Citizen science enabled planning for species conservation in urban landscapes: the case of Barn Swallows Hirundo rustica in southern China

Urbanization has detrimental effects on biodiversity, yet how species respond to urban planning zoning outcomes and environmental changes at different spatial scales when selecting urban breeding habitats remains understudied. Mitigating such impacts on wildlife is instrumental to create biodiversity-friendly cities while accommodating urban development. We used Barn Swallow nesting site data (2017–2023) collected from a citizen science program to help identify the most influential factors affecting the presence of Barn Swallow nests at site and landscape scales. We analyzed the relationship between Barn Swallow nest site selection in urbanized areas of southern China and land use data, including built-up percentages, cropland and waterbodies, as well as environmental factors such as heat-island effect (land surface temperature), noise pollution (road density and road simplicity), artificial light at night (ALAN) and nesting building attributes (year constructed, height and surroundings). Our findings revealed a positive association between Barn Swallow nest abundance and several anthropogenic factors, including land surface temperature at the site scale, and ALAN and road simplicity at the landscape scale. Our findings indicated the building year also had a negative impact on the Barn Swallow nests. These results suggest that urban design and revitalization efforts can consider mitigating negative effects by implementing measures to regulate noise pollution and nighttime lighting schemes. Furthermore, urban planning could carefully consider the requirements for biodiversity-friendly architectural elements in new constructions and rezoning process of existing urban districts, such as old residential neighborhoods and urban fringes, to minimize impacts on declining nesting sites in urban areas.