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.
2004
Authors
Magne Sætersdal Ivar Gjerde Hans Blom Per Gerhard Ihlen Elisabeth W. Myrseth Reidun Pommeresche John Skartveit Torstein Solhøy Olav AasAbstract
Vascular plants were investigated as a potential surrogate group in complementary small scale site selection, such as woodland key habitats in Scandinavia. We compared the response of vascular plants to environmental gradients to that of seven other plant, fungal and animal groups within a forest reserve in western Norway using data from 59 plots of 0.25 ha. We also examined whether the spatial changes in species (beta-2 index) of vascular plants matched that of the other groups. All seven groups responded to the same gradients in nutrient richness and humidity as the vascular plants. Furthermore, changes in species composition of vascular plants were reflected in comparable degrees of change among the “target“ groups. The lower the degree of change in species composition between plots in the “target“ groups relative to that of vascular plants, the higher the percentage “target“ species encompassed in a complementary selection of sites based on vascular plants. We conclude that in practical site selection of small scale sites of conservation value, such as woodland key habitats, vascular plants may be used in combination with an inventory of important habitats for rare and/or redlisted forest species, such as dead wood, old trees, deciduous trees, and cliffs.
Authors
Steen Koekebakker Gudbrand LienAbstract
No abstract has been registered
Abstract
The notion of an ecological damage has so far neither been given a proper theoretical nor a pragmatic or operational foundation. Yet one of the most widespread motivations for the scientific study of ecosystems is a “protectional” one by which an improved scientific understanding is sought in order to be able to prevent future ecological damages. We review the possibilities of valuating changes in the environment, in health or in ecosystems as a damage. The conceptual separation of potential from actual behaviour/structure is a prerequisite to any of them. The critical point here is the formal and empirical basis for the knowledge about these potentials. We contrast the dynamic systems theory approach derived in physics with an interactive computing approach recently developed in computer science. The former requires to distinguish facts and values and leads to notorious difficulties when applied at the ecosystem level. The latter and novel approach opens the possibility for a consistent definition of a damage at the ecosystem level whenever a tradition of (sustainable) utilization of such systems is available. The documentation, actualisation and dissemination of the tacit (expert) knowledge can be improved by the use of interactive simulations in which a virtual standard can defined by the respective experts themselves.
Abstract
No abstract has been registered
2003
Authors
Grete StokstadAbstract
Several factors influence the value of a lamb carcass throughout the slaughtering season, and therefore have implications for the optimal slaughtering time of lambs. The expected price of the carcass varies through the season due to: Variations in the weight of the lambs, and the growth through the season. The classification of the carcass, i.e., the price per kg changes as the lambs grow. The prices of the various quality changes throughout the season. The quality of the grazing fields limits the possible weight gain and influences the classification of lams. The grazing resources are in general limited, and will affect the possibility of fattening lambs in the fall. The objective with this study is to come up with a tool to help in determining when to slaughter which lambs in the fall when resources are limited. In order to make good decisions, the first step is to calculate the profitability of various slaughtering decisions. I use known characteristics of the lambs as weight, sex etc. to determine expected value of the carcass if slaughtered at various point in time in the future. In order to determine expected quality for the carcasses I have used a multinomial ordered probit regression model to determine the probability for obtaining a particular classification. A linear programming model is used to choose the best alternatives given limited grassing resources. The model can be used to determine optimal slaughtering decisions given a particular group of lambs and resources. By limiting the possible choices in the model, the model user may also investigate the losses associated with alternative slaughtering schemes. In this paper I describe the forecasting models for determining the value of the carcass, I describe the general linear programming model and show some results from running the model.
Abstract
No abstract has been registered
Authors
Ali Temiz Morten Eikenes U.C. Yildiz Fred G. Evans Bjørn JacobsenAbstract
No abstract has been registered
Authors
Halvor B. Gjærum Mary Namaganda Kåre LyeAbstract
No abstract has been registered
Abstract
No abstract has been registered
Abstract
This report contains all papers presented at the OECD Expert meeting in Oslo October 7th - 9th 2002, in addition to the list of participants. The topic of the meeting was the development of landscape indicators. In brief, the Expert Meeting agreed that interested OECD Member countries should consider the following recommendations; • Invest in the scientific understanding and further development of an indicator framework for agricultural landscapes, representing the linkages between landscape structure, function and management, • Build upon the existing national and international experiences in policy monitoring, evaluation and predictive scenarios, • Encourage pro-active collaboration, information exchange and methodological integration, • Contribute to, and cooperate with, other international initiatives related to developing agricultural landscape indicators, • Establish an informal expert network to follow up recommendations of the meeting.