Gardens constantly change during their lifetime due to the growth and death of plants and to the effects (or lack) of management activities. The loss of garden areas, as well as the building’s collapse, can drastically impact the view and understanding of archaeological areas. The study and reconstruction of ancient lost gardens is a complex topic, and it seems that there is a lack of a general methodological approach for assessing the revitalization and valorization activities of these gardens, especially when considering the floristic features. Here, we discuss the required steps for developing the various intervention components for achieving a deep knowledge and understanding of natural, historical, and philosophical features of the place and its culture, from the past to the current conditions. Considering this knowledge, we propose a revitalization and a cultural valorization approach of the natural elements, and we discuss the limitations and issues arising in lost garden studies.

Plant colonization on archaeological structures is limited by the substrate conditions of stone surfaces. Despite its relevance for ecological studies and the management plans of archaeological sites, the knowledge on monuments substrate (e.g., stones, microhabitats, microsites), which could be suitable sites for plant establishment, is an underestimated topic. Here, we aim to identify the substrate preference of plants in colonizing stone surfaces as a first step in evaluating the biodeterioration risk. We selected the Pasargadae World Heritage Site (WHS) for its variety of different conditions, and we assessed the substrate preference of 142 ruderal plants occurring on nine monuments, two types of stones, and eight microsites. Our data indicated that stone typology and microsite conditions affected species composition, diversity, and richness. The porosity of the different limestone and the progressive weathering phenomena resulted as relevant factors in plant colonization. Significantly, microsites as a junction of two stone blocks (M1a) and big fractures covered by soil (M3) hosted the most favorable conditions, which needed periodic monitoring during the maintenance activities of the site. Evaluating the substrate preference of ruderal plants can contribute to the identification of the high-risk areas for plant colonization, which need to be considered in the management plans of archaeological sites.

The art of the Achaemenid Empire flourished in Ancient Persia from the 6th to 4th centuries BCE, and featured stone-carved monumental structures adorned with recurring zoological and floral patterns. Such representations clearly had a symbolic meaning intimately connected to religious expression and the will of deities. Considering the lack of any comprehensive analysis of botanical features, we investigate the recurring plant patterns and the variety of plants depicted. An analysis of the documentation referring mainly to monuments in the two main capitals of Darius I, Persepolis and Susa, showed the presence of certain repetitive elements, such as the so-called rosettes (composed variously of Asteraceae capitula and Nymphaea flowers), palms (Phoenix dactylifera, the tree of life), pines, flowers or bunches and metamorphic elements. Some plants are described in this paper for the first time in the context of Persian iconography, such as Mandragora officinalis in offering scenes as a symbol of fertility and protection against evil spirits, Pinus brutia var. eldarica as a symbol of immortality and elevation to the gods, and the capitula of Matricaria/Leucanthemum as solar symbols. Further interesting elements include cf. Myrtus communis in some crowns and probably cf. Ephedra sp. in offering scenes. Achaemenid art was deeply influenced by the Zoroastrian religion of ancient Persia with its great attention to nature as well as by the nearby civilizations of the Mesopotamian area and Egypt. Most elements were also associated with psychotropic or medicinal attributes, which contributed to their position as symbols of power.

The study explores the application of natural biocides (oregano essential oil and eugenol, directly applied in solutions or encapsulated within silica nanocapsules) for safeguarding stone cultural heritage from biodeterioration, using green algae (Chlorococcum sp.) and cyanobacteria (Leptolyngbya sp.) as common pioneer biodeteriogens. Core-shell nanocontainers were built for a controlled release of microbicidal agents, a safe application of chemicals and a prolonged efficacy. The qualitative and quantitative evaluations of biocide efficiency at different doses were periodically performed in vitro, after six scheduled intervals of time (until 100 days). The release kinetics of composite biocide-embedding silica nanocapsules were characterized by the UV-Vis spectroscopy technique. Data showed both promising potential and some limitations. The comparative tests of different biocidal systems shed light on their variable efficacy against microorganisms, highlighting how encapsulation influences the release dynamics and the overall effectiveness. Both the essential oils showed a potential efficacy in protective antifouling coatings for stone artifacts. Ensuring compatibility with materials, understanding their differences in biocidal activity and their release rates becomes essential in tailoring gel, microemulsion or coating products for direct on-site application.

Microbial colonization can lead to various biodeterioration phenomena in outdoor stone monuments. To prevent these issues and mitigate the negative effects of chemical control, recent research has focused on encapsulating biocides in nanostructures. We tested the antifouling efficiency of the new multifunctional coating through in situ experiments performed on the Aurelian Walls in Rome. We selected two different biocides (2-mercaptobenzothiazole and zosteric sodium salt) and loaded them into two different silica nanocontainers (nanocapsules and mesoporous particles), which were dispersed in TEOS coatings. These coatings were applied to four common lithotypes (marble, travertine, mortar, and brick). Subsequently, we accelerated the colonization by inoculating microorganisms onto half of the samples, subjecting all samples to aging cycles. We conducted colorimetric, infrared spectroscopy, and other microscopic analyses to assess their durability and antimicrobial action. Our 3-year survey indicates that the coatings demonstrated antifoulant efficiency across all samples, with higher effectiveness observed on brick and mortar compared to travertine and marble. Among the nanostructures, nanocapsules exhibited greater efficiency than mesoporous particles, and regarding the biocides, the commercial one outperformed the natural one. These findings highlighted the potential of such systems in preserving cultural heritage; however, further research and product development is imperative for practical implementation.

The Global Frameworks for Enhancing Natural and Cultural Capital, as expressed in the Charter of Rome (2014), have relevant importance in the broader context of sustainable development goals (SDGs). The intricate connection between cultural and natural heritage emerges in various documents from UNESCO, IUCN, and ICOMOS; however, the categories and methods for their assessment are not completely defined. Evolving from the concept of “mixed properties” used in the UNESCO definitions, we introduce the concept of CUNA places: cultural places of high relevance for nature. It provides a methodological tool for identifying and typifying these places based on their values, attributes, and significance. Then, we propose definitions and categories for three different CUNA typologies, comprising 16 categories, considering both tangible and intangible heritage. We also provide a preliminary application to the city of Rome, where a rich historical heritage intersects with outstanding natural values. All the typologies and categories of CUNA places are present in Rome, and further analysis could show the multifaced aspects represented here. On a broader scale, such an application offers the opportunity to enhance the heritages that could be valorized, strengthening the territorial identity, promoting sustainable development, and generating income for conservation efforts.