Different diversity measures of forest floor assemblages were evaluated in order to check if they can be used as indicators of forest naturalness. We compared vascular and bryophyte vegetation of two habitat types in an unmanaged beech-dominated reserve and five managed stands of different ages. We used systematically collected data characterizing four spatial scales obtained by successively aggregating neighbouring quadrats. Species richness did not always differentiate near natural sites from managed sites, and the observed difference depended very much on the spatial scale used. The behaviour of Shannon-Wiener diversity function can only be understood if both the species richness and the evenness components are considered. Near natural plots had high Shannon-Wiener diversity values even at the finest spatial scale not only because of high number of species, but also because of high evenness. We found that a simple measure of pattern diversity — spatial variation of species importance — was the most eff...