Enhancing urban biodiversity: assessing plant-pollinator interactions and diversity in Italian cities

In the last decades, a global decline in biodiversity has been taking place due to the strong impact of anthropogenic activities. However, in large cities, refuges for pollinators persist1 and, from a One-Health and urban sustainability perspective, it is pivotal to implement suitable green areas to support biodiversity2. The research aims to assess pollinators’ diversity, focusing on wild bees, and provide valuable information on pollination networks allowing a comprehensive understanding of urban ecosystems. This took place within the Spoke 5 activities (Urban Biodiversity) of the NBFC plan. To characterise pollination services, monitoring activities have been implemented across six major Italian cities, selecting sites according to different green area sizes and fragmentation. More than 6,000 samples of wild bees and hoverflies and their interactions have been collected. Integrative techniques to identify the insects and their interactions (i.e., pollen) have been applied, allowing a more comprehensive understanding of pollination networks in urban ecosystems. Based on early findings, experimental sites have been established in Milan to reinforce and enhance biodiversity. These initiatives encompass the installation of artificial nests for diverse urban wildlife taxa including the creation of small insect nesting areas, and the introduction of trophic resources such as flower strips. The reinforcements will be actively monitored to assess their effectiveness. The study sheds light on the complex relationship between the environment and regulating ecosystem services, contributing to the development of policies regarding the management and implementation of food and nest resources for pollinators, for a more sustainable and healthful urban environment.