Search for dissertations about: "species composition"

Showing result 1 - 5 of 663 swedish dissertations containing the words species composition.

  2. 1. Effects of climate change on boreal wetland and riparian vegetation

    Author : Lotta Ström; Roland Jansson; Christer Nilsson; Sarah Gergel; Umeå universitet; []
    Keywords : NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; biomass; flooding; hydrologic niche; invasibility; riparian zone; riparian plant species; river margin; climate scenario; seed sowing experiment; species composition; species richness; transplant experiment; Terrestrial ecology; Terrestrisk ekologi;

    Abstract : Models of climate change predict that temperature will increase during the 21th century and the largest warming will take place at high northern latitudes. In addition to warming, predictions for northern Europe include increased annual precipitation and a higher proportion of the precipitation during winter falling as rain instead of snow. READ MORE

  4. 2. Biodiversity and Species Extinctions in Model Food Webs

    Author : Charlotte Borrvall; Bo Ebenman; Owen Petchey; Linköpings universitet; []
    Keywords : NATURAL SCIENCES; NATURVETENSKAP; biodiversity; food webs; redundancy; relaxation time; stability; stochasticity; species deletion; species extinction; Biology; Biologi;

    Abstract : Many of the earth’s ecosystems are experiencing large species losses due to human impacts such as habitat destruction and fragmentation, climate change, species invasions, pollution, and overfishing. Due to the complex interactions between species in food webs the extinction of one species could lead to a cascade of further extinctions and hence cause dramatic changes in species composition and ecosystem processes. READ MORE

  5. 3. Bacterial Activity and Community Composition in the Rhizosphere. Influence of plant species, root age, nitrogen addition and mycorrhizal status

    Author : Katarina Söderberg; Biologiska institutionen; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; CLPP; Microbiology; bacteriology; virology; mycology; Mikrobiologi; bakteriologi; virologi; mykologi; Biolog; PLFA; mycorrhizal status; nitrogen addition; along roots; plant species; root age; thymidine and leucine incorporation; bacterial composition; Rhizosphere; bacterial activity;

    Abstract : Microbial activity in soil is generally assumed to be limited by carbon availability. The soil closest to roots, the rhizosphere, is therefore a zone of high microbial activity due to carbon containing substances released by the root. In this work short-term effects in the rhizosphere have been the subject of investigation. READ MORE

  6. 4. The impact of cormorant nesting colonies on plants and arthropods

    Author : Gundula S. Kolb; Peter Hambäck; Lenn Jerling; Post David; Stockholms universitet; []
    Keywords : NATURAL SCIENCES; NATURVETENSKAP; seabirds; cormorants; islands; nitrogen; phosphorus; plants; arthropods; δ15N; Baltic Sea; ecological stoichiometry; species richness; species composition; numeric response; Biology; Biologi; Plant Ecology; växtekologi;

    Abstract : Seabirds concentrate large amounts of marine nutrients on their nesting islands. This nutrient input can have large consequences for island food webs and community structure. The high nutrient load may also cause runoff into surrounding waters and affect marine communities. READ MORE

  7. 5. Possibilities to Utilize Species from the Mozambican Forest Biomass for the Production of Essential Oils : Study of Eucalyptus and Pinus Species and Application of Citronellal as Raw Material for Flavour Chemistry

    Author : Felisberto P. Pagula; KTH; []
    Keywords : Eucalyptus species; essential oil composition; citronellal; hydroxycitronellal;

    Abstract : This thesis deals partly with the isolation and chemicalanalysis of essential oils from selected Eucalyptus and Pinusspecies grown in Mozambique, and partly with the synthesis ofmore valuable compounds from citronellal isolated fromEucalyptus citriodora Hook oil.More than 60 constituents in the volatile oils wereidentified by gas chromatography and gas chromatography-massspectrometry by comparison with authentic substances andliterature data. READ MORE