Measuring dominance and diversity in ecological communities: Choosing the right variables

Although there are many studies in searching for the most useful community diversity index, the importance of choosing an appropriate parameter has been neglected. Here, we examined dominance and diversity in early postfire chaparral communities using different variables, i.e. plant density, cover and biomass. Significant different results were produced by applying different parameters and the difference may be caused by the inconsistency in density, cover, and biomass allocated in each life form. Among the three parameters, biomass was most successful in detecting differences among communities because the apportionment of biomass among species was more variable than that of density. Although the three species variables represent different aspects of community properties and their relative performance may vary among communities, we recommend the use of biomass or productivity data as the most appropriate variable because it can best represent per capita resource use and resource partitioning among organisms in competitive situations.