A PRACTICAL MODEL OF METAPOPULATION DYNAMICS

1. This paper describes a novel approach to modelling of metapopulatio n dynamics. The model is constructed as a generalized incidence functi on, which describes how the fraction of occupied habitat patches depen ds on patch areas and isolations. 2. The model may be fitted to presen ce/absence data from a metapopulation at a dynamic equilibrium between extinctions and colonizations. 3. Using the estimated parameter value s, transient dynamics and the equilibrium fraction of occupied patches in any system of habitat patches can be predicted. The significance o f particular habitat patches for the long-term persistence of the meta population, for example, can also be evaluated. 4. The model is fitted to data from three butterfly metapopulations. The model predicts well the observed minimum patch size for occupancy and the numbers of exti nctions and colonizations per year (turnover rate). The results sugges t that local populations of the three butterflies in patches of 1 ha, which may support of the order of 1000 adult butterflies, have an expe cted lifetime of 20-100 years.