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.
2011
Forfattere
Felix Herzog Katalin Balázs Peter Dennis Tetyana Dyman Wendy Fjellstad Jürgen Friedel Salah Garchi Philippe Jeanneret Rob Jongman Maximilian Kainz Gerardo Moreno Charles Nkwiine Maurizio Paoletti Philippe Pointereau Jean-Pierre Sarthou Siyka Stoyanova Davide ViaggiSammendrag
Farmland biodiversity is an important component of Europe’s biodiversity. More than half the continent is occupied by agricultural lands. They host specific habitats and species, which – in addition to the conservation values they provide – perform vital ecological functions. Indicators are needed to enable the monitoring of biodiversity at the farm level for the purpose of assessing the impacts of farming practices and of agricultural policies. Our research aims at identifying farmland biodiversity indicators which are scientifically sound, operational and relevant for stakeholders. We screened the literature for farmland biodiversity indicators and, in an iterative process with stakeholders, we identified 28 candidate indicators for genetic, species and habitat diversity. Those selected biodiversity indicators, as well as 14 management parameters that are known to relate to biodiversity, were assessed in 12 case study regions across Europe. Each case study region represents a typical production system (i.e. specialist field crops, horticulture and permanent crops; specialist grazing with cattle and other livestock types; mixed crop and livestock farming). In each region, 8 – 20 farms were randomly selected, mostly within the two groups of organic and non-organic farms, to obtain a gradient of farming intensity. Indicators were measured applying standardized sampling procedures and farm interviews. Sampling effort was recorded in order to assess the cost of indicator measurement. For each case study region, biodiversity indicators are presently being evaluated in conjunction with management indicators. Surrogate indicators will be proposed when possible and indicators will be prioritized taking into account their validity, practicality, cost and priority for stakeholders. Based on preliminary results, the presentation will focus on the relation between direct (species and habitat diversity) indicators and indirect (farm management) parameters. Part of this research was funded by the EU FP7 contract KBBE-2B-227161. For more information consult www.biobio-indicator.org
Forfattere
Holger LangeSammendrag
Spatial dependencies among environmental variables are often quantified by spatial autocorrelation functions. The latter basically assume linearity and isotropy, requirements usually not satisfied for measured data. Typical symptoms of violated assumptions are biased parameter estimations. Relaxing the assumptions of linear dependencies and isotropy, we present a conceptual generalization of spatial analysis where locally varying anisotropies in the geographical space are uncovered by investigating nonlinear dependencies among observations. The framework is illustrated by generalizing two examples: distance decay relations and spatial filtering. The proposed alternative is based on geodesic ecological and anisotropic spatial distances.
Forfattere
Eirik NordhagenSammendrag
We studied drying of wood chips by surplus heat from two hydroelectric plants in the western part of Norway. The wood was chipped and loaded into the dryer; a tractor-trailer and a container were used. The dryers had perforated floors where warm air from the plants was funnelled into the dryer, using an electric fan of 4 kW. Four separate trials were conducted in September and October 2009. The drying capacity of the trailer and the container was roughly 11.5 m3 and 29 m3 loose respectively. The effective height at which drying took place was 1.2 m and 1.9 m. The average temperatures of the air channelled into the dryers was 15–18 °C in the trailer and 24–26 °C in the container. The fan was operated for 139 hours (twice) for the trailer and 121.5 and 67.5 hour periods for the container. The fan used 556 kWh (twice), 486 kWh and 270 kWh of electricity respectively. The chips located at the bottom dried first, and chips located above dried later. The water content in the chip was measured to 66.1 to 52.1% (wet base) before and 9.6 to 6.9% (wet base) after drying. The amount of water removed from the container was approximately 28 kg per hour and 22 kg per hour from the trailer. For the container, drying cost roughly 9 Euro per MWh; the cost of the trailer was nearly twice as much. This indicates that the drying volume should be as high as possible. Drying determines net calorific value and hence market value of wood chip.
Sammendrag
1. In the face of a rapidly changing environment, long-term studies provide important insights into patterns of vegetation and processes of change, but long-term studies are rare for many ecosystems.2. We studied recent vegetation changes at a fine scale in a Sphagnum-dominated bog in south Sweden by resurveying part of the bog 54 years after the original phytosociological survey. We used an indirect approach to identify changes in vegetation composition in relation to environment because of a lack of permanent sampling units. By applying a weighted averaging technique, we calculated relative changes in species optimum values for different environmental gradients as represented by indicator values for light, temperature, pH, moisture and nutrients.3. Species composition of the mire vegetation has changed significantly over the past five decades, as indicated by significant changes in species frequencies and species optima for the gradients examined. Species with lower indicator values for moisture and light and higher indicator values for nutrients have become more frequent on the mire. In particular, species of trees and dwarf shrubs increased in frequency, whereas typical mire species decreased (e.g. Trichophorum cespitosum (L.) Hartm.) or disappeared fromthe study site (e.g. Scheuchzeria palustris L.).4. Synthesis. Composition of the mire vegetation is found to be dynamic at different temporal and spatial scales. Increased air temperature and nutrient availability in south Sweden over the past few decades may have augmented productivity (e.g. tree growth), resulting in drier and shadier conditions for several species. This study successfully demonstrated the applicability of an indirect approach for detecting long-term vegetation change at a fine scale. This approach is an effective way of using historic and modern phytosociological data sets to detect vegetation and environmental change through time.
Forfattere
Hans Dieter Nagel Thomas Scheuschner Angela Schlutow Oliver Granke Nicholas Clarke Richard FischerSammendrag
Based on intensive forest monitoring data, critical loads for acidification and eutrophication as well as their exceeedances were modelled for 107 Level II plots using the simple mass balance approach. Dynamic modelling using the VSD model was carried out for 77 plots using different deposition scenarios.Results show widespread soil acidification in the year 1980 with nearly 60% of the plots affected by critical load exceedances. A continued positive future development until 2020 is clearly visible, leading to full protection at least under the most ambitious deposition scenario.Critical loads for nutrient nitrogen were exceeded on 60% of the plots in 1980 and continue to be so in 2020 on between 10 and 30% of the plots depending on the scenario. Dynamic modelling shows that soil solution pH can recover to pre-industrial values but that over the all the 77 plots the C:N ratio shows a continuous decrease until 2050.A comparison with to measured solid soil pH from large scale plots confirms recovery for acidified soils until 2008 but shows increased acidification on soils with pH above 4.0. and points to the fact that full recovery from acidification will take decades. Decreasing C:N and continued exceedance of critical loads for nutrient nitrogen point to soil eutrophication as a major and continued area of concern.
Forfattere
Jan Svtlík Isabella Børja Toril Drabløs Eldhuset Holger Lange Frank Newell Kidder Douglas Lawrence GodboldSammendrag
Fungi are the main degraders of organic matter and are associated symbiotically with over 80% of terrestrial plants (Smith and Read 1997). Thus, the extent of the mycelial network is an indicator of the decomposing or symbiotic activity. Although the importance of fungi in soil is undisputable, the determination of the extent of hyphal mats and the hyphal biomass is difficult to assess. Methods for estimating hyphae in soil are mostly based on the gridline intersect method originally developed to determine the root length or recently by measuring of the ergosterol content, fungal sterol found in the cell membranes....
Sammendrag
This study is a part of a larger project designed to find out the causes of top dieback symptoms in Norway spruce in SE Norway. Because sapwood tracheids constitute a water transport system while parenchyma serves as a reserve tissue (Sellin, 1991), the separation and quantification of the sapwood and heartwood may contribute to understanding of the healthy tree functioning. As the extent of sapwood is related to tree vitality, it reflects the tree growth, health and effect of environmental factors (Sandberg & Sterley, 2009). Therefore, the sapwood cross-sectional area is widely used as a biometric parameter indicating the tree vitality, although its estimation and evaluation is prone to scaling errors....
Forfattere
Arnold ArnoldussenSammendrag
Publiced earlier in English in 2006. In 2011 revised and translated into Chinese.
Forfattere
Johannes BreidenbachSammendrag
The aim in the analysis of sample surveys is frequently to derive estimates of sub-population characteristics. This task is denoted small area estimation (SAE). Often, the sample available for the sub-population is, however, too small to allow a reliable estimate. Frequently, auxiliary variables exist that are correlated with the variable of interest. Several estimators can make use of auxiliary information which may reduce the variance of the estimate.
Sammendrag
No abstract has been registered