructed dedicated staff. To this end, an intense dialog between scientists, engineers and those in charge of warning, as well as further experience with new comprehensive prototype systems jointly operated by scientists and practitioners, will be essential.

A 350 year drought reconstruction from Alpine tree ring stable isotopes

Abstract: [1] Climate reconstructions based on stable isotopes in tree rings rely on the assumption that fractionation-controlling processes are strongly linked to meteorological variables. In this context, we investigated the climate sensitivity of 350 years of carbon and oxygen isotope ratios of tree ring cellulose from European larch obtained at a high-elevation site in the Swiss Alps (∼2100 m above sea level). Unlike tree ring width and maximum latewood density, which contain only summer temperature information at this site, we found that our stable isotope series reveal additionally to temperature a striking sensitivity to precipitation (mainly for carbon) and sunshine duration (mainly for oxygen) during July and August. A drought index reflecting the combined temperature and precipitation influence provided the most stable correlations over time for the carbon isotope series. All of these climate-isotope relationships are preserved in the isotope series obtained from younger trees at the same site, while strong intertree correlations further emphasize the high climate sensitivity. We thus present the first carbon-isotope-based summer drought reconstruction for the Swiss Alps, which provides new evidence for interannual to long-term changes in summer regional moisture variability from 1650 to 2004 in Europe, revealing extreme drought summers in the second half of the 18th century and throughout the 20th century.