Abstract
This thesis investigates competition and ecological speciation by comparing habitat use, foraging ecology and physiology of two fish populations (Coregonus spp.) in a temperate lake. It demonstrates that dietary differences is not always the driver behind coexistence and that thermal biology may play an important role in species divergence and niche specialisations in freshwater fish communities. Additionally, the thesis shows that small differences in temperature preference can be very important for species interactions, and that climatic changes therefore may have large consequences for aquatic ecosystems.
List of papers
I Helland, I. P., C. Harrod, J. Freyhof and T. Mehner. 2008. Co-existence of a pair of pelagic planktivorous coregonid fishes. Evolutionary Ecology Research. 10:373-390. The paper is not available in DUO. |
II Helland, I.P., L. A. Vøllestad, J. Freyhof and T. Mehner. Morphological differences between two ecologically similar sympatric fish species. Submitted manuscript. The paper is not available in DUO. |
III Helland, I. P., J. Freyhof, P. Kasprzak, and T. Mehner. 2007. Temperature sensitivity of vertical distributions of zooplankton and planktivorous fish in a stratified lake. Oecologia. 151:322-330. The paper is not available in DUO. The published version is available at: https://doi.org/10.1007/s00442-006-0541-x |
IV Mehner, T., I.P. Helland, S. Busch, C. Riese, P. Kasprzak and J. Freyhof. Opposite thermal refuges from vertically migrating planktivorous fish in two coexisting Bosmina species. Submitted manuscript. The paper is not available in DUO. |
V Helland, I.P., C. Clemmesen, C. Petereit, T. Mehner. Starvation does not explain abundance decline during early larval stage of vendace (Coregonus albula). Unsubmitted manuscript. The paper is not available in DUO. |