Contribution to the knowledge of biodeteriogenic flora on three historical calabrian (southern Italy) churches.
The effect of biodeteriogenic living organisms on historical and archeological sites is a well-known problem affecting the world's cultural heritage. Indeed, the growth inside the bricks of shrubs and herbs roots can cause breakage, collapse and, detachment of materials. The knowledge of the spontaneous vascular flora present on monuments is essential for protection and safeguarding of cultural heritage. In this paper, we identify and describe biodeteriogenic vascular flora of three historical Calabrian (Southern Italy) churches, showing the relationship between plant biodiversity and exposure and building material of churches. The species present on the wall and in perimeter for each church were sampled noting substrate type, surface inclination (vertical or horizontal) and exposure. The total number of plant species recorded was 27. Hemicryptophytes (41%) prevail over the other biological forms and the most represented families are that of the Asteraceae. Parietaria judaica is the only species present in all three sites. Substrate type, climatic condition and surface inclination affect the floristic composition. Sixteen out of 27 species grow on vertical surfaces, all Geophythes and Chamaephytes grow on horizontal surfaces, while Therophytes were rather on vertical surfaces. A significant difference was found in the Hazard Index values in the three churches. Only one site, presents a high average value of Hazard Index, due to the simultaneous presence of Ailanthus altissima, Ficus carica, Rubus ulmifolius and Sambucus nigra . The data collected indicate that the flora growing on wall of three Calabrian churches partially reflects the floristic context in which they are located. The diversity of the vegetational spectrum is remarkable, most of the plants are ruderal herbaceous, many weeds and invasive, and for the most part typical of the Mediterranean environment. The data collected contribute to the knowledge of the spontaneous vascular flora present on three historical Calabrian churches and their biodiversity, also in terms of conservation interest, considering its biodeteriogenic potential in the evaluation of the impact of the vegetation on each monument.