The negative effects of altered habitat (increased isolation and smaller populations) may be mitigated if a species has the capacity to respond evolutionarily in an opportunistic way, e.g. by evolving increased dispersal rates or perhaps a more 'clever' dispersal behaviour. However, an interesting complication of dispersal behaviour is that while affecting the species spatiotemporal dynamics, dispersal itself is affected by the spatiotemporal dynamics.

This project is concerned with dispersal (conditional and unconditional) and the theory of Ideal Free Distribution (IFD). One scenario for movement between patches of density dependent growth is that it is guided by a density gradient between the alternative patches, i.e. according to IFD individuals may move from patches with low expected fitness (high density) towards patches with higher expected fitness (low density). By relying on individual-based simulations the genetic effects that influences adaptive dispersal as well as genetic consequences of dispersal behaviour is sought represented in the models.

From an evolutionary perspective the emergence and maintenance of dispersal have been attributed to several forces of selection. Inbreeding avoidance, relaxation of kin competition, and averaging out temporal fluctuations in fitness are often mentioned as factors that create an adaptive environment in favour of elevated levels of dispersal. In contrast, lower competitive ability of emigrants (e.g. due to lack of local adaptation) and a direct cost of dispersal (e.g. higher predation risk, lower food intake, or energetic costs) will limit the advantages of dispersal.

Our aim is to disclose some of the interrelations and relative importance of the evolutionary mechanisms behind dispersal behaviour in an evolutionary perspective.

Morris, D. W., Diffendorfer, J. E. & Lundberg, P. 2004. Dispersal among habitats varying in fitness source-sink dynamics, balanced dispersal or pulsed migration through ideal habitat selection? Oikos 107: 559-575.

Kokko, H. & Lundberg, P. 2001. Dispersal, offspring retention and partial migration in saturated habitats. The American Naturalist 157: 188-202.

Morris, D. W., Lundberg, P. & Ripa, J. 2001. Hamilton's rule confronts ideal-free habitat selection. Proceedings of the Royal Society of London, Series B: Biological Sciences 268: 921-924.