Lichen recolonization on restored calcareous statues of three Venetian villas

Works of art exposed to the open air are usually subject to recolonization after restoration. This problem is evident in the case of Venetian villas in northeastern Italy, which are generally surrounded by historical gardens and parks with outdoor stables, fountains, and statues of high artistic interest, strongly colonized by lichen communities. Ecology applied to conservation of artwork is a recent field and available data tend to concern the composition of lichen communities before restoration, while data on lichen recolonization after restoration are still scanty. Therefore, the aim of this work is to evaluate lichen recolonization after restoration on selected calcareous statues exposed in the gardens of three Venetian villas in different environmental conditions: (1) Villa Manin, located in an agricultural landscape in the Friulan plain; (2) Villa Pisani, in an urban landscape in the Venetian plain; and (3) Villa Tauro or “Centenere”, in an agricultural landscape in the Pre-Alpine region. For each site, detailed information on the restoration practices and lichen colonization before restoration was available. Lichen recolonization was evaluated on the basis of 51 samples carried out in 2004 and subjected to numerical classification. Intensive restoration practices were employed to clean the statues and protect them from lichen recolonization; however, the effectiveness of these practices in the long term proved to be very low. Recolonization was evident in the three sites, exceeding 50% of the mean cover before restoration and involving four species-poor lichen communities. Some differences in species cover and composition were found among the three sites and they could be related to different environmental conditions. In the case of the statues in the parks of Venetian villas it is very difficult to prevent biological recolonization over the long term, and a maintenance program should be more effective than a complete restoration.