[8] As pointed out by Gleason,[6] the variety shapes of OFD can be explained, to a large degree, by the size of the sampling interval.
For instance, McGeoch and Gaston (2002)[1] show that the number of satellite (rare) species declines with the increase of sampling grains, but the number of core (common) species increases, showing a tendency from a bimodal OFD towards a right-skewed unimodal distribution.
[16] Three basic models have been proposed to explain the bimodality found in occupancy frequency distributions.
[16][18] This model is appropriate to explain the range structure of a community that is influenced by metapopulation processes, such as dispersal and local extinction.
[19] However, it is not robust because the shape of the occupancy frequency distribution generated by this model is highly sensitive to species immigration and extinction parameters.
This model further provokes the Harte-Maddux debate: Harte et al.[23] demonstrated that the power law form of the species–area relationship may be derived from a bisected, self-similar landscape and a community-level probability rule.