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Birmensdorf, Switzerland

Turowski J.M.,Swiss Federal Institute of forest
Journal of Geophysical Research: Earth Surface | Year: 2011

The Hamamori distribution is frequently used to describe the variability of bed load transport rates in bed form-dominated environments. However, the original derivation contains several incorrect steps. Here a corrected and generalized derivation is presented. It is shown that Hamamori's original distribution function arises if the underlying assumptions are adapted slightly. Two formalisms are presented to obtain probability distributions of instantaneous bed load transport rates from growth functions of ripples and from the distribution of ripple heights. Six distribution functions, among them the exponential distribution, the Hamamori distribution, and the gamma distribution, are compared to two laboratory data sets, one for gravel and one for sand transport, and to field data from a sand-bed river. For the gravel bed laboratory measurements, the Hamamori distribution gives a good description of the data for intermediate transport rates, while the gamma distribution performs best overall. For the sand-bed laboratory data, the exponential distribution shows the best performance. A distribution function derived from Rayleigh-distributed ripple heights performs best for the field data. Copyright 2011 by the American Geophysical Union. Source

Egli S.,Swiss Federal Institute of forest
Annals of Forest Science | Year: 2011

• Introduction: Fruit-body production of mushrooms is not well understood to date as many factors interact with mushroom growth in nature. Weather conditions play a key role, but they do not completely explain the growth and productivity of wild mushrooms. Mycorrhizal fungi depend on photosynthetically fixed carbon produced by their associated trees, and the physiological state of host trees may well drive the growth of these fungi. We raise the question of whether mycorrhizal fungi can be used as indicators for tree health. • Discussion: In the 1980s, a decline in the species richness and abundance of ectomycorrhizal species was observed in Europe, which was then seen as reflecting the degree of forest dieback. An analysis of the results of a long-term study over 32 years in the fungus reserve La Chanéaz confirms this decline: since 1975, the mycorrhizal species have considerably decreased in abundance in relation to the other species. We discuss potential causes of this development and raise questions about a possible relationship between a decrease in mycorrhizal fungi and the health of the associated forest trees. • Conclusion: We do not yet know enough about forest mushrooms to be able to use them as bio-indicators of tree health. More research is needed, especially about the functional significance of ectomycorrhizal fungi on a species level. © The Author(s) 2011. Source

Tobias S.,Swiss Federal Institute of forest
Integrated Environmental Assessment and Management | Year: 2013

This article presents a literature review that explores the challenges for planning in urban regions in connection with the preservation of ecosystem services. It further presents some best practice examples for meeting these challenges. The demand for the provision of ecosystem services within urban regions changed during the transition from a largely agrarian society to an industrial society and, most recently, to a service society. Although in the past, provisioning services such as food production or the provision of raw material were decisive for urban development, today cultural services, e.g., clear views or nearby recreation areas, have become increasingly important. According to the literature, soil sealing is the greatest threat urbanization poses toward ecosystem services, as it compromises all of them. Spatially extensive cities with a high building density particularly inhibit regulating services like the regulation of temperature or water surface runoff. Conversely, scattered settlement patterns may lead to very small remnants of open space that cannot reasonably serve as natural habitat, agricultural land, or recreation area. The challenges for planning in urban regions are: 1) specifying regulations that define outer limits to the development of each settlement unit, 2) comprehensive planning with focal points for development, and limiting access and development at other places, and 3) compensating for new soil sealing by restoring nearby sealed areas. The article presents 3 best-practice examples that support these principles: designating areas with a particular soil quality that should not be built over, offering incentives for corporate planning in urban regions, and restoring a country road in connection with a motorway construction. © 2013 SETAC. Source

Manel S.,Aix - Marseille University | Manel S.,CIRAD - Agricultural Research for Development | Holderegger R.,Swiss Federal Institute of forest | Holderegger R.,ETH Zurich
Trends in Ecology and Evolution | Year: 2013

Landscape genetics is now ten years old. It has stimulated research into the effect of landscapes on evolutionary processes. This review describes the main topics that have contributed most significantly to the progress of landscape genetics, such as conceptual and methodological developments in spatial and temporal patterns of gene flow, seascape genetics, and landscape genomics. We then suggest perspectives for the future, investigating what the field will contribute to the assessment of global change and conservation in general and to the management of tropical and urban areas in particular. To address these urgent topics, future work in landscape genetics should focus on a better integration of neutral and adaptive genetic variation and their interplay with species distribution and the environment. © 2013 Elsevier Ltd. Source

Steiner T.,Swiss Federal Institute of forest
Medicine and science in sports and exercise | Year: 2011

It is unclear if hemoglobin mass (Hbmass) and red cell volume (RCV) increase in endurance athletes with several years of endurance training from adolescence to adulthood. The aim of this study, therefore, was to determine with a controlled cross-sectional approach whether endurance athletes at the ages of 16, 21, and 28 yr are characterized by different Hbmass, RCV, plasma volume (PV), and blood volume (BV). BV parameters (CO rebreathing), VO(2max) and other blood, iron, training, and anthropometric parameters were measured in three endurance athlete groups AG16 (n = 14), AG21 (n = 14), and AG28 (n = 16) as well as in three age-matched control groups (<2 h endurance training per week): CG16 (n = 16), CG21 (n = 15), and CG28 (n = 16). In AG16, body weight-related Hbmass (12.4 ± 0.7 g·kg(-1)), RCV, BV, and VO(2max) (66.1 ± 3.8 mL·kg·(-1)min(-1)) were lower (P < 0.001) than those in AG21 (14.2 ± 1.1 g·kg(-1), 72.9 ± 3.6 mL·kg·(-1)min(-1)) and AG28 (14.6 ± 1.1 g·kg(-1), 73.4 ± 6.0 mL·kg·(-1)min(-1)). Results for these parameters did not differ between AG21 and AG28 and among the control groups. VO(2max), PV, and BV were higher for AG16 than for CG16 (12.0 ± 1.0 g·kg(-1), 58.9 ± 5.0 mL·kg·(-1)min(-1)) but not Hbmass and RCV. Our results suggest that endurance training has major effects on Hbmass and RCV from ages 16 to 21 yr, although there is no further increase from ages 21 to 28 yr in top endurance athletes. On the basis of our findings, an early detection of the aptitude for endurance sports at age 16 yr, solely based on levels of Hbmass, does not seem to be possible. Source

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