Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2013
Authors
Felix Herzog Philippe Jeanneret Youssef Ammari Siyka Angelova Michaela Arndorfer Debra Bailey Katalin Balázs András Báldi Marion Bogers Robert Bunce Jean-Philippe Choisis David Cuming Peter Dennis Tetyana Dyman Sebastian Eiter Zoltán Elek Eszter Falusi Wendy Fjellstad Thomas Frank Jürgen Friedel Salah Garchi Ilse Geijzendorffer Tiziano Gomiero Gergely Jerkovich Rob Jongman Max Kainz Esezah Kakudidi Eszter Kelemen Roland Kölliker Norman Kwikiriza Anikó Kovács-Hostyánszki Luisa Last Gisela Lüscher Gerardo Moreno Charles Nkwiine John Opio Marie-Louise Oschatz Maurizio Guido Paoletti Károly Penksza Philippe Pointereau Susanne Riedel Jean-Pierre Sarthou Manuel Schneider Norman Siebrecht Daniele Sommaggio Siyka Stoyanova Erich Szerencsits O. Szalkovski Stella Targetti Davide Viaggi Jerylee Wilkes-Allemann Sebastian Wolfrum Sergiy Yashchenko Tommaso ZanettiAbstract
No abstract has been registered
Abstract
To better understand the historic range of variability in the fire regime of Fennoscandian boreal forests we cross-dated 736 fire scars of remnant Scots pine (Pinus sylvestris L.) wood samples in a 3.6 km2 section of the Trillemarka-Rollagsfjell Reserve of south-central Norway. Using a kernel range application in GIS we spatially delineated 57 individual forest fires between 1350 and the present. We found a strong anthropogenic signal in the fire regime from 1600 and onwards: (i) infrequent variably sized fires prior to 1600 shifted to frequent fires gradually decreasing in size during the 1600s and 1700s, with only a few small fires after 1800; (ii) time intervals between fires and the hazard of burning showed substantial differences pre- and post-1600; (iii) fire seasonality changed from late- to early-season fires from the 1626 fire and onwards; and (iv) fire severity decreased gradually over time. Written sources corroborated our results, narrating a history where anthropogenic forest fires and slash-and-burn cultivation expanded with the increasing population from the late 1500s. Concurrently, timber resources increased in value, gradually forcing slash-and-burn cultivators to abandon fires on forest land. Our results strengthen and expand previous Fennoscandian findings on the anthropogenic influence of historic fire regimes.
Authors
Joachim Paul Spindelbøck Zöe Cook Matthew I. Daws Einar Heegaard Inger Elisabeth Måren Vigdis VandvikAbstract
Background and Aims: Across their range, widely distributed species are exposed to a variety of climatic and other environmental conditions, and accordingly may display variation in life history strategies. For seed germination in cold climates, two contrasting responses to variation in winter temperature have been documented: first, an increased ability to germinate at low temperatures (cold tolerance) as winter temperatures decrease, and secondly a reduced ability to germinate at low temperatures (cold avoidance) that concentrates germination towards the warmer parts of the season. Methods: Germination responses were tested for Calluna vulgaris, the dominant species of European heathlands, from ten populations collected along broad-scale bioclimatic gradients (latitude, altitude) in Norway, covering a substantial fraction of the species' climatic range. Incubation treatments varied from 10 to 25 °C, and germination performance across populations was analysed in relation to temperature conditions at the seed collection locations. Key Results: Seeds from all populations germinated rapidly and to high final percentages under the warmer incubation temperatures. Under low incubation temperatures, cold-climate populations had significantly lower germination rates and percentages than warm-climate populations. While germination rates and percentages also increased with seed mass, seed mass did not vary along the climatic gradients, and therefore did not explain the variation in germination responses. Conclusions: Variation in germination responses among Calluna populations was consistent with increased temperature requirements for germination towards colder climates, indicating a cold-avoidance germination strategy conditional on the temperature at the seeds' origin. Along a gradient of increasing temperatures this suggests a shift in selection pressures on germination from climatic adversity (i.e. low temperatures and potential frost risk in early or late season) to competitive performance and better exploitation of the entire growing season.
Abstract
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Authors
Stefanos Xenarios Paul PavelicAbstract
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Authors
Ghislain Tchoromi Tepa-Yotto Trond Hofsvang Ignace Godonou Ingrid Tchibozo May SæthreAbstract
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Abstract
When calculating the Bandt and Pompe ordinal pattern distribution from given time series at depth D, some of the D! patterns might not appear. This could be a pure finite size effect (missing patterns) or due to dynamical properties of the observed system (forbidden patterns). For pure noise, no forbidden patterns occur, contrary to deterministic chaotic maps. We investigate long time series of river runoff for missing patterns and calculate two global properties of their pattern distributions: the Permutation Entropy and the Permutation Statistical Complexity. This is compared to purely stochastic but long-range correlated processes, the k-noise (noise with power spectrum f−k), where k is a parameter determining the strength of the correlations. Although these processes closely resemble runoff series in their correlation behavior, the ordinal pattern statistics reveals qualitative differences, which can be phrased in terms of missing patterns behavior or the temporal asymmetry of the observed series. For the latter, an index is developed in the paper, which may be used to quantify the asymmetry of natural processes as opposed to artificially generated data.
Abstract
No abstract has been registered