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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Skogsbrandens spridning : - ett laborationsexperiment med vanligt förekommande skogliga vegetationstyper i södra Sverige / Forest fire spread : - a laboratory experiment with commonly occurring forest vegetation types in southern Sweden

Boräng, Benjamin, Arvidsson, Erik January 2020 (has links)
Större och mer svårbekämpade bränder har de senaste åren svept fram på flera platser runtom i världen. Ett föränderligt klimat skapar långa torrperioder till följd av höga temperaturer och värmeböljor. Räddningstjänster i de drabbade länderna ställs ofta inför en monumental uppgift med att hantera svårsläckta bränder i många gånger extrema förhållanden. Utifrån detta är det av vikt att undersöka de bakomliggande orsakerna och faktorer som spelar in, innan, under och efter en skogsbrand för att ge en mer nyanserad bild av de utmaningar räddningstjänsten ställs inför.Syftet med detta examensarbete var vidare att undersöka antändning- och spridningsbenägenhet samt värmeutveckling i tre olika typer av vanligt förekommande undervegetation i skogarna i Götaland. Resultaten från studien visar att granmarksproverna har en mindre intensiv spridning i förhållande till tallmarksproverna. Spridningen sker däremot såväl över proverna som under ytan och skapar glödbrand. Vikten av eftersläckningsarbete tillsammans med värmekamera för att upptäcka glödbrand bör därför anses som mycket viktigt utifrån de resultat som framkommit.
2

Post-fire community changes in peatland dwelling beetles : A before-after-control impact study of beetle communities in Swedish mires after a megafire

Happ, Janina January 2021 (has links)
As a consequence to climate change and resulting severe weather events such as prolonged hot and dry periods, wildfire frequency increases globally. Progressively, these effects are noticeable in high latitude countries such as Sweden where a megafire burned 13 100 ha of managed coniferous forest in 2014. While the effect of fire on species communities has been much studied, species surveys often only collect data opportunistically after a wildfire, making inferences about the fire effect uncertain. In this study my aim was to examine the response of peatland dwelling beetles (Coleoptera) to fire by comparing beetle communities of burned drained Swedish peatlands and adjacent non-burned (reference) areas. The first beetle survey took place in 2009, the second was carried out in 2020, 6 years after the fire occurred. Both surveys used pitfall traps in a burned and un-burned area, which were divided into two types of mires, fen and bog, respectively. As a result of the post-fire recovery, dead wood accumulated in the burned area and shrubs and young trees replaced the original vegetation. The reference area did not show significant changes in vegetation. Over all 188 species were found in 2009 and 256 in 2020. In 2009 most species were found in the pre-fire area while in 2020 most species were found in the reference area. Further, two red-listed species (conservation category NT) were found in the fire area as well as two new species for Västmanland country. As expected, the fire had a large impact on the beetle community, where once dominant species declines and got replaced by more dispersive or more moisture striving species. In contrast to my expectations, not only the fire area showed notable changes in the beetle community regarding diversity and composition, also the reference area showed changes in species dominance and a high species turnover. Although the before-after-control-impact study design illustrates the independence of the fire impact to the changes in species composition over time, the results suggest that the time between the surveys (10 years) was the main factor for the community change.

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