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745 Uppsatser om Threatened species - Sida 42 av 50
Kaliumgödsling på torvmark - effekt på tillväxten hos planterade granar (Picea abies)
Peat lands are a great potential resource for increased forest growth in Sweden, there are approximately 6.5 million hectares of peat lands, whereof around 70% produce less wood than one m3sk/ha and year and are therefore classed as forest waste land. There are over 200 000 hectares of peat land that is already drained and wooded, and that may be suitable for fertilization. Forest production on peat soils usually requires drainage and fertilization. Dewatering requires ditching the area, so that the roots can have access to oxygen. Nitrogen is often abundant in the peat but other nutrients; especially potassium is in short supply. The purpose of this work was to examine the effects of potassium fertilization on the growth of spruces that were planted on drained peat land and how different amount of fertilizers affects the growth. Potassium deficiency is strongly growth inhibiting, since potassium is important for substance transport in the tree. Potassium is also important for the carbohydrate formation, and because increasing the sugar content of the cells constitutes a lower freezing temperature does potassium availability in the soil play a major role in the winter resistance of many species. Potassium is not found in any organic compounds in the tree, but is present in cell and tissue fluids. A fertilization trial was started in 1978 in Siljansfors Experimental Forest. The plots in the experiment were fertilized with different amounts of potassium and one plot was left without fertilization. All plots that were fertilized with potassium grew considerably better than the unfertilized plot. The difference in production between the unfertilized plot and the plot that received the most potassium was 7.2 m3sk/ha and year. The unfertilized plot can still be classified as waste land. The theoretical production capacity was estimated using a Swedish system for site quality estimation of wetlands after ditching (dikningsbonitering). The plot with most potassium produced after fertilizationaproximately in level with theoretical estimations. Key words: Peat land, Fertilization, Ditching, Growth, site quality..
Synchronizing migration with birth: an exploration of migratory tactics in female moose
Migration and giving birth are crucial decisions for animals during their life cycle, which may have lasting consequences on their population demography and fitness. Migration can entail a variety of possible effects for an individual, such as access to high quality food and reduced risk for predation. The moose (Alces alces) in northern Sweden is partially migratory and moose females are known to give birth to one or two calves. The synchrony between time of calving and timing of migration has not been compared before, especially in terms of energy maximizing and time minimizing perspectives, which may provide vital cues for fitness benefits of migration. I investigated effect of timing of birth and individual life history on distance, timing, stopovers and duration of 190 individually marked female moose that have been tracked for multiple years in ten different areas in northern Sweden.
Djurskyddskontroller ur lantbrukarnas perspektiv - från kommun till länsstyrelse
On the first January 2009 the official animal welfare control were transferred from the municipalities to the County Administrative board. With this transition, some changes occurred for those who work as animal welfare inspectors. The aim for this study was to examine farmers' view on the transition between the municipalities and County Administrative board, in order to compare the two authorities. I have also studied the farmers view about animal welfare inspectors' knowledge, both theoretical and practical. The questionnaire also included questions about farmers' view on animal welfare legislation.
Skyddsrum och kärnvapen : En diskursanalys av 1950- och 1960-talets försvars- och civilförsvarsdebatt i svensk press
Shelters and Nuclear weaponsA discourse analysis of the Swedish defense and civil defense debate during the Cold warSweden during the Cold War set into motion one of the world?slargest civil defense policies at the time, second only to neutral Switzerland. The governments expenditure was far greater per capita than both that of USA and Soviet Union and included massive evacuation plans for Stockholm and other large cities in Sweden, with the hopeful expectation to bring down the amount of people in each of them to 15000 in case of a foreign hostile nuclear attack. The policies included construction of shelters with room for 2,5 million of about 7 million citizens in total at the time along with gasmasks for the whole population. Not only this, Sweden was considered one of the biggest military powers of that time in relation to its size and population.
Inga miljövinster med ekologisk produktion? : Lägesrapport över den svenska jordbruksdebatten
Organic agriculture is financially promoted in Sweden by special environmental support and as consumers we are all encouraged to buy organic food. At the same time scholars at the Swedish University of Agricultural Sciences claim that organic farming does not provide any environmental benefits. The main criticism is that organic farming has lower yields than conventional, which means that more land is needed to produce the same amount of food as in conventional farming, leading to deforestation and loss of biodiversity. As for climate change, the critics claim that the significantly higher productivity in conventional crop production compared to organic, releases surplus land, which could be used for bio-fuel production and thereby replace the fossil fuels. The critics also claim that organic farming causes higher nutrient leaching than conventional.
Identifiering av fel i skogliga beståndsregister med hjälp av satellitdata :
This thesis has focused on the possibility to use a satellite image method developed by Metria Mijöanalys to identify stands that are wrongly registered in Holmen Skogs database. The method is only intended for identifying stand with poor descriptions in Holmen?s database that needs to be updated and not for updating the stand information.
The study area is located several km west of Hudiksvall on the borderline between Gävleborgs- och Västernorrlands län. The area is covered by a SPOT image from 2005. By which Metria Miljöanalys has made estimates of forest parameters for all stands in the area, and compared them with corresponding estimates according to the stand database.
Översvämningskartering av Vombs ängar
Vomb meadows is an area well knows for its rich bird life. During the 19:thcentury until mid 20:th century, the meadows were flooded annually in order toincrease the hay yield. The river Klingavälsån situated along the west side of themeadows, used to be a shallow river, meandering across the landscape. In the1940?s the river was straightened and made deeper.
137Cesium i myrsamhällen i Gävleborgs län 24 årefter Tjernobylolyckan
24 years have passed since the Chernobyl accident when radionuclides were spread over largeareas of Europe, including the Scandinavian countries. Today, measurable activities of 137Csare still observed in many Swedish ecosystems.Ants (belonging to the order Hymenoptera) are social insects which collect organic materialfrom a large area around their nests. This study focuses on the 137Cs activity in ant nests andthe cesium accumulation in these nests. The aims were (1) to estimate the 137Cs fall-out in1986, (2) estimate the radiation exposure of ants and (3) find how 137Cs is distributed in an anthill. Seven ant hills (occupied by the species Formica polyctena) were studied near the villageof Hille, situated north of the city of Gävle in central Sweden.
Kaninhållning för sällskapsbruk
The domesticated rabbit stems from the European Wild rabbit and researchers have found that they share most of the characteristics and behaviors of their wild ancestor. They form mating groups in which strong hierarchic orders are formed and they are known for their ability to dig warrens which serve as one of the most important resources for this species. Although research has been performed to increase the welfare of rabbits kept in laboratory settings little is known about the housing, behavior and welfare of the pet rabbit. Among the research that has been performed within the area results have shown that the animals are kept in small solitary cages and that although many rabbits are purchased mainly for the children many animals cannot be handled by children due to display of aggression. Another conclusion drawn is that the animals are kept in ways that differs greatly from their natural environment.
Tillämpning av kNN-Sverige i Södra Skogs verksamhet : behovsinventering, databearbetning och förberedelse för praktisk implementering
The digital map product kNN-Sweden contains nationwide data of the country?s forest land. The estimated forest variables are mean age, mean tree height, volume per tree species and total volume. Today Södra Skog?s assessments of timber potentials are mainly based on experience rate and subjective assumptions.
Contortatallens roll för virkesförsörjningen på Holmen Skog, Region Iggesund : konsekvensanalys av fyra hushållningsstrategier för contortatall
Large areas of Lodgepole pine (Pinus contorta var. latifolia) were planted in the 1970s - and '80s. The purpose of the fast-growing species was to increase growth and with short rotation periods allow a rapidly increased harvest level. Today a large proportion of the young forests owned by Holmen Skog, Iggesund are covered by Lodgepole pine and an active forest management is required to spread the harvested volume over time which is desirable by a market perspective. The purpose of this essay is to investigate the possibility of spreading the harvested volume of Lodgepole pine over time.
Klövhälsa hos får : ur ett nationellt och internationellt perspektiv
Lameness causes suffering and poor performance in sheep, as in other species. The cause of lameness often originates in problems of the claws. Many claw diseases of sheep are described in British and Australian research, but this field has previously not been of special concern in Sweden.
This graduate thesis contains the first claw health survey made on Swedish sheep. The chief objective was to give an overview of sheep claw diseases and to assess claw health in adult sheep.
Från gles skog och brokiga ungskogar till homogen produktionsskog : en skogshistorisk studie av Hällforsmarken under 1900-talet
The forest in the northern part of Sweden has changed dramatically during the last centuries. The forest has gone through a large-scale transformation, from it being only used locally for domestic purposes to becoming very important raw material for Sweden in the industrial age. The strategy by foresters during the second half of the 20th century has been to create pure production forests for commercial forestry. This has mainly succeeded and we have today homogenous production forests that give a high profit to the owners. The aim of the study is to compare the state of the forest in the former state forest Hällforsmarken in the years 1925 and 2000 and to interpret the changes which has taken place.
Resultat från tre klonförsök med fågelbär, Prunus avium L, i södra Sverige :
This study was based on measurements of growth and shape of 50 clones of wild cherry, Prunus avium L, in south Sweden and aimed at finding out wether or not any of these clones are useful for commercial propagation.
Initially, a short assembly of documented knowledge concerning wild cherry as a timber producing tree species was put together. The study of the 50 clones includes information gathered during the fall of 2006 from four trials located in the counties of Blekinge, Småland and Västergöland. The oldest trial, founded in Tranemåla, Blekinge, in 1992, was focused on offspring and aimed at discerning differences between provenances and at developing an adapted plant material. The other experiments were both clone trials and founded in 2002. These are based on 50 individuals selected from the offspring trial in Tranemåla.
Kan man genom kartstudier förutse häckningsframgång för ängshök (Circus pygargus) i Uppland? :
Montagu´s harrier (Circus pygargus) is a diurnal, Eurasian raptor, which migrates from its northern breeding grounds to winter in sub-Saharan Africa. In Sweden, its core breeding area is centred on the island of Öland, with a stable breeding population of approximately 40 pairs. The province of Uppland is on the northern end the distribution range, where 4-8 pairs have regularly bred since the 1980s.
In Sweden, the Montagu?s harrier is classified as an endangered (EN) species. This classification is partly due to a lack of preferred nesting habitat, such as shrub-lands or dense wetlands with Claudium spp.