Synanthropic birds increase their consumption of non-native plants and affect the structure of feeding networks in urban green areas of Mérida, Yucatán, México

Urbanization modifies bird and plant communities, affecting ecological processes such as fruit consumption and the structure of interaction networks. Our study evaluated how the abundances of synanthropic and non-synanthropic birds, along with native and non-native plants, influence fruit consumption and bird-plant feeding networks in 12 urban green areas in Mérida, Yucatán, Mexico. Over a year, we recorded bird-plant interactions, measured species abundances, and analyzed feeding networks using metrics of specialization, nestedness, and evenness. We found that, in Mérida, urban green areas are dominated by synanthropic birds and non-native plants, promoting feeding networks that are more resilient but less specialized. We found that non-native fruit consumption was significantly associated with the abundances of synanthropic birds and non- native plants, while native fruit consumption depended primarily on the abundance of native plants and showed no significant relationships with birds. Feeding networks in areas with higher synanthropic bird abundance were less specialized, more nested, and more even, indicating a homogenization of interactions in urbanized sites. In contrast, non-synanthropic birds and native plants abundances showed weak or non-significant relationships with network structure. While synanthropic birds play an important role in feeding networks in urban environments and may stabilize certain interactions, it poses risks to the conservation of native biodiversity and ecological processes. Therefore, it is essential to implement management strategies that prioritize native species to maintain the ecological functionality of urban green areas.