Dr Patrik Karell

Contact details

Phone: +358-2-2153421

Fax: +358-2-251 7013

E-mail: patrik.karell(at)abo.fi

Postal address:

Environmental and Marine Biology

Åbo Akademi University

Artillerigatan 6

FI-20520 ÅBO


Room: 2052, Biocity, 2nd floor

Research Interests

My research interests focus on functional and evolutionary ecology with emphasis on life-history evolution. In particular, I am interested in how variation in immune function, parasite resistance and physiology affect individual fitness, and how such selection processes translate into evolutionary responses in the population. This ecoimmunological concept is at the core of my current research where I use tawny owls as a model system. The tawny owl is a fascinating model species, because of its highly heritable plumage colour polymorphism ranging from reddish-brown to grey plumage. The central objective of my current project is to study the evolution and maintenance of such melanin-based colour polymorphism. Colour polymorphism is thought to have evolved and to be maintained by morph-specific sensitivity to environmental conditions. The aim of this project is to investigate how the colour morphs of the tawny owl are adapted to changes in the environment. I have previously found that there is strong survival selection against the brown morph of the tawny owl under adverse winter conditions and that the costs of parasitism differ between colour morphs. Currently, I am exploring the impact of blood parasites (avian malaria) on fitness of the colour morphs and whether metabolic and energetic differences between the colour morphs are responsible for the observed differences in their over-winter survival.

Research Approach

Detailed data on the tawny owl population I am working with has been collected since 1978. This gives me an opportunity to use the long-term individual-based data to study long-term population and evolutionary dynamics in relation to environmental variation and to utilize the population to conduct field experiments to study proximate mechanisms of selection. I also collaborate with tawny owl ringers in Finland in order to combine data and study dispersal and variation in evolutionary dynamics on a larger scale.

List of publications

  • Patrik Karell, Jon E. Brommer, Kari Ahola & Teuvo Karstinen. 2013. Brown tawny owls moult more flight feathers than grey ones. Journal of Avian Biology, 44:235-244. doi:10.1111/j.1600-048X.2012.05868.x

  • Johan Ekroos, Markus Öst, Patrik Karell, Kim Jaatinen & Mikael Kilpi. 2012. Philopatric predisposition to predation-induced ecological traps: habitat-dependent mortality of breeding eiders. Oecologia. DOI: 10.1007/s00442-012-2378-9

  • Karell, P., Ahola, K., Karstinen, T., Kolunen, H., Siitari, H. & Brommer, J.E. 2011 Blood parasites mediate morph-specific maintenance costs in a colour polymorphic wild bird. Journal of Evolutionary Biology, 24: 1783-92.

  • Karell, P., Ahola, K., Karstinen, T., Valkama, J. & Brommer, J.E. 2011 Climate change drives microevolution in a wild bird. Nature Communications, 2: 208 / ncomms1213.

  • Karell, P., Lehtosalo, N., Pietiäinen, H. & Brommer, J.E. 2010. Ural owl predation on field and bank voles by size, sex and reproductive state. Annales Zoologici Fennici, 47: 90-98.

  • Kontiainen P., Pietiäinen, H., Karell, P., Pihlaja, T. & Brommer, J.E. 2010. Hatching asynchrony is an individual property of female Ural owls which improves nestling survival. Behavioral Ecology, 21: 722–729.

  • Brommer, J.E., Pietiäinen, H., Ahola, K., Karell, P., Karstinen, T. & Kolunen, H. 2010. The return of the vole cycle in southern Finland refutes the generality of the loss of cycles through “climatic forcing”. Global Change Biology, 78: 577-586.

  • Karell, P., Ahola, K., Karstinen, T., Zolei, A. & Brommer, J.E. 2009. Population dynamics in a cyclic environment: Consequences of cyclic food abundance on tawny owl reproduction and survival. Journal of Animal Ecology, 78: 150-162

  • Karell, P., Pietiäinen, H., Siitari, H., Pihlaja, T., Kontiainen, P. & Brommer, J.E. 2009. Parental allocation of additional food to own health and offspring growth in a variable environment. Canadian Journal of Zoology 87: 8-19.

  • Kontiainen, P., Pietiäinen, H., Huttunen, K., Karell, P., Kolunen, H., Brommer, J.E. 2009. Aggressive Ural owl mothers recruit more offspring. Behavioral Ecology, 20: 789-796.

  • Karell, P., Kontiainen, P., Pietiäinen, H., Siitari, H. & Brommer, J.E. 2008. Maternal effects on offspring Igs and eggsize in relation to natural and experimentally improved food conditions. Functional Ecology 22: 682-690.

  • Kontiainen, P., Brommer, J. E., Karell, P. & Pietiäinen, H. 2008. Heritability, plasticity and canalization of Ural owl egg size in a cyclic environment. Journal of Evolutionary Biology 21: 88-96.

  • Kekkonen, J., Kolunen, H., Pietiäinen, H., Karell, P. & Brommer, J. E. 2008. Tawny owl reproduction and offspring sex ratios under variable food conditions. Journal of Ornithology 149: 59-66.

  • Karell, P., Pietiäinen, H., Siitari, H. & Brommer, J. E. 2007. A possible link between parasite defence and residual reproduction. Journal of Evolutionary Biology 20: 2248-2252.

  • Brommer, J.E., Karell, P. & Pietiäinen, H. 2004. Supplementary fed Ural owls increase their reproductive output with a one year time lag. Oecologia 139: 354-358.

  • Brommer, J. E., Karell, P., Pihlaja, T., Painter, J., Primmer, C. & Pietiäinen, H. 2003. Ural owl sex allocation and parental investment under poor food conditions. Oecologia. 137: 140-147.

  • Submitted manuscripts in review

  • Ekroos, J., Öst, M., Karell, P., Jaatinen, K. & Kilpi, M. Philopatry predisposes to predation-induced ecological traps: habitat-dependent mortality of breeding eiders. Submitted

  • Pavon-Jordan, D., Karell, P., Ahola, K., Kolunen, H., Pietiäinen, H., Karstinen, T. & Brommer, J. E. Consequences of winter climate, habitat alteration, food supply, population density and their possible interactions for annual survival in two owl species: can a signal be detected? Submitted

  • Popular science publications (in Swedish)

  • Karell, P. Kattugglan i Finland: ett liv med varierande sorktillgångar och kalla vintrar Skogsbruket 2/2009.

  • Karell, P. Familjeplanering hos slagugglan. Universitas Helsingiensis 3/2004.