Urban green spaces with high connectivity and complex vegetation promote occupancy and richness of birds in a tropical megacity

Abstract Urban growth often leads to land-use changes that result in biodiversity loss and reduced human benefits. In urban zones, green areas facilitate physicochemical processes (such as carbon capture, reducing environmental temperature and noise pollution), offer multiple benefits to human beings (e.g., water filtration and purification), and support numerous vertebrate populations, including birds. In the tropics, the capacity of green spaces to maintain bird populations is regulated by characteristics of these areas (e.g., vegetation structure) and environmental seasonality. In order to generate ecological knowledge to help conserve bird diversity in large urban settlements, this study aimed to (1) identify the most influential variables on the distribution of bird species in green areas of a tropical megacity, and (2) assess how bird richness varies between the dry and rainy seasons. Across two dry and rainy seasons between 2021 and 2022, detection records of 108 bird species were obtained from 101 green areas. Air temperature and sampling time were the primary factors influencing bird detection. Bird occupancy and richness were higher in parks near other green areas in first dry and increased with tree richness during the rainy seasons. Floral abundance explained the occupancy and richness in the second dry season. In 2021, the highest richness was observed during the dry season, while in 2022, the highest richness was estimated during the rainy season. These findings highlight the importance of resource availability and spatial arrangement in urban green areas for bird diversity, offering insights for conservation and maintaining ecosystem benefits in urban environments.