Species Richness and Diversity

Abstract

AbstractThis chapter reviews the literature on species richness and species diversity. The two concepts are closely related, but are not synonyms. Species richness is estimated dividing the number of species by the geographic area. On the other hand, species diversity is a function of the number of species present (i.e. species richness or number of species) and the evenness with which the individuals are distributed among these species (i.e. species evenness, species equitability, or abundance of each species). In this chapter, we divide the literature under the subheading ‘total species richness’, ‘tree and herb species richness’, and ‘total species diversity’. The review of the literature reveals that some studies observed an increase in species richness and species diversity when fallows age, while others found an increase at the beginning but then a drop in levels (or constant levels) in later stages. A few studies even concluded that there is no difference among age classes. Therefore, we are not able to extrapolate a general model for how total species richness is impacted by fallow duration. Similarly, the time needed for total species richness to recover to levels found in old-growth forest also shows great variations.KeywordsSpecies richnessSpecies diversityIntermediate disturbance hypothesisSuccessional stagesShannon-wiener indexSimpson’s index