Epiedaphic Coleoptera in the Dadia forest reserve (Thrace, Greece): the effect of human activities on community organization patterns

In this work we described and compared the community organization patterns of Coleoptera in various sites of the Dadia forest reserve, including different types of vegetation and management practices (grazing, cultivation, afforestation). Sampling was carried out every two months for a year, by means of pitfall traps. For studying diversity and community structure, we used Renyi's parametric index of diversity and fitted the geometric series model on rank/abundance data. In order to study the changes of species composition, we used the Indicator Value method (IndVal), after a tree clustering of our sampling sites. According to our results, although the three management practices increased the diversity of epiedaphic Coleoptera, their effects on the community organization patterns were different. Grazing did not affect the species composition of the communities but altered the community structure. The communities in the ungrazed forests were over-dominated by one species, while those of the grazed sites were hierarchically structured. On the other hand, the main effect of cultivation on the coleopteran communities was a profound change in species composition. The cultivated site was dominated by characteristic species that were almost absent from all other sites. Afforestation caused intermediate changes in both community structure and composition. Finally, although certain species of Coleoptera seemed to be good indices for assessing human impacts on natural environment, the study of changes in the community organization patterns is even more appropriate.