Strong requirements for weak diversities

Abstract

Weikard et al. (Diversity and Distributions, 12, 215-217) show that the taxonomic diversity measure proposed by Ricotta (2004) violates 'weak species monotonicity'. This condition requires that the addition of a species to a given species set should always increase diversity if abundances change only marginally. They further propose a new taxonomic diversity index that overcomes this drawback. In this paper, some statistical properties of this new diversity index are briefly analysed. © 2006 Blackwell Publishing Ltd.