Is evenness altered by fire in natural assemblages of soil arthropods?

We studied evenness and species richness in two assemblages of soil arthropods at six contiguous study plots in Mediterranean ecosystems of central Italy, three of these plots being burnt and three unburnt. We analysed these aspects of community structure by diversity-dominance diagrams comparisons made through analysis of covariance on respective slopes and ordinate intercepts. We observed consistent patterns in both Collembola and Oniscidea assemblages, either in burnt and unburnt plots. Evenness did not change among study plots and across habitats, either before or after fire, whereas species' composition was significantly altered by fire. Results from our study implied that evenness and species diversity are clearly affected in a different and independent way by fire. Hence, it is not acceptable to focus on only the evenness when looking at the effects of controlled fires for environmental management reasons.