Identifying species involved in biodeterioration processes is helpful, however further effort is needed to assess their ecological requirements and actual activity. Black fungi (BF) represent one of the most underestimated threats to stone cultural heritage in the Mediterranean basin; they are difficult to kill or remove due to their ability to grow inside the rock and cope with several stresses. Despite this, little is known about BF and factors favoring their growth on stone surfaces. Eighteen BF species were here investigated for temperature and salt tolerance, and metabolic traits by plate assays. The relation between some highly damaged monuments and their BF settlers was assessed using X-ray diffraction analysis, mercury intrusion porosimetry, and SEM. The sensitiveness to four commonly used traditional biocides was also tested. All strains were able to grow within the range of 5–25 °C and in the presence of 3.5% NaCl. Instrumental analyses were fundamental in discovering the relation between halophilic strains and weathered marble sculptures. The acid, cellulase, esterase, and protease production recorded proved BF’s potential to produce a chemical action on carbonate stones and likely affect other materials/historical artefacts. Besides, the use of carboxymethylcellulose and Tween 20 should be evaluated in restoration practice to prevent tertiary bioreceptivity. Agar diffusion tests helped identify the most resistant species to biocides, opening the perspective of its use as reference organisms in material testing procedures.

Wall paintings have been a cultural expression of human creativity throughout history. Their degradation or destruction represents a loss to the world’s cultural heritage, and fungi have been identified as a major contributor to their decay. We provide a critical review of fungi isolated from worldwide wall paintings between 1961–2021. One-hundred three scientific papers were reviewed focusing on fungal diversity, isolation protocols, and spatial distribution of data. The study sites were grouped into five environmental categories on the basis of the expected major microclimatic conditions (temperature, relative humidity, ventilation), and the possible relationship with the species found was investigated. The highest number of records were localized in Europe, with 38 sites on a total of 74, 20 of which were from Italy. A total of 378 fungal entries were obtained, consisting of 1209 records, belonging to 260 different species and 173 genera. The accuracy level in taxa determination was highly variable among different papers analyzed. Data showed a dominance of Ascomycota, mainly of orders Eurotiales and Hypocreales probably due to their wide distribution and easily air dispersed spores and due to the possible pitfalls linked to the isolation methods, favoring rapidly growing taxa. Statistical analyses revealed that fungal communities were not strictly linked to environmental categories with different ventilation, temperature, and humidity. Such findings may be due to the wide geographical area, the wide heterogeneity of the data, and/or the absence of standardized sampling and analyses protocols. They could also be the result of the dominance of some prevailing factors in the various sites that mask the influence one of each other.

Biological growth represents one of the main threats for the conservation of subterranean cultural heritage. Knowledge of the conditions which favour the various taxonomic groups is important in delineating their control methods. Combining our experience regarding hypogea in Italy and the Republic of Korea, we aim to perform a critical review and comparison of the Biodeterioration Patterns (BPs) found, the materials used, and the conservative treatments applied. For this purpose, we focused on Etruscan tombs (Italy, 7th to 3th century BC) and the ancient tombs of the Baekje Dynasty (Republic of Korea, 6th to 7th centuries AD), most of which have been designated UNESCO World Heritage Sites, collecting original and bibliographic data as well as official documents. Results highlight the rich biodiversity of the bacterial and fungal species. Phototrophs were observed only in niches with sufficient light and the development of roots was also detected. Changes in humidity and temperature, the nature of the soil, nutrient accumulation, and vegetation above the hypogea along with human activities explain the different BPs. The effects of biocide treatments are also discussed, such as the emergence of dangerous fungal species. The shared data also enhance the role of overlaying tumuli and vegetation as well as protective barriers to reduce biological risk.

Balinese Hinduism has incorporated local animistic traditions and offerings, which play a key role in the religious ceremonies called “five holy ceremonies” or Panca yadnya. Since plants constitute fundamental elements of these offerings, we aimed to contribute to their knowledge. We analyzed plants used during ceremonies by interviewing key informants in four ancient villages of Bali (Bali aga). We identified exclusive and common species associated with different kinds of ceremonies and assessed whether there was any pattern in the selection of plants for the various offerings. We recorded 125 species (112 genera, 49 families), most of which belong to the wild ethnoflora of Bali, but also 36 species that are not native to the Malesian region. The religious relationships among ceremonies, called yadnyas, reveal specific compositions of the offerings, with the plants falling into two main groups: common, which comprises 58 plants shared by all yadnyas, and specific, mostly connected to a single yadnya. This pattern of plant use is similar to the previously detected pattern in the traditional ecological knowledge (TEK) of aga villages. The use of plants for Panca yadnya can help avoid cultural erosion related to globalization.