Search for dissertations about: "size-structure"

Showing result 1 - 5 of 24 swedish dissertations containing the word size-structure.

2. 1. Lake bathymetry as driver of salmonid population size structure and biomass

   Author : Sven Norman; Pär Byström; Karin A. Nilsson; Jan Karlsson; Per-Arne Amundsen; Umeå universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Lake bathymetry; habitat-specific resource production; ontogenetic niche shifts; size structure; Arctic char; brown trout; populationsbiologi; Population Biology; Limnology; limnologi; zooekologi; Animal Ecology;

   Abstract : Most fish species undergo ontogenetic niche shifts from feeding on pelagic zooplankton, to larger benthic invertebrates and in some cases also to fish. These ontogenetic niche shifts have strong impact on the interactions within and between species, with effects on individual growth, population abundance and food web dynamics. READ MORE

4. 2. Food Web Ecology -- individual life-histories and ecological processes shape complex communities

   Author : Martin Hartvig; Evolutionär ekologi; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; food web; community ecology; community assembly; size-structure; life-history omnivory; ontogeny; trophic interactions; trait based model; topology; emergent organisation; size-spectrum;

   Abstract : This thesis sets out a food web framework for size-structured populations. The framework enables an ecological approach to food web modelling as the individual life-history from birth, through maturation, and ultimately death is explicitly resolved with the use of bioenergetics based on individual body size. READ MORE

5. 3. Thermal adaptation along a latitudinal gradient in damselflies

   Author : Viktor Nilsson-Örtman; Frank Johansson; Karl Gotthard; Umeå universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Growth rate; metabolic theory of ecology; universal temperature dependence; environmental gradients; thermal performance; thermal sensitivity; environmental variability; optimality theory; life history; acclimation; size structure; competition; cannibalism; intraguild predation;

   Abstract : Understanding how temperature affects biological systems is a central question in ecology and evolutionary biology. Anthropogenic climate change adds urgency to this topic, as the demise or success of species under climate change is expected to depend on how temperature affects important aspects of organismal performance, such as growth, development, survival and reproduction. READ MORE

6. 4. Invasion of top and intermediate consumers in a size structured fish community

   Author : Per Ask; Lennart Persson; Daniel E Schindler; Umeå universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Invasion; intraguild predation; size-structure; cannibalism; climate; temperature; Arctic char; ninespine stickleback; Freshwater ecology; Limnisk ekologi; biology; biologi;

   Abstract : In this thesis I have investigated the effects of invading top and intermediate consumers in a size-structured fish community, using a combination of field studies, a lake invasion experiment and smaller scale pond and aquaria experiments. The lake invasion experiment was based on introductions of an intermediate consumer, ninespine stickleback (Pungitius pungitius L. READ MORE

7. 5. Ontogenetic scaling and the development of within-cohort size structure

   Author : Magnus Huss; Lennart Persson; Pär Byström; David Post; Umeå universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; cannibalism; competition; density-dependence; resource feedbacks; hatching; growth; ontogenetic niche shifts; Perca fluviatilis; size variation; larval fish; Freshwater ecology; Limnisk ekologi; zooekologi; Animal Ecology;

   Abstract : It is increasingly recognized that individuals of the same species differ from each other and influence and respond to their environment in unique ways. This thesis deals with size variation among individuals that not only are of the same species but also of similar age. READ MORE