Search for dissertations about: "species traits"
Showing result 1 - 5 of 340 swedish dissertations containing the words species traits.
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1. Functional Traits in Sphagnum
Abstract : Peat mosses (Sphagnum) are ecosystem engineers that largely govern carbon sequestration in northern hemisphere peatlands. I investigated functional traits in Sphagnum species and addressed the questions: (I) Are growth, photosynthesis and decomposition and the trade-offs between these traits related to habitat or phylogeny?, (II) Which are the determinants of decomposition and are there trade-offs between metabolites that affect decomposition?, (III) How do macro-climate and local environment determine growth in Sphagnum across the Holarctic?, (IV) How does N2 fixation vary among different species and habitats?, (V) How do species from different microtopographic niches avoid or tolerate desiccation, and are leaf and structural traits adaptations to growth high above the water table?Photosynthetic rate and decomposition in laboratory conditions (innate growth and decay resistance) were related to growth and decomposition in their natural habitats. READ MORE
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2. Multi-trait Branching Models with Applications to Species Evolution
Abstract : This thesis provides an analysis of the evolution of discrete traits and their effect on the birth and survival of species using the theory of supercritical, continuous time Markov branching processes. We present a branching modeling framework that incorporates multi-trait diversification processes associated with the emergence of new species, death of existing species, and transition of species carrying one type of a trait to another. READ MORE
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3. Ground beetle dynamics in intensively managed agricultural landscapes
Abstract : In this thesis I have focused on studying dynamics of ground beetle assemblages in intensively managed agricultural landscapes. By definition, the land cover of these landscapes is dominated by annually tilled farmland, comprising a range of different crop types, in the context of the southern Swedish province of Scania mostly winter wheat, spring barley, winter rapeseed, and sugar beets. READ MORE
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4. Biotic resistance in freshwater fish communities
Abstract : Invasions of non-native species cause problems in ecosystems worldwide, and despite the extensive effort that has been put into research about invasions, we still lack a good understanding for why some, but not other, communities resist these invasions. In this doctoral thesis I test hypotheses on biotic resistance using a large dataset of more than 1000 both failed and successful introductions of freshwater fish into Swedish lakes. READ MORE
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5. Regional and local variation in plant species richness
Abstract : In this thesis, I examine the variation in plant species richness along gradients of productivity and disturbance in grasslands and forest habitats in southern Sweden, and I compare the documented patterns with theoretical predictions. Moreover, I evaluate the relative importance of habitat quality and habitat configuration for the occurrence of field layer species in deciduous forests. READ MORE
