A methodological framework for assessing pollinator suitability in urban areas

Abstract Interest in the suitability of urban areas for pollinators is steadily increasing, as pollinator decline and biodiversity loss are closely linked to human activities, particularly urbanization and land-use change. Although recent studies have begun exploring urban pollinator habitats, these areas are often considered inhospitable when assessed with coarse-scale assessment tools, which risk overlooking mosaics of green patches that provide essential foraging and nesting resources. The configuration and density of these green spaces vary widely, strongly influencing their potential to support pollinators. However, standardized methods for evaluating pollinator-friendly urban areas remain limited. This study presents a methodological tool for urban planning, the Green Patch Suitability Assessment, which enables comparative evaluation of urban patches at fine spatial resolution. The framework combines (i) a classification system of urban green areas (patches); (ii) a multidimensional index of patch-level pollinator suitability, and (iii) a high-resolution topographic database integrating patch from multiple commonly used urban and landscape planning datasets. Applied in a municipality in Northern Italy, the tool demonstrates the capacity to identify small green patches often overlooked in coarser datasets and to evaluate the potential effects of a newly approved municipal plan aimed at enhancing green areas and biodiversity. Scenario analysis confirmed that the framework is sufficiently sensitive to detect the effects of the nature-based solutions proposed in the city plan, thus providing a practical and operational tool for urban planning capable of assessing the contribution of small green patches that would otherwise remain unrecognized using coarser-resolution databases.