Some like it hot: adaptation to the urban heat island in common dandelion

Abstract

The Urban Heat Island Effect (UHIE) is a globally consistent pressure on species living in cities. Rapid adaptation to the UHIE may be necessary for urban wild flora to persist in cities, but experimental evidence is lacking. Here, we report the first evidence of genetic differentiation in a plant species in response to the UHIE. We collected seeds from common dandelion (Taraxacum officinale) individuals along an urban-rural gradient in the city of Amsterdam (The Netherlands). In common-environment greenhouse experiments, we assessed the effect of elevated temperatures on plant growth and the effect of vernalisation treatments on flowering phenology. We found that urban plants accumulate more biomass at higher temperatures and require shorter vernalisation to induce flowering compared to rural plants. Differentiation was also observed between different intra-urban subhabitats, with park plants displaying a higher vernalisation requirement than street plants. Our results show strong differentiation between urban and rural dandelions in temperature-dependent growth and phenology, consistent with adaptive divergence in response to the UHIE. Rapid adaptation to the UHIE may be a potential explanation for the widespread success of dandelions in urban environments.

Habitat diversification associated with urban development has a little effect on genetic structure in the annual native plant Commelina communis in an East Asian megacity

“…Urban areas usually consist of various habitat types, such as remnant agricultural land, park land, and roadsides, which significantly differ in their environmental conditions and habitat configurations (Baldock et al., 2019 ; Vakhlamova et al., 2022 ). Recent studies have emphasised the importance of within‐city habitat diversity, which promotes phenotypic trait differentiation across habitat types (Kostanecki et al., 2021 ; Santangelo, Roux, & Johnson, 2022 ; Woudstra et al., 2023 ). Among species that initially inhabit agricultural environments, populations in urban agricultural lands are likely influenced by habitat reduction and fragmentation through increasing development, whereas populations in urban parks and roadsides are likely established through immigration to smaller newly created habitats that are already highly fragmented.…”