Sökning: "stage-structured"

Visar resultat 1 - 5 av 6 avhandlingar innehållade ordet stage-structured.

  1. 1. The dynamics in harvested populations

    Författare :Anders Wikström; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; fluctuations; temporal; state-space; Harvest; cod; vendace; elasticity; stage-structured; stochastic; growth-rate; Baltic Sea; Bothnian Bay;

    Sammanfattning : We are interested in the effect of harvesting on population fluctuations and for that purpose we develop and analyze an age-structured model where recruitment is a stochastic process and the adult segment of the population is harvested. When a constant annual harvest is taken the coefficient of variation of the adult population increases for most parameter values due to the age truncation effect, i. LÄS MER

  3. 2. The effects of stage-specific differences in energetics on community structure

    Författare :Tim Schellekens; Andre de Roos; Tom Anderson; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; ontogenetic diet shift; stage-structured biomass model; food-dependence; growth; development; Earth sciences; Geovetenskap; NATURAL SCIENCES; NATURVETENSKAP; Earth Sciences with Specialization Environmental Analysis; geovetenskap med inriktning mot miljöanalys;

    Sammanfattning : When intraspecific individuals differ in resource intake, scramble competition occurs among inferior individuals growing food-dependently. Scramble can be released through predation mortality. As a consequence of this release, production rates in inferior individuals increase and biomass overcompensation in the subsequent life-stages may occur. LÄS MER

  4. 3. POPULATION DYNAMICS AND TREE GROWTH STRUCTURE IN MATHEMATICAL ECOLOGY

    Författare :Tin Nwe Aye; Linus Carlsson; Sergei Silvestrov; Masood Ayapoor; Christian Engström; Mälardalens högskola; []
    Nyckelord :Mathematics Applied Mathematics; matematik tillämpad matematik;

    Sammanfattning : This thesis is based on four papers related to mathematical biology, where three papers focus on population dynamics and one paper concerns tree growth and stem structure. The first two papers are mainly devoted to studying the dynamics of physiologically structured population models by using Escalator Boxcar Train (EBT) method. LÄS MER

  5. 4. Habitat use in fish communities : size- and environment-dependent mechanisms affecting biotic interactions and population regulation

    Författare :Ulrika Beier; Sveriges lantbruksuniversitet; Sveriges lantbruksuniversitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : Through the influence of abiotic factors, the habitat use of organisms affects their metabolism as well as other species- and size-dependent individual-based rates. The habitat-specific performances of individuals interacting in different habitats thereby affect biotic interactions. LÄS MER

  7. 5. Essays on energy demand and renewable natural resource management

    Författare :Justice Tei Mensah; Sveriges lantbruksuniversitet; Sveriges lantbruksuniversitet; []
    Nyckelord :SAMHÄLLSVETENSKAP; SOCIAL SCIENCES;

    Sammanfattning : This thesis is a collection of five self-contained papers in the area of energy demand and renewable natural resource management. Paper 1 analyzes the dynamics in cooking fuel choices among Ghanaian households over the period 2005 and 2013 and further investigate the main forces driving households’ choice of cooking fuel. LÄS MER