The Nonconcept of Species Diversity: A Critique and Alternative Parameters

TLDR

Recent literature on species diversity is plagued by semantic, conceptual, and technical problems, and multispecific collections exhibit statistical properties that do not align with a linear diversity scale. The authors argue that species diversity is a meaningless concept and propose abandoning it, urging ecologists to adopt more critical species‑number relations and alternative composition parameters. They introduce two biologically interpretable parameters: the proportion of potential interindividual encounters that are interspecific, and the expected number of species in a random sample of n individuals.

Abstract

The recent literature on species diversity contains many semantic, conceptual, and technical problems. It is suggested that, as a result of these problems, species diversity has become a meaningless concept, that the term be abandoned, and that ecologists take a more critical approach to species-number relations and rely less on information theoretic and other analogies. As multispecific collections of organisms possess numerous statistical properties which conform to the conventional criteria for diversity indices, such collections are not intrinsically arrangeable in linear order along some diversity scale. Several such properties or "species composition parameters" having straightforward biological interpretations are presented as alternatives to the diversity approach. The two most basic of these are simply ▵1 =[n/n-1][1-Σi (N _i/_N)2 ] =the proportion of potential interindividual encounters which is interspecific (as opposed to intraspecific), assuming every individual in the collection can encounter all other individuals, E(Sn ) = Σi [1-(N-Nin )/(Nn )] =the expected number of species in a sample of n individuals selected at random from a collection containing N individuals, S species, and Ni individuals in the ith species.