Sökning: "limnisk och marin ekologi Marin ekologi"

Visar resultat 6 - 10 av 94 avhandlingar innehållade orden limnisk och marin ekologi Marin ekologi.

1. 6. Resource aquisition and allocation in lichens

   Författare :Lena Dahlman; David Richardson; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; Amino acid; Arginine; carbohydrates; chlorophyll; ergosterol; microclimate; Lichen growth; nitrogen stress; photosynthesis; proteins; respiration; Symbiosis lichen ; nitrogene uptake; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi; ekologisk botanik; Ecological Botany;

   Sammanfattning : Lichens are fascinating symbiotic systems, where a fungus and a unicellular alga, most often green (bipartite green algal lichens; 90% of all lichens), or a fi lamentous cyanobacterium (bipartite cyanobacterial lichens; 10% of all lichens) form a new entity (a thallus) appearing as a new and integrated organism: in about 500 lichens the fungus is associated with both a cyanobacterium and an alga (tripartite lichens). In the thallus, the lichen bionts function both as individual organisms, and as a symbiont partner. LÄS MER

3. 7. Function and dynamics of woody debris in boreal forest streams

   Författare :Niklas Dahlström; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; Boreal forest; CPOM; CWD; forest management; geomorphology; LWD; riparian forest; retention; residence time; streams; Sweden; woody debris; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi;

   Sammanfattning : The work in this thesis deals with (1) the effects of woody debris on stream channel morphology and retention of organic material, and (2) the dynamics of woody debris and its relation to riparian forest history and composition. The studied stream reaches are situated in mature, productive forests in the boreal zone of Sweden. LÄS MER

4. 8. Population dynamics of tundra-living grey-sided voles

   Författare :Per Ekerholm; Lauri Oksanen; Rolf Anker Ims; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; Population dynamics; Tundra; Grey-sided vole; Cycles; Vole specialist predators; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi; zooekologi; Animal Ecology;

   Sammanfattning : This thesis deals with the dynamics of tundra living voles with emphasis on the most common one, the grey-sided vole (Clethrionomys rufocanus). The tundra area chosen for the study was Finnmarksvidda, a vast flatland in northernmost Norway. LÄS MER

5. 9. Rarity in boreal stream: patterns, causes and consequences

   Författare :Per-Ola Hoffsten; Bo W. Svensson; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; Central Sweden; site occupancy; dispersal limitation; natural disturbances; recolonization; flight-morphology; metapopulation; habitat stability; spring specialists; Crunoecia irrorata; niche limitation; Isogenus nubecula; nestedness; longitudinal distribution; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi; zooekologi; Animal Ecology;

   Sammanfattning : Patterns of site occupancy among boreal stream insects were studied in central Sweden with focus on sparsely distributed species and the role of dispersal and niche limitations.In the study of dispersal limitation, I found that effects of an extraordinarily harsh winter in small to medium-sized streams were strongest in sites located in small streams and far from lake outlets. LÄS MER

7. 10. Living on the edge : effectiveness of buffer strips in protecting biodiversity on boreal riparian forests

   Författare :Kristoffer Hylander; Christer Nilsson; Bengt Gunnar Jonsson; Ellen Macdonald; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; boreal forest; bryophyte; buffer strip; ecological boundary; edge effect; headwater stream; land snail; liverwort; moss; phytometer; riparian forest; substrate; terrestrial gastropod; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi; ekologisk botanik; Ecological Botany;

   Sammanfattning : The objective of this thesis is to evaluate the ecological consequences of buffer strip retention on riparian and terrestrial biodiversity. Earlier studies on forest buffer strips have evaluated their effectiveness in relation to water quality and aquatic biota. However, forests along streams are species rich habitats for many organism groups. LÄS MER