Search for dissertations about: "Seasonal cycles"

Showing result 1 - 5 of 40 swedish dissertations containing the words Seasonal cycles.

2. 1. Migratory behaviour of Baltic salmon (Salmo salar L.) : adaptive significance of annual cycles

   Author : Torleif Eriksson; Lars-Ove Eriksson; Kees Groot; Umeå universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Migratory behaviour; annual cycles; Baltic salmon; Salmo salar; annual time program; swimming behaviour; mortality; maturity; life history;

   Abstract : This thesis evaluates the adaptive significance of annual cycles on the migratory behaviour of Baltic salmon (Salmo salar L.). The studies have included field experiments as well as laboratory studies gf maturity and migratory behaviour patterns of smolts and postsmolts mainly from the Angerman river population. READ MORE

4. 2. Geographic variation in life cycles : Local adaptation and ecological genetics in a temperate butterfly

   Author : Olle Lindestad; Karl Gotthard; Sören Nylin; Christopher W Wheat; Greg Ragland; Stockholms universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; voltinism; local adaptation; insect; life cycle; seasonality; genomics; life history; zoologisk ekologi; Animal Ecology;

   Abstract : Conditions in nature change with the seasons, necessitating seasonal adaptations that synchronize the life cycles of organisms with their surroundings. Such regulatory adaptations must vary between populations to track local variation in climate and seasonality; this local adaptation is facilitated by locally specific seasonal cues, but may be hampered by gene flow and genetic history. READ MORE

5. 3. 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

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. Molecular analysis of factors regulating wood formation and seasonal growth cycles in hybrid aspen

   Author : Anna Karlberg; Sveriges lantbruksuniversitet; Sveriges lantbruksuniversitet; []
   Keywords : LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES; LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES;

   Abstract : Of all of the organisms on the planet, trees are perhaps the ultimate survivors. Their unique growth characteristics allow them to become both the largest and the oldest organisms on Earth. READ MORE