Functional Diversity

Abstract

The objectives of this chapter are to explore the variety of metrics and approaches for analyzing the functional composition and diversity of species assemblages. Important topics will include the consideration of how uni-and multivariate trait data are utilized in functional diversity analyses, the use of raw trait distance matri-ces versus trait dendrograms, and the degree of similarity between functional diver-sity metrics. 4.2 Background The number of articles in ecology that are taking a " trait-based " approach is cur-rently exploding with many of these articles seeking to quantify the functional diversity of the species in a community or assemblage (e.g., [73–92]). As we will see shortly, functional diversity can be quantified in a number of ways, but we can coarsely define it here as the diversity or dissimilarity of the ecological strategies or performance of species upon the basis of their morphological physiological traits. Traits directly or indirectly correlated with species performance (i.e., growth, mor-tality, reproduction) are increasingly termed " functional traits " and I will tend to use that nomenclature in the following text. Despite the recent surge in interest, the measurement of functional diversity in communities or assemblages dates back at least 50 years with some of the most interesting early examples investigating the volume and packing of trait space of species in assemblages spanning an environmental or richness gradient [94–97]. For example, early work by Ricklefs and colleagues [93, 94] investigated whether the Chapter 4