Urban warming affects local plant assemblages

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Green bristle grass (Setaria viridis)

Green bristle grass (Setaria viridis), a C4 species. Photo by Andy via iNaturalist licensed under CC BY-NC 4.0

Urbanization represents an environmental challenge and urban land cover in 2030 is predicted to be three times the area observed in 2000. The urban heat island (UHI) phenomenon is a pronounced climatic effect that may even affect the local plant assemblages of urban areas. In this study, researchers used differences in plants’ photosynthetic pathways to test the hypothesis that UHI favours so-called C4 plants thriving in warmer climates as opposed to C3 plants that prefer colder climates. Researchers downloaded GBIF-mediated occurrences of plants in the UK and Germany and classified species according to photosynthetic pathway- C3 or C4. Using remotely sensed temperature readings, the researchers showed that summer temperatures in urban regions were 2-3°C warmer in both countries. As expected, overall C4 abundance was low in both countries, but increased significantly in urban regions with similar patterns for species richness, showing how UHI is able to restructure plant assemblages in urban areas.

Citation information 

Duffy GA and Chown SL (2016) Urban warming favours C4 plants in temperate European cities. Journal of Ecology. Wiley-Blackwell 104(6): 1618–1626. Available at doi:10.1111/1365-2745.12652.