SEPARABILITY OF LOCAL AND REGIONAL DYNAMICS IN METAPOPULATIONS

Many models of metapopulations describe the regional dynamics of local extinction and recolonization separately from the local dynamics with in the habitat patches. A strict justification of this approach has no t been given yet. In this work we systematically derive the processes of extinction and colonization from the local dynamics and the dispers al of the individuals. We show that local and regional dynamics can be described separately only if the variances of environmental fluctuati ons and the rates of dispersal (emigration and immigration) are below particular bounds, If environmental fluctuations and dispersal satisfy these conditions the local dynamics have a much faster time scale tha n the regional dynamics and extinction and recolonization can each be described by a single rate which depends on the parameters of the loca l dynamics and dispersal. (C) 1997 Academic Press.