The distribution is the area occupied by a population or species, the dispersion is the pattern of spacing of the animals within it, and dispersal, migration, and local movement are the actions that modify dispersion and distribution.Dispersal plays a key role in dictating the rate of spread of a species reintroduced into a new area or of one recovering from catastrophic decline.Dispersion and dis tribution are states; dispersal, migration, and local movement are processes.