Theoretical Ecology Group

Institutt for biologi
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Trait-based Marine Ecosystem Models

Studies of biodiversity and community ecology are often descriptive and empirical/statistical, and food-web models start out with defining the players in the game. Biodiversity is, however, the end point of a cascade of interactions propagating from individuals’ life histories, behaviours and interactions with the environment they inhabit. Biodiversity and ecosystem structure are therefore variables, not rigid parameters, and should be predictions from - not input into - ecosystem models.

Trait-based models characterise individuals in some detail in order to study how the ecosystems work at large. The models used in this project will be adaptive in the sense that individual traits will be subject to natural selection. This enables the models to include a very important force in relation to ecosystem functioning and biodiversity – namely the continuous adaptation of gene pools to changing biotic and abiotic forces. Community- and ecosystem dynamics thus become an emergent property of the models solely dependent on the description of individual traits and the physical environment. The trait-based approach is therefore not limited by the need to pre-define functional groups as is the case in the majority of contemporary ecosystem models.

We also explore models of microbial biodiversity as a trade-off between ability of fast growth and risk of viral attacks, applying tthe 'killing the winner-principle'. The microbial community is well suited for developing and testing trait-based ecosystems models due to short generation time, well known physiology and encounter mechanics as well as diverse trophic organization (virus, bacteria, algae) and biodiversity.

Varpe Ø, Fiksen Ø. 2010.
Seasonal plankton-fish interactions: light regime, prey phenology, and herring foraging
Ecology. 91: 311-318. [ doi:10.1890/08-1817.1 ] [ pdf ]
Huse G, Fiksen Ø. 2010.
Modelling encounter rates and distribution of mobile predators and prey
Progress in Oceanography. 84: 93-104. [ doi:10.1016/j.pocean.2009.09.011 ] [ pdf ]
Fiksen Ø, Eliassen S, Titelman J. 2005.
Multiple predators in the pelagic: modelling behavioural cascades
Journal of Animal Ecology. 74: 423-429. [ pdf ]
Fiksen Ø. 2000.
The adaptive timing of diapause - a search for evolutionarily robust strategies in Calanus finmarchicus
ICES Journal of Marine Science. 57: 1825-1833. [ pdf ]


Dag L. Aksnes
Sergey Budaev
PhD Student
Ryan J. Dillon
Associate Professor
Sigrunn Eliassen
PhD student
Johanna Fall
Group Leader, Professor
Øyvind Fiksen
PhD Student
Nadia Fouzai
Jarl Giske
PhD Student
Camilla Håkonsrud Jensen
PhD Student
Judy Jinn
Christian Jørgensen
PhD Student
Tom J. Langbehn
Christian Lindemann
PhD Student
Gabriella Ljungström
Adjunct Professor
Marc Mangel
Adèle Mennerat
Anders F. Opdal
PhD student
Nicolas J. I. Rodriguez
PhD Student
Jacqueline Weidner
PhD Student
Johanna Myrseth Aarflot