Urbanisation generates multiple trait syndromes for terrestrial taxa worldwide
Authors: Hahs Amy K. , Fournier Bertrand , Aronson Myla F. J. , Nilon Charles H. , Herrera-Montes Adriana , Salisbury Allyson , Threlfall Caragh G. , Rega-Brodsky Christine C. , Lepczyk Christopher A. , La Sorte Frank A , MacGregor-Fors Ian , MacIvor J. Scott , Jung Kirsten , Piana Max R. , Williams Nicholas S.G. , Knapp Sonja , Vergnes Alan , Acevedo Aldemar A. , Gainsbury Alison M. , Rainho Ana , Hamer Andrew J. , Shwartz Assaf , Voigt Christian C. , Lewanzik Daniel , Lowenstein David M. , O’Brien David , Tommasi Desiree , Pineda Eduardo , Carpenter Ela Sita , Belskaya Elena , Lövei Gabor , Makinson James C , Castañeda-Oviedo Jennifer , Coleman Joanna , Sadler Jon P. , Shroyer Jordan , Shapiro Julie Teresa , Baldock Katherine C. R. , Ksiazek-Mikenas Kelly , Matteson Kevin C. , Barrett Kyle , Siles Lizette , Aguirre Luis F. , Armesto Luis Orlando , Zalewski Marcin , Herrera-Montes Maria Isabel , Obrist Martin K. , Tonietto Rebecca K. , Torrado Ricardo , Gagné Sara A. , Hinners Sarah J. , Latty Tanya , Surasinghe Thilina D. , Sattler Thomas , Ulrich Werner , Magura Tibor , Elek Zoltan , Kotze D. Johan , Moretti Marco 
Published: May 2023

Cities can host significant biological diversity. Yet, urbanisation leads to the loss of habitats and, potentially, to local extinctions. Understanding how multiple taxa respond to urbanisation globally is essential to promote and conserve biodiversity in cities and surrounding landscapes. Using a dataset with site-level occurrence and trait data of 5302 species from six terrestrial fauna taxonomic groups across 379 cities on 6 continents, we show that urbanisation produces taxon-specific changes in trait composition, with traits related to reproductive strategy consistently showing the strongest response. The effect of urbanisation on community trait composition is strongest at the largest spatial scale considered, and more closely linked to landscape composition (% urban) than arrangement (aggregation), although latitude and climatic variables remain a stronger influence. This study did not find evidence in support of a global urban taxa syndrome, but instead we suggest that there are four general urban trait syndromes, with resources associated with reproduction and diet likely to be driving patterns in traits associated with mobility and body size. Functional diversity measures showed a wide range of responses, leading to a shift in trait space that is most likely driven by the distribution and abundance of critical resources, and the urban trait syndrome displayed by individual species within a community. Further research is required to understand the interactions between the four general urban trait syndromes, resource distribution and abundance and changes in functional diversity of taxa at different spatial and temporal scales. Maximising opportunities to support species within taxa groups with different urban trait syndromes should be pivotal in conservation and management programmes within and among cities. This will reduce the likelihood of biotic homogenisation at the taxa level, and helps ensure that urban environments have the ecological capacity to respond to challenges such as climate change, further habitat fragmentation and loss, and other disruptions. These actions are critical if we are to reframe the role of cities in global biodiversity loss.