Resilience and resistance of viticultural biodiversity in the urban ecosystem. The case of the grapevine collection of the Botanical Garden of Rome

Urban viticulture, a globally growing phenomenon, is gaining interest as a strategic multifunctional land use for sustainable cities. In the urban ecosystem, vineyards may represent: i) an economic system that supports short supply chains, ii) a land use that provides essential ecosystem services for well-being and quality of life, like carbon storage, biodiversity maintenance, soil health, food education, social integration; iii) a place of cultural significance, iv) a landscape of appreciated aesthetic value. The knowledge of plant-environment relations becomes essential to ensure resilience, productivity, and ecosystem functions of the agricultural systems in an urban context. The city of Rome together with its peri-urban Roman ager is one of the largest European agricultural municipalities. Inside the Botanical Garden of Rome there is the 'Italian vineyard', a core collection of 149 Italian and international grapevine cultivars, managed according to the principles of organic agriculture. This urban vineyard has been subjected to eco-physiological assessments to understand the response of the grapevine biodiversity to the physical extreme features of the urban environment, especially in relation to the thermal and radiative regimes. The analyses conducted on the vine collection during the 2020-2021 season involved: i) the characterization of the vineyard microclimate through bioclimatic indices; ii) the vegetative-productive response to the urban environment of a set of genotypes; iii) the measure of gas exchange efficiency and response to radiative stress. The climatic study highlighted the increasing occurrence of extreme thermal events. The physiological determinations allowed to group the grapevine cultivars based on stomatal conductance and evolution of leaf senescence, and therefore on the basis of their tolerance to the urban environment. The preliminary results provide indications for a sustainable use of genetic resources in urban viticulture and strategies to increase the resilience and adaptability of Vitis vinifera to the urban ecosystem.