ABSTRACT

This chapter discusses some of the theoretical and descriptive modeling studies in ecology that have featured the lognormal. It focuses on the lognormal as a model of the abundances of species and not as a model of the size growth of individual organisms. The chapter examines the lognormal as a theoretical model of population abundance. It describes a different stochastic growth model leading to the lognormal. The model is a stochastic differential equation based on the Gompertz growth equation. The chapter explores three typical modifications of the lognormal. First, ecological data sets often consist of count data. Second, ecological abundance surveys often contain an overly large number of samples with abundances of zero. Third, ecological abundances observed in samples sometimes grew from random numbers of initial propagules in each sample. The lognormal is commonly used in ecology in a purely descriptive role as a model of abundance of a single species present in different samples.