Urbanization and a green corridor do not impact genetic divergence in common milkweed (Asclepias syriaca L.)
Breitbart ST, Agrawal AA, Wagner HH and others. Scientific reports, November 2023.
Read the paper Free to read · doi:10.1038/s41598-023-47524-8
What this paper is about
Common milkweed populations across a city were tested for genetic divergence, including whether a green corridor running through the urban area made any difference.
Neither urbanization nor proximity to the corridor had an effect. Differences between urban and rural plants are more likely to be plasticity than genetics.
Summarised here from the abstract below. Not the authors’ words.
Abstract
Urbanization is altering landscapes globally at an unprecedented rate. While ecological differences between urban and rural environments often promote phenotypic divergence among populations, it is unclear to what degree these trait differences arise from genetic divergence as opposed to phenotypic plasticity. Furthermore, little is known about how specific landscape elements, such as green corridors, impact genetic divergence in urban environments. We tested the hypotheses that: (1) urbanization, and (2) proximity to an urban green corridor influence genetic divergence in common milkweed (Asclepias syriaca) populations for phenotypic traits. Using seeds from 52 populations along three urban-to-rural subtransects in the Greater Toronto Area, Canada, one of which followed a green corridor, we grew ~ 1000 plants in a common garden setup and measured > 20 ecologically-important traits associated with plant defense/damage, reproduction, and growth over four years. We found significant heritable variation for nine traits within common milkweed populations and weak phenotypic divergence among populations. However, neither urbanization nor an urban green corridor influenced genetic divergence in individual traits or multivariate phenotype. These findings contrast with the expanding literature demonstrating that urbanization promotes rapid evolutionary change and offer preliminary insights into the eco-evolutionary role of green corridors in urban environments.
Abstract reproduced from the published paper, which is licensed CC BY. Copyright remains with the authors.
Milkweeds in this paper
- Common Milkweed Asclepias syriaca
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title = {Urbanization and a green corridor do not impact genetic divergence in common milkweed (Asclepias syriaca L.) (listing)},
author = {{Milkweed USA}},
year = {2026},
url = {https://milkweedusa.com/research/urbanization-and-a-green-corridor-do-not-impact-genetic-2023/},
note = {Accessed DATE}
}