Preliminary studies on meristematic fungal ecology

Microorganisms colonize all types of cultural artefacts causing biodeterioration; yet the species involved need more studies. In particular, dematiaceous meristematic fungi seem more widespread on lapideous materials than previously thought. This group of fungi, on 13 different medieval monuments located in 3 regions of Northern Italy (Liguria, Lombardia and Valle d’Aosta), have been investigated in this work. The monuments were built in the X-XIII centuries, with local stones weathered and deformed to different extent. The sites were sampled three times in a year, every four months, beginning in March 2001. Fungal strains were isolated from stones using dilution plate technique and needle procedures (Urzì et al., 1992; Wollenzien et al., 1995). A total of 38 meristematic fungal strains was obtained and they were subdivided in 8 different morphological groups on the basis of cultural and microscopic characteristics. The sampled stones were without lichens; nevertheless these organisms, when present on the same wall, were investigated to obtain some ecological information. Avoiding any form of damage, samples were collected by bistouries and were identified using analytical keys (Clauzade & Roux, 1985; Wirth, 1995). The nomenclature of the species followed Nimis (2003). A total of 26 saxicolous lichen species was recorded. Percentage of occurrence of lichen species within latitudinal European areas (Wirth, 1995) for the releve groups in the three different regions and phytogeographical elements were assembled in a data matrix and were submitted to ordination by Correspondence Analysis (COA), using SYN-TAX 2000 PC program (Podani, 2001), in order to evaluate the relationships between releve groups and phytogeographical affinity of lichen floras. The results of the lichen species are grouped following a continentality trend. Cluster analysis and ordination by Principal Component Analysis (PCA) were conducted on a matrix of lichen species and meristematic fungi occurrence data. The results suggested that also different morphological groups of meristematic fungi presented the same continentality gradient of lichens.