The degree to which abundances are divided equitably among community species or evenness is a basic property of any biological community. Several evenness indices have been proposed to summarize community structure. However, despite their potential applicability in ecological research, none seems to be generally preferred. In this paper we show that, unlike other evenness indices without any clear information-theoretical meaning, Hill's parametric diversity measure E ,0 has an immediate relation to Rényi's generalized information. Therefore, E ,0 might be adequate for (...) summarizing community structure within the context of a general theoretical framework of diversity analysis based on information theory. (shrink)

Traditional diversity indices are computed from the abundances of species present and are insensitive to taxonomic differences between species. However, a community in which most species belong to the same genus is intuitively less diverse than another community with a similar number of species distributed more evenly between genera. In this paper, we propose an information-theoretical measure of taxonomic diversity that reflects both the abundances and taxonomic distinctness of the species. Unlike previous measures of taxonomic diversity, such as Rao's quadratic (...) entropy, in this new measure the analyzed taxonomic properties are associated with the single species instead of species pairs. (shrink)

The degree to which abundances are evenly divided among the species of a given community is a basic property of any biological community. Several evenness indices have thus far been proposed in ecological literature. However, despite their vast potential applicability in ecological research, none seems to be generally preferred. In this paper, I first summarize the basic requirements that evenness measures should meet to adequately behave in ecological studies. Then, I discuss the major drawbacks of these requirements and propose an (...) alternative family of measures that are based on the notion of specificity used in fuzzy set theory for measuring the uncertainty associated with a fuzzy set. (shrink)