Diversity analysis: a fresh approach

In any science it is important to find meaningful measures that describe the systems under study. These measures will be the raw material for theories, and will allow meaningful comparisons between systems. Much of the success of a science depends on the choice of basic measures; poor choices can cause a field to stagnate, while insightful choices can make it easy to find regularities in nature. In this regard diversity analysis in ecology has always been a polemical field, with many differing opinions about how to best characterize biological diversity. There have been so many arguments about how to measure diversity that some authors (for example Hulbert 1971) have given up on the matter and concluded that there is no such thing as the concept of "diversity" per se. Indeed, the variety of diversity indices in the literature is bewildering. When these different diversity indices are applied to a system with S equally common species, some give S, some give log S, some give 1-1/S, etc. The mathematical behaviors of these indices are so different that there are bound to be problems when they are treated as if they were interchangeable in formulas or methods that use "diversity" as a variable. A method that might give good results with one index is likely to give meaningless results with some other indices. In a complex science like biology, the fuzziness of the diversity concept may not be a bad thing; different meanings of the term "diversity" may be useful in different situations. Nevertheless, it is important to be aware of the fuzziness, else it leads only to confusion.