Search for dissertations about: "Species changes"

Showing result 1 - 5 of 929 swedish dissertations containing the words Species changes.

2. 1. Semi-natural meadows in southern Sweden - changes over time and the relationship between nitrogen supply and management

   Author : Gudrun A I Berlin; Biologiska institutionen; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Plant community dynamic; Nitrogen; Mowing; Meadows; Management; Long-term study; Landscape changes; Field experiment; Community diversity; Fertilisation; Species changes; Species turnover; Plant ecology; Växtekologi;

   Abstract : In this thesis, I have studied continuously managed semi-natural meadows in south-central Sweden. The purpose was 1) to make a survey of meadow vegetation in the region 2) to compare two investigations of the vegetation, one from 1963-1966 and one from 1990 3) to investigate experimentally in the field how increased nitrogen supply rate as well as changed management intensity effects the nitrogen economy and species richness in two meadow communities. READ MORE

4. 2. Climate-induced changes : Its effects on plankton food webs from the Baltic Sea

   Author : Claudia Romero-Oliva; Edna Graneli; Linnéuniversitetet; []
   Keywords : NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Climate-induced changes; temperature; acidification; marine food web; natural plankton community; spring; summer; Baltic Sea; Marine ecology; Marin ekologi; Akvatisk ekologi; Aquatic Ecology;

   Abstract : The Earth’s climate is determined different processes occurring in the atmosphere, land and ocean.Anthropogenic activities (mainly combustion of fossil fuels) have increased since the 1950’s, andthus the concentration of greenhouse gases that are warming up the planet. READ MORE

5. 3. Global Changes and European Terrestrial Ecosystems

   Author : Emmanuel Gritti; Institutionen för naturgeografi och ekosystemvetenskap; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; European species; Climatic risk; pedology; cartography; climatology; Fysisk geografi; geomorphology; Physical geography; Vegetation modelling; Pollen analysis; Plant invasion; geomorfologi; marklära; kartografi; klimatologi; Global Changes;

   Abstract : Global environmental changes are topics of important societal concern and current scientific interest. These changes are driven by many different forcing and feedbacks occurring at various time and geographic scales and are largely influencing the various Earth systems. READ MORE

6. 4. 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

7. 5. Interaction strength and responses of ecological communities to disturbances

   Author : Maria Christianou; Bo Ebenman; Peter de Ruiter; Linköpings universitet; []
   Keywords : Species deletion; secondary extinctions; keystone species; keystone links; species reintroductions; Lotka-Volterra models; local stability; permanence; resilience; sensitivity analysis; diversity; complexity; food webs; competition communities; NATURAL SCIENCES; NATURVETENSKAP;

   Abstract : Ecological communities are continuously exposed to natural or anthropogenic disturbances of varied intensity and frequency. The way communities respond to disturbances can depend on various factors, such as number of species, structural characteristics of the community, stability properties, species characteristics and the nature of the disturbance. READ MORE