TY  - JOUR
A1  - Poethke, Hans J.
A1  - Hovestadt, Thomas
T1  - Evolution of density-and patch-size-dependent dispersal rates
N2  - Based on a marginal value approach, we derive a nonlinear expression for evolutionarily stable (ES) dispersal rates in a metapopulation with global dispersal. For the general case of density-dependent population growth, our analysis shows that individual dispersal rates should decrease with patch capacity and-beyond a certain threshold-increase with population density. We performed a number of spatially explicit, individual-based simulation experiments to test these predictions and to explore further the relevance of variation in the rate of population increase, density dependence, environmental fluctuations and dispersal mortality on the evolution of dispersal rates. They confirm the predictions of our analytical approach. In addition, they show that dispersal rates in metapopulations mostly depend on dispersal mortality and inter-patch variation in population density. The latter is dominantly driven by environmental fluctuations and the rate of population increase. These conclusions are not altered by the introduction of neighbourhood dispersal. With patch capacities in the order of 100 individuals, kin competition seems to be of negligible importance for ES dispersal rates except when overall dispersal rates are low.
KW  - Metapopulation
KW  - Dichte
KW  - Verteilung
KW  - density-dependent dispersal
KW  - metapopulation
KW  - patch size
KW  - ESS
KW  - dispersal rate
KW  - individual based model (IBM)
Y1  - 2002
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-49659
ER  - 
TY  - JOUR
A1  - Poethke, Hans J.
A1  - Pfenning, Brenda
A1  - Hovestadt, Thomas
T1  - The relative contribution of individual and kin selection to the evolution of density-dependent dispersal rates
N2  - Questions: What are the relative contributions of kin selection and individual selection to the evolution of dispersal rates in fragmented landscapes? How do environmental parameters influence the relative contributions of both evolutionary forces? Features of the model: Individual-based simulation model of a metapopulation. Logistic local growth dynamics and density-dependent dispersal. An optional shuffling algorithm allows the continuous destruction of any genetic structure in the metapopulation. Ranges of key variables: Depending on dispersal mortality (0.05-0.4) and the strength of environmental fluctuations, mean dispersal probability varied between 0.05 and 0.5. Conclusions: For local population sizes of 100 individuals, kin selection alone could account for dispersal probabilities of up to 0.1. It may result in a ten-fold increase of optimal dispersal rates compared with those predicted on the basis of individual selection alone. Such a substantial contribution of kin selection to dispersal is restricted to cases where the overall dispersal probabilities are small (textless 0.1). In the latter case, as much as 30% of the total fitness of dispersing individuals could arise from the increased reproduction of kin left in the natal patch.
KW  - dispersal rate
KW  - dynamics
KW  - environmental correlation
KW  - evolutionary modelling
KW  - genetics
KW  - individual-based model
KW  - kin competition
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-48225
ER  -