Sökning: "population dynamics"

Visar resultat 21 - 25 av 564 avhandlingar innehållade orden population dynamics.

1. 21. Spatial and temporal population dynamics in the mountain tundra – mesopredator and prey

   Författare :Rasmus Erlandsson; Anders Angerbjörn; Dennis Murray; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; population dynamics; cyclic; mountain tundra; arctic fox; Norwegian lemming; small rodents; mesopredator; predation; survival; reproduction; zoologisk ekologi; Animal Ecology;

   Sammanfattning : It is well known that competition, predation and fluctuating food resources can have strong effect on individual fitness and population dynamics. The complexity of natural systems can make it complicate to disentangle those processes, but environments with relatively simple food webs, and strong cyclic population dynamics offer contrasting conditions resembling experimental treatments. LÄS MER

3. 22. Modelling animal populations

   Författare :Åke Brännström; Umeå universitet; []
   Nyckelord :population model; stochastic population model; population dynamics; discrete time model; Beverton-Holt model; Skellam model; Hassell model; Ricker model; first principles; coupled map lattice; CML; area integral; square function; Mathematics; matematik;

   Sammanfattning : This thesis consists of four papers, three papers about modelling animal populations and one paper about an area integral estimate for solutions of partial differential equations on non-smooth domains. The papers are: I. Å. Brännström, Single species population models from first principles. LÄS MER

4. 23. Evolutionary consequences of ecological interactions

   Författare :Etsuko Nonaka; Åke Brännström; Göran Englund; Richard Svanbäck; Per Lundberg; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; adaptive dynamics; eco-evolutionary dynamics; ecological speciation; ecosystem; individual based; population dynamics; phenotypic plasticity; predator-prey; sexual selection;

   Sammanfattning : Eco-evolutionary dynamics integrates the reciprocal interactions betweenecology and evolution. These two branches of biology traditionally assumethe other as static for simplicity. However, increasing evidence shows thatthis simplification may not always hold because ecology and evolution canoperate in similar timescales. LÄS MER

5. 24. Socio-economic dynamics in sparse regional structures

   Författare :Örjan Pettersson; Ulf Wiberg; Umeå universitet; []
   Nyckelord :SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; Northern Sweden; Norrland; Sparsely populated areas; Countryside; Rural change; Regional development; Forestry; Population; Welfare; Glesbygd-- Sverige -- Norrland; Regional utveckling-- Sverige -- Norrland; Norrland-- sociala förhållanden; Norrland-- ekonomiska förhållanden;

   Sammanfattning : The aim of the thesis is to describe and analyse socio-economic changes in northern Sweden. Focus is on the period 1985-2000. LÄS MER

7. 25. Dynamics of omnivorous crayfish in freshwater ecosystems

   Författare :Karin Olsson; Biologiska institutionen; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; crayfish; freshwater ecosystems; niche width; growth rate; stable isotope analysis; recruitment; RNA:DNA analysis; Ecology; food availability and quality; trophic position; population dynamics;

   Sammanfattning : In this thesis I examine the dynamics of crayfish in streams and lakes. I have studied the influence of abiotic and biotic factors on abundance, growth, trophic position, niche breadth, and recruitment of crayfish, by conducting field studies, an outdoor channel experiment and timeseries analysis. LÄS MER