Phenotypic variation in urban environments: mechanisms and implications

• Published in: Trends in ecology & evolution (Amsterdam) 2022-02, Vol.37 (2), p.171-182
• Main Authors: Thompson, M.J., Capilla-Lasheras, P., Dominoni, D.M., Réale, D., Charmantier, A.
• Format: Article
• Language: English
• Subjects: Biodiversity; Biological Evolution; Biological Variation, Population; Cities; city; diversity; heterogeneity; intraspecific variation; Life Sciences; Phenotype; Populations and Evolution; trait variation; Urbanization
• ISSN: 0169-5347; 1872-8383
• DOI: 10.1016/j.tree.2021.09.009

In the past decade, numerous studies have explored how urbanisation affects the mean phenotypes of populations, but it remains unknown how urbanisation impacts phenotypic variation, a key target of selection that shapes, and is shaped by, eco-evolutionary processes. Our review suggests that urbanisation may often increase intraspecific phenotypic variation through several processes; a conclusion aligned with results from our illustrative analysis on tit morphology across 13 European city/forest population pairs. Urban-driven changes in phenotypic variation will have immense implications for urban populations and communities, particularly through urbanisation’s effects on individual fitness, species interactions, and conservation. We call here for studies that incorporate phenotypic variation in urban eco-evolutionary research alongside advances in theory. Phenotypic variation is a neglected phenotypic dimension that could provide valuable biological insights in urban research.Our synthesis suggests that urbanisation modifies key processes that shape intraspecific variation and may increase phenotypic variation in several urban systems.We show how urbanisation increases phenotypic variation in an example using tit species across European cities.Efforts that examine phenotypic variation alongside means in urban research will make valuable contributions towards determing the ecological and evolutionary implications of urban-modified phenotypic variation.