Chapter 2 - Spatial pattern

Abstract

In this chapter, we discuss the characterization of spatial pattern using statistical frequency distributions. The necessity of sampling for estimation of animal and plant distribution and abundance has led to their use to describe spatial pattern. We recognize four classes of spatial pattern: regular, random (Poisson), aggregated, and super-aggregated. Regular spatial distributions are very rare and random distributions described by the Poisson distribution are also not common. As the simplest and most tractable member of the binomial family of discrete distributions, the Poisson is often the default distribution against which actual distributions are compared. In contrast, aggregated populations are the norm. Other distributions in the binomial family describe the frequency distributions of aggregated populations. Super-aggregated populations, although more common than is generally recognized, are also uncommon. Also discussed is how aggregations may occur.