Vermetid bioconstructions along the Ionian coast of Apulia, Italy

Vermetid bioconstructions, formed by sessile gastropods of the genus Dendropoma, are unique reef-like structures that provide essential ecological functions and services along the rocky coastlines of the Mediterranean. Recent molecular studies have revealed that Dendropoma petraeum constitutes a species complex, including a distinct, yet undescribed tax on (Dendropoma sp.) found in the Ionian–Aegean region. Despite its ecological importance, this taxon remains poorly studied. This study provides the first systematic assessment of Dendropoma sp. bioconstructions along approximately 35 km of coastline in the Province of Taranto (southern Italy, western Mediterranean). Surveys conducted at five sites, which combined in situ measurements with photographic documentation, identified three distinct morphotypes: ledges, islets, and pillows. The analyses of morphological (e.g. width, thickness, topographic complexity) and biological (e.g. density, shell size distribution) parameters revealed considerable spatial variability. Differences in size structure, density, and topographic complexity were observed across sites, with the most developed formations found on the islets of Campomarino and Torre Ovo. The results confirm that Dendropoma sp. is a dominant reef-builder in the Ionian Sea, extending its known biogeographic range and highlighting the ecological importance of its formations. Given their vulnerability and recognition under various conservation frameworks, the findings of this study provide a necessary baseline for future monitoring and management initiatives. Integrating this data with existing information from the Apulian Adriatic coast may help in developing a regional conservation strategy for vermetid reefs.