The aim of the study was to specify the current status and direction of transformations of leaf beetle assemblages taking part in the rapid process of succession of vegetation towards the types of forest communities occurring in the Krzemionki Opatowskie reserve. At five sampling sites (in five plant associations) 30 species of Chrysomelidae were recorded. Five typical forest species (Chrysomela populi, Pyrrhalta viburni, Calomicrus pinicola, Altica brevicollis and Cryp-tocephalus labiatus) accounted for 16.67% of the number of species and 12.85% of the number of individuals caught in the reserve. The forest association richest in species (18) was Querco ro-boris-Pinetum (Que_Pin). This was followed by Tilio-Carpinetum association (Til_Car, 15 spp.), and then a mosaic of Tilio-Carpinetum and Querco roboris-Pinetum (Til_Car/Que_Pin), and Peucedano-Pinetum (Peu_Pin) (11 spp. each). The fewest number of species (10) were noted in Potentillo albae-Quercetum (Pot_Que). The most similar were the fauna of Potentillo albae--Quercetum (Pot_Que) and Querco roboris-Pinetum (Que_Pin) (55.08% similarity). The most distinct was the fauna of Peucedano-Pinetum (Peu_Pin). We can conclude that the structure of the leaf beetle assemblages in the forest associations studied in the reserve is at present an adaptive mixture of faunas characteristic of all the intermediate successional stages of vegetation, changing in this area in a relatively short time. The considerable diversity of fauna is the result of an ‘eco-tone in time’, i.e. the continuous presence of open-land species, which until recently had dominated here, accompanied by forest species characteristic of the current habitat types.