Urban environments increase generalization of hummingbird–plant networks across climate gradients
Authors: Maruyama Pietro Kiyoshi , Bosenbecker Camila , Cardoso João Custódio F. , Sonne Jesper , Ballarin Caio S. , Souza Camila S. , Leguizamón Johana , Lopes Ariadna Valentina , Maglianesi María A. , Fernández Otárola Mauricio , Parra Juan L. , Pena João Carlos , Ramírez-Burbano Mónica B. , Rodríguez-Flores Claudia I. , Rech André R. , Zanata Thais B. , Acevedo-Quintero Juan Fernando , Almeida Gabriela , Anselmo Pedro Amaral , Amorim Felipe W. , Montoya-Arango Sergio , Araujo Andréa Cardoso , de Araújo Francielle Paulina , del Coro Arizmendi María , Brito Lucilene , Castillo-García Alejandra , Cherutte Amanda Graciela , Costa Carolina Figuerêdo , Ferreira Fernando Henrique Santos , Dias Filho Manoel Martins , da Frota Angélica Vilas Boas , Iepsen Alice Scheer , Freitas Leandro , de Almeida Ingrid Gabriela , Gomes Ana Caroline Silva , Hachuy-Filho Leandro , Lara Carlos , Lasprilla Liliana Rosero , Llano Julian , Nakamura Vivian , Nunes Neto Edvaldo , Nunes Cristiane Estrêla C. , Machado Caio Graco , Maianne Monique , Marin-Gomez Oscar , Márquez-Luna Ubaldo , Mendes Ruara Soares , Mesa Juan Guillermo , Oliveira Rafael , Lima-Passos Jeane , Pereira Janayna Andreza S. , Restrepo-González Alejandro , Rigotto Sarah Mendonça , Rodrigues Bruno Magro , Rui Ana Maria , Ruiz Diana Betancur , Sandoval Luis , Santana Carina Araujo , Silva Jéssica Luiza S. , Silva Larissa Lais , Santos Vinicius Calda , Silva Paulo Antonio , Vargas-Espinosa Maria Cristina , Vitorino Breno Dias , Wolowski Marina , Sazima Ivan , Sazima Marlies , Dalsgaard Bo , Vizentin-Bugoni Jeferson , Oliveira Paulo E. 
Published: November 2024

Urbanization has reshaped the distribution of biodiversity on Earth, but we are only beginning to understand its effects on ecological communities. While urbanization may have homogenization effects strong enough to blur the large-scale patterns in interaction networks, urban community patterns may still be associated with climate gradients reflecting large-scale biogeographical processes. Using 103 hummingbird–plant mutualistic networks across continental Americas, including 176 hummingbird and 1,180 plant species, we asked how urbanization affects species interactions over large climate gradients. Urban networks were more generalized, exhibiting greater interaction overlap. Higher generalization was also associated with lower precipitation in both urban and natural areas, indicating that climate affects networks irrespective of habitat type. Urban habitats also showed lower hummingbird functional trait diversity and over/underrepresentation of specific clades. From the plant side, urban communities had a higher prevalence of nonnative nectar plants, which were more frequently visited by the hummingbird species occurring in both urban and natural areas. Therefore, urbanization affected hummingbird–plant interactions through both the composition of species and traits, as well as floral resource availability. Taken together, we show that urbanization consistently modifies ecological communities and their interactions, but climate still plays a role in affecting the structure of these novel communities over the scale of continents.