Lessons From the Past: Trait-Driven Local Extinctions of Bats in Urban Areas

Urban areas are rapidly expanding globally, leading to significant habitat loss and fragmentation, which pose serious challenges to wildlife conservation. In this work, we adopt an integrated approach by collating data from a range of sources to analyze the long-term impacts of urbanization on bat assemblages by comparing historical and contemporary occurrences in urban areas, using four major Italian cities. Using museum collections, scientific literature, recent field surveys, and citizen science data, we compiled bat species checklists for each city, differentiating between historical and recent data. This approach allowed the assessment of both past (1821–1989) and present (1990–2024) bat assemblages, providing evidence of 22 apparent local extinction events involving 56% of the species recorded across the four cities. We explored the relationship between bat species traits (body size, wing morphology, echolocation call frequency, thermal adaptation, hunting strategy, and dietary preferences) and their vulnerability to urban extinction. Results indicated that body size, hunting strategy and habitats, and echolocation frequencies are key traits affecting bat persistence in urban areas. In particular, species with specialized foraging strategies in terms of hunting habitats and behavior, as well as those that echolocate at higher frequencies, were significantly more likely to experience local extinctions. We underscore the deep impact of urbanization on bat assemblages and highlight the importance of considering ecological traits and long-term monitoring data to understand the effects of urbanization on bats and wildlife in general. Conservation efforts should be more effectively focused on mitigating the adverse effects of urbanization on vulnerable species, and promoting the coexistence of humans and urban wildlife.