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Visar resultat 1 - 5 av 16 avhandlingar som matchar ovanstående sökkriterier.

1. 1. The influence of voles and lemmings on the vegetation in a coniferous forest during a 4-year period in northern Sweden

   Författare :Lars Ericson; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES;

   Sammanfattning : .... LÄS MER

3. 2. Borgare och byråkrater : omvandlingen av Stockholms stadsförvaltning 1599-1637

   Författare :Lars Ericson Wolke; Stockholms universitet; []
   Nyckelord :HUMANIORA; HUMANITIES;

   Sammanfattning : .... LÄS MER

4. 3. Macroalgae in the Baltic Sea : responses to low salinity and nutrient enrichment in Ceramium and Fucus

   Författare :Lena Bergström; Lars Ericson; Lena Kautsky; Erik Bonsdorff; Christine A Maggs; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; adaptation; asexual reproduction; Baltic Sea; Gulf of Bothnia; salinity; macroalgae; nutrients; sexual reproduction; stress; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi; ekologisk botanik; Ecological Botany;

   Sammanfattning : The brackish Baltic Sea is a marginal environment for both marine and freshwater species. The rate of ecological differentiation is presumably high due to strong selection pressure from a gradient of decreasing salinity that has been present in its current state for only about 3 000 years. LÄS MER

5. 4. Ecology of lichens in boreal coniferous forests with reference to spatial and temporal patterns

   Författare :Per-Anders Esseen; Lars Ericson; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Lichens; epiphytes; Alectoria; Bryoria; Cladonia; Usnea; Picea abies; Pinus sylvestris; dispersal; litterfall; succession; diversity; spatial patterns;

   Sammanfattning : The thesis deals with the ecology of lichens in two contrasting types of forest, epiphytic lichens in old Picea abies forest of the fi re-refugia type and epigeic as well as epixylic lichens in a successional sequence of fire- susceptible Pinus sylvestris forests. Results in five separate papers form the basis for a discussion of general patterns of dispersal, succession and life strategies in lichens. LÄS MER

7. 5. Top-down and bottom-up effects in a Fennoscandian tundra community

   Författare :Doris Grellmann; Lars Ericson; Lauri Oksanen; Richard Inouye; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; consumer-resource interactions; exclosures; food web dynamics; grey-sided voles; lemmings; NPK-fertilization; plant defences; reindeer; soil microbes; vertebrate grazing;

   Sammanfattning : The objective of this thesis was to investigate the effects of mammalian grazers, such as microtine rodents and reindeer, (top-down effects) and nutrient availability (bottom- up effects) on the plant community of a tundra heath.I conducted a large-scale fertilization experiment and studied the impact of grazers using exclosures. LÄS MER