Monitoring biodiversity in oak woods: structure and composition of Great Capricorn Beetle (Cerambyx cerdo) populations

Abstract: The Great Capricorn Beetle (Cerambyx cerdo) is a saproxylic insect highly
dependent on oak trees. The presence of this species was reported in the Natura 2000 site
“Gravine di Matera” (code IT9220135), a 7000-hectares protected area in southern Italy. From June to early July 2019, we conducted the first monitoring study of this species, assessing the population size and habitat preference. Baited traps were positioned on trees of different oak species present in the area to assess the population size of the great Capricorn beetle across the study area. Overall, 78 beetles (37 females, 41 males) were caught during 16 days of sampling. The highest densities of C. cerdo were encountered on downy oak trees (Quercus pubescens). Tree size appears to be positively correlated with the number of C. cerdo individuals captured on the tree, demonstrating the importance of the presence of large veteran trees for the conservation of this beetle species. From June 2022 we studied the presence of C. cerdo in Apulia Region applying the first national monitoring program for Natura 2000 species. We used the same traps of monitoring methodology to capture insects in adequate habitats. First results have demonstrated the presence of C. cerdo in the Natura 2000 site “Murgia Alta” (code IT9120007), where it was not still reported.