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.
2015
Authors
Inger HansenAbstract
This literature review documents behavioural differences in organic and conventional sheep and goats in Norway. Increased indoor space results in increased lying time, more synchronized lying behaviour, less displacements and higher milk yield in sheep, and increased lying time and lower frequency of agonistic behaviour in goats. Sheep and goats spend 45-50 % of their time outdoors when given access to an outdoor yard during winter. Under normal thermal conditions, fully fleeced sheep do not need solid floors of welfare reasons in Norway. Neither do dairy goats in insulated buildings. The significance of different milk feeding strategies in goat kids is poorly documented, but studies on lambs and calves show that suckling increases the growth rate, gives better social competence and more exploratory behaviour. Thus, the organic regulations in Norwegian sheep and goat production have some positive impact on behavioural indicators of sheep and goat welfare, especially during winter housing.
Authors
Nicholas Clarke Per Gundersen Ulrika Jönsson-Belyazid O. Janne Kjønaas Tryggve Persson Bjarni Diðrik Sigurðsson Inge Stupak Lars VesterdalAbstract
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Authors
Ryan BrightAbstract
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Authors
Frederik T. Hansen Donald M. Gardiner Erik Lysøe Patricia Romans Fuertes Bettina Tudzynski Philipp Wiemann Teis Esben Sondergaard Henriette Giese Ditlev E. Brodersen Jens Laurids SørensenAbstract
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Authors
Steffen Werne Margarita Novoa-Garrido Martin Riis Weisbjerg Eduarda Molina-Alcaide Vibeke Lind Felix HeckendornAbstract
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Abstract
The eddy covariance (EC) method is one key method to quantify fluxes in biogeochemical cycles in general, and carbon and energy transport across the vegetation-atmosphere boundary layer in particular. EC data from the worldwide net of flux towers (Fluxnet) have also been used to validate biogeochemical models. The high resolution data are usually obtained at 20 Hz sampling rate but are affected by missing values and other restrictions. In this contribution, we investigate the nonlinear dynamics of EC fluxes using Recurrence Analysis (RA). High resolution data from the site DE-Bay (Waldstein-Weidenbrunnen) and fluxes calculated at half-hourly resolution from eight locations (part of the La Thuile dataset) provide a set of very long time series to analyze. After careful quality assessment and Fluxnet standard gapfilling pretreatment, we calculate properties and indicators of the recurrent structure based both on Recurrence Plots as well as Recurrence Networks. Time series of RA measures obtained from windows moving along the time axis are presented. Their interpretation is guided by three different questions: (1) Is RA able to discern periods where the (atmospheric) conditions are particularly suitable to obtain reliable EC fluxes? (2) Is RA capable to detect dynamical transitions (different behavior) beyond those obvious from visual inspection? (3) Does RA contribute to an understanding of the nonlinear synchronization between EC fluxes and atmospheric parameters, which is crucial for both improving carbon flux models as well for reliable interpolation of gaps? (4) Is RA able to recommend an optimal time resolution for measuring EC data and for analyzing EC fluxes? (5) Is it possible to detect non-trivial periodicities with a global RA? We will demonstrate that the answers to all five questions is affirmative, and that RA provides insights into EC dynamics not easily obtained otherwise.