Search for dissertations about: "grey-sided voles"

Found 5 swedish dissertations containing the words grey-sided voles.

2. 1. Population dynamics of tundra-living grey-sided voles

   Author : Per Ekerholm; Lauri Oksanen; Rolf Anker Ims; Umeå universitet; []
   Keywords : 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;

   Abstract : 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. READ MORE

4. 2. Top-down and bottom-up effects in a Fennoscandian tundra community

   Author : Doris Grellmann; Lars Ericson; Lauri Oksanen; Richard Inouye; Umeå universitet; []
   Keywords : 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;

   Abstract : 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. READ MORE

5. 3. The long-term decline of the grey-sided vole (Clethrionomys rufocanus) in boreal Sweden: importance of focal forest patch and matrix

   Author : Pernilla Christensen; Birger Hörnfeldt; Rolf A. Ims; Umeå universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; : Destructive sampling; high quality habitat; focal habitat; landscape; habitat fragmentation; threshold; clear-cut; patch size and quality; long-term time-series; Terrestrial ecology; Terrestisk ekologi;

   Abstract : There has been a long-term decline in number of cyclic vole populations in boreal Sweden since the 1970s. Several hypotheses have been suggested to explain this decline. Commonly for C. glareolus, C. READ MORE

6. 4. Cycles of voles, predators, and alternative prey in boreal Sweden

   Author : Birger Hörnfeldt; S. Erlinge; Umeå universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; 3-4 year cycles; Clethrionomys glareolus; Clethrionomys rufocanus; Microtus agrestis; snap-trapping; rate of change; population regulation; delayed density-dependence; time-lag mechanism; seasonality; predation; food; predator avoidance; foraging behaviour; Aegolius funereus; nest boxes; numerical response; nomadism; Vulpes vulpes; Sarcoptes scabiei vulpes; Lepus timidus; Francisella tularensis; Tetraonidae; hunting statistics; zooekologi; Animal Ecology;

   Abstract : Bank voles, grey-sided voles, and field voles had synchronous 3-4 year density cycles with variable amplitudes which averaged about 200-fold in each species. Cycles of vole predators (red fox and Tengmalm's owl), and their (foxes') alternative prey (mountain hare and forest grouse) lagged behind the vole cycles. READ MORE

7. 5. Predator-prey interactions of raptors in an arctic environment

   Author : Jesper Nyström; Anders Angerbjörn; A. Rolf Ims; Stockholms universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Ecology of raptors; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi;

   Abstract : This thesis concerns the predator-prey interactions of three raptor species in a Swedish arctic community: the gyrfalcon (Falco rusticolus), the rough-legged buzzard (Buteo lagopus) and the golden eagle (Aquila chrysaetos). The gyrfalcon behaved like a highly specialised ptarmigan (Lagopus spp.) predator. READ MORE