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.
2020
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Mountain grazing conditions represent a constraint on lamb growth performance for various reasons. One approach to counteract these effects is to graze lambs on improved pastures. We tested the effects of grazing ewes and/or their lambs on established grass-clover (GCM), chicory alone (CHA), and grassclover-chicory (GCC) stands on spring (Exp.1) and summer (Exp.2) pastures on lamb performance. We hypothesized that CHA and GCC would sustain higher spring and autumn daily gain of lambs compared with GCM. In Exp.1, 12 twin-rearing ewes together with their 24 lambs were randomly allocated into three sward types replicated twice (n=2 ewes, 4 lambs/replicate) and monitored for 25 d before sending to mountain pasture. In Exp.2, 24 weaned lambs from the mountain pasture were again randomly allocated to one of the above pasture types and grazed for 28 d. We observed differences in chemical composition and estimated energy values between swards containing chicory and GCM swards. However, these did not affect lamb performance during both experiments, contrary to our previous findings, suggesting that grazing sheep either selected against chicory, or the observed differences in chemical composition among sward types were not strong enough to influence performance, or a combination of the two possible effects
Abstract
The Norwegian sheep industry is based on utilization of “free” rangeland pasture resources. Use of mountain pastures is dominating, with about two million sheep grazing these pastures during summer. Regional challenges related to e.g., loss of sheep to large carnivores make farmers think differently. The Norwegian coastline is among the longest globally and is scattered with islets and islands. Alone along the coast of Nordland county, it is estimated more than 14,000 islands. Use of islands for summer pasture is an alternative but there is a limited knowledge about such a management system. In this study, we examined lambs' average daily gain on island pastures at the coast of Norway. In total 230 lambs on three islands (Sandvær, Sjonøya, and Buøya), with varying pasture quality and stocking rate, for 3 years (2012, 2013, and 2014). At Sandvær as much as 92% of the island was characterized as high nutritional value while at Sjonøya and Buøya only 15%, was characterized high nutritional value. We found an average daily lamb growth rate of 0.320 kg d−1. Lambs on Sandvær had a higher daily gain (P < 0.05) than those on Sjonøya and Buøya, and lambs' average daily gain was significantly lower (P < 0.05) in 2013 compared to 2012 and 2014. We conclude that with a dynamic and adaptive management strategy there is a potential to utilize islands for sheep grazing during summer.
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Authors
Liv Guri Velle Siri Vatsø Haugum Pål Thorvaldsen Richard Thelford Bente Halvorsen Kristine Grimsrud Vigdis VandvikAbstract
The combined impact of climate and land-use change poses increasing threats to nature and nature's benefit to people. The LandPress project makes use of the severe Norwegian winter-drought in 2014 as a case study; and combines geographical, ecological and social science approaches to explore the drivers of ecosystem resilience to drought die-back, the ecological processes and implications of drought responses, and management options for mitigating damage and costs. First, by means of remote sensing, we assess the role of climate, environment and land-use in regulating resilience of Calluna heaths to drought die-back locally and along a biogeographic gradient. We find that drought-damage in heather varies across landscapes, and can be quantified by aerial photos, allowing us to establish that both environment (slope) and land-use (prescribed fire) influence ecosystem resistance to drought. Second, we conduct a drought experiment to understand and assess the impacts of severe drought events on coastal heathland ecosystem dynamics and functioning. After the three first years we find only weak effects on plant communities, but distinct responses in plant functional traits suggesting that ecosystem resistance to drought decreases with time since the last prescribed fire. Third, we experimentally assess whether prescribed burning can be used to promote Calluna's resilience after severe drought, and find that prescribed burning efficiently removes damaged heather, stimulating post-fire vegetation development and restore ecosystem functioning after drought. Finally, we conduct a cost-benefit analysis to understand the contribution of land management to the provision of ecosystem services, with focus on securing low fire-risk landscapes. We find that management has more benefits than food production; land-use can reduce the extent of extreme drought, reduce fire risk and help us keep the ecosystem functioning. Our project demonstrates the importance of understanding how interactions between climate-change and land-use and is crucial in developing new management strategies.
Authors
Heleen A de Wit Ahti Lepistö Hannu Marttila Hannah Wenng Marianne Bechmann Gitte Blicher-Mathiesen Karin Eklöf Martyn N. Futter Pirkko Kortelainen Brian Kronvang Katarina Kyllmar Jelena RakovicAbstract
Agricultural, forestry‐impacted and natural catchments are all vectors of nutrient loading in the Nordic countries. Here, we present concentrations and fluxes of total nitrogen (totN) and phosphorus (totP) from 69 Nordic headwater catchments (Denmark: 12, Finland:18, Norway:17, Sweden:22) between 2000 and 2018. Catchments span the range of Nordic climatic and environmental conditions and include natural sites and sites impacted by agricultural and forest management. Concentrations and fluxes of totN and totP were highest in agricultural catchments, intermediate in forestry‐impacted and lowest in natural catchments, and were positively related %agricultural land cover and summer temperature. Summer temperature may be a proxy for terrestrial productivity, while %agricultural land cover might be a proxy for catchment nutrient inputs. A regional trend analysis showed significant declines in N concentrations and export across agricultural (−15 μg totN L−1 year−1) and natural (−0.4 μg NO3‐N L−1 year−1) catchments, but individual sites displayed few long‐term trends in concentrations (totN: 22%, totP: 25%) or export (totN: 6%, totP: 9%). Forestry‐impacted sites had a significant decline in totP (−0.1 μg P L−1 year−1). A small but significant increase in totP fluxes (+0.4 kg P km−2 year−1) from agricultural catchments was found, and countries showed contrasting patterns. Trends in annual concentrations and fluxes of totP and totN could not be explained in a straightforward way by changes in runoff or climate. Explanations for the totN decline include national mitigation measures in agriculture international policy to reduced air pollution and, possibly, large‐scale increases in forest growth. Mitigation to reduce phosphorus appears to be more challenging than for nitrogen. If the green shift entails intensification of agricultural and forest production, new challenges for protection of water quality will emerge possible exacerbated by climate change. Further analysis of headwater totN and totP export should include seasonal trends, aquatic nutrient species and a focus on catchment nutrient inputs.
Abstract
No abstract has been registered
Abstract
Knowledge about population genetic structure and dispersal capabilities is important for the development of targeted management strategies for agricultural pest species. The apple fruit moth, Argyresthia conjugella (Lepidoptera, Yponomeutidae), is a pre-dispersal seed predator. Larvae feed on rowanberries (Sorbus aucuparia), and when rowanberry seed production is low (i.e., inter-masting), the moth switches from laying eggs in rowanberries to apples (Malus domestica), resulting in devastating losses in apple crops. Using genetic methods, we investigated if this small moth expresses any local genetic structure, or alternatively if gene flow may be high within the Scandinavian Peninsula (~850.000 km2, 55o - 69o N). Genetic diversity was found to be high (n = 669, mean He = 0.71). For three out of ten tetranucleotide STRs, we detected heterozygote deficiency caused by null alleles, but tests showed little impact on the overall results. Genetic differentiation between the 28 sampling locations was very low (average FST = 0.016, P < 0.000). Surprisingly, we found that all individuals could be assigned to one of two non-geographic genetic clusters, and that a third, geographic cluster was found to be associated with 30% of the sampling locations, with weak but significant signals of isolation-by-distance. Conclusively, our findings suggest wind-aided dispersal and spatial synchrony of both sexes of the apple fruit moth over large areas and across very different climatic zones. We speculate that the species may recently have had two separate genetic origins caused by a genetic bottleneck after inter-masting, followed by rapid dispersal and homogenization of the gene pool across the landscape. We suggest further investigations of spatial genetic similarities and differences of the apple fruit moth at larger geographical scales, through life-stages, across inter-masting, and during attacks by the parasitoid wasp (Microgaster politus).
Authors
Erik J. M. Koenen Dario Isidro Ojeda Alayon Royce Steeves Jérémy Migliore Freek T. Bakker Jan J. Wieringa Catherine Kidner Olivier J. Hardy R. Toby Pennington Anne Bruneau Colin E. HughesAbstract
Phylogenomics is increasingly used to infer deep‐branching relationships while revealing the complexity of evolutionary processes such as incomplete lineage sorting, hybridization/introgression and polyploidization. We investigate the deep‐branching relationships among subfamilies of the Leguminosae (or Fabaceae), the third largest angiosperm family. Despite their ecological and economic importance, a robust phylogenetic framework for legumes based on genome‐scale sequence data is lacking. We generated alignments of 72 chloroplast genes and 7621 homologous nuclear‐encoded proteins, for 157 and 76 taxa, respectively. We analysed these with maximum likelihood, Bayesian inference, and a multispecies coalescent summary method, and evaluated support for alternative topologies across gene trees. We resolve the deepest divergences in the legume phylogeny despite lack of phylogenetic signal across all chloroplast genes and the majority of nuclear genes. Strongly supported conflict in the remainder of nuclear genes is suggestive of incomplete lineage sorting. All six subfamilies originated nearly simultaneously, suggesting that the prevailing view of some subfamilies as ‘basal’ or ‘early‐diverging’ with respect to others should be abandoned, which has important implications for understanding the evolution of legume diversity and traits. Our study highlights the limits of phylogenetic resolution in relation to rapid successive speciation.