Generalists are the most urban‐tolerant of birds: a phylogenetically controlled analysis of ecological and life history traits using a novel continuous measure of bird responses to urbanization

Abstract

Identifying which ecological and life history traits influence a species’ tolerance to urbanization is critical to understanding the trajectory of biodiversity in an increasingly urbanizing world. There is evidence for a wide array of contrasting patterns for single trait associations with urbanization. In a continental‐scale analysis, incorporating 477 species and >5 000 000 bird observations, we developed a novel and scalable methodology that evaluated the ecological and life history traits which most influence a species’ adaptability to persist in urban environments. Specifically, we assigned species‐specific scores based on continuous measures of response to urbanization, using VIIRS night‐time light values (i.e. radiance) as a proxy for urbanization. We identified generalized, phylogenetically controlled patterns: bird species which are generalists (i.e. large niche breadth), with large clutch size, and large residual brain size are among the most urban‐tolerant bird species. Conversely, specialized feeding strategies (i.e. insectivores and granivores) were negatively associated with urbanization. Enhancement and persistence of avian biodiversity in urban environments probably relies on protecting, maintaining and restoring diverse habitats serving a range of life history strategies.

A continental measure of urbanness predicts avian response to local urbanization

“…Code and data necessary to reproduce these analyses have been uploaded as Supplementary material and available archived from the Zenodo Digital Repository: <http://dx.doi.org/10.5281/zenodo.3559181> (Callaghan et al ).…”

“…Urbanization will continue to impact biodiversity in a multitude of ways (Elmqvist et al 2016), and understanding species-specific responses to urbanization (Gehrt and Chelsvig 2004) is essential to understand how to best mitigate the threats to native fauna most at-risk of urbanization (Møller 2010). Indeed, much research has investigated which biological and ecological traits are associated with urban-adapted birds in an attempt to identify those species most at-risk (Kark et al 2007, Croci et al 2008, Evans et al 2011, Callaghan et al 2019b. We provide significant methodological enhancements to these approaches, serving as a foundation for future studies to investigate the ecological and conservation validity of how biodiversity responds to urbanization across spatial scales (Hostetler andHolling 2000, Clergeau et al 2006b).…”

“…This was done by including only complete eBird checklists -where the observer recorded all birds heard and/or seen -from mainland Australia, which followed the travelling, random, stationary, area or BirdLife Australia protocols. We also filtered these checklists to those which recorded birds between 5 and 240 min and travelled less than 5 km or less than 500 ha area searches (La Sorte et al 2014, Callaghan et al 2017, 2019b, Johnston et al 2018, minimizing the chance that outliers would be included in the analyses. All checklists shared among multiple observers were randomly subsampled (i.e.…”

Metropolitan lizards? Urbanization gradient and the density of lagartixas (Tropidurus hispidus) in a tropical city

“…The results indicate that lagartixas are urban dwellers (sensu Fischer et al, ). Generalist species, with broad environmental tolerance, apparently are able to exploit novel habitats and succeed under the multiple environmental and ecological scenarios that are common in urban ecosystems (Bonier, Martin, & Wingfield, ; Callaghan et al, ; Ducatez et al, ; Winchell, Carlen, et al, ). This raises the possibility of a rapid adaptive evolution resulting in increased fitness and facilitating urban life (Johnson & Munshi‐South, ; Littleford‐Colquhoun et al, ; Winchell, Maayan, et al, ; Winchell et al, ).…”

“…The combination of these traits, including behavioral flexibility and learning abilities, has been shown to be associated with urban tolerating species (Batabyal & Thaker, 2019;Callaghan et al, 2019;Littleford-Colquhoun, Clemente, Whiting, Ortiz-Barrientos, & Frere, 2017;Shochat et al, 2006;Sol, Gonzalez-Lagos, Moreira, Maspons, & Lapiedra, 2014;Sol, Lapiedra, & Gonzalez-Lagos, 2013;Winchell, Carlen, Puente-Rolón, & Revell, 2018). This understanding, however, is limited as most studies have focused almost completely on birds and mammals (e.g., Chiari, Dinetti, Licciardello, Licitra, & Pautasso, 2010;Sol et al, 2014;Santini et al, 2019; but see Walsh, Goulet, Wong, &Chapple, 2018 andWinchell, Carlen, et al, 2018).…”