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.
2016
Abstract
This paper describes a method in which horses learn to communicate by touching different neutral visual symbols, in order to tell the handler whether they want to have a blanket on or not. Horses were trained for 10–15 min per day, following a training program comprising ten steps in a strategic order. Reward based operant conditioning was used to teach horses to approach and touch a board, and to understand the meaning of three different symbols. Heat and cold challenges were performed to help learning and to check level of understanding. At certain stages, a learning criterion of correct responses for 8–14 successive trials had to be achieved before proceeding. After introducing the free choice situation, on average at training day 11, the horse could choose between a “no change” symbol and the symbol for either “blanket on” or “blanket off” depending on whether the horse already wore a blanket or not. A cut off point for performance or non-performance was set to day 14, and 23/23 horses successfully learned the task within this limit. Horses of warm-blood type needed fewer training days to reach criterion than cold-bloods (P < 0.05). Horses were then tested under differing weather conditions. Results show that choices made, i.e. the symbol touched, was not random but dependent on weather. Horses chose to stay without a blanket in nice weather, and they chose to have a blanket on when the weather was wet, windy and cold (χ2 = 36.67, P < 0.005). This indicates that horses both had an understanding of the consequence of their choice on own thermal comfort, and that they successfully had learned to communicate their preference by using the symbols. The method represents a novel tool for studying preferences in horses.
Authors
Atle Mysterud William Ryan Easterday Vetle Malmer Stigum Anders Aas Erling Meisingset Hildegunn ViljugreinAbstract
No abstract has been registered
Authors
R. Venancio G.J. Moraes R.C. Castilho N.S. Iwanicki G.F. Moreira Lise Grøva Karin Westrum Ingeborg KlingenAbstract
Tick-borne diseases, such as anaplasmosis and babesiosis, are of major concern for Norwegian sheep farmers. Ticks can be controlled on and off the host, usually with the long-term, high-rotation use of chemicals. Fungal pathogens, predatory mites and ants are thought to be important tick killers in nature. However, the prevalence and diversity of predatory mites in tick habitats has barely been evaluated. It is known that most soil mite species of the cohort Gamasina (order Mesostigmata) are predators. Until now, 220 mesostigmatid species have been reported from Norway, most of them belonging to the Gamasina. One of the first recommended steps in a biological control program involves the determination of the fauna in the pest habitat. The objective of this study was to determine the groups of gamasines co-occurring with I. ricinus in sheep grazing areas in Isfjorden and Tingvoll in Western Norway. A total of 2,900 gamasines of 12 families was collected. The most numerous families were Parasitidae (46.9%) and Veigaiidae (25.7%), whereas the most diverse families were Laelapidae, Macrochelidae, Parasitidae and Zerconidae. Our results showed that the tick density was significantly related only to locality, elevation and rainfall. Differences in the prevailing environmental conditions resulted in more outstanding differences between Gamasina abundances than diversities. Based on our present knowledge of the potential of different gamasine groups as biological control agents, the results suggested that laelapid mites should be among the priority groups to be further evaluated for their role in the natural control of I. ricinus in Norway.
Authors
Lise Dalsgaard Rasmus Astrup Clara Antón-Fernández Signe Kynding Borgen Johannes Breidenbach Holger Lange Aleksi Lehtonen Jari LiskiAbstract
Boreal forests contain 30% of the global forest carbon with the majority residing in soils. While challenging to quantify, soil carbon changes comprise a significant, and potentially increasing, part of the terrestrial carbon cycle. Thus, their estimation is important when designing forest-based climate change mitigation strategies and soil carbon change estimates are required for the reporting of greenhouse gas emissions. Organic matter decomposition varies with climate in complex nonlinear ways, rendering data aggregation nontrivial. Here, we explored the effects of temporal and spatial aggregation of climatic and litter input data on regional estimates of soil organic carbon stocks and changes for upland forests. We used the soil carbon and decomposition model Yasso07 with input from the Norwegian National Forest Inventory (11275 plots, 1960–2012). Estimates were produced at three spatial and three temporal scales. Results showed that a national level average soil carbon stock estimate varied by 10% depending on the applied spatial and temporal scale of aggregation. Higher stocks were found when applying plot-level input compared to country-level input and when long-term climate was used as compared to annual or 5-year mean values. A national level estimate for soil carbon change was similar across spatial scales, but was considerably (60–70%) lower when applying annual or 5-year mean climate compared to long-term mean climate reflecting the recent climatic changes in Norway. This was particularly evident for the forest-dominated districts in the southeastern and central parts of Norway and in the far north. We concluded that the sensitivity of model estimates to spatial aggregation will depend on the region of interest. Further, that using long-term climate averages during periods with strong climatic trends results in large differences in soil carbon estimates. The largest differences in this study were observed in central and northern regions with strongly increasing temperatures.
Abstract
No abstract has been registered
Abstract
This study examined the P fertilization effects of 11 sewage sludges obtained from sewage treated with Al and/or Fe salts to remove P by a pot experiment with ryegrass (Lolium multiflorum) and a nutrient-deficient sand−peat mixture. Also it investigated whether fertilization effects could be predicted by chemical sludge characteristics and/or by P extraction. The mineral fertilizer equivalent (MFE) value varied significantly but was low for all sludges. MFE was best predicted by a negative correlation with ox-Al and ox-Fe in sludge, or by a positive correlation with P extracted with 2% citric acid. Ox-Al had a greater negative impact on MFE than ox-Fe, indicating that Fe salts are preferable as a coagulant when aiming to increase the plant availability of P in sludge. The results also indicate that sludge liming after chemical wastewater treatment with Al and/or Fe salts increases the P fertilization effect.
Authors
Gudrun Schwilch Lea Bernet Luuk Fleskens Elias Giannakis Julia Leventon Teodoro Maranon Jane Mills Chris Short Jannes Stolte Hedwig van Delden Simone VerzandvoortAbstract
Despite numerous research efforts over the last decades, integrating the concept of ecosystem services into land management decision-making continues to pose considerable challenges. Researchers have developed many different frameworks to operationalize the concept, but these are often specific to a certain issue and each has their own definitions and understandings of particular terms. Based on a comprehensive review of the current scientific debate, the EU FP7 project RECARE proposes an adapted framework for soil-related ecosystem services that is suited for practical application in the prevention and remediation of soil degradation across Europe. We have adapted existing frameworks by integrating components from soil science while attempting to introduce a consistent terminology that is understandable to a variety of stakeholders. RECARE aims to assess how soil threats and prevention and remediation measures affect ecosystem services. Changes in the natural capital's properties influence soil processes, which support the provision of ecosystem services. The benefits produced by these ecosystem services are explicitly or implicitly valued by individuals and society. This can influence decision- and policymaking at different scales, potentially leading to a societal response, such as improved land management. The proposed ecosystem services framework will be applied by the RECARE project in a transdisciplinary process. It will assist in singling out the most beneficial land management measures and in identifying trade-offs and win–win situations resulting from and impacted by European policies. The framework thus reflects the specific contributions soils make to ecosystem services and helps reveal changes in ecosystem services caused by soil management and policies impacting on soil. At the same time, the framework is simple and robust enough for practical application in assessing soil threats and their management with stakeholders at various levels.
Abstract
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Authors
Erin K. Cameron Thibaud Decaëns Emmanuel Lapied David Porco Nico EisenhauerAbstract
No abstract has been registered
Abstract
Black currant is a woody plant in which growth and development are intimately controlled by, and synchronised with seasonal changes in photoperiod and temperature. Concern over the potential impact of global warming on plant phenology and yield, led us to initiate relations. An experimental system with single-stemmed potted plants was developed which allowed a research program to address both qualitative and quantitative assessment of climatic responses. Growth cessation and flowering were both induced by short days, with critical photoperiods of approximately 17 and 16 h, respectively, for most cultivars. Both processes were advanced and promoted by increasing autumn temperature with an optimum in the 18-21°C region. An exception was cultivars of high-boreal origin, which had an early growth cessation at low temperature. Unexpectedly, however, not all plants flowered after exposure to 10 h photoperiod, and the number of flowers decreased as the photoperiod was reduced from the near-critical length of 15 h. This was due to premature dormancy induced by an abrupt change to photoperiods well below the critical level. Field experiments revealed that cultivars of varying geographic origin, exhibited a typical latitudinal cline in their photoperiodically controlled timing of growth and flowering responses. Breaking of bud dormancy and promotion of flower bud development required chilling at -5°C for 14 weeks or more for optimal responses. However, while chilling at -10°C for 8 weeks resulted in dormancy release, continued chilling to 16 weeks inhibited bud break completely. We therefore propose that excessive chilling induces secondary bud dormancy in black currant. The observed high chilling requirements of black currants concur with the reported vulnerability of this crop to declining winter chill in the wake of the ongoing global warming. Furthermore, such conditions also induce a particularly deep bud dormancy state that further increases the chilling need.