Sensitivity of diversity indices: a study of dipterous assemblages
It is an essential property of diversity indices that increases in the abundance or frequency of the most frequent species result in a decline in diversity, whereas increases in the abundance of the rarest species lead to an increase in diversity. At the same time, without resort to mathematical operations, it is difficult to determine the sign and measure of alteration in diversity when increasing an additional frequency while leaving all others unaltered. A more concrete task is to determine the index response to a partial alteration of fixed percentage in the frequencies of the multi-species community or collection. Plotting the observed responses or sensitivity values against the frequencies concerned makes possible a good overview of the sensitivity relations. The mathematical groundwork of sensitivity analysis with respect to diversity indices has already been elaborated. To date, however, the methodological possibilities engendered by such analyses have yet to be exploited.
In the present work, sensitivity relations are discussed for apple-bait Drosophilidae collections and human faeces trap collections of flies inhabiting brook valleys in the low mountains of Hungary. Inspection of the results enables us to identify the range of frequencies at which significant increases or decreases in diversity will result. A relatively small increase of so-called nearly indifferent or quasineutral frequencies lying within that frequency range has a trivial influence on diversity values. While sensitivity is astonishingly sizeable with a few dominant case numbers, all other frequencies scarcely influence the index value.
KeywordsHill’s indices Hurlbert’s indices Rank - abundance curves Sensitivity parameters Shannon index
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- Boyle, T.P., G. M. Stnillie, J. C. Anderson and D. R. Beeson. 1990. A sensitivity analysis of nine diversity and seven similarity indices. Research Journal Water Pollution Control Federation 62:749–762.Google Scholar
- Izsák, J. 1991. New aspects of sensitivity investigations on diversity indices. A case study. Biometrie unci Informatik in Medizin und Biologie 22:107–115.Google Scholar
- Izsák, J. 1992. Sensitivity studies on Hurlbert’s indices of diversity. Biométrie – Praximétrie 32:101–114.Google Scholar
- Izsák, J. 1998. DIVERSI 1.1: A program for diversity calculations. Abstr. Bot. 22:157–160.Google Scholar
- Izsák, J. and P. Juhász-Nagy. 1984. Studies of diversity indices on mortality statistics. Annales Universitatis Scientiarum Budapestinensis de Rolando Eötvös Nominatae, Sectio Biologica 24–26:11–27.Google Scholar
- Izsák, J. and L. Papp. 1994. Numerical properties of jackknifed diversity indices tested on loose sets of coenological samples (Diptera, Drosophilidae). Coenoses 9:59–61.Google Scholar
- Papp, L. 1992. Drosophilid assemblages in mountain creek valleys in Hungary (Diptera: Drosophilidae) I. Folia Entomologica Hungarica 53:139–153.Google Scholar
- Papp, L. 1993a. Flies (Diptera) visiting human faeces in mountain creek valleys in Hungary. Parasitología Hungarica 25:85–96.Google Scholar
- Papp, L. 1993b. On the Abundance of Flying Insects (The Theory of Capturing Flies). (in Hungarian) Akadémiai Kiadó, Budapest, 46 pp.Google Scholar
- Pielou, E.C. 1979. A quick method of determining the diversity of foraminiferal assemblages. J. Paleontol. 53:1237–1242.Google Scholar
- Schmid, F. 1991. Zur Sensitivitat von Disparitätsmassen. Allgemeine Statistisches Archiv 75:155–167.Google Scholar
- Taillie, C. and G. P. Patil. 1979. Diversity, entropy, and Hardy-Weinberg equilibrium. In: I. F. Grassle, G. P. Patil, W. Smith and C. Taillie (eds.), Ecological Diversity in Theory and Practice, Internatl. Coop. Publ. House, Burtonsville, MD, pp. 63–72.Google Scholar
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