Groups of associated organisms that are substantially more influenced by local subgroups of conspecifics than they are by more distant .
Key in this definition is both that populations are broken up into a number of but also that these subpopulations interact in some manner, such as in terms of emigration and immigration. Two individuals found within the same subpopulation nevertheless are substantially more likely to interact with each other than with individuals that currently are members of other subpopulations.
Another way of saying this is that a metapopulation is a population that displays some mixing, that is, movement within itself, but both a lack of complete mixing and something other than a linear decrease in likelihood of interaction as a function of distance (particular abrupt drop offs in likelihood of interaction at some distance corresponding to outside of the subpopulation's range).
The concepts of along with clumped disperson can be used to describe the underlying basis of metapopulations. Spatial structure is the tendency of the population to resist mixing due to impediments on movement while a clumped dispersion is a description of the breaking up of a larger population into smaller subpopulations. For a population to exist as a metapopulation rather than multiple independent populations then clumping as well as impediments to mixing, however, cannot be absolute.