Density Dependence. An important continuing assumption guiding
ecological studies is that "density"-the number of prior foundings and
failures in a population-is an important factor affecting future population
dynamics. Thus, on the one hand, prior foundings suggest available resources
that act to encourage additional births; on the other hand, increased failure
• rates signal depleted resources that may operate to discourage new entrants.
Changing density levels signal both resource munificence as well as the extent
of competition for its use. Hannan and Freeman employ the concept of density
dependence to account for the routinely observed trajectory of populations of
organizations that characteristically exhibit a period of growth, the rate of
which gradually increases up to some point (the carrying capacity of the
environment) at which a leveling-off occurs to be followed by a gradual decline