S. Mahunka szerk.: Folia Entomologica Hungarica 51. (Budapest, 1990)
r 0 steppe open — 1 forest — Fig. 2. The dendogram of three stages of succession, based on the squared Eucli dean distance t . Open: Open dolomitic grassland; Steppe: Dolomitic steppe meadow; Forest: Sessile-turkey oak forest Discussion The succession of plants living on dolomite is well known (Jakucs 1981). The first stage is the lichen-moss phase, followed by the open dolomitic grassland community (I.) , which becomes more and more closed during the successional process. The next stage is the dolomitic steppe meadow phase (II.) , which contains many species from the previous stage. This is a closed, or almost closed vegetation. In the present study the forest is the climax community, the end of the ecological succession (sessile-turkey oak forest (III.)). The two grassy communities of these successional stages are much more similar to each other than the forest community to any of them. The present study pointed out great differences between the community structure parameters of the beetle communities associated with these vegetation phases, but the extent of these differences are relative, somewhat depending on the methods applied. The number of species, species abundances and the diversity values were more similar between the beetles of the forest and steppe phases, than any of them compared to those of the 'open habitat'. This differs from the botanical results, where the two grassy communities are the most similar ones (Jakucs 1981). The 'open habitat' consists of a great portion of bare rocks, but the other two sites are covered by soil and unbroken vegetation. High similarity occurred when beetles of the 'forest habitat' and the 'steppe habitat' were quantitatively compared. Qualitatively the similarity was low, because of the low number of common species. The latter was high in the case of the 'steppe habitat' and the 'open habitat'. The 'open habitat', which is at the beginning of the ecological succession, contains only a few species and individuals of plants and beetles. The next stage is the dolomitic steppe meadow having developed from the open doloTable 6. Expected changes of community structure parameters during the ecological succession based on the general theory, and the observed changes in the case of beetles Successional stages Expected Observed Developmental Mature Developmental Mature Species richness low high low high Abundance low high low high Diversity low high low high medium Equitability low high low high medium -r— 10
