Mate sampling behaviour of black grouse females (Tetrao tetrix)

We studied female mate sampling behaviour in lekking black grouse (Tetrao tetrix). Females mainly visited males occupying territories in the centre of the lek with relatively large territories. They were also more likely to visit males that had high attendance. The same factors were also correlated with male mating success. A multiple regression model including these factors explained more of the variance in female visits per male (53%) than in mating success (33%). The pattern of female sampling conformed with a pool comparison (best-of-n) tactic. Such a tactic is expected if the costs of sampling are low. Females of high body mass visited more males than lighter females, however, which indicates that females may vary in their search tactics and suggests that there may be search costs. The existence of costs is further suggested by the fact that if the mate from a previous year was still present, females always mated with the same male in the following year. Though search costs were not measured directly, our findings suggest that some costs are negligible (e.g. energetic exhaustion or predation) whereas others (timing of mating) may be more important.     

Models for waste life cycle assessment: Review of technical assumptions

A number of waste life cycle assessment (LCA) models have been gradually developed since the early 1990s, in a number of countries, usually independently from each other. Large discrepancies in results have been observed among different waste LCA models, although it has also been shown that results from different LCA studies can be consistent. This paper is an attempt to identify, review and analyse methodologies and technical assumptions used in various parts of selected waste LCA models. Several criteria were identified, which could have significant impacts on the results, such as the functional unit, system boundaries, waste composition and energy modelling. The modelling assumptions of waste management processes, ranging from collection, transportation, intermediate facilities, recycling, thermal treatment, biological treatment, and landfilling, are obviously critical when comparing waste LCA models.This review infers that some of the differences in waste LCA models are inherent to the time they were developed. It is expected that models developed later, benefit from past modelling assumptions and knowledge and issues. Models developed in different countries furthermore rely on geographic specificities that have an impact on the results of waste LCA models. The review concludes that more effort should be employed to harmonise and validate non-geographic assumptions to strengthen waste LCA modelling.     

Plant and Soil System Responses to Ozone After 3 Years in a Lysimeter Study with Juvenile Beech (Fagus sylvatica L.)

A lysimeter study was performed to monitor effects of elevated ozone on juvenile trees of Fagus sylvatica L. as well as on the plant–soil system. During a fumigation period over almost three growing seasons, parameters related to plant growth, phenological development and physiology as well as soil functions were studied. The data analyses identified elevated ozone to delay leaf phenology at early and to accelerate it at late developmental stages, to reduce growth, some leaf nutrients (Ca, K) as well as some soluble phenolics (hydroxycinnamic acid derivatives, total flavonol glycosides). No or very weak ozone effects were found in mobile carbon pools of leaves (starch, sucrose), and other phenolic compounds (flavans). Altered gene expression related to stress and carbon cycling corresponded well with findings from leaf phenology and chemical composition analyses indicating earlier senescence and oxidative stress in leaves under elevated ozone. Conversely in the soil system, no effects of ozone were detected on soil enzyme activities, rates of litter degradation and lysimeter water balances. Despite the fact that the three reported years 2003–2005 were climatically very contrasting including a hot and dry as well as an extremely wet summer, and also mild as well as cold winters, the influence of ozone on a number of plant parameters is remarkably consistent, further underlining the phytotoxic potential of elevated tropospheric ozone levels.     

Initial Changes in Refilled Lysimeters Built with Metal Polluted Topsoil and Acidic or Calcareous Subsoils as Indicated by Changes in Drainage Water Composition

Soil translocation for recultivation of soil removed from construction sites and for the preparation of refilled lysimeters inevitably involves disturbance of soil structure, and, if intermediate storage is included, also drying and rewetting of the soil. We report on an experiment with model forest ecosystems, where uncontaminated forest subsoils were covered with non-contaminated or freshly heavy metal (mainly Zn and Cu) contaminated topsoil in large lysimeters. Monitoring of the chemical composition of the drainage water revealed two distinct soil conditioning phases. During an initial phase of about a year strongly elevated nitrate and sulfate concentrations occurred that were attributed to a mineralisation flush caused by the increased accessability of mineralisable nitrogen and sulfur in destroyed aggregates. These effects were significantly larger in lysimeters with calcareous subsoil than in those with acidic subsoil. The second phase was characterised by a gradual decrease in dissolved organic carbon and sulfate concentrations, in particular in the acidic subsoil. This decrease may be attributed to the depletion of pools made accessible during aggregate destruction or the formation of new aggregates. These chemical changes had only little effects on the concentrations of copper and zinc in the drainage water. Based on our results, it can be concluded that large refilled lysimeters can be used for many purposes without risk of compromised results, if a conditioning phase of about 1 year with sufficiently moist soil conditions is respected. Nevertheless, gradual changes in soil chemical characteristics still occur after this initial phase. Implications for the recultivation of sites using relocated soils are discussed.     

Proposal for the integration of decentralised composting of the organic fraction of municipal solid waste into the waste management system of Cuba

Municipal solid waste (MSW) generation and management in Cuba was studied with a view to integrating composting of the organic fractions of MSW into the system. Composting is already included as part of the environmental strategy of the country as an appropriate waste management solution. However, no programme for area-wide implementation yet exists. The evaluation of studies carried out by some Cuban and international organisations showed that organic matter comprises approximately 60-70% of the MSW, with households being the main source. If all organic waste fractions were considered, the theoretical amount of organic waste produced would be approximately 1 Mio. Mg/a, leading to the production of approximately 0.5 Mio. Mg/a of compost. Composting could, therefore, be a suitable solution for treating the organic waste fractions of the MSW. Composting would best be carried out in decentralised systems, since transportation is a problem in Cuba. Furthermore, low technology and low budget composting options should be considered due to the problematic local economic situation. The location for such decentralised composting units would optimally be located at urban agricultural farms, which can be found all over Cuba. These farms are a unique model for sustainable farming in the world, and have a high demand for organic fertiliser. In this paper, options for the collection and impurity-separation in urban areas are discussed, and a stepwise introduction of source-separation, starting with hotel and restaurant waste, is suggested. For rural areas, the implementation of home composting is recommended.     

Co-digestion of grease trap sludge and sewage sludge

Redirection of organic waste, from landfilling or incineration, to biological treatment such as anaerobic digestion is of current interest in the Malmö-Copenhagen region. One type of waste that is expected to be suitable for anaerobic digestion is sludge from grease traps. Separate anaerobic digestion of this waste type and co-digestion with sewage sludge were evaluated. The methane potential was measured in batch laboratory tests, and the methane yield was determined in continuous pilot-scale digestion. Co-digestion of sludge from grease traps and sewage sludge was successfully performed both in laboratory batch and continuous pilot-scale digestion tests. The addition of grease trap sludge to sewage sludge digesters was seen to increase the methane yield of 9–27% when 10–30% of sludge from grease traps (on VS-basis) was added. It was also seen that the grease trap sludge increases the methane yield without increasing the sludge production. Single-substrate digestion of grease trap sludge gave high methane potentials in batch tests, but could not reach stable methane production in continuous digestion.     

Material Flows in Sweden 2004

This paper presents and discusses the method and results of account for material flows in Sweden for the year 2004. The results show that it is possible to compile material flow data from existing sources in the Swedish statistical system. By using the European classification system of goods, the Combined Nomenclature, as the basic unit of the data collection, both data collection and aggregation into material flow categories were made possible. Although these data exist in the statistical system, they are not easily available for the scientific community. This is due to several reasons, such as the aggregation of data in the system of statistics not corresponding to the material flow account structure and the fact that data on import and export of materials are organised differently than data for domestic extraction. Almost 50% of the material flows in Sweden are flows of minerals, mainly construction minerals followed by iron ores. Most of the extracted iron ores are exported. In comparison with other European countries this generates a unique situation with Sweden as the only net exporter of iron ores. The flow of biomass in terms of wood is also considerable (26% of the Swedish material flows in 2004). The domestic material consumption (inflow) per capita in 2004 was 8 tonnes minerals, 6 tonnes biomass and almost 3 tonnes of fossil fuels. Of the material flows of fossil fuels petroleum and natural gas dominates with 90%.     

Life cycle assessment of a national policy proposal - the case of a Swedish waste incineration tax

At the core of EU and Swedish waste policy is the so-called waste hierarchy, according to which waste should first be prevented, but should otherwise be treated in the following order of prioritisation: reuse, recycling when environmentally motivated, energy recovery, and last landfilling. Some recent policy decisions in Sweden aim to influence waste management in the direction of the waste hierarchy. In 2001 a governmental commission assessed the economic and environmental impacts of introducing a weight-based tax on waste incineration, the purpose of which would be to encourage waste reduction and increase materials recycling and biological treatment. This paper presents the results of a life cycle assessment (LCA) of the waste incineration tax proposal. It was done in the context of a larger research project concerning the development and testing of a framework for Strategic Environmental Assessment (SEA). The aim of this paper is to assess the life cycle environmental impacts of the waste incineration tax proposal, and to investigate whether there are any possibilities of more optimal design of such a tax. The proposed design of the waste incineration tax results in increased recycling, but only in small environmental improvements. A more elaborate tax design is suggested, in which the tax level would partly be related to the fossil carbon content of the waste.     

Flexible and robust strategies for waste management in Sweden

Treatment of solid waste continues to be on the political agenda. Waste disposal issues are often viewed from an environmental perspective, but economic and social aspects also need to be considered when deciding on waste strategies and policy instruments. The aim of this paper is to suggest flexible and robust strategies for waste management in Sweden, and to discuss different policy instruments. Emphasis is on environmental aspects, but social and economic aspects are also considered. The results show that most waste treatment methods have a role to play in a robust and flexible integrated waste management system, and that the waste hierarchy is valid as a rule of thumb from an environmental perspective. A review of social aspects shows that there is a general willingness among people to source separate wastes. A package of policy instruments can include landfill tax, an incineration tax which is differentiated with respect to the content of fossil fuels and a weight based incineration tax, as well as support to the use of biogas and recycled materials.