On properties driving diversity index selection

TL;DR

This paper investigates how properties of diversity indices influence their selection for conservation, emphasizing the importance of capturing phylogenetic diversity and handling uncertainty in edge lengths, with practical case study illustrations.

Contribution

It formalizes criteria for selecting phylogenetic diversity indices based on their properties and demonstrates their application through a case study, comparing with existing indices.

Findings

Certain properties guide the choice of diversity indices.

New mechanisms for index selection are proposed.

Case study illustrates the practical impact of property-driven selection.

Abstract

Phylogenies are commonly used to represent the evolutionary relationships between species, and often these phylogenies are equipped with edge lengths that indicate degrees of evolutionary difference. Given such a phylogeny, a popular measure for the biodiversity of a subset of the species is the phylogenetic diversity (PD). But if we want to focus conservation efforts on particular species, we may use a phylogenetic diversity index, a function that shares out the PD value of an entire phylogeny across all of its species. With these indices, various species-level conservation strategies can be evaluated. This work explores how the most suitable diversity indices can be found. In particular, how formalizing the requirement for diversity indices to capture high levels of PD, or to maintain a scoring of taxa in the presence of uncertain edge lengths drives the selection of a suitable index. Furthermore, we provide illustrations of these new mechanisms for diversity index selection in a case study. This analysis includes the comparison to popular phylogenetic indices from the conservation literature.