335 research outputs found
Fear effects on bank voles (Rodentia: Arvicolinae): testing for repellent candidates from predator volatiles
No full textBACKGROUND Arvicolinae rodents are known pests causing damage to both agricultural and forest crops. Today, rodenticides for rodent control are widely discouraged owing to their negative effects on the environment. Rodents are the main prey for several predators, and their complex olfactory system allows them to identify risks of predation. Therefore, the potential use of predators' scents as repellents has gained interest as an ecologically based rodent control method. In a two-choice experiment, we investigated the potential repellent effects of five synthetic predator compounds: 2-phenylethylamine (2-PEA), 2-propylthietane (2-PT), indole, heptanal and 2,5-dihydro-2,4,5-trimethylthiazoline (TMT), at 1% and 5% doses, using the bank vole (Myodes glareolus) as a rodent model. RESULTS The compound 2-PEA reduced both the food contacts and the time spent by voles in the treatment arm compared to the control arm. Likewise, 2-PT-treated arms reduced the food contacts, and the voles spent less time there, although this latter difference was not significant. Indole also showed a tendency to reduce the time spent at the treatment arm; however, this result was not significant. Unexpectedly, TMT had the reverse effect in showing attractive properties, possibly due to odor cues from differently sized predators and intraguild predation in nature. We found no dose-related effects for any compounds tested. CONCLUSION Our results suggest that the 2-PEA and 2-PT are both effective odor stimuli for triggering reduced food contacts and area avoidance, and they may be good repellent candidates. We suggest further testing of 2-PEA and 2-PT in field experiments to further determine their dose-efficiency as repellents against rodents in more natural environments
Labor-Force Participation Rates and the Informational Value of Unemployment Rates: Evidence from Disaggregated US Data
No full textThe informational value of the aggregate US unemployment rate has recently been questioned be-cause of a unit root in the labor-force participation rate; the lack of mean reversion implies that long-run changes in unemployment rates are highly unlikely to reflect long-run changes in jobless-ness. This paper shows that this critique also extends to unemployment rates for sub-populations, such as prime-aged males.Unit-root test;
Future Waste Scenarios for Sweden based on a CGE-model
No full textOver the last decades, waste quantities have grown steadily in close relation to economic growth. To tackle the problem of continuing waste growth within the EU, waste prevention was listed among four top priorities in the EU Sixth environment Action Programme. A Computable General Equilibrium (CGE) model is here used for projecting future quantities of hazardous and non-hazardous waste in Sweden to 2030. The effects of driving forces behind waste generation are illustrated by comparing the results of waste projections for a Baseline scenario and four alternative scenarios. The scenarios differ mainly in GDP growth rates and in the assumptions about future waste intensities of the economic activities of firms and households. We use a high-resolution data set on waste flows of 18 various types of non-hazardous waste and 16 various types of hazardous waste attributed to six waste-generating sources for the base year 2006. Waste generated in the scenarios, thus, relate to firms’ material input, output, employees, capital scrapping and fuel combustion as well as households’ consumption. The impact of economic growth in increasing the generation of nonhazardous and hazardous waste is apparent when comparing the growth of waste from 2006 to 2030 in the five scenarios. On the contrary, technological change resulting in less waste intensive production processes and changed behaviour among households, making their activities less waste intensive, have a strong reducing effect, especially on generation of non-hazardous waste relating to firms’ material input.general equilibrium model; waste generation; decoupling; waste intensities waste scenarios.
Elever som anses oroliga och stökiga, problem eller utmaning
No full text Stockholms Universitet Specialpedagogiska Institutionen Förberedande kurs i specialpedagogik 30 p. Vt. 2009. C-uppsats. Karlsson, S & Löf, A-L. (2009) Elever som anses oroliga och stökiga, problem eller utmaning ABSTRAKT Syftet med den här studien är att beskriva hur några specialpedagoger uppfattar och reflekterar kring miljömässiga förutsättningar för inlärning för elever som blir sedda som oroliga och stökiga. Våra frågeställningar är: Hur uttrycker sig specialpedagogerna om elever som de ser som stökiga och oroliga? Hur säger specialpedagogerna att skolan skapar förutsättningar och åtgärder för lärande hos de elever som anses vara oroliga och stökiga? Hur framträder inkluderings - respektive exkluderingstankar i specialpedagogernas utsagor? Undersökningen bygger på den kvalitativa forskningsintervjun, där resultaten grundar sig i intervjuer från en specialpedagog vilken arbetar inom den kommunala grundskolan, en specialpedagog i grundsärskolan, 7 specialpedagoger från grundsärskolan och en rektor från en friskola. Dessa respondenter beskriver situationer och upplevelser utifrån sitt arbete kring begreppet "oroliga och stökiga" elever. Resultaten av studien visar att pedagogerna har en liknande syn på när och varför oro och stökighet uppstår samt hur den optimala inlärningen bör se ut för alla elever. Pedagogernas förhållningssätt och arbetssätt hjälper till att lyfta det positiva hos eleverna, genom att stärka och motivera eleverna i deras inlärningsprocess. Vi konstaterar att resultaten visar att då inlärningen har sin grund i didaktiken, där man ser samband mellan mål och undervisningsmetoder, breddas inkluderingsmöjligheterna och vidgar normalitetsbegreppet. Nyckelord: koncentrationssvårigheter, förhållningssätt, pedagogisk miljö, inkludering och exkludering, en skola för alla. Susanne Karlsson Handledare: Inger Assarson Anna-Lena Löf Examinator: Magnus Magnusson
Root spatial distribution and biomass partitioning in Quercus robur L. seedlings: the effects of mounding site preparation in oak plantations
No full textIn a reforestation field experiment undertaken in southern Sweden and planted with pedunculate oak, three site preparation treatments (herbicide application (H), mounding site preparation (MSP) and combined herbicide and mounding treatment (H + MSP)) were compared to an undisturbed control (C). We analysed root spatial and biomass distribution in 48 harvested seedlings. Compared to the control, both MSP and H treatments resulted in a significantly higher root system biomass (means C: 16.4 g, H: 45.7 g, MSP: 41.4 g, MSP + H: 102.2 g). The proportion of lateral root biomass increased from 38% (C) to 62% (MSP + H), while the two remaining treatments (H, MSP) attained percentages of 48% and 51%, respectively. The treatments did not alter seedlings' allometry and root:shoot ratio significantly. However, biomass distribution of different root system parts varied among treatments, so that lateral root biomass increased relative to leaf biomass from C to MSP + H variant. Site preparation treatments (MSP, MSP + H) increased the horizontal extension of root biomass, compared to C and H variants. We conclude that mounding site preparation is an efficient method for the reforestation of pedunculate oak stands. Due to the comparative positive effects on root system development, MSP presents an alternative to herbicide treatment, particularly at sites where the use of chemicals is restricted
Forest diversity and productivity: Implications for forest health in future climates
No full textPág.11Tree species diversity is an important determinant of the capacity of forests to support biodiversity and provide multiple ecosystem services. Tree diversity is also an important determinant of the ecological stability or vulnerability of the forests against disturbances, such as insect outbreaks or pathogen epidemics. Forest management decisions regarding the tree species diversity are therefore at the very core of successful adaptation of forestry to climate change and for sustainable forest management to meet the energy and raw material needs of the circular bioeconomy. In this chapter, we focus on three strategies that have been suggested as measures for adapting the forest management to climate change and that have the potential to influence tree diversity in forests, viz. introduction of diversity using non-native tree species, assisted migration, or use of admixtures. We discuss the forest health risks of these strategies and some avenues that can help to mitigate these risks in future forest management.Peer reviewe
Risk of drought damage in Swedish forests
No full text<p>The dataset compiled here was used in a study whose objective was to estimate the drought vulnerability for the dominant boreal tree species (Norway spruce, Scots pine, and birch) using the extensive tree-ring network and tree, stand, and site information from the Swedish National Forest Inventory (NFI). The observed climate data used in the modeling process were obtained from the Swedish Meteorological and Hydrological Institute (SMHI). We used tree-ring data from Swedish NFI temporary plots, with cores that were taken between 2010 and 2018, for further analysis. The risk of drought damage was calculated based on the number of years with exceptionally low tree growth because of drought during 1960–2010. We found the most important predictors of forest drought vulnerability and how the risk of drought damage will evolve in space and time due to climate change for the studied species. For more detailed information, please see the reference: Aldea, J. et al., 2023. Current and future drought vulnerability for three dominant boreal tree species. Global Change Biology.</p><p><i>DATA & FILE OVERVIEW</i></p><p>'<strong>DB_model</strong>': stand, tree and site information collected by temporal inventories from the Swedish NFI, used for modelling approach.</p><p>'<strong>DB_sampled</strong>': stand, tree and site information collected by temporal inventories from the Swedish NFI, used for computing spatial predictions.</p><p>'<strong>TRW</strong>': Tree ring width data from the Swedish NFI temporary plots.</p><p>'<strong>climate</strong>': <a href=" https://www.smhi.se/data/ladda-ner-data/griddade-nederbord-och-temperaturdata-pthbv">Gridded Precipitation and Temperature Data from SMHI</a> </p><p> <a href="https://www.smhi.se/en/climate/future-climate/advanced-climate-change-scenario-service/met/sverige/medeltemperatur/rcp45/2071-2100/year/anom">Future climate projections</a> according to different gas-emission scenarios from SMHI</p><p>'<strong>Aldea_R_script</strong>': Main R-scripts used in the modelling process</p>
A review of thinning effects on Scots pine stands: From growth and yield to new challenges under global change
No full textAim of the study: Thinning experiments in Scots pine (Pinus sylvestris L.) stands have been carried out since long in different regions of its distribution. The aim of this paper is to gather the knowledge about the thinning effects on Scots pine stands, from the effects on growth and yield to the provision of ecosystem services in the framework of climate change.
Area of study: The review covered studies from different regions of the distribution area of Scots pine
Aim of the study: Thinning experiments in Scots pine (Pinus sylvestris L.) stands have been carried out for many years in different regions of its distribution. The aim of this paper is to gather knowledge regarding the effects of thinning on Scots pine stands, from the effects on growth and yield to the provision of ecosystem services in the context of climate change.
Area of study: The review covers studies from different regions of the distribution area of Scots pine
Material and methods: We reviewed the effect of thinning on four aspects: growth and yield, stability against snow and wind, response to drought, and ecosystem services.
Main results: Heavy thinning involves a loss in volume yield, although the magnitude depends on the region, site and stand age. Thinning generally does not affect dominant height while the positive effect on tree diameter depends on the thinning regime. The stability of the stand against snow and wind is lower after the first thinning and increases in the long term. The impact of extreme droughts on tree growth is lower in thinned stands, which is linked to a better capacity to recover after the drought. Thinning generally reduces the wood quality, litter mass, and stand structural diversity, while having neutral or positive effects on other ecosystem services, although these effects can vary depending on the thinning regime. However, scarce information is available for most of the ecosystem services.
Research highlight: Existing thinning experiments in Scots pine stands provided valuable information about thinning effects, but new experiments which cover a broad range of ecosystem services under different site conditions are still needed
Analysing future solid waste generation - Soft linking a model of waste management with a CGE-model for Sweden
No full textParallel to the efforts of the EU to achieve a significant and overall reduction of waste quantities within the EU, the Swedish parliament enacted an environmental quality objective stating that ‘the total quantity of waste must not increase …’ i.e. an eventual absolute decoupling of waste generation from GDP. The decoupling issue is ad-dressed, in the present paper, by assessing future waste quantities, for a number of economic scenarios of the Swedish economy to 2030 with alternative assumptions about key factors affecting waste generation and waste management costs. We use an integrated top-down/bottom-up approach by linking a CGE-model of the Swedish economy with a systems engineering model of the Swedish waste management system. In this way, we can in more detail consider the interaction between waste generation and waste management costs (waste disposal prices) when assessing future waste quantities. A relative decoupling of waste generation takes place in all scenarios, i.e. total waste quantities increase at a lower rate than GDP. Absolute decoupling, which re-quire total waste quantities to stabilize or to reduce, does not take place in any of the scenarios. This means that the present Swedish Environmental quality objective of stabilizing waste quantities is not met in any of the scenarios with total waste genera-tion levels of 110 per cent up to nearly 200 per cent of that in 2006. The overall impression from our analysis is that costs are high for reducing waste generation irrespective of the type of waste reduced. In other words, the waste treat-ment costs are low compared to the costs for reducing waste. This situation also means that the use of policy instruments, which induce substitution by increasing the price of waste disposal services, will have very small reducing effects on the generation of all types of waste unless the price increase brings about an introduction of waste preventing techniques and affect households in the direction of a less waste intensive behaviour. For example, the policy instruments used must affect the pattern of household consumption pattern more directly, as a differentiation of the value added tax, rather than to be directed towards the waste management sector. Economic policy instruments introduced in the waste management sector are more likely to affect the choice of waste management solutions than prevent waste generation. Linking a macroeconomic and a systems engineering model for waste manage-ment, gives us a tool useful also for capturing the macroeconomic effects, such as GDP growth and structural changes, when designing policy instruments intended to prevent waste generation or take waste management in a more sustainable direction.general equilibrium model; systems engineering; solid waste; waste management; waste generation; decoupling; EMEC; NatWaste; top-down/bottom-up; waste policy instruments
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