Urbanization leads to similar, anthropogenic-induced conditions in cities across the world. Even though cities are located in distinct biomes with variable climates and unique biodiversity, these novel ecosystems completely transform the native landscape in predictable ways. Urban habitats often have many things in common: buildings, artificial light, heat, noise, and—of course—people. In a new essay in PLOS Biology, Peter Mikula, Daniel T. Blumstein and Piotr Tryjanowski discuss how this similarity in conditions can lead to “behavioral homogenization” in urban wildlife: animals displaying similar behavioral traits across individuals, populations, and species.
One of the most well-known examples of behavioral homogenization in urban wildlife is an increased tolerance of humans. Human tolerance is typically measured as flight initiation distance (FID): the distance at which an animal flees from an approaching human. Previous research has found that decreases in FID are widespread across urban populations of lizards, mammals, and birds (Samia et al. 2015). Increases in tolerance of humans in urban areas are typically attributed to habituation, in which animals gradually increase their tolerance over time in response to consistent exposure to humans. However, other processes may be at play, such as differential sorting–where more tolerant animals settle near humans and less tolerant ones stay away–or natural selection, where less tolerant individuals are less likely to survive (Uchida et al. 2024).
However, increased tolerance of humans is not the only aspect of behavioral homogenization common across cities. Mikula and colleagues also discussed how urban wildlife can converge on similar foraging behaviors centered around anthropogenic food sources. Urban living often results in a loss of migratory behavior since food resources and warmer temperatures are available year-round. Urbanization can also lead to behavioral homogenization in communication, activity patterns, social behavior, and nesting site selection.
Mikula and colleagues highlight that while behavioral homogenization offers a pathway to urban tolerance, it may make species more vulnerable to future disturbance by reducing behavioral diversity. Future work in urban behavioral homogenization will improve our understanding of how species are able to tolerate novel conditions, and how they may continue to change over time.
Read more in PLOS Biology:
Mikula, P., Blumstein, D. T., & Tryjanowski, P. (2026). Behavioral convergence under urbanization: An overlooked dimension of biotic homogenization. PLOS Biology, 24(3), e3003689. https://doi.org/10.1371/journal.pbio.3003689
References:
Image credit: Vaan Photography on Pedels
Samia, D. S. M., Nakagawa, S., Nomura, F., Rangel, T. F., & Blumstein, D. T. (2015). Increased tolerance to humans among disturbed wildlife. Nature Communications, 6(1), 8877. https://doi.org/10.1038/ncomms9877
Uchida, K., Blumstein, D. T., & Soga, M. (2024). Managing wildlife tolerance to humans for ecosystem goods and services. Trends in Ecology & Evolution, 39(3), 248–257. https://doi.org/10.1016/j.tree.2023.10.008
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