Formulating diversity vector for ecosystem comparison

Extensive variations in the taxonomic variety and morphology of living organisms and their spatial distribution have created a major problem for precise assessment of biodiversity. Biodiversity is fundamentally a multidimensional concept and cannot be reduced sensibly to a single number [Purvis, A., Hector, A., 2000. Getting the measure of biodiversity. Nature 405, 212–219]. A number of diversity indices are available but each has its own limitations, as they are not adequate for comprehensive representation of biodiversity of an ecosystem. We propose a vector for making a comprehensive quantitative and qualitative description of ecosystem diversity. This vector gives a fair idea about the physical and biological aspects of the ecosystem and can be used for modeling and comparison of intra- and inter-ecosystem diversity in the form of concise numerical information. The diversity vector has five components: environmental index, life-form index, Shannon–Weiner index, taxonomic index and functional index. The scheme takes care of species abundance, taxonomic variety and satisfies monotonicity. Moreover, these components can be easily calculated. Field data from two contrasting ecosystems are used to explain the scheme. Though we have confined to the plant kingdom, the scheme can be logically extended to incorporate the animal kingdom.