Search for dissertations about: "trophic level effect"

Showing result 1 - 5 of 33 swedish dissertations containing the words trophic level effect.

2. 1. Climate change effects on marine species across trophic levels

   Author : Nan Hu; Enhet akvatisk ekologi; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; trophic levels; predation; gastropods; mussels; ocean acidification; ocean warming; interactive effects; interaction types; meta-analysis;

   Abstract : Climate change and anthropogenic activities are producing a range of new selection pressures, both abiotic and biotic, on marine organisms. While there are numerous studies that have investigated the response of individual marine organisms to climate change, few studies have focused on differences in organismal responses across trophic levels. READ MORE

4. 2. Perspectives from a human-centred archaeology : Iron Age people and society on Öland

   Author : Helene Wilhelmson; begravning och social identitet Gravarkeologiska forskargruppen – Död; []
   Keywords : HUMANIORA; HUMANITIES; Osteology; bioarchaeology; Iron Age; Scandinavia; 3D; digital; Image Based Modeling; GIS; isotopes; Oxygen; Strontium; Carbon; Nitrogen; trophic level effect; fractionation; chronology; network; Virtual Taphonomy; human-centred archaeology; mortographies; dietary shift; integration; immigration; diet; migration; violence; burial; Viking Age; Öland; island;

   Abstract : The objective of this study was to develop, test and evaluate a specifically defined interdisciplinary approach—the human-centred approach—as applied to a case study, Iron Age Öland. Four themes were selected to highlight different aspects of particular interest in Öland: taphonomy, diet, migration, and social organization. READ MORE

5. 3. Food web dynamics in open and closed systems

   Author : Johan Lövgren; Lennart Persson; Jonathan Chase; Umeå universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Ecology; allochtonous input; cross habitat foraging; donor control; heterogeneity within trophic level; compensation; food web; littoral; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi;

   Abstract : This thesis is a summary of enclosure and microcosm experiments that aimed to study the impact of allochtonous subsidies on food web dynamics in a heterogeneous food web. In the enclosure studies, a three trophic level littoral food web was used. READ MORE

6. 4. Complexity and Change in a Simple Food Web : Studies in the Baltic Sea (FAO Area 27.IIId)

   Author : Henrik Österblom; Sture Hansson; Robert W Furness; Stockholms universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Avian cholera; Bottom-up; Bycatch; Clupea harengus; Ecosystem; Food web; Gadus morhua; Halichoerus grypus; Regime shift; Sprattus sprattus; Top-down; Trophic cascade; Uria aalge; Marine ecology; Marin ekologi;

   Abstract : An influence at one trophic level can result in dynamic impacts also on other components of a food web. These dynamics are known as trophic cascades, and can be both top-down and bottom-up. After a near-collapse of the Baltic cod Gadus morhua stock in the 1980s, its main prey sprat Sprattus sprattus increased dramatically. READ MORE

7. 5. Interactions between gray-sided voles (Clethrionomys rufocanus) and vegetation in the Fennoscandian tundra

   Author : Jonas Dahlgren; Lauri Oksanen; Johan Olofsson; John Terborgh; Umeå universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; gray-sided voles; tundra vegetation; trophic cascades; plant-herbivore interactions; bilberry; plant communities; herbivory; plant resistance; Terrestrial ecology; Terrestisk ekologi;

   Abstract : I have, in this thesis, studied the interactions between gray-sided voles (Clethrionomys rufocanus) and tundra vegetation, on islands in, and mainland sites close to the lake Iešjávri, in northern Norway. As isolated islands are virtually free of predation, I have been able to compare plant-herbivore interactions in the presence and absence of predators. READ MORE