Die Kristallstruktur des monoklinen α-Bi2O3

The Science of Nature -     

Conflict resolution by participatory management: remote sensing and GIS as tools for communicating land-use needs for reindeer herding in northern Sweden

When seeking to resolve complex land-management issues, geographical assessment of resources that are in short supply or in dispute can aid the communication of knowledge and the understanding among and between different stakeholders. In this paper, we illustrate how remote sensing and GIS can be used to gather and compile information regarding land-use activities and patterns among reindeer herders and other land users (forestry, mining, tourism, etc) in northern Sweden. The project represents a novel user-oriented effort largely based on the work carried out by the principal end user, i.e. the reindeer herders themselves. The basis for development of land-use plans for reindeer husbandry, was the following: to collect and digitally systemize traditional ecological and landscape knowledge of reindeer habitat use; to integrate this information with results from field inventories and satellite-based vegetation classifications; to map activities of other land users. The resulting land-use plans provide information that can facilitate consultation between the reindeer herders and other stakeholders and can facilitate operational work in reindeer management. This project can serve as a model for participatory involvement and planning, bringing indigenous knowledge and advanced remote-sensing techniques together in an interactive process.     

Perspectives and challenges in the future use of plant nutrients in tilled and mixed agricultural systems

Producing an adequate quantity of healthy food without polluting the environment is a serious challenge for future agriculture around the world. The Food 21 research program in Sweden has researched all aspects--economic, environmental, and social--of sustainable farming systems. This paper presents some of the research from that and other relevant international research programs that have focused on better nutrient-use efficiency, especially for nitrogen and phosphorus. It shows that a range of sustainable solutions to nutrient-use efficiency exists, some of which are complex but some very simple. Government policies, including subsidies; research and technology; and public acceptance of farming practices all combine to create these solutions. Participatory approaches to knowledge transfer are needed, in which scientists, policy makers, farmers, advisers, and consumers exchange information and together build sustainable farming systems.     

Nitrogen deposition and the biodiversity of boreal forests: implications for the nitrogen critical load

The critical load concept is used to establish the deposition levels which ecosystems can tolerate without significant harmful effects. Here we summarize work within the Swedish research program Abatement Strategies for Transboundary Air Pollution (ASTA) assessing the critical load of N for boreal forests. Results from both field experiments in an area with low background N deposition in northern Sweden, and from a large-scale monitoring study, show that important vegetational changes start to take place when adding low N doses and that recovery of the vegetation after ceasing N input is a very slow process. The data presented indicate that changes in key ecosystem components occur even at a lower rate of N input than the present recommended empirical critical load for boreal forest understorey vegetation of 10-15 kg N ha(-1) yr(-1). Based on the data presented, we suggest that the critical load should be lowered to 6 kg N ha(-1) yr(-1).     

Farm cooperation to improve sustainability

In this paper, it is demonstrated that partnership arrangements between farmers might be a way to secure the economic viability of their farms as well as to increase profitability. The article discusses empirical analyses of three different forms of collaboration, with an emphasis on the environmental improvements associated with collaboration. Collaboration between a dairy farm and a crop farm is analyzed in the first case. The results show that potential gains from improved diversification and crop rotation are substantial, and even larger when the collaboration also involves machinery. The second analysis considers external integration between farrowing and finishing-pig operations. Gains from collaboration originate from biological and technical factors, such as improved growth rate of the pigs and better utilization of buildings. Finally, an evaluation of a group of collaborating crop farmers is performed. In this case, the benefits that arise are mainly due to reduced machinery costs and/or gains due to other factors, such as improved crop rotation and managerial/marketing strategies.     

Estimating reduction of nitrogen leaching from arable land and the related costs

The EU Water Framework Directive will require river-basin management plans in order to achieve good ecological status and find the most cost-efficient nitrogen (N) leaching abatement measures. Detailed scenario calculations based on modeling methods will be valuable in this regard. This paper describes the approach and an application with a coefficient method based on the simulation model SOILNDB for quantification of N leaching from arable land and for prediction of the effect of abatement scenarios for the R?nne? catchment (1900 km2) in southern Sweden. Cost calculations for the different measures were also performed. The results indicate that the individual measures-cover crop and spring plowing, late termination of ley and fallow, and spring application of manure-would only reduce N leaching by between 5% and 8%. If all measures were combined and winter crops replaced by their corresponding spring variants, a 21% reduction in N leaching would be possible. However, this would require total fulfillment of the suggested measures.     

Food alert in bumblebees (Bombus terrestris): possible mechanisms and evolutionary implications

The return of a successful bumblebee forager stimulates nestmates to leave the nest and search for food. Here we investigate the mechanisms by which this happens. Successful Bombus terrestris foragers perform irregular runs in their nest, often lasting for several minutes. Run duration is at its maximum when food has just been discovered. Running likely serves to distribute a pheromone, since the information flow between "runners" and "recruits" can be disrupted by eliminating air exchange, while leaving other potential means of communication intact. In addition, nectar stores in the nest may be monitored continuously. A sudden influx of nectar into the nest also causes measurable increases in forager activity. The implications of bumblebee recruitment behavior for the evolution of communication in bees are discussed.     

The interaction of temperature and sucrose concentration on foraging preferences in bumblebees

Several authors have found that flowers that are warmer than their surrounding environment have an advantage in attracting pollinators. Bumblebees will forage preferentially on warmer flowers, even if equal nutritional reward is available in cooler flowers. This raises the question of whether warmth and sucrose concentration are processed independently by bees, or whether sweetness detectors respond to higher sugar concentration as well as higher temperature. We find that bumblebees can use lower temperature as a cue to higher sucrose reward, showing that bees appear to process the two parameters strictly independently. Moreover, we demonstrate that sucrose concentration takes precedence over warmth, so that when there is a difference in sucrose concentration, bees will typically choose the sweeter feeder, even if the less sweet feeder is several degrees warmer.     

Does the nutrition profile of vitamins, fatty acids and microelements counteract the negative impact from organohalogen pollutants on bone mineral density in Greenland sledge dogs (Canis familiaris)?

There is a great need for understanding the impact from dietary OHCs (organohalogen compounds) on bone mineral composition - and thereby osteoporosis - in especially arctic wildlife such as polar bears (Ursus maritimus) as well as humans. For that purpose, we measured BMD (bone mineral density) by DXA scanning (g/cm(-2)) in 15 age and weight normalized sledge dog (Canis familiaris) bitches and their 26 pups divided into a control group (n=26) given 50-200 g/day clean pork (Suis scrofa) fat and a treated group (n=15) given 50-200 g/day OHC polluted minke whale (Balaenoptera acutorostrata) blubber as main lipid sources. The results showed that BMD increased significantly with age (linear regression: p<0.0001, r(2)=0.83, n=41) while no sex difference was found in the F-generation (two-way ANOVA: all p>0.3). No differences in BMD(femur) or BMD(vertebrae) between exposed and control individuals in the bitch generation were found (linear mixed effect model: both p>0.38). Likewise, no difference between exposed and control subadults and juveniles in the F-generation was found (two-way ANOVA: all p>0.33). Correlation analyses between BMD(femur), BMD(vertebrae) and groups of OHCs, respectively, did not show any statistically significant relationships nor a clear or decreasing trend (Pearson's: p: 0.07-0.78; r: -0.2-0.59; n: 10-18). As the groups were similar regarding genetics, age and sex are the only factors that can explain this observation. Either the pollutants did not have an impact on BMD using the present time frame and OHC concentrations (threshold levels not reached), or the difference in food composition (mainly vitamins and n3 fatty acids) conceal the potential OHC impact on BMD. Such information is important when evaluating the positive and negative health consequences from eating polluted marine species.